References of Palm Oil Studies on Cholestrol

References of Palm Oil Studies on Cholestrol

  1. French MA, Sundram K, Clandinin MT. Cholesterolaemic effect of palmitic acid in relation to other dietary fatty acids. Asia Pac. J. Clin. Nutr. 2002; 11(suppl).

    The effect of dietary intake of high palmitic acid levels in combination with other fatty acids in normal subjects was assessed. Palmitic acid (10% of energy) was fed in conjunction with decreasing levels of linoleic acid to determine if a threshold level of linoleic acid prevented palmitic acid from being hypercholesterolaemic. Healthy subjects received each of the diet treatments for 21 days, followed by washout periods of 7 days. In a second experiment, the effect of exchanging palmitic acid for trans fatty acids on plasma lipoprotein cholesterol levels and on rates for endogenous synthesis of cholesterol in normal subjects was investigated. Diet treatment lasted for 30 days. On day 30 of each diet treatment, a priming dose of deuterium was consumed, followed by a subsequent blood sample at 24 h. Blood cholesterol fractions were isolated and analysed by isotope ratio mass spectrometry to measure cholesterol fractional synthetic rates. In the first experiment, total plasma cholesterol levels increased as the percentage of linoleic acid decreased. The data indicated that high levels of palmitic acid were not hypercholesterolaemic if intake of linoleic acid was greater than 4.5% of energy. When the diet contained trans fatty acids plasma total and low-density lipoprotein-cholesterol increased and cholesterol synthesis increased with a decrease in high-density lipoprotein-cholesterol.
     
  2. Ng TK, Hayes KC, DeWitt GF, Jegathesan M, Satgunasingam N, Ong AS, Tan D. Dietary Palmitic and Oleic Acids Exert Similar Effects on Serum Cholesterol and Lipoprotein Profiles in Normocholesterolemic Men and Women. Journalof the American College of Nutrition, 1992;11(4), 383-390.

    To compare the effects of dietary palmitic acid (16:0) vs oleic acid (18:1) on serum lipids, lipoproteins, and plasma eicosanoids, 33 normocholesterolemic subjects (20 males, 13 females; ages 22-41 years) were challenged with a coconut oil-rich diet for 4 weeks. Subsequently they were assigned to either a palm olein-rich or olive oil-rich diet followed by a dietary crossover during two consecutive 6-week periods. Each test oil served as the sole cooking oil and contributed 23% of dietary energy or two-thirds of the total daily fat intake. Dietary myristic acid (14:0) and lauric acid (12:0) from coconut oil significantly raised all the serum lipid and lipoprotein parameters measured. Subsequent one-to-one exchange of 7% energy between 16:0 (palm olein diet) and 18:1 (olive oil diet) resulted in identical serum total cholesterol (192, 193 mg/dl), low-density lipoprotein cholesterol (LDL-C) (130, 131 mg/dl), high-density lipoprotein cholesterol (HDL-C) (41, 42 mg/dl), and triglyceride (TG) (108, 106 mg/dl) concentrations. Effects attributed to gender included higher HDL in females and higher TG in males associated with the tendency for higher LDL and LDL/HDL ratios in men. However, both sexes were equally responsive to changes in dietary fat saturation. The results indicate that in healthy, normocholesterolemic humans, dietary 16:0 can be exchanged for 18:1 within the range of these fatty acids normally present in typical diets without affecting the serum lipoprotein cholesterol concentration or distribution. In addition, replacement of 12:0 + 14:0 by 16:0 + 18:1, but especially 16:0 or some component of palm olein, appeared to have a beneficial impact on an important index of thrombogenesis, i.e., the thromboxane/prostacyclin ratio in plasma.
     
  3. Zhang J, Ping W, Chunrong W, Shou CX, Keyou G. Nonhypercholesterolemic effects of a palm oil diet in Chinese adults. J Nutr. 1997 Mar;127(3):509S-513S.

    The effects on serum lipids of palm oil (PA) used in Chinese diets were compared with those of soybean oil (SO), peanut oil (PE) and lard (LA) in normocholesterolemic subjects and with that of PE in hypercholesterolemic subjects. Normocholesterolemic subjects [120 men, 18-25 y, total cholesterol (TC) 2.8-5.0 mmol/L] were assigned to four groups to consume test diets for six consecutive weeks after a run-in period of 3 wk. About 30% of dietary energy was derived from fat, 75-80% of which came from test oils. In comparison with the entry level, the average serum TC and LDL cholesterol (LDL-C) were 6.7 and 13.1% lower, respectively, in the PA group and 22.8 and 30.7% higher, respectively, (P < 0.05) in the LA group. At the end of the test, serum TC, LDL-C and the ratio of TC/HDL cholesterol (HDL-C) in the PA group were significantly lower than those of the LA group. Hypercholesterolemic subjects (31 men, 20 women, 32-68 y, TC 5.5-7.0 mmol/L) were divided into two groups. For 6 wk, one group (15 men, 10 women) consumed the PA diet; another group (16 men, 9 women) consumed the PE diet. After a 3-wk interval, the two groups interchanged diets for another 6 wk. The test diets again contained about 30% energy from fat, 60-65% of which came from test oils. Compared with entry values, the PA diet caused significant reductions in serum TC, LDL-C and TC/HDL-C during the first 6 wk and also a significant reduction in TC/HDL-C during the second 6 wk. The PE diet had no significant influence on serum lipids in either experimental period.
     
  4. Van Jaarsveld PJ, Smuts CM, Benade AS. Effect of palm olein oil in a moderate-fat diet on plasma lipoprotein profile and aortic atherosclerosis in non-human primates Asia Pac J Clin Nutr. 2002;11 Suppl 7:S424-32

    Several studies have reported on the effect of palm olein oil (PO; palmitic acid content approximately 38%) incorporation into the diet on blood cholesterol concentration. Information on the effect of PO on atherosclerosis is, however, lacking. In vervet monkeys (Cercopithecus aethiops), low-density lipoprotein cholesterol (LDL-C) concen-trations can be modulated by the type and amount of fat in the diet. The vervet is a proven model for both the type and composition of human atherosclerotic lesions. The aim of this study was to determine the effect of PO in a moderate-fat moderate-cholesterol diet (MFD) on plasma lipoproteins and the progression of atherosclerosis in a non-human primate model after 25.5 months of dietary exposure. Thirty adult male vervets, never exposed to a Western-type atherogenic diet, were stabilised on a MFD (28%E fat; 26 mg cholesterol/1000 kJ) with a polyunsaturated to saturated fatty acid (P/S) ratio of 0.4 for six weeks. Baseline LDL-C, high-density lipoprotein (HDL)-C and bodyweight were used to stratify the vervets into three comparable groups of 10 each. One group continued with the MFD in which 11.0%E was derived from lard (AF). In the other two groups, the AF was substituted isocalorically with either sunflower oil (SO) or PO. Plasma lipids were measured at 6-monthly intervals and atherosclerosis was assessed in the aorta and in five peripheral arteries after 25.5 months of dietary exposure. The frequency of atherosclerosis in peripheral arteries and aortas was low. PO, relative to SO and AF, significantly reduced the risk for developing early lesions in peripheral arteries (P = 0.0277 and P = 0.0038, respectively) and, relative to AF, in aortas (P = 0.0335). The cholesterolaemic effect of MFD-PO was not significantly different from MFD-SO and MFD-AF. However, at 24 months the plasma total cholesterol concentration with MFD-AF was significantly higher than with MFD-SO (P = 0.0256). It is confirmed that a MFD with PO is no different from AF or SO in its cholesterolaemic effect. The anti-atherogenic efficacy of a MFD with PO, relative to SO and AF, was demonstrated in a non-human primate model of atherogenesis.
     
  5. Van Jaarsveld PJ, Benade AJ. Effect of palm olein oil in a moderate-fat diet on low-density lipoprotein composition in non-human primates Asia Pac J Clin Nutr. 2002;11 Suppl 7:S416-23

    Plasma low-density lipoprotein cholesterol (LDL-C) concentrations in vervet monkeys (Cercopithecus aethiops) can be modulated by the type and amount of fat in the diet. There is, however, a paucity of information on the effect of different types and quantity of dietary fat on the plasma LDL composition in vervets. The objective of this study was to determine the effect of different sources of dietary fat on the concentrations and composition of circulating plasma LDL in vervets consuming moderate-fat diets containing either animal fat, sunflower oil or palm olein. Fifty adult male vervets, never exposed to a Western-type atherogenic diet, were randomly assigned to two groups. For 6 weeks 30 vervets were fed a moderate-fat (28%E) moderate-cholesterol (26 mg cholesterol/1000 kJ) diet (MFD) with a polyunsaturated to saturated fatty acid ratio (P/S) of 0.4; 20 vervets were fed a high-fat (34%E) high-cholesterol (98 mg cholesterol/1000 kJ) diet (HFD) with a P/S ratio of 0.6. Fasting blood samples were collected from all 50 vervets for plasma lipid measurements. The 30 vervets receiving the MFD were stratified into three comparable experimental groups of 10 each according to their LDL-C and high-density lipoprotein cholesterol (HDL-C) concentrations and bodyweight. One group continued with the MFD, in which 11%E was derived from lard (MFD-AF); in the other two groups the lard was substituted isocalorically with either sunflower oil (SO) (MFD-SO) or palm olein oil (PO) (MFD-PO). The three groups were fed the respective experimental diets for 24 months and LDL component concentrations and composition were assessed at 6-monthly intervals. In the long-term study the MFD-AF, MFD-SO and MFD-PO groups showed no significant time-specific group differences at 6, 12, 18 or 24 months with regard to the LDL component concentrations, composition, as well as the LDL molecular weight. As expected, after 6 weeks of dietary exposure the HFD group had significantly higher plasma and lipoprotein total cholesterol, LDL component and apolipoprotein AI concentrations, as well as a higher LDL-C : HDL-C ratio compared to the MFD group (P 0.0005). LDL particle size was not significantly different between the HFD and MFD groups, but the HFD group had significantly fewer triacylglycerol and significantly more unesterified cholesterol molecules per LDL particle compared to the MFD group (P 0.0018). PO in a MFD is no different from AF or SO in its effect on LDL component concentrations, composition or particle size. The increased LDL-C concentration seen with the HFD could be accounted for by a more than two-fold increase in the number of circulating LDL particles and not as a result of enrichment of particles with cholesterol.
     
