Relationship between Dietary Habits and Plasma Homocysteine Concentrations in Elderly Japanese Women and Men

The plasma homocysteine concentration is a good indicator of various diseases such as cardiovascular disease, stroke, and dementia. This study examined the relationship between plasma homocysteine concentrations and dietary habits in a population of elderly Japanese people from the Amami Islands. Data from 1131 participants collected during a baseline survey for the Japan Multi-institutional Collaborative Cohort study, which is a prospective cohort study, were used. Information on dietary habits was collected using a food frequency questionnaire. The plasma homocysteine concentration was associated with age in women only. Smoking in men and menopause were significantly associated with homocysteine concentrations. Analysis of blood biochemical data showed that estimate of glomerular filtration rate negatively correlated with plasma homocysteine in women (R = −0.91, p < 0.001) and men (R = −0.49, p < 0.001). There was no common food associated with homocysteine concentrations among the groups, but in each group, some food types were associated with homocysteine concentrations. In men, Chinese tea was a common factor showing a negative correlation with homocysteine concentrations. Natto showed a negative correlation with homocysteine concentrations in non-smoking men (β = −0.11, p < 0.05) and premenopausal women (β = −0.20, p < 0.01). Eggs (β = −0.21, p < 0.01) and food processed from fish eggs (β = −0.21, p < 0.01) negatively correlated with homocysteine concentrations in smoking men. Miso soup (β = −0.13, p < 0.01) and yoghurt (β = −0.10, p < 0.05) negatively correlated with homocysteine concentrations in postmenopausal women. Consumption of folate-rich food did not necessarily correlate with a low plasma Hcy concentration.