“Sustaining Healthy Lifestyles from Fats and Bioactives”
Summary of Session 3
Palm oil fatty acids: Busting the myths associated with saturated fatty acids.
MPOC recently held the Virtual Palm International Nutra-Cosmeceutical Conference (PINC 2021), where speakers highlighted the current scientific understanding on the impact of saturated fatty acids consumption on human health. Palm oil consumption and its effects on serum lipid levels and cardiovascular disease in humans is still a subject of debate because it contains palmitic acid, which is a saturated fatty acid. Up to now, there is no solid evidence linking saturated fat to heart disease or stroke.
The understanding of saturated fat consumption would raise blood cholesterol level and thereby increase the risk of heart disease is currently being reassessed. The health agencies advocated for reduction in fat intake, including saturated fat intake, as a means to lower cardiovascular disease burden. However, over the last four decades, increase in obesity and diabetes as well as rise in metabolic syndrome has resulted in numerous challenges to the saturated fat theory. Current research findings show that the interaction between dietary fat, blood cholesterol and heart disease are complex and dynamic. Dr. Pramod Khosla presented several scientific findings which show the neutral effect of saturated fat in the diet on total blood cholesterol/HDL ratio. He explained that trans fatty acids from partially hydrogenated vegetable oil is the only fat that shows the worst outcomes for heart disease and also diabetes. The associations of saturated fat and heart disease as well as ischemic stroke are currently less convincing scientifically. He added that in the early years of the debate, the role of carbohydrates was given less attention. Studies show that highly processed carbohydrates are actually more harmful to health than saturated fats. The effects of saturated fat on health are dependent both on the presence of other nutrients and the associated dietary pattern. Dr. Pramod Khosla stressed that research is needed to provide evidence-based dietary recommendations on multiple dietary patterns. He concluded that roles of saturated fat should not be viewed in isolation and dietary guidelines need to be reconciled with specific dietary patterns.
Cardiovascular disease (CVD) contributes heavily to mortality amongst non-communicable diseases (NCDs). For years CVD prevention in the population advocated saturated fat reduction to target LDL-C lowering. With the clustering of cardiometabolic risk factors within the NCDs, termed as metabolic syndrome (MetS), the public health approach is towards ‘whole foods’ whilst still emphasizing saturated fat reduction. This centric view on dietary fats is now disputed with evidence suggesting that carbohydrate may perhaps be the culprit in contributing to mortality from CVD.
In the Global Burden of Disease ranking, dietary risks contribute substantially to the development of the NCDs, and this risk is the highest for Malaysia in the South East Asian Region (SEAR). Concerns are raised about its contribution to CVD and MetS risks as Malaysian population largely consumes palm oil. The diet-disease evidence traditionally addresses single nutrient approaches but examining population diets in the context of heterogeneous dietary habits and ethnicity is vital to generate relevance to dietary messaging in food-based dietary guidelines. A ‘meal centric’ approach enables identifying dietary patterns within local populations revealing food combinations within dishes and meals, and the ‘eating mode’.
Given the knowledge gap between dietary consumption patterns and CVD and MetS risks in the predominantly palm oil consuming Malaysian population, Prof. Tilakavati and her team undertook the Malaysia Lipid Study (MLS) with an urban-living cohort to address key questions related to dietary macronutrients’ consumption and their associations with CVD and MetS risks. Primary analysis assessed the pattern of carbohydrate-fat contributions to total daily energy intake from consumed diets. Secondary analyses assessed the diet-food matrix in terms of dietary patterns, to elucidate the ‘eating mode’ as determined by lifestyle and cultural diversity. This presentation highlights research outputs from the MLS which will inform prevention strategies to drive health promotion inclusive of locally specific personal medicine approaches.
According to Prof. Tilakavati, these MLS data overall support the hypothesis that cardiometabolic health may benefit to a greater extent with restrictions on carbohydrate consumption rather than total fat. Experimental reduction in dietary carbohydrates in human studies was shown to lead to improvements through reduced TAG and increased HDL-C, overall MetS and diabetes, even without weight loss or even in the presence of high saturated fat intake. Their findings suggest a potential role for adjusting fat-carbohydrate dietary combinations in modulating insulin resistance and atherogenic risk in the Malaysian population. High carbohydrate intake (>285g) coupled with high fat (>70g) consumption was associated with negative impacts on CVD risk, especially on dyslipidemia and hypertension2.
This finding is also in accord with emerging evidence highlighting a prominent role for carbohydrates in CVD risk as opposed to total or saturated fat alone. She also added that our traditional understanding of dietary factors and accompanying dietary recommendations for CVD management may require reassessment in light of this and other emerging evidence.
In comparison to other vegetable oils, the palm oil is known to tick almost all the boxes- it is low cost, stable against oxidation, versatile, provides good texture and neutral taste and has long shelf life. The association between saturated fat intake and coronary and all-cause mortality has been questioned by recent meta-analyses3. According to Dr. Franca Marangoni, Meta analyses have shown that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of coronary heart disease (CHD) or cardiovascular diseases (CVD). Also, it is found that there is no association between the intakes of saturated fat and total fat with cardiovascular risk. Another finding has further demonstrated that a higher consumption of dietary saturated fatty acids (SFA) is associated with a lower risk of stroke, and every 10g per day increase of SFA is associated with a 6% of relative risk reduction in the rate of stroke. No statistical correlation was found between palmitic acid of more than 10% of total calories and coronary heart disease, according to another study. Palm oil as a substitute of mono-unsaturated and poly-unsaturated fatty acids does not significantly affect the lipid profile in young people, nor in people consuming diets with less than 35% of total fat of total calories, which is an upper-limit by most dietary guidelines. Due to high melting point, SFA is solid at body temperature-and due to this they are not efficiently absorbed and are largely excreted along with faeces. Health effects of dietary risks across 195 countries were studied in which the first 15 dietary factors related to mortality rate were identified-and excess saturated fatty acids is not one of them. In the same study, it was deduced that the factors were all relating to the lack of specific nutrients rather than its excess. The stereospecific distribution of saturated fat in palm oil triglycerides suggests that the biological effects of saturated fatty acids in palm oil might be less relevant than those expected based on pure composition data. Palm oil intake does not appear to be a public health priority as a source of saturated fat, within the limit of intakes indicated by national and international dietary guidelines, as part of a healthy and balanced diet.