  6. Bosch V, Aular A, Medina J, Ortiz N, Apitz R. Changes in of plasma lipoproteins after the use of palm oil in the diet of a group healthy adults Arch Latinoam Nutr. 2002 Jun;52(2):145-50

    Although saturated fat acids have long known to have harmful effects on cholesterol and triacylglycerides levels in blood, new concepts have emerged form recent research on this matter. The purpose of this study was to know the effect of the consumption of palm olein on triacylglycerides and cholesterol levels as well as lipoprotein fractions in the blood plasma of healthy individuals from both sexes. MATERIALS AND METHODS: Different types of fats were administered for 12 weeks to 60 subjects, 45 male, 15 female, between 19 and 45 years of age, who were divided into three groups: the mix group (MG) was administered oil, margarine, and mayonnaise prepared with 50% olein; the olein group (OG) consumed fats prepared with 100% olein; and the control group (CG) consumed regular fats of customary use by the population. The diets provided 25 to 30% of calories. Blood samples were obtained for lipid analysis at the beginning and the end of the study. Plasma triacylglycerides and cholesterol concentrations were determined by means of enzyme and lipoprotein methods (VLDL, LDL; and HDL) by ultracentrifugation. RESULTS AND DISCUSSION: By comparing the groups’ means no significant differences were found (p > 0.05) in blood lipids. Individual differences show a slight increase in VLDL-C in OG compared to MG and CG. No differences were found in LDL concentration. CONCLUSIONS: These results contribute evidence to differentiate between the effects of saturated vegetables oils, such as coconut oil, and of palm olein. The authors recommend not extrapolate the effects of type of oil to another in connection with TC increase in blood.
     
  7. Ong AS, Goh SH. Palm Oil: A healthful and cost-effective dietary component. Food Nutr Bull. 2002 Mar;23(1):11-22. Review.

    Palm oil is an excellent choice for food manufacturers because of its nutritional benefits and versatility. The oil is highly structured to contain predominantly oleic acid at the sn2-position in the major triacylglycerols to account for the beneficial effects described in numerous nutritional studies. Oil quality and nutritional benefits have been assured for the variety of foods that can be manufactured from the oil directly or from blends with other oils while remaining trans-free. The oxidative stability coupled with the cost-effectiveness is unparalleled among cholesterol-free oils, and these values can be extended to blends of polyunsaturated oils to provide long shelf-life. Presently the supply of genetic-modification-free palm oil is assured at economic prices, since the oil palm is a perennial crop with unparalleled productivity. Numerous studies have confirmed the nutritional value of palm oil as a result of the high monounsaturation at the crucial 2-position of the oil’s triacylglycerols, making the oil as healthful as olive oil. It is now recognized that the contribution of dietary fats to blood lipids and cholesterol modulation is a consequence of the digestion, absorption, and metabolism of the fats. Lipolytic hydrolysis of palm oil glycerides containing predominantly oleic acid at the 2 position and palmitic and stearic acids at the 1 and 3 positions allows for the ready absorption of the 2-monoacrylglycerols while the saturated free fatty acids remain poorly absorbed. Dietary palm oil in balanced diets generally reduced blood cholesterol, low-density lipoprotein (LDL) cholesterol, and triglycerides while raising the high-density lipoprotein (HDL) cholesterol. Improved lipoprotein(a) and apo-A1 levels were also demonstrated from palm oil diets; an important benefits also comes from the lowering of blood triglycerides (or reduced fat storage) as compared with those from polyunsaturated fat diets. Virgin palm oil also provides carotenes apart from tocotrienols and tocopherols that have been shown to be powerful antioxidants and potential mediators of cellular functions. These compounds can be antithrombotic, cause an increase of the prostacyclin/thromboxane ratio, reduce restenosis, and inhibit HMG-CoA-reductase (thus reducing) cholesterol biosynthesis). Red palm oil is a rich source of beta-carotene as well as of alpha-tocopherol and tocotrienols
     
  8. Gupta SV, Khosla P. Palmitic and stearic acids similarly affect plasma lipoprotein metabolism in cynomolgus monkeys fed diets with adequate levels of linoleic.acid. J Nutr. 2001 Aug;131(8):2115-20.

    Specific saturated fatty acids [SFA; palmitic acid (16:0) for stearic acid (18:0)] would differentially affect plasma lipids and lipoproteins, when diets contained the currently recommended levels of total SFA, monounsaturated fatty acids and polyunsaturated fatty acids (PUFA). Ten male cynomolgus monkeys were fed one of two purified diets (using a cross-over design) enriched either in 16:0 (palmitic acid diet) or 18:0 (stearic acid diet). Both diets provided 30% of energy as fat (SFA/monounsaturated fatty acid/PUFA: 1/1/1). The palmitic acid and stearic acid diets were based on palm oil or cocoa butter (59% and 50% of the total fat, respectively). By adding different amounts of sunflower, safflower and olive oils, an effective exchange of 16:0 for 18:0 of approximately 5% of energy was achieved with all other fatty acids being held constant. Monkeys were rotated through two 10-wk feeding periods, during which time plasma lipids and in vivo lipoprotein metabolism (following the simultaneous injection of (131)I-LDL and (125)I- HDL were evaluated). Plasma triacyglycerol (0.40 +/- 0.03 vs. 0.37 +/- 0.03 mmol/L), plasma total cholesterol (3.59 +/- 0.18 vs. 3.39 +/- 0.23 mmol/L), HDL cholesterol (1.60 +/- 0.16 vs 1.53 +/- 0.16 mmol/L) and non-HDL cholesterol (2.02 +/- 0.26 vs. 1.86 +/- 0.23 mmol/L) concentrations did not differ when monkeys consumed the palmitic acid and stearic acid diets, respectively. Plasma lipoprotein compositional analyses revealed a higher cholesteryl ester content in the VLDL fraction isolated after consumption of the stearic acid diet (P < 0.10), as well as a larger VLDL particle diameter (16.3 +/- 1.7 nm vs. 13.8 +/- 3.6 nm; P < 0.05). Kinetic analyses revealed no significant differences in LDL or HDL transport parameters. These data suggest that when incorporated into diets following current guidelines, containing adequate PUFA, an exchange of 16:0 for 18:0, representing approximately 11 g/(d.10.46 mJ) [ approximately 11 g/(d.2500 kcal)] does not affect the plasma lipid profile and has minor effects on lipoprotein composition. Whether a similar effect would occur in humans under comparable dietary conditions remains to be established.
  1. Van Jaarsveld PJ, Smuts CM, Tichelaar HY, Kruger M, Benade AJ. Effect of palm oil on plasma lipoprotein concentrations and plasma low-density lipoprotein composition in non-human primates. Int J Food Sci Nutr. 2000;51 Suppl:S21-30.

    Palm oil (PO) contains approximately 43% of palmitic acid. It is the most abundant saturated fatty acid in the diet and it is generally considered the primary cholesterol (C)-raising fatty acid. However, the effect of palmitic acid on plasma cholesterol appears to depend on the cholesterol content of the diet. The aim of this study was to determine the effect of PO with either a high-fat, high-C or moderate-fat, moderate-C diet on lipoprotein C and low-density lipoprotein (LDL) composition. Fifty adult, male vervet monkeys were randomly assigned to the high-fat diet group (HFD: 35%E fat, approximately 0.106 mg C/kJ; n = 30) and the moderate-fat diet group (MFD: 30%E fat, approximately 0.027 mg C/kJ; n = 30). Baseline LDL-C, high-density lipoprotein (HDL)-C and body weight were used to stratify the vervets into comparable experimental groups within each dietary group. The HFD group was divided into two groups of 10 each: one group continued with the HFD in which 8.1%E was derived from lard (AF); in the other group, AF was substituted isocalorically with PO. The MFD group was divided into three groups of 10 each: one group continued with the MFD in which 11.8%E was derived from AF; in the other two groups, the AF was substituted isocalorically with either sunflower oil (SO) or PO. This article presents preliminary results on plasma lipoproteins and LDL composition after 6 months of dietary intervention. Plasma total and LDL-C was higher in all the groups, but the mean changes elicited by PO with either the HFD or MFD were no different from that observed with AF and SO. There was no difference in the mean change of LDL molecular weight within the HFD and MFD. It is concluded that PO is no different from AF (HFD and MFD) or SO (MFD) in its cholesterolaemic effect.
     
