The interrelated effects of n-6/n-3 and polyunsaturated/saturated ratios of dietary fats on the regulation of lipid metabolism in rats

J. H. Lee, M. Fukumoto, H. Nishida, I. Ikeda, M. Sugano

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82 Citations (Scopus)

Abstract

The effects of various n-6/n-3 (0.45-9.31) and polyunsaturated/saturated (P/S; 0.25-6.08) ratios of dietary fatty acids on various lipid parameters were studied in rats using a combination of palm oil, safflower oil, soybean oil and perilla oil. When the n-6/n-3 ratio was changed while maintaining a constant P/S ratio (1.2), the concentration of serum cholesterol tended to increase linearly with the increasing n-6/n-3 ratio, whereas liver cholesterol tended to decrease. Serum triglyceride level increased linearly up to a n-6/n-3 ratio, ratio of approximately 5, whereas liver triglyceride was not influenced. When the n-6/n-3 ratio was kept relatively constant (5.6-6.4), serum and liver cholesterol levels decreased up to a P/S ratio of approximately 2, whereas serum triglyceride tended to be low below this value. The ratio of arachidonate to linoleate in tissue phosphatidylcholine (PC) was also influenced by the n-6/n-3 and P/S ratios; it increased up to a n-6/n-3 ratio of approximately 4, whereas it decreased up to a P/S ratio of approximately 2. The percentage of eicosapentaenoic and docosahexaenoic acid (n-3) in tissue phosphatidylcholine was positively related to dietary n-3 fatty acid levels. Prostacyclin (PGI2) production by thoracic aorta reached a plateau at a n-6/n-3 ratio of approximately 5, whereas it tended to decrease with an increasing P/S ratio. Platelet production of thromboxane A2 exhibited a parabola-like pattern with a peak value at a n-6/n-3 ratio of approximately 2, whereas it was independent of the P/S ratio. These results indicate that a P/S ratio of approximately 2 and a n-6/n-3 ratio of approximately 5 are the points of maximum influence upon the lipid level and eicosanoid production.

Original languageEnglish
Pages (from-to)1893-1899
Number of pages7
JournalJournal of Nutrition
Volume119
Issue number12
DOIs
Publication statusPublished - 1989 Jan 1
Externally publishedYes

Keywords

  • dietary fat
  • male rats
  • n-6/n-3 ratio
  • phospholipid
  • polyunsaturated/saturated fatty acid ratio
  • prostacyclin
  • serum and liver lipids
  • thromboxane A

ASJC Scopus subject areas

  • Medicine (miscellaneous)
  • Nutrition and Dietetics

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