EFFECT OF FIBER FROM FRUITS AND VEGETABLES ON METABOLIC RESPONSES OF HUMAN-SUBJECTS .3. ZINC, COPPER, AND PHOSPHORUS BALANCES

Intakes and excretions of zinc, copper, and phosphorus were determined for 12 men when they consumed a diet low in fiber and when they consumed a diet containing fiber from fruits and vegetables (high-fiber diet). All subjects consumed both diets for 26 days each. The low-fiber diet was supplemented with copper so that it was equivalent to the high-fiber diet in this respect. Mean daily intakes on the low- and high-fiber diets, respectively, were: zinc, 13.2 and 12.6 mg; copper, 1.8 and 1.6 mg; phosphorus, 1.639 and 1.690 g. Mean daily balances on the low- and high-fiber diets, respectively, were: zinc, +3.5 and -0.9 mg; copper, +0.2 and -0.4 mg; phosphorus, +0.361 and +0.292 g. Zinc and copper balances differed significantly on the two diets (P < 0.001 and P < 0.005, respectively), but phosphorus balances did not. The fiber supplied by the fruits and vegetables contained more lignin and cellulose and less hemicellulose than would an equivalent amount of fiber from bran. The bran would supply more magnesium, zinc, and copper than this particular diet containing fruits and vegetables.