Scientific Opinion on Dietary Reference Values for zinc
Following a request from the European Commission, the Panel on Dietetic Products, Nutrition and Allergies (NDA) derived Dietary Reference Values for zinc, using a two-stage factorial approach and reference values for body weight. The first stage of estimating physiological requirements used studies that had physiologically plausible data, specifically related to faecal excretion of endogenous zinc. Adult physiological requirements were closely related to body size, and sex differences were not detectable after adjustment for body weight. Average Requirements (ARs) for dietary zinc necessary to meet physiological requirements were estimated using saturation response modelling, taking into account the inhibitory effect of dietary phytate on zinc absorption. Estimated ARs and Population Reference Intakes (PRIs) are provided for phytate intake levels of 300, 600, 900 and 1 200 mg/day, which cover the range of mean/median intakes observed in European populations. ARs range from 6.2 to 10.2 mg/day for women with a reference weight of 58.5 kg and from 7.5 to 12.7 mg/day for men with a reference weight of 68.1 kg. PRIs were derived from the zinc requirement of individuals with a body weight at the 97.5th percentile for reference weights for men and women and range from 7.5 to 12.7 mg/day for women and from 9.4 to 16.3 mg/day for men. ARs for infants from seven months of age and for children were estimated factorially, based on extrapolation from estimates of adult losses plus zinc needs for growth, and range from 2.4 to 11.8 mg/day. PRIs for infants and children were derived by assuming a coefficient of variation of 10 %, and range from 2.9 to 14.2 mg/day. For pregnancy and lactation, additional zinc requirements related to fetal and maternal tissues and transfer of zinc into breast milk, respectively, were considered and additional PRIs of 1.6 and 2.9 mg/day, respectively, were estimated.