  2. Chandrasekharan N. Changing concepts in lipid nutrition in health and disease. Med J Malaysia. 1999 Sep;54(3):408-27; quiz 428. Review.

    Fat remains a hot topic because of concerns over associations between consumption of fats and the incidence of some chronic conditions including coronary artery disease, diabetes, cancer and obesity. Dietary fats serve multiple purposes. The effects of dietary fats generally reflect the collective influences of multiple fatty acids in the diet or food. This presentation highlights some recent developments on the role of dietary fats and oils in health and disease. Debate continues over the role of dietary modification in coronary prevention by lipid lowering. The degree to which a recommended diet will result in health benefits for an individual is difficult to predict, because the outcome will depend on the influence of other factors such as a person’s genetic constitution, level of physical activity and total diet composition. There can now be little doubt about the importance of genetic factors in the etiology of cardiovascular disease, diabetes, obesity and cancer. The importance of antioxidant status in the prevention of cardiovascular disease as well as many cancers is being increasingly recognised. It is now evident that not all saturated fatty acids are equally cholesterolemic. Recent accounts evaluating palm oil’s effects on blood lipids and lipoproteins suggest that diets incorporating palm oil as the major dietary fat do not raise plasma total and LDL cholesterol levels to the extent expected from its fatty acid composition. Palm oil is endowed with a good mixture of natural antioxidants and together with its balanced composition of the different classes of fatty acids, makes it a safe, stable and versatile edible oil with many positive health and nutritional attributes. In recent times, adverse health concerns from the consumption of trans fatty acids arising from hydrogenation of oils and fats have been the subject of much discussion and controversy. Trans fatty acids when compared with cis fatty acids or unhydrogenated fats have been shown to lower serum HDL cholesterol, raise serum LDL cholesterol and when substituted for saturated fatty acids, increase lipoprotein Lp (a) level, an independent risk factor for the development of coronary heart disease. The idea of which foods, nutrients and supplements are “healthy” is often being amended as new scientific data is presented and then simplified for the consumers. What was once perceived as a healthy diet is often no longer considered as such and vice versa. Dietary recommendations have to change with time and the evidence available. Nutritional recommendations should encourage eating a great variety of nutrient sources within our food supply in moderation. Various lifestyle options to improve health should also be promoted.
     
  3. Kritchevsky D, Tepper SA, Chen SC, Meijer GW, Krauss RM. Cholesterol vehicle in experimental atherosclerosis. 23. Effects of specific synthetic triglycerides. Lipids. 2000 Jun;35(6):621-5.

    Earlier work has shown that increasing concentration of palmitic acid at the sn-2 position of a fat enhances the atherogenic properties of that fat. This effect has been observed with lard, tallow, cottonseed oil, and palm oil. In the experiment reported here, we have studied the atherogenic effects of four synthetic fats fed to rabbits as 58% (w/w) of the total fat (15%) (w/w) of a semipurified diet containing 0.05% cholesterol. The fats being tested were: 1,3-stearoyl-2-oleoylglycerol (SOS); 1,2-stearoyl-3-oleoylglycerol (SSO); 1,3-palmitoyl-2-oleoylglycerol (POP); and 1,2-palmitoyl-3-oleoylglycerol (PPO). After 20 wk on diet there were no differences among the groups in weight gain, liver weight, serum, or liver lipids. These data are consistent with our previous findings. There were significant differences in atherosclerosis. The most severe atherosclerosis was observed in group PPO and the least in groups SSO and POP. Severity of atherosclerosis was graded visually on a 0-4 scale. The average atherosclerosis [(aortic arch and thoracic aorta) divided by 2] was: SOS–1.35; SSO–0.97; POP–0.83; and PPO–1.80. Fecal fat excretion (an indicator of fat absorption) was higher in the two groups fed the stearic acid-rich fats and lower in groups fed the palmitic acid-rich fats. There were no differences in low density lipoprotein particle size. The results confirm previous findings concerning the increased atherogenicity of fats bearing palmitic acid at the sn-2 position. The mechanism underlying these observations is moot but may, in part, reflect greater absorption of the atherogenic fat.
     
  4. Muller H, Jordal O, Kierulf P, Kirkhus B, Pedersen JI. Replacement of partially hydrogenated soybean oil by palm oil in margarine without unfavorable effects on serum lipoproteins. Lipids. 1998 Sep;33(9):879-87.

    We have compared the effects of three different margarines, one based on palm oil (PALM-margarine), one based on partially hydrogenated soybean oil (TRANS-margarine) and one with a high content of polyunsaturated fatty acids (PUFA-margarine), on serum lipids in 27 young women. The main purpose of the study was to test if replacement of trans fatty acids in margarine by palmitic acid results in unfavorable effects on serum lipids. The sum of saturated fatty acids (12:0, 14:0, 16:0) was 36.3% of total fatty acids in the PALM-diet, the same as the sum of saturated (12:0, 14:0, 16:0) (12.5%) and trans (23.1%) fatty acids in the TRANS-diet. This sum was 20.7% in the PUFA-diet. The content of oleic acid was 37.9, 35.2, and 38.6%, respectively, in the three diets, whereas linoleic acid amounted to 16, 13.5, and 27.3%, respectively. Total fat provided 30-31% and the test margarines 26% of total energy in all three diets. The subjects consumed each of the diets for 17 d in a Latin-square crossover design. There were no significant differences in total cholesterol, low density lipoprotein (LDL)-cholesterol and apolipoprotein B (apoB) between the TRANS- and the PALM-diets. High density lipoprotein (HDL)-cholesterol and apoA-1 were significantly higher on the PALM-diet compared to the TRANS-diet whereas the ratio of LDL-cholesterol to HDL-cholesterol was lower, although not significantly (P = 0.077) on the PALM-diet. Total cholesterol, LDL-cholesterol, and apoB were significantly lower on the PUFA-diet compared to the two other diets. HDL-cholesterol was not different on the PALM- and the PUFA-diets but it was significantly lower on the TRANS-diet compared to the PUFA diet. Compared to the PUFA-diet the ratio of LDL- to HDL-cholesterol was higher on both the PALM- and the TRANS-diets whereas apoA-1 was not different. Triglycerides and lipoprotein (a) were not significantly different among the three diets. We concluded that nutritionally, palmitic acid from palm oil may be a reasonable alternative to trans fatty acids from partially hydrogenated soybean oil in margarine if the aim is to avoid trans fatty acids. A palm oil-based margarine is, however, less favorable than one based on a more polyunsaturated vegetable oil.
     
  5. Choudhury N, Truswell AS, McNeil Y. Comparison of plasma lipids and vitamin E in young and middle-aged subjects on potato crisps fried in palmolein and highly oleic sunflower oil. Ann Nutr Metab. 1997;41(3):137-48.

    We previously found no difference in healthy young adults’ plasma cholesterols between palmolein and olive oil as the major dietary lipid, although the former is high in palmitic acid (16:0) but the latter in oleic acid (18:1 cis). In the experiment reported here we compared the effects of palmolein against another monounsaturated oil, highly oleic sunflower oil (HOSO), on plasma cholesterol in both young and middle-aged healthy adults. The test oils were provided as frying oil of potato crisps (150 g/day in men; 100 g/day in women) against low-fat background diets in free-living motivated volunteers. The design was a randomised double-blind 4-week/3-week crossover trial. Compliance was monitored with continuous dietary diaries and by measuring (fasting) plasma lipid fatty-acid pattern. Plasma lipids and vitamin-E compounds were measured at the start and twice at the end of each test period. In combined young plus older subjects (n = 42) mean plasma total and low-density-lipoprotein cholesterol (LDL-c) values were both 7% (significantly) lower on HOSO than on palmolein, but because high-density-lipoprotein cholesterol (HDL-c) was also 5% lower, the LDL-c/HDL-c ratio was only 3% lower on HOSO than on palmolein. The difference between the present results with HOSO and previous results with olive oil both compared against palmolein suggest that olive oil is associated with higher plasma cholesterols than other monounsaturated oils. In both the young and older subgroup, LDL-c was lower on HOSO but because HDL-c moved down too in the young subgroup, the LDL-c/HDL-c ratio was lower on HOSO only in the older subjects. Palmolein has an unusual pattern of E vitamins, with a high content of tocotrienols, notably the gamma-isomer. Unlike alpha-tocopherol however, there was no sign of these tocotrienols in subjects’ plasmas.
     
