Elsevier

Atherosclerosis

Volume 178, Issue 2, February 2005, Pages 371-379
Atherosclerosis

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

https://doi.org/10.1016/j.atherosclerosis.2004.09.007Get rights and content

Abstract

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.

Introduction

The low coronary heart disease (CHD) mortality in Japan, where fish is an important component of the diet, suggests that consumption of fish may be protective against the atherosclerotic diseases [1]. An inverse association between fish intake and risk of death from CHD has been found in prospective studies in Western countries [2], but no data on this matter have been reported for Japan.

The putative beneficial effect has been attributed to the long chain n-3 polyunsaturated fatty acids (PUFA), eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3) for which the main dietary sources are fish, shellfish, and marine mammals [3], and fatty fish intake has been reported to be protective against CHD [4]. In many n-3 PUFA supplementation studies, significant lowering of triglycerides was observed [5], [6], [7], but the effect on high density lipoprotein (HDL) cholesterol has been reported variously to be decrease [5], increase [5], [7] and none [6], [8]. Moreover, studies concerning associations between dietary fish intake and HDL cholesterol of individuals are sparse and their findings inconclusive [9], [10].

In Japan, westernization of dietary habits and population average serum total cholesterol level have continued to increase [11]. Recently, mean cholesterol level in young adults in Japan was found to be similar to that of persons of the same age in the U.S. [12]. However, age-adjusted mortality from CHD remains significantly lower in Japan than in the U.S. and other Western countries [12]. Although smoking rates remain high, low levels of low density lipoprotein (LDL) cholesterol, body mass index (BMI) and high HDL cholesterol among Japanese have been suggested to contribute to the low CHD mortality [13]. It is known that BMI and smoking habit correlate negatively with HDL cholesterol level, while alcohol intake and physical activity correlate positively [10], [14]. In women, menopause [15] and hormone replacement therapy [16], [17] are also reported to have effects on HDL cholesterol concentration. But the influence of most specific dietary factors on HDL cholesterol level is unclear. High fish consumption in Japan might be expected to have a favorable effect on HDL cholesterol level.

In the International Study of Macronutrients and Blood Pressure (INTERMAP), dietary surveys were conducted with a highly standardized protocol in random samples in 17 centers in four countries (Japan, People's Republic of China, U.K. and U.S.) [18]. INTERLIPID was an INTERMAP ancillary study of CHD risk factors in four Japanese population samples in Japan and a Japanese–American population sample in Hawaii [19], stimulated in part by earlier data indicating that Japanese–Americans had higher total fat and saturated fatty acids intake and lower fish consumption [20] than Japanese in Japan. The objective of this study was to examine the association in these five samples between long chain n-3 PUFA intake and serum HDL cholesterol level taking age, BMI, physical activity, smoking, hormone replacement therapy in women and intake of other nutrients and alcohol into consideration as potential confounding variables.

Section snippets

Materials and methods

Detailed methods of the INTERMAP study have been described [18], [21]. They are summarized briefly here. In the INTERMAP study, blood pressure measurements were made on four different days; medical and lifestyle information, four 24-h dietary recalls, and two 24-h urine collections were obtained for each participant. In addition, non-fasting blood was drawn from INTERLIPID participants [19]. Data based on specific analytes measured in these samples, as well as, dietary data and other

Results

For both genders, there was no significant difference in height between Japanese in Japan and Japanese in Hawaii, but body weight and BMI were significantly higher in Hawaii than in Japan (p < 0.001 for both variables, Table 1). For both genders, smoking rate was higher in Japan than in Hawaii (p < 0.001) and male smokers in Japan smoked significantly greater numbers of cigarettes per day than those in Hawaii (p = 0.006). Lipid lowering drugs were used by a significantly greater percentage of men and

Discussion

The present study found a significant positive relationship between long chain n-3 PUFA intake and serum HDL cholesterol concentration among middle-aged men of Japanese ancestry with adjustment for age, BMI, physical activity index, number of cigarettes per day, and intake of other nutrients and alcohol. In accordance with previous findings [10], [14], BMI and cigarette smoking showed significant inverse relations to HDL cholesterol while alcohol intake and physical activity were positive

INTERLIPID study leadership

  • Chairperson of INTERMAP in Japan: Hirotsugu Ueshima.

  • Secretary general in Japan: Akira Okayama.

  • Principal and Co-Principal Investigators in Japan: S. Saitoh, S. Tanaka, K. Shimamoto (Sapporo, Japan); H. Nakagawa, K. Miura, K. Yoshita (Kanazawa), A. Okayama, S.R. Choudhury, Y. Kita (Aito Town, Japan); T. Hashimoto, K. Sakata, S. Morioka (Wakayama, Japan).

  • Principal and Co-Principal Investigators in Hawaii: J.D. Curb, B. Rodriguez, K. Masaki.

  • National Nutritionists, Japan: N. Okuda, K. Yoshita.

Acknowledgments

This study was partly supported by the Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (A), no. 090357003 in Japan and the Suntory Company; the Pacific Research Institute is supported by the Robert Perry Fund and the Hawaii Community Foundation. The INTERMAP Hawaii Center was funded by the National Heart, Lung, and Blood Institute, National Institutes of Health (Grant 5-RO1-HL54868-03). The INTERMAP study is supported by the National Heart, Lung, and

References (32)

  • K. Chiba et al.

    Nationwide survey of high-density lipoprotein cholesterol among farmers in Japan

    Prev Med

    (1983)
  • M.L. Daviglus et al.

    Fish consumption and the 30-year risk of fatal myocardial infarction

    N Engl J Med

    (1997)
  • A. Leaf et al.

    Cardiovascular effects of n-3 fatty acids

    N Engl J Med

    (1988)
  • C.M. Oomen et al.

    Fish consumption and coronary heart disease mortality in Finland, Italy, and The Netherlands

    Am J Epidemiol

    (2000)
  • H. Iso et al.

    Serum fatty acids and fish intake in rural Japanese, urban Japanese, Japanese American and Caucasian American men

    Int J Epidemiol

    (1989)
  • C. Bolton-Smith et al.

    Dietary and non-dietary predictors of serum total and HDL-cholesterol in men and women: results from the Scottish Heart Health Study

    Int J Epidemiol

    (1991)
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