Why has Japan become the world's most long-lived country: insights from a food and nutrition perspective

Abstract

In an international comparison of recent mortality statistics among G7 countries, Japan had the longest average life expectancy, primarily due to remarkably low mortality rates from ischemic heart disease and cancer (particularly breast and prostate). As recently as the 1960s, life expectancy in Japan was the shortest among the G7 countries, owing to relatively high mortality from cerebrovascular disease-particularly intracerebral hemorrhage-and stomach cancer. Mortality rates for these diseases subsequently decreased significantly while the already low rates for ischemic heart disease and cancer also decreased, resulting in Japanese life expectancy becoming the longest. The low mortality rates from ischemic heart disease and cancer are thought to reflect the low prevalence of obesity in Japan; low intake of red meat, specifically saturated fatty acids; and high intakes of fish, specifically n-3 polyunsaturated fatty acids, plant foods such as soybeans, and nonsugar-sweetened beverages such as green tea. The decreasing mortality rates from cerebrovascular disease are thought to reflect the increases in animal foods, milk, and dairy products and consequently in saturated fatty acids and calcium, together with a decrease in salt intake which may have led to a decrease in blood pressure. This decrease in salt and highly salted foods also seems to account for the decrease in stomach cancer. The typical Japanese diet as characterized by plant food and fish as well as modest Westernized diet such as meat, milk and dairy products might be associated with longevity in Japan.

Fig. 1. Annual trends of life expectancy at birth (years) in selected countries.

The figure was prepared by the author using datafrom “OECD Health Statistics 2019” (https://www.oecd.org/health/health-data.htm).

Fig. 2. Annual trends in age-standardized circulatory diseases mortality rates per 100,000 world standard population in selected countries.

The figure was prepared by the author using datafrom “WHO Mortality Database” (http://apps.who.int/healthinfo/statistics/mortality/whodpms/).

Fig. 3. Annual trends in age-standardized cancer mortality rates per 100,000 world standard population in selected countries.

The figure was prepared by the author using datafrom “WHO Mortality Database” (http://apps.who.int/healthinfo/statistics/mortality/whodpms/).

Fig. 4. Annual trends in age-standardized mortality rate per 100,000 Japan 1985 model population for leading causes of death.

The figure was prepared by the author using datafrom “Vital Statistics, Ministry of Health, Labour and Welfare” (https://www.e-stat.go.jp/).

Fig. 5. Annual trend of average energy and nutrient intakes in Japan.

The figure was prepared by the author using datafrom “National Health and Nutrition Survey, Ministry of Health, Labour and Welfare” (https://www.mhlw.go.jp/bunya/kenkou/kenkou_eiyou_chousa.html).