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The ratio of n-6 to n-3 polyunsaturated fatty acids in the rat diet alters serum lipid levels and lymphocyte functions.
Lipids 1996; 31(7):737-45L

Abstract

Previous studies have reported that feeding rats diets rich in fish oils, which contain high proportions of the n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic and docosahexaenoic acids, results in lowering of blood lipid levels and suppression of lymphocyte functions tested ex vivo and in vivo. The effects of other n-3 PUFA, such as alpha-linolenic acid, which is found in high proportions in linseed oil, are not as well documented. Therefore, in the present study, weanling male rats were fed for six weeks on one of five high-fat (20% by weight) diets made by mixing together sunflower and linseed oils; the resulting blends had n-6/n-3 PUFA ratios of 112.5:1 (pure sunflower oil), 14.8:1, 6.5:1, 0.81:1, and 0.33:1 (pure linseed oil); the levels of all other components in the diet were identical. The final body weight and total dissectable fat were lowest in rats fed the pure linseed oil diet. Serum cholesterol, triacylglycerol and nonesterified fatty acid concentrations decreased as the n-6/n-3 PUFA ratio of the diet decreased. The fatty acid composition of the serum and of spleen lymphocytes was influenced by the diet fed-there was a progressive decrease in the proportions of linoleic and arachidonic acids and a progressive increase in the proportion of alpha-linolenic acid as the n-6/n-3 PUFA ratio of the diet decreased. Eicosapentaenoic and docosahexaenoic acids were detected in the serum but not in spleen lymphocytes. Inclusion of alpha-linolenic acid in the diet resulted in significant suppression of spleen lymphocyte proliferation in response to the T-cell mitogen concanavalin A and in spleen lymphocyte natural killer cell activity, both measured ex vivo. The localized graft vs. host response, a measure of cell-mediated immunity in vivo, progressively decreased as the n-6/n-3 PUFA ratio of the diet decreased. Thus, this study shows that dietary alpha-linolenic acid results in lowered blood lipid levels and suppressed lymphocyte functions ex vivo and in vivo. With respect to these effects, alpha-linolenic acid is as potent as dietary fish oil.

Authors+Show Affiliations

Department of Biochemistry, University of Oxford, United Kingdom.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

8827697

Citation

Jeffery, N M., et al. "The Ratio of N-6 to N-3 Polyunsaturated Fatty Acids in the Rat Diet Alters Serum Lipid Levels and Lymphocyte Functions." Lipids, vol. 31, no. 7, 1996, pp. 737-45.
Jeffery NM, Sanderson P, Sherrington EJ, et al. The ratio of n-6 to n-3 polyunsaturated fatty acids in the rat diet alters serum lipid levels and lymphocyte functions. Lipids. 1996;31(7):737-45.
Jeffery, N. M., Sanderson, P., Sherrington, E. J., Newsholme, E. A., & Calder, P. C. (1996). The ratio of n-6 to n-3 polyunsaturated fatty acids in the rat diet alters serum lipid levels and lymphocyte functions. Lipids, 31(7), pp. 737-45.
Jeffery NM, et al. The Ratio of N-6 to N-3 Polyunsaturated Fatty Acids in the Rat Diet Alters Serum Lipid Levels and Lymphocyte Functions. Lipids. 1996;31(7):737-45. PubMed PMID: 8827697.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The ratio of n-6 to n-3 polyunsaturated fatty acids in the rat diet alters serum lipid levels and lymphocyte functions. AU - Jeffery,N M, AU - Sanderson,P, AU - Sherrington,E J, AU - Newsholme,E A, AU - Calder,P C, PY - 1996/7/1/pubmed PY - 1996/7/1/medline PY - 1996/7/1/entrez SP - 737 EP - 45 JF - Lipids JO - Lipids VL - 31 IS - 7 N2 - Previous studies have reported that feeding rats diets rich in fish oils, which contain high proportions of the n-3 polyunsaturated fatty acids (PUFA) eicosapentaenoic and docosahexaenoic acids, results in lowering of blood lipid levels and suppression of lymphocyte functions tested ex vivo and in vivo. The effects of other n-3 PUFA, such as alpha-linolenic acid, which is found in high proportions in linseed oil, are not as well documented. Therefore, in the present study, weanling male rats were fed for six weeks on one of five high-fat (20% by weight) diets made by mixing together sunflower and linseed oils; the resulting blends had n-6/n-3 PUFA ratios of 112.5:1 (pure sunflower oil), 14.8:1, 6.5:1, 0.81:1, and 0.33:1 (pure linseed oil); the levels of all other components in the diet were identical. The final body weight and total dissectable fat were lowest in rats fed the pure linseed oil diet. Serum cholesterol, triacylglycerol and nonesterified fatty acid concentrations decreased as the n-6/n-3 PUFA ratio of the diet decreased. The fatty acid composition of the serum and of spleen lymphocytes was influenced by the diet fed-there was a progressive decrease in the proportions of linoleic and arachidonic acids and a progressive increase in the proportion of alpha-linolenic acid as the n-6/n-3 PUFA ratio of the diet decreased. Eicosapentaenoic and docosahexaenoic acids were detected in the serum but not in spleen lymphocytes. Inclusion of alpha-linolenic acid in the diet resulted in significant suppression of spleen lymphocyte proliferation in response to the T-cell mitogen concanavalin A and in spleen lymphocyte natural killer cell activity, both measured ex vivo. The localized graft vs. host response, a measure of cell-mediated immunity in vivo, progressively decreased as the n-6/n-3 PUFA ratio of the diet decreased. Thus, this study shows that dietary alpha-linolenic acid results in lowered blood lipid levels and suppressed lymphocyte functions ex vivo and in vivo. With respect to these effects, alpha-linolenic acid is as potent as dietary fish oil. SN - 0024-4201 UR - https://www.unboundmedicine.com/medline/citation/8827697/The_ratio_of_n_6_to_n_3_polyunsaturated_fatty_acids_in_the_rat_diet_alters_serum_lipid_levels_and_lymphocyte_functions_ L2 - https://onlinelibrary.wiley.com/resolve/openurl?genre=article&sid=nlm:pubmed&issn=0024-4201&date=1996&volume=31&issue=7&spage=737 DB - PRIME DP - Unbound Medicine ER -