Impact of quality of dietary fat on serum cholesterol and coronary heart disease: Focus on plant sterols and other non-glyceride components.

Elevated serum low density lipoprotein (LDL) cholesterol is a strong risk factor for coronary heart disease; dietary as well as therapeutic regimens target reduction of serum LDL cholesterol to decrease the morbidity and mortality of coronary heart disease. The fatty acid composition of dietary fat has a marked impact on serum LDL cholesterol and other risk factors of dietrelated chronic diseases (metabolic syndrome, diabetes and coronary heart disease). Besides fatty acids, which constitute >95% of their content, fats in foods contain other fat-soluble chemicals collectively called non-glyceride components. Sterols are a major part of the non-glyceride components of fats in plant foods and get concentrated in vegetable oils. Current evidence suggests that properly solubilized plant sterols or stanols incorporated in ester or free form in various food formulations effectively restrict the absorption of both dietary and biliary cholesterol causing 10%–14% reduction in serum LDL cholesterol in normal, hyperlipidaemic and diabetic subjects. The carotenoid-lowering effect of foods enriched with plant sterols can be corrected by increasing the intake of foods rich in carotenoids. The use of foods enriched with plant sterols as a part of a heart-healthy diet is recommended only after consulting a clinician. Recent studies strongly suggest that even smaller amounts of sterols available from natural plant foods and vegetable oils are important dietary components for lowering serum LDL cholesterol. Furthermore, some of the other non-glyceride components of food fats have one or more of the following functions—vitamin activity, serum LDL cholesterol-lowering and antioxidant activity. Since the hypocholesterolaemic and antioxidant effects of a combination of the non-glyceride components may be more than their individual effects, increasing dietary plant sterols and nonglyceride components from natural plant foods and vegetable oils could provide an additional dietary means for prevention/ correction of dyslipidaemia and increasing the antioxidant potential of human diets. The food-based dietary guidelines recommended to ensure an optimal fat quality in the diet of Indians provide high levels of natural plant sterols and other health-promoting non-glyceride components in addition to adequate absolute levels of individual fatty acids and their optimal balance. National policies to promote these dietary guidelines may contribute to the prevention of coronary heart disease and other diet-related chronic diseases.

Requirements of dietary fats to meet nutritional needs & prevent the risk of atherosclerosis--an Indian perspective.

To arrive at the fat requirements for Indians, invisible fat and fatty acid compositions were determined in commonly consumed foods. Taking into account the WHO guidelines and the invisible fat intake of Indians, the visible fat requirements according to age, physical activity and physiological status were calculated. The data from both dietary and plasma fatty acids showed that while the requirements of linoleic acid (18:2 n-6, LA) were fully met due to their high levels in cereals and many vegetable oils, alpha-linolenic acid (18:3, n-3 ALNA) intakes were low. Long-term high intakes of ALNA or long chain n-3 polyunsaturated fatty acids (LCn-3 PUFA) reduce the risk of coronary heart disease (CHD). Metabolic studies were therefore conducted in Indian subjects to investigate the effects of using fish oils (LC n-3 PUFA) and ALNA rich oils (canola oil and mustard oil, MO) in comparison to oils which have negligible ALNA (groundnut oil, GNO and palmolein, PO) on plasma lipids, essential fatty acid (EFA) status and platelet aggregation. The results showed that at a level of 6-7 energy per cent LA, about 0.2 to 0.5 energy per cent LC n-3 PUFA or 1.4 energy per cent ALNA produced anti-atherogenic effects. However, high levels of erucic acid (22:1, EA) present in MO prevented these beneficial effects. Since absolute levels as well as the ratio of n-6 to n-3 PUFA are essential for optimal health, the use of more than one oil (correct choice) is recommended. However, it is necessary to evaluate the long-term health benefits of the recommended oil combinations before permitting commercial preparation and endorsing health claims. Regular consumption of plants foods which are good sources of ALNA can also contribute to improving n-3 status. Non-vegetarians, however, have the choice of eating fish to accomplish this.

Nutrition & health implications of palm oil in Indian diets.

To boost the edible oil production and attain self-sufficiency, one of the long-term strategies undertaken by the Indian government is promotion of palm oil production through oil palm cultivation. Compared to other traditional oils (except coconut oil) used in India, palm oil and palmolein have high saturated fatty acids and low linoleic acid levels. Studies conducted to evaluate the nutritional and health implications of substituting other oils with palmolein show that despite having low linoleic acid, the use of palm oil may not adversely affect the linoleic acid status of Indian population. Substitution of groundnut oil with palmolein in cereal based lactovegetarian diets providing about 30 per cent total fat calories, doubles the saturated fatty acids and reduces by half the linoleic acid content. The effects of this substitution in volunteers from the middle income group did not raise serum cholesterol and aggregability of platelets indicating that palm oil may not produce the deleterious effects associated with saturated fatty acids. The tocols present in palm oil are natural biological antioxidants and can therefore augment the antioxidant potential of Indian diets. Red palm oil is the richest natural source of carotenes which are powerful biological antioxidants. The major carotene in red palm oil is beta-carotene. Therefore, red palm oil can be used to prevent vitamin A deficiency which is widespread in India.