  6. Zock PL, de Vries JH, Katan MB. Impact of myristic acid versus palmitic acid on serum lipid and lipoprotein levels in healthy women and men. Arterioscler Thromb. 1994 Apr;14(4):567-75

    The cholesterol-raising effect of dietary saturated fatty acids is largely accounted for by lauric, myristic, and palmitic acids. Dairy fat is a major source of myristic acid, and palm oil is especially rich in palmitic acid. Myristic acid is suspected of being much more cholesterolemic than palmitic acid, but direct comparisons have been lacking. We therefore fed 36 women and 23 men three diets that differed from each other in palmitic, oleic, and myristic acid content by about 10% of total energy. We used palm oil, high-oleic acid sunflower oil, and a specially produced high-myristic acid fat to achieve these differences. Each diet was consumed for 3 weeks in random order. Mean serum cholesterol was 4.53 mmol/L on the high-oleic acid diet, 4.96 mmol/L on the palmitic acid diet, and 5.19 mmol/L on the myristic acid diet (P < .0001 for all comparisons). Myristic acid raised low-density lipoprotein (LDL) cholesterol by 0.11 mmol/L, high-density lipoprotein (HDL) cholesterol by 0.12 mmol/L, and apolipoprotein (apo) A-I by 7.2 mg/dL relative to palmitic acid; increases relative to oleic acid were 0.50 mmol/L for LDL cholesterol, 0.15 mmol/L for HDL cholesterol, 6.0 mg/dL for apoB, and 8.9 mg/dL for apoA-I (P < .01 for all comparisons). The HDL cholesterol and apoA-I levels on the palmitic and oleic acid diets were the same. None of the responses differed significantly between woman and men. Myristic acid and palmitic acid both caused high LDL cholesterol and apoB levels and low HDL to LDL ratios.
     
  7. Choudhury N, Tan L, Truswell AS. Comparison of palm olein and olive oil: effects on plasma lipids and vitamin E in young adults.Am J Clin Nutr. 1995 May;61(5):1043-51.

    Twenty-one healthy normocholesterolemic young adults, men and women, completed a randomized 30-d/30-d crossover comparison of the effect of palmolein and olive oil on plasma lipids. The subjects were free-living volunteers who changed to low-fat diets to which one of the test oils was added (used as a spread, for baking, or for frying) in turn. Complete food records were kept throughout: the test oils were compared at 17% of total dietary energy. Under the conditions of this experiment plasma total and low-density-lipoprotein (LDL) cholesterol were almost identical with the two oils, so that when the palmitic acid (16:0) in palm oil replaced oleic acid (18:1) in olive oil the expected increase in LDL cholesterol was not seen. These results indicate that 16:0, though saturated, is not always a plasma cholesterol-raising fatty acid. Palmolein is rich in vitamin E, alpha-tocopherol, and especially tocotrienols, but the latter were barely detectable in plasma.
     
  8. Sundram K, Hornstra G, Von Houwelingen AC, Kester AD. Replacement of dietary fat with palm oil: effect on human serum lipids, lipoproteins and apolipoproteins. Br J Nutr. 1992 Nov;68(3):677-92.

    Thirty-eight male volunteers participated in a double-blind cross-over trial evaluating the effect of replacing the usual sources of saturated fat in the Dutch diet (animal fats and hydrogenated oils) by palm oil, which is virtually free of cholesterol and trans-fatty acids, on serum lipids, lipoproteins and apolipoproteins. Maximum (about 70%) replacement had no significant effect on serum total cholesterol or most lipoprotein fractions, but resulted in an 11% increase in serum high-density-lipoprotein (HDL)2-cholesterol relative to the control (P2 = 0.01). The palm-oil diet also caused an 8% decrease in low-density-lipoprotein (LDL):HDL2 + HDL3-cholesterol ratio (P2 = 0.02) as well as a 9% decrease in triacylglycerols in the low-density-lipoprotein fractions (P2 = 0.01). Palm oil consumption resulted in a 4% increase in serum apolipoprotein AI (P2 = 0.008) and a 4% decrease in apolipoprotein B (P2 = 0.01) relative to the control diet; the B:AI apolipoprotein ratio was decreased by 8% (P2 < 0.0001). These results were not significantly affected by the different lipoprotein E phenotypes of the volunteers. Although the observed differences were relatively modest, the present study, nonetheless, indicates that dietary palm oil, when replacing a major part of the normal fat content in a Dutch diet, may slightly reduce the lipoprotein- and apolipoprotein-associated cardiovascular risk profiles.
  1. Khosla P, Hayes KC. Comparison between the effects of dietary saturated (16:0), monounsaturated (18:1), and polyunsaturated (18:2) fatty acids on plasma lipoprotein metabolism in cebus and rhesus monkeys fed cholesterol-free diets. Am J Clin Nutr. 1992 Jan;55(1):51-62.

    Cebus and rhesus monkeys were fed cholesterol-free diets providing 40% of energy as fat for 6-wk periods. The fats were high-linoleic acid safflower oil (HLSO), high-oleic acid safflower oil (HOSO), or palm oil (PO), rich in polyunsaturated (18:2), monounsaturated (18:1), or saturated (16:0) fatty acids, respectively. In cebus monkeys, plasma cholesterol concentrations during HLSO intake were 17-19% lower than those during HOSO or PO intake, attributed to a decrease in high-density lipoprotein (HDL). Plasma triglyceride (TG) and low-density-lipoprotein (LDL) cholesterol concentrations were comparable during all dietary treatments. Sixty-eight percent of total LDL catabolism was receptor mediated in all dietary groups and this was associated with similar apolipoprotein B pool sizes and fractional catabolic rates. Rhesus monkeys revealed similar cholesterol concentrations (total, LDL, and HDL) during all dietary treatments. TG concentrations during PO intake were 34% and 63% higher than those during HOSO and HLSO intakes, respectively. Hence, dietary 16:0 and 18:1 produce similar effects on LDL and HDL metabolism in normocholesterolemic primates.
     
  2. Elson CE. Tropical Oils: Nutritional and scientific issues. Crit Rev Food Sci Nutr. 1992;31(1-2):79-102. Review.

    Individually and in combination with other oils, the tropical oils impart into manufactured foods functional properties that appeal to consumers. The use of and/or labeling in the ingredient lists give the impression that these oils are used extensively in commercially processed foods. The estimated daily intake of tropical oils by adult males is slightly more than one fourth of a tablespoon (3.8 g), 75% of which consists of saturated fatty acids. Dietary fats containing saturated fatty acids at the beta-position tend to raise plasma total and LDL-cholesterol, which, of course, contribute to atherosclerosis and coronary heart disease. Health professionals express concern that consumers who choose foods containing tropical oils unknowingly increase their intake of saturated fatty acids. The saturated fatty acid-rich tropical oils, coconut oil, hydrogenated coconut oil, and palm kernel oil, raise cholesterol levels; studies demonstrating this effect are often confounded by a developing essential fatty acid deficiency. Palm oil, an essential fatty acid-sufficient tropical oil, raises plasma cholesterol only when an excess of cholesterol is presented in the diet. The failure of palm oil to elevate blood cholesterol as predicted by the regression equations developed by Keys et al. and Hegsted et al. might be due to the dominant alpha-position location of its constituent saturated fatty acids. If so, the substitution of interesterified artificial fats for palm oil in food formulations, a recommendation of some health professionals, has the potential of raising cholesterol levels. A second rationale addresses prospective roles minor constituents of palm oil might play in health maintenance. This rationale is founded on the following observations. Dietary palm oil does not raise plasma cholesterol. Single fat studies suggests that oils richer in polyunsaturated fatty acid content tend to decrease thrombus formation. Anomalously, palm oil differs from other of the more saturated fats in tending to decrease thrombus formation. Finally, in studies comparing palm oil with other fats and oils, experimental carcinogenesis is enhanced both by vegetable oils richer in linoleic acid content and by more highly saturated animal fats. The carotenoid constituents of red palm oil are potent dietary anticarcinogens. A second group of antioxidants, the tocotrienols, are present in both palm olein and red palm oil. These vitamin E-active constituents are potent suppressors of cholesterol biosynthesis; emerging data point to their anticarcinogenic and antithrombotic activities. This review does not support claims that foods containing palm oil have no place in a prudent diet.
     
  3. Van Jaarsveld PJ, Smuts CM, Tichelaar HY, Kruger M, Benade AJ. Effect of palm oil on plasma lipoprotein concentrations and plasma low-density lipoprotein composition in non-human primates. Int J Food Sci Nutr. 2000;51 Suppl:S21-30.

    In a recent study from this laboratory, rhesus monkeys fed a 90% palm oil/10% soybean oil-containing diet (PS), rich in 16:0 and 18:1 fatty acids, had decreased total and LDL cholesterol concentrations compared to monkeys fed a 90% coconut oil/10% soybean oil-containing diet (CS), rich in 12:0 and 14:0 fatty acids. To investigate the metabolic basis of these changes, homologous 125I-VLDL and 131I-LDL were injected simultaneously into eight monkeys (four per dietary group). Analysis of apo B specific activity curves revealed that PS monkeys had an increased pool size of VLDL apo B (P less than 0.02), a 3-fold increase in the total VLDL apo B transport rate (P less than 0.001), a decreased pool size of LDL apo B (P less than 0.01) and a 2-fold decrease in the total transport rate of LDL apo B (P less than 0.001), while the irreversible FCR for VLDL apo B and LDL apo B was similar between dietary groups. PS monkeys derived a greater percentage of LDL apo B from VLDL catabolism resulting in a greater transport rate of LDL apo B from VLDL catabolism (P less than 0.055), in comparison to CS monkeys. For CS monkeys the proportion as well as the amount of LDL apo B derived from VLDL-independent catabolism (i.e., LDL apo B derived from sources other than VLDL catabolism) was higher (P less than 0.001) than the values obtained in PS monkeys. In both dietary groups the proportion of VLDL apo B converted to LDL apo B was similar, although the absolute amount was higher for the PS monkeys (P less than 0.06). The proportion of VLDL apo B directly removed from the circulation was similar for both dietary groups, with the absolute amount being higher for the PS monkeys (P less than 0.001). Consistent with the lower pool size of LDL apo B and the higher pool size of VLDL apo B observed in PS monkeys, plasma and LDL cholesterol concentrations tended to be lower, whereas plasma triacylglycerol and VLDL cholesterol concentrations tended to be higher, but these changes were not statistically significant. Although total apo B and VLDL apo B transport rates were increased 2-3-fold in PS monkeys, LDL apo B concentration was reduced by 40% (P less than 0.02) attributed to a significant reduction in the mass and proportion of LDL apo B derived independent of VLDL catabolism.
     
