Nutrient minerals in drinking-water
Rolling revision of the WHO Guidelines for Drinking-water Quality
Nutrient minerals are included in the plan of work of the rolling revision of the WHO Guidelines for Drinking-water Quality.
A WHO Expert Workshop on nutritional components of drinking-water was held in November 2003 in Rome. The result of the workshop was a report on “Nutrient minerals in drinking water and the potential health consequences of long-term consumption of demineralized and remineralized and altered mineral content drinking waters.” The workshop concluded that drinking-water was generally not a significant contributor to daily dietary nutrition but could be important in cases of dietary insufficiency.
Calcium and magnesium in hard water have been shown to be associated with reduced ischaemic cardiac mortality in hard water areas. Stabilization of desalinated waters should include the introduction of adequate calcium and magnesium where practical. It was concluded that drinking-water may be important as a source of skeletal fluoride, and it has been suggested that there is a minimum level of fluoride in water below which net loss of fluoride from the skeleton may occur.
- Publication of Nutrient Minerals in Drinking-water meeting report in 2005;
- Eventual revision of background documents on fluoride, hardness and selenium to take beneficial effects into consideration (for more details, refer to relevant agenda items);
- Addition of text to Policies and Procedures Manual to reflect new approach on essentiality
Progress to date
- The Nutrition report was submitted to WHO departments in February 2004 for comments.
- The Chemical Aspects Working Group has not previously considered the essentiality of minerals in sufficient depth and has decided to progressively start taking essentiality and potential beneficial effects into consideration. This decision has arisen because of increasing evidence that in populations that are marginal for nutrition for a particular mineral, concentrations in drinking-water may be important. It is therefore important to achieve a suitable balance for essential minerals between protection against adverse effects and the potential for beneficial effects.
- The beneficial effects issue has been carried forward into the respective agenda items on fluoride, hardness and selenium.
- Text has been prepared for inclusion in the Policies and Procedures Manual.
- The Guidelines for Drinking-water Quality Working Group meeting (Geneva, 2005) was informed that the Nutrition report is now ready for editing and publication, and they expressed their support for the proposed plan of work.