In animals, dietary energy restriction is reported to increase longevity, whereas in humans, all cohort studies from Western countries have not shown an association between the low energy intake and longevity. We examined the association between total energy intake and longevity in Japan where dietary pattern is different from that in the West.
A total of 7,704 Japanese aged 30-69 years were followed from 1980 to 2009. Participants were divided into the quintiles of total energy (kcal/day) based on data collected from the National Nutrition Survey. Hazard ratios and 95% confidence intervals (CIs) were derived through the use of Cox proportional hazards models to compare the risk of death across and between the quintiles.
There was a significant association between increased energy intake and all-cause mortality risk in only men (P for linear trend=0.008). In cause-specific analysis, compared with the lowest quintile, there was rise in coronary heart disease (CHD) mortality among men (HR; 2.63, 95%CI; 0.95-7.28, P for linear trend 0.016) and women (HR; 2.91, 95%CI; 1.02-8.29, P for linear trend 0.032) and cancer mortality among men (HR; 1.50, 95%CI; 0.999-2.24, P for linear trend 0.038) in the top quintile.
We observed significant associations of high energy intake with all-cause and cancer mortality among men and with CHD mortality among men and women. Further studies are needed to confirm the benefits of caloric restriction.