Gangliosides are sialic acid-containing glycosphingolipids. Gangliosides are found in human milk; understanding of the potential role of gangliosides in infant development is emerging, with suggested roles in the brain and gut. Ganglioside accretion in the developing brain is highest in utero and in early neonatal life, during the periods of dendritic branching and new synapse formation. Further, brain contains the highest relative ganglioside content in the body, particularly in neuronal cell membranes concentrated in the area of the synaptic membrane. Gangliosides are known to play a role in neuronal growth, migration and maturation, neuritogenesis, synaptogenesis, and myelination. In addition to their roles in development and structure of the brain, gangliosides also play a functional role in nerve cell communication. It is less well known whether dietary gangliosides can influence the development of cognitive function. This review summarizes current knowledge on the role gangliosides play in brain development.

The study assessed the effect of low doses of fatty acids from fish or flaxseed oil on plasma lipid concentrations in normal humans consuming diets with either high (0.87, n = 11) or low (0.48, n = 15) dietary polyunsaturated/saturated fatty acid (P/S) ratios. The dose of (n-3) fatty acids reflected an (n-3) intake that could easily be attained by selection of foods in a normal diet. The individuals were initially supplemented with olive oil [35 mg 18:1/(kg body weight.d)], and then were randomly assigned to either flaxseed or fish oil [35 mg 18:3(n-3) or 35 mg 20:5(n-3) + 22:6(n-3)/(kg body weight.d), respectively] treatments. Participants consumed each oil supplement for 3 mo. Blood samples were drawn for analysis at the end of each 3-mo period. Plasma triacylglycerol, total, LDL and HDL cholesterol concentrations, and lipoprotein fatty acid concentrations are shown. Fish oil reduced plasma triacylglycerol and increased lipoprotein levels of 20:5(n-3) and 22:6(n-3). The flaxseed oil did not alter plasma triacylglycerol level and produced small changes in 20:5(n-3) and 22:6(n-3) concentrations. Total, LDL and HDL cholesterol levels were not affected by either (n-3) fatty acid. Significant differences in plasma triacylglycerol concentrations and total and LDL cholesterol levels were found between the two dietary P/S groups after all oil treatment periods. Levels of 18:3(n-3), 20:4(n-6), 20:5(n-3), and 22:6(n-3) in LDL were also different in high vs. low dietary P/S groups for all oil treatments and in the VLDL for the olive oil and fish oil supplementation. This study indicates that low intake of purified fish oil induces changes in plasma triacylglycerol, 20:5(n-3) levels in VLDL, LDL, and HDL, and 22:6(n-3) levels in LDL and HDL that are apparent after 3 mo and which might influence atherogenicity of lipoprotein particles in normal free-living individuals.

It has been suggested that the fat composition of infant formula should provide arachidonic acid [20:4(n-6)] and docosahexaenoic acid [22:6(n-3)] or increased alpha-linolenic acid [18:3(n-3)] to optimize the (n-3) and (n-6) fatty acid content of brain during infant development. This experiment examined the effects of feeding increased levels of 18:3(n-3), 20:4(n-6) and 22:6(n-3) on brain development in neonatal rats. Diets varying in (n-6) and (n-3) fatty acid content with or without 20:4(n-6) or 22:6(n-3), at levels proposed for infant formula, were fed to nursing dams from parturition and subsequently to weaned pups until 6 wk of age. Neuronal and glial cells were isolated from the frontal region, cerebellum and hippocampus of the brain. Fatty acid analyses of ethanolamine- and choline-phosphoglycerides indicated that small changes in the dietary (n-6)/(n-3) ratio significantly altered neuronal and glial membrane fatty acid composition. Brain regions and cell types varied in amount and rate of 20:4(n-6) and 22:6(n-3) accretion. Fatty acid composition of individual phosphoglycerides was distinct and exhibited changes with age. Inclusion of both 20:4(n-6) and 22:6(n-3) in the diet resulted in alteration of brain fatty acid composition reflecting the fatty acid composition of the diet. If analogous developmental changes occur in human brain, then these results imply that addition of 20:4(n-6) and 22:6(n-3) or a reduced 18:2(n-6):18:3(n-3) ratio in infant formula may result in fatty acid profiles of neuronal and glial cells in formula-fed infants similar to those observed in breast-fed infants.

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Results from animal studies indicate that the type of dietary fat consumed has a profound effect on insulin action in tissues. Feeding a semipurified diet high in polyunsaturated to saturated fatty acid (P/S) ratio to insulin-dependent diabetic rats as compared to feeding them a diet low in P/S ratio increased insulin binding and insulin action in adipocytes [1] and skeletal muscle [2,3]. Alteration in the fatty acid composition of plasma membrane phospholipid by dietary P/S ratio has been suggested to be a cause of these changes in insulin action. Beneficial effects of fish oil in preventing the development of insulin resistance in rats caused by a high intake of saturated fatty acids have also been reported [4,5].Individuals with insulin-dependent diabetes mellitus are prone to develop disorders in lipid and lipoprotein metabolism, of which hyperlipidaemia is the most common [6,7]. Elevated plasma triacylglycerol and reduced HDL cholesterol also increase the risk Diabetologia (1997) Summary This study was conducted to examine the effect of w 3 fatty acid supplementation on plasma lipid, cholesterol and lipoprotein fatty acid content of non-insulin-dependent diabetic individuals consuming a higher (0.65, n = 10) or lower (0.44, n = 18) ratio of dietary polyunsaturated to saturated fatty acid (P/ S). The participants were initially given an olive oil supplement (placebo) equivalent to 35 mg of 18:1 ⋅ kg body weight -1 ⋅ day -1 for 3 months. This was followed by two w 3 supplement periods in a randomized crossover. In these 3-month periods, participants were given a linseed oil supplement equivalent to 35 mg of 18:3w3 ⋅ kg body weight -1 ⋅ day -1 or a fish oil supplement equivalent to 35 mg of 20:5w3 + 22:6w3 ⋅ kg body weight -1 ⋅ day -1 . At the end of each supplement period, a blood sample was drawn from each participant for lipid, lipoprotein, insulin, glucagon and C-peptide analyses. At the end of each 3-month period a 7-day dietary record was completed to calculate dietary fat intake and P/S ratio.Results indicate that fish oil significantly reduced plasma triacylglycerol level (p < 0.05) and increased 20:5w3 and 22:6w3 content of all lipoprotein lipid classes. Linolenic acid supplementation had no effect on plasma triacylglycerol level, but it increased 18:3w3 content of lipoprotein cholesterol ester fractions (p < 0.05). A slight increase in 20:5w3, but not 22:6w3, content was noted in lipoprotein lipid classes as a result of 18:3w3 supplementation. LDL and HDL cholesterol, insulin, glucagon and C-peptide levels were not affected by either w 3 supplement. It is concluded that a modest intake of w 3 fatty acids, such as could be obtained from consuming fish regularly, will reduce plasma triglyceride level without affecting LDL or HDL cholesterol levels. [Diabetologia (1997) Corresponding author: Dr. M. T. Clandinin, Nutrition and Metabolism Research Group, Department of Agriculture, Food and Nutritional Science, University of Alberta, 4-10 Agriculture/Forestry Centre, Edmonton, Alberta T6G 2P5, Canada A...