NSF International and the International Life Sciences Institute with the generous support of its cosponsors and contributors assembled a diverse group of nutrition, medical, epidemiological and scientific experts in Baltimore, Maryland on April 24-26 for the International Symposium on Health Aspects of Calcium and Magnesium in Drinking Water. The symposium was attended by 162 participants from 25 different countries.

The symposium presented a wide range of perspectives regarding the question of the value of providing drinking water with a small amount of magnesium and/or calcium. The symposium was not designed to reach a conclusion; that will be a function of subsequent WHO Expert Committee and Guidelines activities. It is clear that large portions of the world’s population are deficient in daily magnesium and calcium intake relative to recommended values and the intake seems to decrease further with age.

Water treatment processes can readily add minerals at low cost, and softening processes in the central treatment plant and the home can be adjusted to obtain desirable levels of calcium and magnesium in the drinking water. Water manufactured by desalination or reuse should be remineralized prior to entry into the water distribution system to increase alkalinity and control its corrosivity toward piping. Remineralization methods that include addition of calcium and magnesium are more desirable than other techniques because they also contribute nutrient minerals to water that will be consumed or used in food preparation.

There are several ways to improve the total intake of nutrient minerals that are not mutually exclusive. The selection is a matter of success potential, cost, widespread impact across the population, public health policy and law. The preferable approach is probably via improved diet e.g. by greater consumption of vegetables and dairy products.

Some bottled water and beverages can be fortified to provide supplemental nutrients. This is a particularly efficient approach since bottled water is growing in popularity in many areas, all of the water is consumed, and the incremental unit costs are negligible.

In general, a combination of these approaches tailored to each society would probably achieve the most success. The public needs to know what they are consuming so that they can make informed choices, but care must be exercised to protect against excessive calcium and magnesium consumption for some individuals and in some circumstances.

A summary report of the symposium is expected to be published in Water Conditioning & Purification International magazine this summer.