Alpha-linolenic Acid Content Research Articles

Dietary manipulation by perilla oil and fish oil of hepatic lipids and its influence on peroxisomal beta-oxidation and serum lipids in rat and mouse.

Rats and mice were fed a diet, prepared with soybean oil (SO), perilla oil (PO) or fish oil (FO), for 4 weeks. Compared with the groups of SO-feeding, FO-feeding increased content of eicosapentaenoic acid (20:5 n-3), docosapentaenoic acid (22:5 n-3) and docosahexaenoic acid (22:6 n-3) and PO-feeding elevated the content of alpha-linolenic acid (18:3 n-3), 20:5 n-3 and 22:5 n-3 or hepatic lipids of both rats and mice. FO-feeding increased the activity of peroxisomal beta-oxidation in the livers of both rats and mice. The activities of peroxisomal beta-oxidation in rats and mice that were fed FO diet at a high fat (40% of energy) concentration corresponded to 20% and 30%, respectively, of the maximum activities induced by peroxisome proliferators (4-chlorophenoxyisobutyric acid or perfluorooctanoic acid). To a lesser extent, PO-feeding elevated this activity too. There were significant correlations between peroxisomal beta-oxidation activity and the content of either 20:5 n-3, 22:5 n-3 or 22:6 n-3 in hepatic lipids. FO-feeding decreased effectively serum level of cholesterol of both rats and mice. The reduction in serum cholesterol by feeding PO was less pronounced than that observed with FO-feeding. A high correlation was found between 22:6 n-3 content in hepatic lipids and serum concentration of cholesterol. Although FO-feeding lowered the level of circulating triacylglycerol, PO-feeding produced no change. No substantial correlation was observed between the hepatic content of n-3 fatty acid and the concentration of serum triacylglycerol.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of low level flaxseed suplementation on the fatty acid composition of mammary glands and tumors in rats

The high alpha-linolenic acid (ALA; C18:3n-3) content of flaxseed oil and the observed protective effects of omega-3 fatty acids on cancer have led to the hypothesis that the fatty acid composition of flaxseed may render it protective against cancer. Previous studies have suggested that supplementation of a basal high-fat diet with flaxseed flour (FF) at the 5% level may influence the risk for mammary carcinogenesis but it is unknown whether the fatty acid composition of its oil (1.9% in the diet) contributed to this effect. This study showed that feeding 5% FF significantly increased the ALA and decreased the C22:5n-6 contents of the mammary glands and tumors of carcinogen-treated rats and the mammary gland of the non-carcinogen treated rats. There were small but insignificant effects on the endogenously synthesized long chain fatty acids (e.g. 16:0, 16:1n-7, 18:0 and 18:1n-9) and the longer chain unsaturated fatty acids (e.g. 20:5n-3 and 22:6n-3) derived as a result of chain elongation and desaturation of ALA. The results suggest that the fatty acid composition of the mammary tissues and tumors may be affected even at low level of flaxseed oil, and that this oil may have a role in the observed effect of flaxseed on tumorigenesis. Further studies are required to explore this possibility.

Polyunsaturated Fatty Acids in Adipose Tissue in European Men Aged 38 Years in Relation to Serum Lipids, Smoking Habits, and Fat Distribution

Fat biopsies were taken from 327 men aged 38 years from five different European communities in 1988-1989. Linoleic acid content varied widely (F = 110.6, p less than 0.001) and was lowest in men from Poland (8.6%) and highest in men from Belgium (16.7%). Adipose tissue content of alpha-linolenic acid was subject to less variation (F = 13.9, p less than 0.001) and was lowest in men from Italy (0.5%) and highest in men from Sweden and the Netherlands (0.9%). In analysis combining information from all centers, linoleic acid was negatively correlated to low density lipoprotein cholesterol (r = -0.15, p less than 0.01) and total cholesterol (r = -0.17, p less than 0.01). alpha-Linolenic acid was negatively correlated to serum triglycerides only (r = -0.14, p less than 0.05). These fatty acids were not related to body mass index, waist/hip ratio, or smoking habits. The authors conclude that there are major differences in the fatty acid composition of adipose tissue in different European populations but that these do not explain the significant differences in serum high density lipoprotein cholesterol and serum triglycerides among the different populations.

The Effect of Three Intravenous Fat Emulsions Containing Different Concentrations of Linoleic and α-Linolenic Acids on the Plasma Total Fatty Acid Profile of Neonates

We determined the fatty acid profile of total plasma lipids in infants who received one of three intravenous fat emulsions that differed primarily in their linoleic and alpha-linolenic acid content: (I) a safflower oil emulsion, (II) a 50:50 mixture of safflower and soybean oils, or (III) a soybean oil emulsion. After 2 weeks of fat therapy, oleic acid, expressed as a percentage of total plasma lipid fatty acids, decreased in all groups, but less so in group III (p less than 0.01). The linoleic acid percentage increased in all groups, but group I had the greatest increase (p less than 0.05). Group II patients had higher percentages of the linoleic acid metabolites, dihomo-gamma-linolenic acid (II greater than I, p less than 0.05; II greater than III, p less than 0.01) and arachidonic acid (II greater than III, p less than 0.05). Group II patients also had higher levels of alpha-linolenic acid (II greater than I, p less than 0.05) and its metabolite, eicosapentaenoic acid (II greater than I, p less than 0.05). Another alpha-linolenic acid metabolite, docosahexaenoic acid, however, increased in group III, remained stable in group II, and decreased in group I (III and II greater than I, p less than 0.05). We conclude that the content of linoleic acid and alpha-linolenic acid in intravenous fat emulsions results in statistically significant changes in the fatty acid profile of total plasma lipids in infants receiving total parenteral nutrition.