  4. Ng TK, Hassan K, Lim JB, Lye MS, Ishak R. Nonhypercholesterolemic effects of a palm-oil diet in Malaysian volunteers. Am J Clin Nutr. 1991 Apr;53(4 Suppl):1015S-1020S

    The effects on serum lipids of diets prepared with palm olein, corn oil, and coconut oil supplying approximately 75% of the fat calories were compared in three matched groups of healthy volunteers (61 males, 22 females, aged 20-34 y). Group I received a coconut-palm-coconut dietary sequence; group II, coconut-corn-coconut; and group III, coconut oil during all three 5-wk dietary periods. Compared with entry-level values, coconut oil raised the serum total cholesterol concentration greater than 10% in all three groups. Subsequent feeding of palm olein or corn oil significantly reduced the total cholesterol (-19%, -36%), the LDL cholesterol (-20%, -42%%) and the HDL cholesterol (-20%, -26%) concentrations, respectively. Whereas the entry level of the ratio of LDL to HDL was not appreciably altered by coconut oil, this ratio was decreased 8% by palm olein and 25% by corn oil. Serum triglycerides were unaffected during the palm-olein period but were significantly reduced during the corn-oil period.
     
  5. Marzuki A, Arshad F, Razak TA, Jaarin K. Influence of dietary fat on plasma lipid profiles of Malaysian adolescents. Am J Clin Nutr. 1991 Apr;53(4 Suppl):1010S-1014S

    We studied the effects of saturated (palm olein) and polyunsaturated (soybean oil) cooking oils on the lipid profiles of Malaysian male adolescents eating normal Malaysian diets for 5 wk. Diets cooked with palm olein did not significantly alter plasma total-cholesterol, LDL cholesterol, and HDL cholesterol concentrations or the ratio of total cholesterol to HDL cholesterol compared with diets cooked with soybean oil. However, the diet cooked with palm olein significantly increased apolipoprotein A-I (11%) and apolipoprotein B (9%) concentrations. Unexpectedly, soybean-oil-cooked diets caused a significant increase (47%) in plasma triglycerides compared with palm-olein-cooked diets. We conclude that palm olein, when used as cooking oil, has no detrimental effects on plasma lipid profiles in Malaysian adolescents.
     
  6. Chong YH, Ng TK. Effects of palm oil on cardiovascular risk. Med J Malaysia. 1991 Mar;46(1):41-50. Review.

    A major public health concern of affluent nations is the excessive consumption of dietary fats which are now closely linked to coronary heart disease. Against this scenario, the tropical oils and palm oil in particular, have been cast as major villains in the U.S.A., despite the fact that palm oil consumption there is negligible. The unsuspecting public may not realise that the call to avoid palm oil is nothing more than a trade ploy since in recent years palm oil has been very competitive and has gained a major share of the world’s edible oils and fats market. Many also lose sight of the fact that, palm oil, like other edible oils and fats, is an important component of the diet. The allegation that palm oil consumption leads to raised blood cholesterol levels and is therefore atherogenic is without scientific foundation. Examination of the chemical and fatty acid composition of palm oil or its liquid fraction should convince most nutritionists that the oil has little cholesterol-raising potential. The rationale for these are: it is considered cholesterol free. its major saturated fatty acid, palmitic acid (16:0) has recently been shown to be neutral in its cholesterolaemic effect, particularly in situations where the LDL receptors have not been down-regulated by dietary means or through a genetic effect. palm oil contains negligible amounts (less than 1.5%) of the hypercholesterolemic saturated fatty acids, namely lauric acid (12:0) and myristic acid (14:0). it has moderately rich amounts of the hypocholesterolaemic, monounsaturated oleic acid (18:1, omega-9) and adequate amounts of linoleic acid. (18:2, omega-6). It contains minor components such as the vitamin E tocotrienols which are not only powerful antioxidants but are also natural inhibitors of cholesterol synthesis. Feeding experiments in various animal species and humans also do not support the allegation that palm oil is atherogenic. On the contrary, palm oil consumption reduces blood cholesterol in comparison with the traditional sources of saturated fats such as coconut oil, dairy and animal fats. In addition, palm oil consumption may raise HDL levels and reduce platelet aggregability. As with all nutrients, there is a need to obtain a balance of different fatty acids found in fats in edible oils and other food sources. There is no single ideal source of fat that answers to the recent American Heart Association’s call to reflect a 1:1:1 ratio of saturated, monounsaturated and polyunsaturated fats in relation to the recommended dietary fat intake of 30% of calories or less.
     
  7. Lindsey S, Benattar J, Pronczuk A, Hayes KC. Dietary palmitic acid (16:0) enhances high density lipoprotein cholesterol and low density lipoprotein receptor mRNA abundance in hamsters. Proc Soc Exp Biol Med. 1990 Nov;195(2):261-9.

    In order to examine the qualitative effect of different fats and specific fatty acids on plasma lipids and lipoprotein metabolism, six low fat, cholesterol-free diets were fed to young male hamsters (10/group) for a 4-week period. Fat blends were formulated with coconut oil, palm oil, soybean oil, high oleic acid safflower oil, butter, corn oil, and canola oil. Diets contained 13% energy as fat and dietary polyunsaturate/saturate ratios ranged from 0.12 to 1.04, one of which incorporated the American Heart Association-recommended concentrations of saturates, monoenes, and polyenes and another reflected the current American Fat Blend. In three diets the polyunsaturate/monounsaturate/saturate ratio was held constant while only the 12:0, 14:0, and 16:0 were varied. Plasma lipoproteins and apoproteins were assessed in conjunction with the abundance of specific hepatic and intestinal mRNA for the low density lipoproteins (LDL) receptor and various apolipoproteins associated with cholesterol metabolism. The plasma cholesterol response was lowest with the American Heart Association blend and equally elevated by the more saturated, low polyene diets (polyunsaturate/saturate, 0.12-0.38). Replacing 12:0 plus 14:0 from coconut oil with 16:0 as palm oil induced a significant increase in high density lipoprotein (HDL) cholesterol with a trend toward decreased LDL. These shifts in lipoprotein cholesterol were corroborated by measures of the LDL/HDL ratio, the plasma apolipoprotein B/apolipoprotein A1 ratio, and differences in the synthesis of apolipoproteins and the LDL receptor based on estimates of the mRNA for these proteins in the liver and gut, using specific cDNA probes for apolipoprotein A1, apolipoprotein B, apolipoprotein E, and the LDL receptor. Although it has been suggested that dietary polyenes lower total plasma cholesterol, including HDL, and that saturated fat increases both these pools of cholesterol, the current data represents the first evidence that a specific saturated fatty acid, i.e., palmitic acid, may enhance HDL production.
  1. Idris CA, Sundram K. Effect of dietary cholesterol, trans and saturated fatty acids on serum lipoproteins in non-human primates. Asia Pac J Clin Nutr. 2002;11 Suppl 7:S408-15

    Nine cynomolgus monkeys were rotated randomly through four dietary treatments with each treatment lasting 6 weeks. A wash-out period of 4 weeks was maintained between each dietary rotation. The animals were fed diets containing 32% energy fat derived from palm olein (POL), lauric-myristic-rich oil blend (LM), American Heart Association (AHA) rich oil blend and hydrogenated soybean oil blend (trans). Diets were fed with (phase 1) or without (phase 2) the addition of dietary cholesterol (0.1%). In phase 1, when animals were fed without dietary cholesterol, plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) was significantly raised and high-density lipoprotein cholesterol (HDL-C) was significantly depressed by the trans diets relative to all other dietary treatments. The resulting LDL-C/HDL-C ratio was also significantly increased. The LM diet increased TC significantly relative to the AHA diet while LDL-C was significantly increased compared to both POL and AHA. Apolipoprotein (apo) B was not affected significantly by these dietary treatments. Apo A1 was significantly increased by POL relative to all other dietary treatments. The trans diet reduced apo A1 and the resulting apo B/A1 ratio was increased significantly by trans relative to all other dietary treatments. Addition of 0.1% dietary cholesterol to these diets almost doubled the plasma TC and LDL-C in all dietary treatments. However, HDL-C was only marginally higher with the addition of dietary cholesterol. The LM + C (cholesterol added) diet resulted in the highest TC and LDL-C that was significant compared to all other dietary treatments. Trans + C increased TC compared to POL + C and AHA + C diets while increases in the LDL-C did not attain significance. The addition of dietary cholesterol did not affect HDL-C between treatments whereas plasma triglycerides were significantly increased by the trans + C diet relative to all other treatments. Both the trans + C and LM + C diets increased apo B and decreased apo A1 relative to the POL + C and AHA + C diets. The resulting apo B/A1 ratio was similarly altered. These results affirm that the lauric + myristic acid combination, along with trans fatty acids, increased lipoprotein-associated coronary heart disease risk factors compared to either POL or AHA.
     
