Individuals with Menke’s disease may be distinctly susceptible to the adverse effects of excess zinc intake. Since Menke’s disease is a defect in the ATPase involved in copper efflux from enterocytes, supplying extra zinc will likely further limit copper absorption (Yuzbasiyan-Gurkan et al., 1992). Brewer and coworkers (1993) demonstrated the effectiveness of zinc therapy in reducing copper accumulation in individuals with Wilson’s disease. The UL is not meant to apply to individuals who are being treated with zinc under close medical supervision.
Utilizing the Third National Health and Nutrition Examination Survey data, the highest reported intake of dietary zinc at the ninety-fifth percentile for all adults was 24 mg/day in men aged 19 to 30 years (Appendix Table C-25), which is lower than the UL of 40 mg/ day. In 1986, approximately 17 percent of women and 15 percent of men consumed supplements that contained zinc (Moss et al., 1989; see Table 2-2). The ninety-fifth percentile intake of zinc coming from food and supplements for adult men and nonpregnant women was approximately 25 to 32 mg/day (Appendix Table C-26). For pregnant and lactating women, the zinc intake from food and supplements was approximately 40 and 47 mg/day, respectively, at the ninety-fifth percentile.
The risk of adverse effects resulting from excess zinc intake from food and supplements appears to be low at the highest intakes noted above. High intakes of zinc are due to the use of supplements, especially during lactation and pregnancy. Doses approaching or equal to the UL are currently being tested in the treatment of diarrhea, pneumonia, and acute respiratory infections, especially in developing countries. The UL is not meant apply to individuals who are receiving zinc for treatment purposes.
Biomarkers of zinc status based on functional outcomes; these may be gene products derived from zinc-influenced systems and