The effect of diet upon the fatty acid composition of optic and trigeminal nerve lipids

Brain phospholipids as dietary source of (n-3) polyunsaturated fatty acids for nervous tissue in the rat

In a previous work, we calculated the dietary alpha-linolenic requirements (from vegetable oil triglycerides) for obtaining and maintaining a physiological level of (n-3) fatty acids in developing animal membranes as determined by the cervonic acid content [22:6(n-3), docosahexaenoic acid]. The aim of the present study was to measure the phospholipid requirement, as these compounds directly provide the very long polyunsaturated fatty acids found in membranes. Two weeks before mating, eight groups of female rats (previously fed peanut oil deficient in alpha-linolenic acid) were fed different semisynthetic diets containing 6% African peanut oil supplemented with different quantities of phospholipids obtained from bovine brain lipid extract, so as to add (n-3) polyunsaturated fatty acids to the diet. An additional group was fed peanut oil with rapeseed oil, and served as control. Pups were fed the same diet as their respective mothers, and were killed at weaning. Forebrain, sciatic nerve, retina, nerve endings, myelin, and liver were analyzed. We conclude that during the combined maternal and perinatal period, the (n-3) fatty acid requirement for adequate deposition of (n-3) polyunsaturated fatty acids in the nervous tissue (and in liver) of pups is lower if animals are fed (n-3) very long chain polyunsaturated fatty acids found in brain phospholipids [this study, approximately 60 mg of (n-3) fatty acids/100 g of diet, i.e., approximately 130 mg/1,000 kcal] rather than alpha-linolenic acid from vegetable oil triglycerides [200 mg of (n-3) fatty acids/100 g of diet, i.e., approximately 440 mg/1,000 kcal].

Do essential fatty acids play a role in brain and behavioral development?

The membrane phospholipids of the brain contain high levels of polyunsaturated fatty acids (PUFA), particularly arachidonic acid, 20:4n-6 and docosahexaenoic acid, 22:6n-3. These long-chain PUFA are synthesized from their respective essential fatty acid (EFA) precursors, linoleic acid, 18:2n-6 and linolenic acid, 18:3n-3. Although the necessity of n-6 fatty acids for optimum growth has been established, a similar requirement for those of the n-3 family is less clear. The rapid accumulation of the long-chain n-3 PUFA in the brain during prenatal and preweaning development suggests that the provision of n-3 fatty acids to the developing brain may be necessary for normal growth and functional development. The intent of this review is to assess the experimental work which addresses this question, most of which has been conducted on rodents. The emphasis will be on studies which measure behavioral outcomes, and particular attention will be paid to methodological issues which affect the interpretation of these data. An integration of the research findings will be presented and discussed in light of possible implications for therapeutic interventions.