  2. Bosch V, Aular A, Medina J, Ortiz N, Apitz R. Changes in of plasma lipoproteins after the use of palm oil in the diet of a group healthy adults. Arch Latinoam Nutr. 2002 Jun;52(2):145-50.

    Although saturated fat acids have long known to have harmful effects on cholesterol and triacylglycerides levels in blood, new concepts have emerged form recent research on this matter. The purpose of this study was to know the effect of the consumption of palm olein on triacylglycerides and cholesterol levels as well as lipoprotein fractions in the blood plasma of healthy individuals from both sexes. MATERIALS AND METHODS: Different types of fats were administered for 12 weeks to 60 subjects, 45 male, 15 female, between 19 and 45 years of age, who were divided into three groups: the mix group (MG) was administered oil, margarine, and mayonnaise prepared with 50% olein; the olein group (OG) consumed fats prepared with 100% olein; and the control group (CG) consumed regular fats of customary use by the population. The diets provided 25 to 30% of calories. Blood samples were obtained for lipid analysis at the beginning and the end of the study. Plasma triacylglycerides and cholesterol concentrations were determined by means of enzyme and lipoprotein methods (VLDL, LDL; and HDL) by ultracentrifugation. RESULTS AND DISCUSSION: By comparing the groups’ means no significant differences were found (p > 0.05) in blood lipids. Individual differences show a slight increase in VLDL-C in OG compared to MG and CG. No differences were found in LDL concentration. CONCLUSIONS: These results contribute evidence to differentiate between the effects of saturated vegetables oils, such as coconut oil, and of palm olein. The authors recommend not extrapolate the effects of type of oil to another in connection with TC increase in blood.
     
  3. Pedersen JI, Muller H, Seljeflot I, Kirkhus B. Palm oil versus hydrogenated soybean oil: Effects on serum lipids and plasma haemostatic variables. Asia Pac J ClinNutr. 2005;14(4):348-57.

    The purpose of this study was to test if replacement of trans fatty acids by palmitic acid in an experimental margarine results in unfavourable effects on serum lipids and haemostatic factors. We have compared the effects of three different margarines, one based on palm oil (PALM-margarine), one based on partially hydrogenated soybean oil (TRANS- margarine) and one with a high content of polyunsaturated fatty acids (PUFA-margarine), on serum lipids in 27 young women. In nine of the participants fasting levels and diurnal postprandial levels of haemostatic variables on the 3 diets were compared. The sum of 12:0, 14:0, 16:0 provided 11% of energy (E%) in the PALM diet, the same as the sum of 12:0, 14:0, 16:0 and trans fatty acids in the TRANS-diet. Oleic acid provided 10-11E% in all three diets, while PUFA provided 5.7, 5.5 and 10.2 E%, respectively. Total fat provided 30-31% and the test margarines 26% of total energy in all three diets. Each of the diets was consumed for 17 days in a crossover design. There were no significant differences in total cholesterol, LDL-cholesterol and apoB between the TRANS- and the PALM-diet. HDL-cholesterol and apoA-I were significantly higher on the PALM-diet compared to the TRANS-diet while the ratio of LDL- to HDL-cholesterol was lower, although not significantly (P = 0.077) on the PALM-diet. Total cholesterol, LDL-cholesterol and apoB were significantly lower on the PUFA-diet compared to the two other diets. HDL-cholesterol was not different on the PALM- and the PUFA-diet while it was significantly lower on the TRANS-diet compared to the PUFA-diet. Triglycerides and Lp(a) were not different among the three diets. The diurnal postprandial state level of tissue plasminogen activator (t-PA) activity was significantly decreased on the TRANS-diet compared to the PALM-diet. t-PA activity was also decreased on the PUFA-diet compared to PALM-diet although not significantly (P=0.07). There were no significant differences in neither fasting levels or in circadian variation of t-PA antigen, PAI-1 activity, PAI-1 antigen, factor VII coagulant activity or fibrinogen between the three diets. Our results suggest that dietary palm oil may have a more favourable effect on the fibrinolytic system compared to partially hydrogenated soybean oil. We conclude that from a nutritional point of view, palmitic acid from palm oil may be a reasonable alternative to trans fatty acids from partially hydrogenated soybean oil in margarine if the aim is to avoid trans fatty acids. A palm oil based margarine is, however, less favourable than one based on a more polyunsaturated vegetable oil.
     
  4. Wilson TA, Nicolosi RJ, Kotyla T, Sundram K, Kritchevsky D. Different palm oil preparations reduce plasma cholesterol concentrations and aortic cholesterol accumulation compared to coconut oil in hypercholesterolemic hamsters. J Nutr Biochem.2005 Oct;16(10):633-40.

    Several studies have reported on the effect of refined, bleached and deodorized palm oil (RBD-PO) incorporation into the diet on blood cholesterol concentrations and on the development of atherosclerosis. However, very little work has been reported on the influence of red palm oil (RPO), which is higher in carotenoid and tocopherol content than RBD-PO. Thus, we studied the influence of RPO, RBD-PO and a RBD-PO plus red palm oil extract (reconstituted RBD-PO) on plasma cholesterol concentrations and aortic accumulation vs. hamsters fed coconut oil. Forty-eight F1B Golden Syrian hamsters (Mesocricetus auratus) (BioBreeders, Watertown, MA) were group housed (three/cage) in hanging polystyrene cages with bedding in an air-conditioned facility maintained on a 12-h light/dark cycle. The hamsters were fed a chow-based hypercholesterolemic diet (HCD) containing 10% coconut oil and 0.1% cholesterol for 2 weeks at which time they were bled after an overnight fast and segregated into four groups of 12 with similar plasma cholesterol concentrations. Group 1 continued on the HCD, Group 2 was fed the HCD containing 10% RPO in place of coconut oil, Group 3 was fed the HCD containing 10% RBD-PO in place of coconut oil and Group 4 was fed the HCD with 10% reconstituted RBD-PO for an additional 10 weeks. Plasma total cholesterol (TC) and non-high-density lipoprotein-cholesterol (HDL-C) (very low- and low-density lipoprotein) concentrations were significantly lower in the hamsters fed the RPO (-42% and -48%), RBD-PO (-32% and -36%) and the reconstituted RBD-PO (-37% and -41%) compared to the coconut oil-fed hamsters. Plasma HDL-C concentrations were significantly higher by 14% and 31% in hamsters fed the RBD-PO and RPO compared to the coconut oil-fed hamsters. Plasma triglyceride (TG) concentrations were significantly lower in hamsters fed RBD-PO (-32%) and the reconstituted RBD-PO (-31%) compared to the coconut oil-fed hamsters. The plasma gamma-tocopherol concentrations were higher in the coconut oil-fed hamsters compared to the hamsters fed the RPO (60%), RBD-PO (42%) and the reconstituted RBD-PO (49%), while for plasma alpha-tocopherol concentrations, the coconut oil-fed hamsters were significantly higher than only the RPO-fed hamsters (21%). The coconut oil-fed hamsters also had significantly higher plasma lipid hydroperoxide concentrations compared to RBD-PO (112%) and the reconstituted RBD-PO (485%). The hamsters fed the coconut oil diet excreted significantly more fecal total neutral sterols and cholesterol compared to the hamsters fed the RBD-PO (158% and 167%, respectively). The coconut oil-fed hamsters had significantly higher levels of aortic total, free and esterified cholesterol compared to the hamsters fed the RPO (74%, 50% and 225%, respectively), RBD-PO (57%, 48% and 92%, respectively) and the reconstituted RBD-PO (111%, 94% and 94%, respectively). Also, aortic free/ester cholesterol ratio in the aortas of hamsters fed RPO was significantly higher than in those fed the coconut oil (124%). In conclusion, hamsters fed the three palm oil preparations had lower plasma TC and non-HDL-C and higher HDL-C concentrations while accumulating less aortic cholesterol concentrations compared to hamsters fed coconut oil.
     
  5. Tiahou G, Maire B, Dupuy A, Delage M, Vernet MH, Mathieu-Daude JC, Michel F, Sess ED, Cristol JP. 1. Lack of oxidative stress in a selenium deficient area in Ivory Coast-potential nutritional antioxidant role of crude palm oil. Eur J Nutr. 2005 Oct ; 43(6):367-74.

