N-3 fatty acids in Indian diets — Comparison of the effects of precursor (alpha-linolenic acid) Vs product (long chain n-3 poly unsaturated fatty acids)

Abstract

Studies were conducted in human volunteers maintained on habitual Indian diets to determine (a) the effective dose of long chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) needed for hypolipidemic and antithrombotic effects and (b) the efficacy of the use of alphalinolenic acid (ALNA), the precursor of LC n-3 PUFA, as a substitute for fish oils. Keeping the levels of linoleic acid constant, the levels of fatty acids were altered either in the form of LC n-3 PUFA or as ALNA. The results show that while 1.4g LC n-3 PUFA may be needed for hypotriglyceridemic effects, 0.6g appears to be sufficient for antithrombotic effects as judged by increase in LC n-3 PUFA levels in plasma and platelet phospholipids, and decrease in platelet aggregation. ALNA supplementation decreased plasma cholesterol levels but, had no effect on triglycerides. The increase in the levels of LC n-3 PUFA in plasma and platelet phospholipids was accompanied by a decrease in platelet aggregation, suggesting that ALNA rich vegetable oils used as a single source of visible fat in Indian diets, is beneficial. On the basis of the absolute increase in LC n-3 PUFA in plasma phospholipids with ALNA and LC n-3 PUFA supplementation, it was calculated that 3.7g ALNA may have biological effects similar to 0.3g LC n-3 PUFA. Therefore, it appears that replacement of part of the vegetable oil intake with mustard/rapeseed oil, so as to furnish n-6/n-3 ratio around 8, may be a feasible approach to ensure beneficial effects of n-3 fatty acids in vegetarians. Further, it also ensures a balanced intake of the other fatty acids.