A Butter Diet Induces Higher Levels of n-3 PUFA and of n-3/n-6 PUFA Ratio in Rat Serum and Hearts than a Safflower Oil Diet

The effects of a 47-week diet of butter of safflower oil as fat in combination with casein or soy protein as protein were observed for the serum concentrations of lipids and fatty acid compositions in rat serum and heart. Serum total cholesterol (Chol) did not differ among the four experimental diet groups. In the butter groups, significantly higher low-density lipoprotein (LDL)-Chol and lower high-density lipoprotein (HDL)-Chol were observed than in the safflower oil groups (p<0.005, respectively). Higher levels of α-tocopherol were found in the butter groups than in the safflower oil groups (p<0.05) and in the casein groups than in the soy protein groups (p<0.01). In comparison with the safflower oil groups, the butter groups showed higher n-3 polyunsaturated fatty acids (PUFA) contents and lower n-6 PUFA contents in serum and the hearts (p<0.005).The ratios of n-3/n-6 PUFA in the butter groups in serum, 0.26 and 0.18, and in the hearts, 0.37 and 0.36, (butter-casein diet and butter-soy protein diet, respectively) were higher than those of the safflower oil groups of under 0.01 in serum and 0.02 and 0.03 in the hearts (safflower oil-casein diet and safflower oil-soy protein diet, respectively) (p<0.005). In the soy protein groups, higher n-3 PUFA contents in the hearts were found than those of the casein groups (p<0.05). This study suggested that the butter diet induces higher levels of n-3 PUFA and a higher n-3/n-6 PUFA ratio than the safflower oil diet in rat serum and hearts over a long feeding period.

Lower Eicosapentaenoic Acid and Higher Arachidonic Acid Levels in Sera of Young Adults in the Netherlands than in Japan

To survey risk factors in coronary heart disease, we compared serum fatty acid composition and lipids for university students in Japan (33 males and 29 females) and in the Netherlands (20 males and 19 females). No significant differences were found between the mean levels of cholesterol (Chol) and triglycerides (TG) between the subjects in the two countries. The mean levels of polyunsaturated fatty acid (PUFA), monounsaturated fatty acid (MUFA) and saturated fatty acid (SFA) of Japanese students were similar to those of the Dutch students. In both countries, the levels of Chol showed a positive correlation with the levels of PUFA, n−6 PUFA, linoleic acid (C18: 2n−6), and arachidonic acid (AA, C20: 4n−6) but no correlation with the percentages of PUFA and the ratio of PUFA/SFA. On the other hand, the TG levels correlated inversely with the percentage of PUFA and the ratios of PUFA/SFA in both countries. When compared to those of Japanese students, low eicosapentaenoic acid (EPA, C20: 5n−3) and high AA were found in the Dutch students (p < 0.001, respectively). The total amounts of n−3 PUFA in the Dutch were significantly lower than those in the Japanese (p < 0.001) but no differences among those of n−6 PUFA. The ratios of EPA/AA and n−3/n−6 PUFA of the Dutch students were lower than those of the Japanese students (p < 0.001, respectively). The ratio of EPA/AA showed a positive correlation with EPA but not with AA in both countries. The levels of Toc which will decrease the risk of coronary vascular disease (CVD) were lower in Japan than those in the Dutch in both sexes (p < 0.01, respectively). These results suggest that the low EPA and high AA levels and the low n−3/n−6 PUFA ratio may lead to greater incidence of CVD.