日本人女性の食事からのカルシウム摂取量

Abstract

This study was initiated 1. to examine if there was any secular changes in dietary calcium (Ca) intake among Japanese women in past 15 years, and 2. to identify the food groups insufficient intake of which may induce Ca insufficiency. 24-Hour food duplicate samples were collected from 433 and 760 adult women in the first (1977-1981) and the second survey (1991-1998), respectively, from various parts of Japan. Daily Ca intakes were estimated from weights of food items in the duplicate samples, taking advantages of food composition tables (FCT-based estimates). Possible difference in means was examined by Student's t-test and multiple comparison test (Scheffe), and that in distribution by chi-square test. The average dietary intake of Ca was 607 and 605 mg/day in the first and the second survey, respectively, with no significant difference. The subjects, separately for the two surveys, were classified by the Ca intake into 5 groups, i.e., those with intake of 419 or less, 420 to 539,540 to 659,660 to 999 and 1,000 or more mg Ca/day, and also by decade of ages. Reduced Ca intake from fish (including shellfish) and vegetables coupled with increased intake from milk (including milk products) were noted among the three low Ca intake groups when the intakes were compared between the two surveys, whereas no food group-specific changes were noted among the two high intake groups. Ca intake from milk was high in the latter two groups. Further analysis showed that low intakes of pulse, fish, milk, vegetables and algae were associated with insufficiency in Ca intakes. Classification by ages showed that Ca insufficiency among those at the ages of 20's was attributable to low intakes of pulse, fish and algae. When compared between the two surveys, reduced intakes of fish and vegetables and increased intake of milk were commonly observed in most age groups, and milk intake was substantially increased at advanced ages. FCT-based estimates and ICP-MS measurements gave 581 and 542 mg/day as averages for the former and the latter, respectively. The observation that the latter is 93% of the former suggests that Ca insufficiency should be taken more seriously than the estimates would suggest.