Zinc and copper intakes and their major food sources for older adults in the 1994-96 continuing survey of food intakes by individuals (CSFII)

Zinc and copper are two trace minerals essential for important biochemical functions and necessary for maintaining health throughout life. Several national food surveys revealed marginally to moderately low contents of both nutrients in the typical American diet. Using data from the respondents greater than or equal to 60 y old in the 1994-96 Continuing Survey of Food Intakes by Individuals (CSFII), we examined average dietary intakes of zinc, copper and relevant dietary factors, primary dietary contributors of zinc and copper; and Zn:Cu ratios of the primary dietary contributors. Data were analyzed with the use of a chi (2) test, Student's t test and multivariate analysis of covariance with Bonferroni correction. The daily zinc intake was 12 +/- 6.4 mg for men and 8.0 +/- 4.0 mg for women (P < 0.05); the daily copper intake was 1.3 +/- 0.7 mg for men and 1.0 +/- 0.5 mg for women (P < 0.05). Foods such as beef, ground beef, legumes, poultry, ready-to-eat and hot cereals, and pork constituted the major sources of zinc. Copper consumption was contributed mainly by legumes, potato and potato products, nuts and seeds, and beef. The less-than-recommended intakes of zinc and copper by the elderly were likely associated with age, low income and less education. The intakes of zinc and copper could be improved by more frequent consumption of food sources rich in these minerals. An inherent limitation of this study was the use of the 24-h dietary recall method, which may underestimate usual dietary intakes. Nonetheless, this study affirms the need for assessment of zinc and copper nutriture in the elderly.