Dietary zinc intake and its effects on zinc nutrition in healthy Japanese living in the central area of Japan.

In the present study, we first examined the dietary zinc intake from food groups in 109 healthy Japanese (24-82 years old, 45 male and 64 female) by means of the 72-h recall method. We then used the ratio of apo/holo-activities of angiotensin converting enzyme (ACE ratio) that is a more sensitive index of zinc nutrition than zinc concentration in the serum and examined the correlation between their zinc intake and ACE ratio. Dietary zinc intake in healthy Japanese was maximal from rice and rice products. There were significant inverse correlations between the ACE ratio and dietary zinc intake from rice and rice products and shellfish, and a significant positive correlation between ACE ratio and dietary zinc intake from other beans and bean processed foods. On the other hand, there were no significant correlations between serum zinc concentrations and dietary zinc intake from any food group except processed fish. These findings suggested that rice is a major source of dietary zinc intake in healthy Japanese. It is also suggested that shellfish also has a major impact on zinc nutrition, although dietary zinc intake from this source is minimal. Since beans contain phytic acid, which inhibits the absorption of dietary zinc, it is suggested that intake of beans causes impairment of zinc nutrition.