Brain development essential fatty acids

Human milk is rich in essential fatty acids of both the omega-3 and omega-6 families. This suggests that the activity of the A -desaturase may be too low in the infant to provide a sufficient amount of these fatty acids for development of tissues, particularly the brain and retina. It has been shown that development of visual acuity in infants is dependent upon the presence of docosahexaenoic acid in mother s milk. Hence, it is recommended that breastfeeding should be carried out for as long as 12 months after birth. These fatty acids are now added to commercial infant feeds (Chapter 15, Table 15.8). 

Pawlosky, R. J., Ward, G-, and Salem, N, (1996), Essential fatty acid uptake and metabolism in the developing rodent brain. Lrpi ifs 31, S103—5107. 

Sources of Essential Fatty Acids for the Developing Brain... 

Menon NK, Dhopeshwarkar GA. Essential fatty acid deficiency and brain development. Prog Lipid Res 1982 21 309-326. 

Uauy R, Hoffman DR. Essential fatty acid requuements for normal eye and brain development. Semin Perinatol 1991 15 449 455. 

Wainwright P. Do essential fatty acids play a role in brain and behavioural development Biol Behav Rev 1992 16 193-205. 

A number of reports indicate that at least a portion of schizophrenic patients have reduced levels of PUFA, particularly ArAc and DHA, in red cell phospholipids, with low levels particularly associated with negative symptoms (Horrobin, 2002). ArAc, DHA and EPA are important for monoaminergic neurotransmission, brain development, and synaptic functioning (Berger et al., 2006). This suggests that supplementation with essential fatty acids could alleviate symptoms of schizophrenia. In preliminary studies, however, DHA essentially had no effect and ArAc appeared to worsen symptoms in some... 

Crawford, M.A., Hassam, A.G., and Stevens, P.A. (1981) Essential Fatty Acid Requirements in Pregnancy and Lactation with Special Reference to Brain Development, Prog. Lipid Res.20,3l Q. 

Fat is needed in pregnancy to snpply sufficient energy as well as precursors for essential fatty acids needed for fetal brain development. In pregnancy, about 30-35 % of calories should come from fat. For a 2,400-cal diet, this translates to 93 g of fat, the equivalent to approximately six tablespoons of fat. For expectant mothers on a fat-free or low-fat medical food, special attention must be paid to providing other sources of dietary fat. 

The developing brain accumulates long-chain (C20 and C22) polyenoic fatty acids, particularly during cell division (Crawford Sinclair, 1972 Sinclair Crawford, 1972). Vz novo synthesis of these acids does not occur in higher animals and they are derived either directly from food or by metabolism from the parent essential fatty acids, linoleate and a-linolenate. 

The results demonstrate that the fetus is not simply dependent on maternal food intake, but that both placenta and fetus actively reprocess the essential fatty acids with the result that long-chain polyenoic acids are incorporated into the developing brain lipids. Although this process is clearly of great importance to brain development, the conversion of a —linolenic acid to docosahexaenoic acid is slow. A low desaturation rate of parent essential fatty acids is consistent with the Zn )iXKO studies reported by Professor Brenner and Dr. Sprecher earlier in this conference and with our iyi )AJ00 observations in the rat (Hassam, Sinclair Crawford, 1975 Hassam Crawford, 1976 Hassam, Rivers Crawford, 1976). In the cat the desaturase was not detected (Rivers, Sinclair Crawford, 1975) iyi )lvo. 

The fourth section is composed of several contributions on essential fatty acids in human nutrition, diet, brain, developing retina, and testes, as well as on enzymological studies. 

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