Studies of arteriosclerosis in Japanese and American men. I. Comparison of fatty acid composition of adipose tissue.

The proportions of fatty acids in lipids of subcutaneous adipose tissue was compared in closely age-matched, urban men from two populations with a great difference in mortality from arteriosclerosis, namely in 50 Americans and 56 Japanese aged 15-65 yr who had died suddenly and unexpectedly. Specimens from both groups were analyzed side by side for fatty acids by gas-liquid chromatography. Compared with Japanese, Americans had significantly (P<0.01) higher proportions of lauric (+ 0.2%), myristic (+ 0.4%), palmitic (+ 1.4%), stearic (+ 2.2%), and oleic (+ 5.3%) and lesser of palmitoleic (- 1.8%), linoleic (-6.3%), and linolenic (-0.4%) acids. Japanese had higher proportions of longer chain polyunsaturated fatty acids. The distributions of fatty acids for the groups at ages 35-44 yr had significant differences. With age, Americans showed significant increases of palmitic and oleic acids and decreases of lauric, myristic, stearic, and linoleic acids; Japanese showed no correlations of proportions of fatty acids with age. The significant correlations between per cent standard body weight and fatty acids in Americans were positive for palmitic and negative for lauric and stearic acids, and in Japanese, negative for myristic acid. The patterns of interacid correlations were dissimilar for the groups. These patterns may be stable characteristics of these groups providing further insight into their fatty acid metabolism. The relationships with the fatty acid compositions of the American and Japanese diets are discussed.