Unsaturated fatty acids

Abstract

There is good scientific evidence that dietary fatty acid composition is involved in the aetiology of many diseases. Increasing the supply of n−3 polyunsaturated fatty acids (PUFA) may reduce the risk of CHD. Several scientific organizations (for example, see Department of Health, 1991, 1994; British Nutrition Foundation, 1992; Scientific Committee for Food, 1993; Food and Agriculture Organization/World Health Organization, 1998) have made recommendations for n−3 PUFA; however, there is a high degree of variation both in terms of the type and amount of n−3 PUFA (up to 7-fold). This variation reflects the different scientific axioms which underlie the different recommendations. Optimal nutrition may be defined in terms of the level of a nutrient required to avoid deficiency, or the amount required to have an effect on biomarkers and functional indicators of nutrient intake, or the level of a nutrient which prevents disease. Functional biomarkers of n−3 PUFA include plasma, platelet and erythrocyte phospholipid-n−3 PUFA levels. Plasma triacylglycerol concentrations represent a functional indicator of n−3 PUFA because n−3 PUFA exert a consistent hypotriacylglycerolaemic effect which is dose-dependent and persistent. In terms of disease status, epidemiological studies have demonstrated that the incidence of CHD is inversely associated with consumption of n−3 PUFA. Despite the health benefits of n−3 PUFA, the mean daily intake falls far short of most of the recommendations. Increasing fish intake is the most obvious way to increase n−3 PUFA intake. However, a large percentage (up to 65) of the population do not eat fish. Thus, there is a need for alternative sources of n−3 PUFA, such as functional foods, whose unique fatty acid composition could fortify staple foods thereby promoting optimal levels of n−3 PUFA intake.