DEVELOPMENT OF A DIETARY MODEL FOR THE STUDY OF MILD ZINC-DEFICIENCY IN HUMANS AND EVALUATION OF SOME BIOCHEMICAL AND FUNCTIONAL INDEXES OF ZINC STATUS

After a 1-wk baseline period, a dietary regimen was developed to induce mild zinc deficiency in 15 males (aged 25.3 +/- 3.3 y, xBAR +/- SD). The regimen consisted of 1 wk on a liquid diet containing 0.6 mg Zn/d and molar ratios of phytate to zinc (phy: Zn) and of phytate x calcium to zinc [(phy x Ca): Zn] of 209 and 4116, respectively, followed by 6 wk on a diet based on soy protein and egg albumin containing 4 mg Zn/d and with phy:Zn and (Ca x phy):Zn of 70 and 2000, respectively. Subjects were then repleted with 30 mg Zn/d for 2 wk. Fasting blood and urine samples were taken weekly. Changes were observed in mean plasma (mu-mol/L) and urinary zinc (mu-mol/d): baseline 97.0 +/- 10.9 and 8.0 +/- 2.7, depletion 80.1 +/- 13.4 and 4.3 +/- 2.3, and repletion 100.8 +/- 13.6 and 8.2 +/- 3.1, respectively (P < 0.05); taste acuity (0.05 < P < 0.10); and cellular immune responses (P < 0.05). Activities of plasma angiotensin-1-converting enzyme and acidic alpha-D-mannosidase were unchanged. Mild zinc deficiency was induced by the dietary regimen.