    BACKGROUND: Previous studies have described an important selenium deficiency in a mountain region (Glanle) in the west of Ivory Coast. AIM OF THE STUDY: To assess the antioxidant capacity of subjects from a selenium deficient area in Ivory Coast (Glanle region). METHODS: This study involved 57 subjects, 18 to 69 years old, living in the Glanle region and 56 healthy controls living in the southern coastal region (Bodou). In the Glanle region families consume basically a vegetarian and crude palm oil diet, whereas in the Bodou region, families eat a fish-based diet with principally refined palm oil. Fasting blood samples were collected to assess the following parameters: lipid status (plasma total lipids; total-, HDL and LDL-cholesterol; triglycerides; phospholipids; fatty acid composition), plasma protein status (total protein, albumin, transthyretin, orosomucoid, CRP, transferrin), antioxidant capacity (plasma selenium, uric acid, retinol, alpha-tocopherol and tocotrienols levels, plasma seleno-glutathione peroxidase (GSHPx) activity) and oxidative stress markers (malondialdehyde (MDA) and advanced oxidation protein products (AOPP)). RESULTS: The mountain region samples (Glanle) were characterized by significantly lower plasma albumin, total-, HDL- and LDL-cholesterol, retinol and selenium levels, plasma PUFA content and GSHPx activity, but significantly higher alpha-tocopherol index and total tocotrienol level, than controls from the coastal area (Bodou). These results suggest a higher exposure risk to oxidative stress for the mountain region subjects. However, the absence of oxidative damage in this group provides evidence of a selenium independent protection mechanism against oxidative stress. This protection is related to lower plasma LDL cholesterol and PUFA content, and to higher alpha-tocopherol index, delta and total tocotrienols. CONCLUSION: The long-term consumption of crude palm oil could be considered as an effective protective factor against oxidative stress.
     
  6. Sanchez- Muniz FJ, Oubina P, Rodenas S, Benedi J, Cuesta C. Platelet aggregation, thromboxane production and thrombogenic ratio in postmenopausal women consuming high oleic acid-sunflower oil or palmolein. Eur J Nutr. 2003 Dec; 42(6):299-306.

    BACKGROUND: Saturated fatty acids exert controversial effects on platelet aggregation and eicosanoid production. AIM: To investigate the effect of a dietary exchange between palmitic acid and oleic acid on both platelet aggregation and thromboxane B2 (TXB(2)) production, and on urine TXB(2), prostacyclin I2 (PGI(2) as 6-keto-protaglandin F(1)alpha), and the thrombogenic ratio (TXB(2)/6-keto-protaglandin F(1)alpha) in fourteen postmenopausal women. EXPERIMENTAL DESIGN: Women were assigned to two consecutive 28-d dietary periods that were high in cholesterol (~400 mg/d) and fat (~46%en). In the first period all subjects followed an oleic acid-rich diet prepared with high oleic acidsunflower oil. This was followed by a second period rich in palmitic acid in the form of palmolein. DETERMINATIONS: Nutrient intakes, ADP-platelet aggregation, platelet TXB(2) production, urine TXB(2) and 6-keto-protaglandin F(1)alpha were measured during two dietary periods and the results obtained correlated to serum cholesterol, lipoproteincholesterol and peroxides, apolipoproteins and plasma tocopherol. RESULTS: The palmolein diet led to an increase in the platelet aggregation rate (p < 0.05) and in the time for the maximal aggregation rate (p < 0.02).No significant differences were observed in platelet TXB(2) production. Palmolein increased urine TXB(2) in pg/mL (p < 0.05) and pg/min (p < 0.01), whereas the thrombogenic ratio (TXB(2)/6-keto-protaglandin F(1)alpha) did not change. Most changes were related to oil change, few to serum cholesterol level (< or > or = 6.2 mmol/L) or age (< or > or = 65 yr). CONCLUSIONS: Palmolein diet activates platelet aggregation more in normocholesterolemics. Though palmolein increased thromboxane and tended to increase prostacyclin in urine in normo- and hypercholesterolemic women, the thrombogenic ratio did not change. These effects were related to the LDL and HDL concentration increases and to the absence of change in the total cholesterol/HDL-cholesterol ratio found Plasma low-density lipoprotein cholesterol (LDL-C) concentrations in vervet monkeys (Cercopithecus aethiops) can be modulated by the type and amount of fat in the diet. There is, however, a paucity of information on the effect of different types and quantity of dietary fat on the plasma LDL composition in vervets. The objective of this study was to determine the effect of different sources of dietary fat on the concentrations and composition of circulating plasma LDL in vervets consuming moderate-fat diets containing either animal fat, sunflower oil or palm olein. Fifty adult male vervets, never exposed to a Western-type atherogenic diet, were randomly assigned to two groups. For 6 weeks 30 vervets were fed a moderate-fat (28%E) moderate-cholesterol (26 mg cholesterol/1000 kJ) diet (MFD) with a polyunsaturated to saturated fatty acid ratio (P/S) of 0.4; 20 vervets were fed a high-fat (34%E) high-cholesterol (98 mg cholesterol/1000 kJ) diet (HFD) with a P/S ratio of 0.6. Fasting blood samples were collected from all 50 vervets for plasma lipid measurements. The 30 vervets receiving the MFD were stratified into three comparable experimental groups of 10 each according to their LDL-C and high-density lipoprotein cholesterol (HDL-C) concentrations and bodyweight. One group continued with the MFD, in which 11%E was derived from lard (MFD-AF); in the other two groups the lard was substituted isocalorically with either sunflower oil (SO) (MFD-SO) or palm olein oil (PO) (MFD-PO). The three groups were fed the respective experimental diets for 24 months and LDL component concentrations and composition were assessed at 6-monthly intervals. In the long-term study the MFD-AF, MFD-SO and MFD-PO groups showed no significant time-specific group differences at 6, 12, 18 or 24 months with regard to the LDL component concentrations, composition, as well as the LDL molecular weight. As expected, after 6 weeks of dietary exposure the HFD group had significantly higher plasma and lipoprotein total cholesterol, LDL component and apolipoprotein AI concentrations, as well as a higher LDL-C : HDL-C ratio compared to the MFD group (P 0.0005). LDL particle size was not significantly different between the HFD and MFD groups, but the HFD group had significantly fewer triacylglycerol and significantly more unesterified cholesterol molecules per LDL particle compared to the MFD group (P 0.0018). PO in a MFD is no different from AF or SO in its effect on LDL component concentrations, composition or particle size. The increased LDL-C concentration seen with the HFD could be accounted for by a more than two-fold increase in the number of circulating LDL particles and not as a result of enrichment of particles with cholesterol.
     
  7. Cuesta C, Rodenas S, Merinero MC, Rodriguez-Gil S, Sanchez-Muniz FJ. Lipoprotein profiles and serum peroxide levels of aged women consuming palmolein or oleic acid-rich sunflower oil diets. Eur J Clin Nutr. 1998 Sep; 52(9):675-83

    OBJECTIVE: To investigate the hypercholesterolemic effects of a dietary exchange between 16:0 and 18:1 while 18:2 was at relatively lower level (approximately 4%) in aged women with initially high total serum cholesterol (TC) and low density lipoprotein cholesterol (LDL-C) values and with high intakes of dietary cholesterol. DESIGN: Subjects were assigned to two consecutive 28 d periods. In the first period all subjects followed an oleic acid-rich diet in the form of oleic acid-rich sunflower oil. This was followed by a second period rich in palmitic acid in the form of palmolein. Nutrient intakes, serum lipids, lipoproteins, antioxidant vitamins, peroxides and LDL-peroxides were measured at two dietary periods. SETTING: Instituto de Nutricion y Bromatologia (CSIC), Departamento de Nutricion y Bromatologia I (Nutricion) and Seccion Departamental de Quimica Analitica, Universidad Complutense, Madrid, Spain. RESULTS: The palmolein period led to an increase in TC (P < 0.001; 17.7%) and serum apolipoprotein (Apo) B levels (P < 0.001; 18.0%). LDL-C and LDL-Apo B concentrations were higher (P < 0.001, 4.33+/-0.94 mmol/L and P < 0.01, 1.08+/-0.20 g/L, respectively) following this period than following the oleic acid-rich sunflower oil diet (3.56+/-0.85 mmol/L, 0.93+/-0.16g/L, respectively). No significant differences were observed in the TC/high density lipoprotein cholesterol (TC/HDL-C) ratio between the two dietary periods. Serum and LDL-peroxides were lower (P < 0.01, 49.5%, and P < 0.001, 69.0%, respectively) after the palmolein diet than after the oleic acid-rich sunflower oil diet. The palmolein diet significantly increased TC, LDL-C, Apo B, VLDL-ApoB, LDL-ApoB in women with TC > or = 6.21 mmol/L or with TC < 6.21 mmol/L, but the increase in Apo B, LDL-C and LDL-Apo B was greater among the women with high TC. The palmolein diet increased HDL-C in women with high or with low TC but this rise was on the borderline of statistical significance (P = 0.06) only in normocholesterolemics. Serum and LDL-peroxides tended to be higher in women with TC > 6.21 mmol/L than in women with TC < 6.21 mmol/L, but palmolein decreased serum and LDL-peroxide in hypercholesterolemics more than in the normocholesterolemics, resulting in serum and LDL-peroxide levels which theoretically are more adequate. CONCLUSIONS: Though palmolein increased LDL-C concentrations, it better protected LDL particles, mainly in women with high TC, against peroxidation than did oleic acid-rich sunflower oil.
  1. Qureshi AA, Qureshi N, Wright JJ, Shen Z, Kramer G, Gapor A, Chong YH, DeWitt G, Ong A, Peterson DM. Lowering of serum cholesterol in hypercholesterolemic humans by tocotrienols (palmvitee). Am J Clin Nutr. 1991 Apr; 53(4 Suppl):1021S-1026S.

