Relationship of the polyunsaturated to saturated fatty acid ratio to cardiovascular risk factors and metabolic syndrome in Japanese: the INTERLIPID study.

AIM: There have been few studies on the relationships of the dietary polyunsaturated to saturated fatty acid ratio (P/S) to cardiovascular risk factors and metabolic syndrome. We hypothesized that there would be favorable relationships. METHODS: Metabolic cardiovascular risk factors from dietary nutrient intake were investigated in 1,004 men and women aged 40-59 years from 4 population samples of Japanese. Multiple linear regression analysis was used to examine the relationship of the dietary P/S ratio to the following risk factors: hemoglobin A1c, blood pressure, serum triglycerides, LDL and total cholesterol, and HDL-cholesterol. Adjusted odds ratio of having metabolic syndrome was also calculated. RESULTS: The dietary P/S ratio was significantly and inversely related to serum total and LDL cholesterol with control for possible confounding variables. We did not find any significant relationship between the P/S ratio and single metabolic risk factors or the prevalence of metabolic syndrome. CONCLUSIONS: Managing the P/S ratio is important to control serum LDL-cholesterol; however, increasing the P/S ratio may not improve metabolic risk factors. Other countermeasures, such as weight control, greater physical activity, and smoking cessation should be recommended to prevent and control metabolic syndrome.

Relation of long chain n-3 polyunsaturated fatty acid intake to serum high density lipoprotein cholesterol among Japanese men in Japan and Japanese-American men in Hawaii: the INTERLIPID study.

Epidemiologic evidence shows an inverse relationship between fish consumption and coronary heart disease (CHD) mortality. Associations between dietary intake of long chain n-3 polyunsaturated fatty acids (PUFA) and serum high density lipoprotein (HDL) cholesterol concentration are unknown. In this study, the association between n-3 PUFA (eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA) and docosapentaenoic acid (DPA)) intake and serum HDL cholesterol among Japanese men and women in Japan and Hawaii was examined. The study population consisted of Japanese ancestries from five research centers of the International Study of Macronutrients and Blood Pressure (INTERMAP) study, in Japan and Hawaii (672 men and 676 women), surveyed between 1996 and 1998. Four 24-h dietary recalls and one set of serum lipid measurements were performed. For men, n-3 PUFA intake and HDL cholesterol were higher in Japan than in Hawaii (n-3 PUFA: 1.32 g/day versus 0.47 g/day, p<0.001). For women, n-3 PUFA intake was higher in Japan than in Hawaii (p<0.001) but HDL cholesterol was not significantly different (p=0.752). After adjustment for age, body mass index, physical activity, number of cigarettes per day, alcohol intake, and hormone replacement therapy (for women), n-3 PUFA intake was positively associated with serum HDL cholesterol in men (4.6 mg/dl higher HDL cholesterol with 1%kcal higher n-3 PUFA intake, p=0.011). This association was not observed in women. This positive association of dietary n-3 PUFA with serum HDL cholesterol may partially explain the low mortality from CHD among Japanese men.