“Sustaining Healthy Lifestyles from Fats and Bioactives”
Summary of Session 4
Current challenges and emerging issues in palm oil nutrition
During the recent Virtual Palm International Nutra-Cosmeceutical Conference (PINC 2021), speakers highlighted current challenges and emerging issues in palm oil nutrition. In the fourth and final session, the trend of plant biofortification, guidelines of dietary fats, and the relationship between consumption of saturated fat and increased risk of coronary heart disease were discussed.
Malnutrition persists at unacceptably high levels on a global scale, in different forms . The question that remains is how to provide adequate macro and micronutrients to millions of people with insufficient food and nutrients? According to Dr. Pressman1 , biofortification can be among the solutions to solve the global issue of malnutrition where one in every nine people in the world is hungry, and one in every three is overweight or obese. Biofortification is a process of increasing the density of minerals and vitamins in a food crop through conventional plant breeding, genetic engineering, or agronomic practices (e.g., primarily via use of fertilizers and foliar sprays).
There are multi-technology approaches in biofortification. For example, genetic engineering enables creation of a single DNA cassette, harboring information to allow increase in multiple micronutrients (vitamins and/or minerals) as well as favorable agronomic traits, possibly in combination with (conventional) breeding. The cassette can be targeted to a specific genomic location in multiple local cultivars of a crop plant of interest, e.g. rice. Micronutrient deficiency is a silent epidemic condition—it slowly weakens the immune system, stunts physical and intellectual growth, and even causes death. Among micronutrient deficiencies, iron deficiency or iron deficiency anemia (IDA), zinc deficiency, and vitamin A deficiency (VAD) are widespread and cause serious consequences. To combat these deficiencies, fortification of food with different biological and chemical supplements and the alterations of the food processing system are essential. As a staple food crop, the biofortification of rice (including bioengineered) is a sustainable alternative that can be highly beneficial for people who have limited access to varied dietary resources. Genetically modified (GM) rice, particularly pro-vitamin A rice engineered with three genes driven by endosperm specific promoters, expressing in endosperm known as “Golden Rice,” and similarly engineered high iron rice with ferritin gene, may meet to fight against “hidden hunger”.
Dr. Pressman suggested that biofortification can be done for palm oil too. Certain criteria must be met before new lines of micronutrient-enriched staple food crops, such as palm oil, are distributed globally to national agricultural research programs. These criteria include; crop productivity (i.e. yield) must be maintained or increased to guarantee widespread farmer acceptance; the micronutrient enrichment levels achieved must have significant impact on human health; the micronutrient enrichment traits must be relatively stable across various edaphic environments and climatic zones; the bioavailability of micronutrients in enriched lines must be tested in humans to ensure that they improve the micronutrient status of people preparing and eating them in traditional ways within normal household environments; and consumer acceptance must be tested (taste and cooking quality must be acceptable to household members) to ensure maximum impact on nutritional health. As far as palm oil is concerned, the biofortification of fatty acids can be carried out as well. Improvement of fat quality traits will give rise to additional crop value in the consumer markets. A study was conducted to identify candidate genes and transcription factors affecting iodine value and fatty acid composition in palm oil. The identified genes and transcription factor have provided valuable information on several potential candidate genes and a transcription factor which are known in other species to strongly influence the biosynthesis of fatty acids and triglycerides. The biofortification of palm oil can ultimately lead to an improved fatty acid profile, where saturated fatty acid level can be controlled to an optimum level, and the level of bioactives such as carotenoids and tocotrienols can be increased. This can lead to wide dietary acceptance and completely eliminate the link between cardiovascular disease risk and palm oil.
Since 1980, consumers have been advised to reduce dietary saturated fat to diminish the risk of cardiovascular disease. This lipid hypothesis was the foundation for the seven-countries study conducted in the 1940s and yet remains controversial although this work is not without its critics and supporters. Over the past decade, numerous clinical trials, observational studies and meta-analyses conducted indicate that reducing the intake of saturated fats in the diet shows no beneficial effect on health on reducing the risk of cardiovascular disease and total mortality. At the same time, when assessing risk of stroke and heart attacks, many substitution studies yield different results. It remains important to consider foods that represent complex matrices, which contain a vast array of nutrients and even phytochemicals that, if routinely consumed in adequate amounts, may improve health outcomes among some individuals. Dr Clemens commented that, as risk factors associated with dietary saturated fat remain contentious, the quality and quantity of evidence deserve careful scrutiny especially when one considers that each fatty acid has unique functions, and that not all saturated fatty acids (SFAs) contribute to heart disease2.
He also added that different SFAs have different biologic effects, which are further modified by the food matrix and the carbohydrate content of the diet. Saturated fatty acids give functional properties to foods and provide energy thus should not be avoided completely. In his presentation, Dr Clemens discussed the Prospective Urban Rural Epidemiology (PURE) study, a large multinational cohort study of individuals aged 35-70 years enrolled from 21 countries in five continents. PURE study reported that high carbohydrate intake was associated with higher risk of total mortality, whereas total fat and individual types of fat were related to lower total mortality. In summary, Dr Clemens mentioned that there is no credible evidence that current population-wide arbitrary upper limits of 10% SFAs in the diet will prevent CVD or reduce mortality. Consuming a variety of natural foods without restricting saturated fatty acids intake would also be beneficial in helping to ensure a nutritionally adequate diet and maintain health.
The low-carbohydrate diet has dominated clinical approaches toward the treatment of obesity and type 2 diabetes until the middle of the 20th century.3 According to Prof. Dr. Diamond, flawed, deceptive and biased research, which began in the middle of the 20th century, led to the dietary advice demonizing saturated fat. An extension of this misconception was the claim that consumption of tropical oils such as coconut and palm oil would elevate blood cholesterol and thereby cause heart disease. He explained that the dietary advice, however, was made based on poorly conducted epidemiological research, government intervention and industry-based financial conflicts of interest. In recent decades, high-quality dietary studies have demonstrated that the low-carbohydrate diet reduces high blood glucose, ideal for weight loss and further leads to healthy levels of blood cholesterol. With regards to palm oil, which has been categorized as tropical oil, a recent meta-analysis confirmed that palm oil consumption has no negative impact on heart disease risk factors such as total cholesterol, bad LDL-cholesterol and triglyceride concentrations. Data published in the British Journal of Nutrition showed an inverse relationship between death rate from heart disease and dietary saturated fat intake. Countries whose saturated fat intake was higher showed a lower heart disease mortality rate. He described that the obesogenic and atherosclerotic components of the “Modern” diet are refined carbohydrate, sugar and trans fat. The regular consumption of food high in processed carbohydrates and sugar coupled with hydrogenated fats high in trans fatty acids in our “Modern” diet contributes to an increase in obesity, heart disease and diabetes. He added that the promotion of low-fat foods as a healthier choice is completely incorrect because they are loaded with sugar to improve palatability. A whole-food diet consisting of local fruits, plants, seafood and saturated fat from healthy sources was always better than the “Modern” diet. There was no scientific evidence to support the current dietary guidelines which demonise saturated fat. Studies also found that fatal heart disease was not reduced by low-fat diets or by substituting saturated fat with vegetable fat high in polyunsaturated fatty acids. In his conclusion, Prof. Dr. Diamond stressed that the excess consumption of food high in carbohydrate and sugar, which raises serum glucose, rather than food rich in saturated fat is the basis of the current worldwide epidemic in obesity, heart disease and type 2 diabetes.