    A double-blind, crossover, 8-wk study was conducted to compare effects of the tocotrienol-enriched fraction of palm oil (200 mg palmvitee capsules/day) with those of 300 mg corn oil/d on serum lipids of hypercholesterolemic human subjects (serum cholesterol 6.21-8.02 mmol/L). Concentrations of serum total cholesterol (-15%), LDL cholesterol (-8%), Apo B (-10%), thromboxane (-25%), platelet factor 4 (-16%), and glucose (-12%) decreased significantly only in the 15 subjects given palmvitee during the initial 4 wk. The crossover confirmed these actions of palmvitee. There was a carry over effect of palmvitee. Serum cholesterol concentrations of seven hypercholesterolemic subjects (greater than 7.84 mmol/L) decreased 31% during a 4-wk period in which they were given 200 mg gamma-tocotrienol/d. This indicates that gamma-tocotrienol may be the most potent cholesterol inhibitor in palmvitee capsules. The results of this pilot study are very encouraging.
     
  2. Sundram K, Khor HT, Ong AS. Effect of dietary palm oil and its fractions on rat plasma and high density lipoprotein lipids. Lipids. 1990 Apr; 25(4):187-93

    Male Sprague Dawley rats were fed semipurified diets containing 20% fat for 15 weeks. The dietary fats were corn oil, soybean oil, palm oil, palm olein and palm stearin. No differences in the body and organ weights of rats fed the various diets were evident. Plasma cholesterol levels of rats fed soybean oil were significantly lower than those of rats fed corn oil, palm oil, palm olein or palm stearin. Significant differences between the plasma cholesterol content of rats fed corn oil and rats fed the three palm oils were not evident. HDL cholesterol was raised in rats fed the three palm oil diets compared to the rats fed either corn oil or soybean oil. The cholesterol-phospholipid molar ratio of rat platelets was not influenced by the dietary fat type. The formation of 6-keto-PGF1 alpha was significantly enhanced in palm oil-fed rats compared to all other dietary treatments. Fatty acid compositional changes in the plasma cholesterol esters and plasma triglycerides were diet regulated with significant differences between rats fed the polyunsaturated corn and soybean oil compared to the three palm oils.
     
  3. Kesteloot H, Oviasu VO, Obasohan AO, Olomu A, Cobbaert C, Lissens W. Serum lipid and apolipoprotein levels in a Nigerian population sample. Atherosclerosis. 1989 Jul; 78(1):33-8.

    Serum lipids and apoproteins have been measured in 307 men and 235 women living around Benin City in Nigeria. Total serum cholesterol values are low compared both to White Western populations and to American Blacks. HDL-cholesterol levels, however, are comparable to values in Western and Oriental men, but lower than in Western women. A highly significant correlation exists between total cholesterol and apo B and between HDL-cholesterol and apo A-I in men and women. The low serum lipid values are related to a low dietary fat intake, almost exclusively from palm oil, in the Nigerian population.
     
  4. Kritchevsky D, Tepper SA, Bises G, Klurfeld DM. Experimental atherosclerosis in rabbits fed cholesterol-free diets. Atherosclerosis. 1982 Feb; 41(2-3):279-84.

    Rabbits were fed a semipurified, cholesterol-free atherogenic diet containing 40% sucrose, 25% casein, 14% fat, 15% fiber, 5% salt mix and 1% vitamin mix. The fats were corn oil (CO), palm kernel oil (PO), cocoa butter (CB), and coconut oil (CNO). The rabbits were bled at 3, 6, and 9 months and killed at 9 months. Serum lipids of rabbits fed CO were unaffected. Serum cholesterol levels (mg/dl) at 9 months were: CO — 64; PO — 436; CB — 220; and CNO — 474. HDL-cholesterol (%) was: CO — 37; PO — 8.6; CB — 25.1; and CNO — 7.0. Average atherosclerosis (arch + thoracic/2) was: CO — 0.15; PO — 1.28; CB — 0.53; and CNO — 1.60. Cocoa butter (iodine value 33) is significantly less cholesterolemic and atherogenic than palm oil (iodine value 17) or coconut oil (iodine value 6). The difference between the atherogenic effects of cocoa butter and palm oil may lie in the fact that about half of the fatty acids of palm oil are C 16 or shorter, whereas 76% of the fatty acids of cocoa butter are C 18 or longer.
     
  5. Tan DT, Khor HT, Low WH, Ali A, Gapor A. Effect of a palm oil vitamin E concentrate on the serum and lipoprotein lipids in humans. Am J Clin Nutr. 1991 Apr;53(4 Suppl):1027S-1030S.

    The effect of a capsulated palm-oil-vitamin E concentrate (palmvitee) on human serum and lipoprotein lipids was assessed. Each palmvitee capsule contains approximately 18, approximately 42, and approximately 240 mg of tocopherols, tocotrienols, and palm olein, respectively. All volunteers took one palmvitee capsule per day for 30 consecutive days. Overnight fasting blood was taken from each volunteer before and after the experiment. Serum lipids and lipoproteins were analyzed by using the enzymatic CHOD-PAP method. Our results showed that palmvitee lowered both serum total cholesterol (TC) and low-density-lipoprotein cholesterol (LDL-C) concentrations in all the volunteers. The magnitude of reduction of serum TC ranged from 5.0% to 35.9% whereas the reduction of LDL-C values ranged from 0.9% to 37.0% when compared with their respective starting values. The effect of palmvitee on triglycerides (TGs) and HDL-C was not consistent. Our results show that the palmvitee has a hypocholesterolemic effect.
     
  6. Clandinin MT, Cook S L, Konard SD, French MA. The effect of palmitic acid on lipoprotein cholesterol levels. Int. J. Food Sci. Nutr, 2000; 51 S61-S71

    The present study assessed the effect of high versus low palmitic acid intakes of plasma lipoprotein cholesterol levels and on rates for endogenous synthesis of cholesterol in normal and hypercholesterolemic subjects. On day 21 of each diet treatment, a fasting blood sample was drawn for lipoprotein determination and to provide a measure of the background level of deuterium. A priming dose of deuterium was consumed and a second blood sample obtained 24 hours after the first sample. Isotope ratio mass spectrometry was used to determine the incorporation of deuterium into the newly synthesized cholesterol molecule and fractional synthetic rates were calculated. Four diets were formulated to provide combinations of two levels of 16:0 at two levels of 18:2n-6. Subjects received each of the four diet treatments for 21 days, followed by washout periods of 21 days. Serum total cholesterol and LDL-cholesterol was not significantly affected by the high level of 16:0 when diets also contained a high level of 18:2n-6. Fractional synthesis rates of cholesterol observed for each diet treatment did not differ significantly, suggesting no relationship between the endogenous synthesis of cholesterol and dietary 16:0 content. The results indicate that 16:0 has no effect on serum lipoprotein profiles in the presence of recommended intakes for 18:2n-6.
     
  7. Idris CA, Sundram K. Effect of dietary cholesterol, trans and saturated fatty acids on serum lipoproteins in non-human primates, Asia Pac. J. Clin. Nutr, 2002; 11 (suppl) S408-S415

    Nine cynomolgus monkeys were rotated randomly through four dietary treatments with each treatment lasting 6 weeks. A wash-out period of 4 weeks was maintained between each dietary rotation. The animals were fed diets containing 32% energy fat derived from palm olein (POL), lauric-myristic-rich oil blend (LM), American Heart Association (AHA) rich oil blend and hydrogenated soybean oil blend (trans). Diets were fed with (phase 1) or without (phase 2) the addition of dietary cholesterol (0.1%). In phase 1, when animals were fed without dietary cholesterol, plasma total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) was significantly raised and high-density lipoprotein cholesterol (HDL-C) was significantly depressed by the trans diets relative to all other dietary treatments. The resulting LDL-C/HDL-C ratio was also significantly increased. The LM diet increased TC significantly relative to the AHA diet while LDL-C was significantly increased compared to both POL and AHA. Apolipoprotein (apo) B was not affected significantly by these dietary treatments. Apo A1 was significantly increased by POL relative to all other dietary treatments. The trans diet reduced apo A1 and the resulting apo B/A1 ratio was increased significantly by trans relative to all other dietary treatments. Addition of 0.1% dietary cholesterol to these diets almost doubled the plasma TC and LDL-C in all dietary treatments. However, HDL-C was only marginally higher with the addition of dietary cholesterol. The LM + C (cholesterol added) diet resulted in the highest TC and LDL-C that was significant compared to all other dietary treatments. Trans + C increased TC compared to POL + C and AHA + C diets while increases in the LDL-C did not attain significance. The addition of dietary cholesterol did not affect HDL-C between treatments whereas plasma triglycerides were significantly increased by the trans + C diet relative to all other treatments. Both the trans + C and LM + C diets increased apo B and decreased apo A1 relative to the POL + C and AHA + C diets. The resulting apo B/A1 ratio was similarly altered. These results affirm that the lauric + myristic acid combination, along with trans fatty acids, increased lipoprotein-associated coronary heart disease risk factors compared to either POL or AHA.
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