Contribution of drinking water to dietary requirements of essential metals.

Drinking water can be a source of essential metals, but only one study published thus far has compared the intake of essential metals in drinking water to dietary reference intakes. This assessment compares the ingestion of chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), selenium (Se), and zinc (Zn) from drinking water at the maximum concentrations that should be found in water, or at concentrations that are potentially more likely to be found in Canadian water, to the recommended dietary allowance or adequate intake values established by the Institute of Medicine. At guideline limits, water provides sufficient Cr and Cu to meet nutritional requirements, and Mn and Zn levels are sufficient for some age categories to meet nutritional requirements. At concentrations that are more likely to be found in Canadian water, adequate intakes for Cr and Mn may be met by water alone for bottle-fed infants, and water was estimated to provide 23-66% of daily Cu requirements. Drinking water might become a significant source of some essential metals in individuals whose diets are low in these metals, especially in the case of Cu.