Industry Insight

Nutritional Benefits of Hard Water Consumption

Water Quality Products invited Stan Hazan, senior director of regulatory affairs and association programs for NSF International, to give an overview of the upcoming symposium on the health effects of calcium and magnesium in drinking water organized by NSF International, the NSF/WHO Collaborating Centre for Drinking Water and the International Life Sciences Institute.

The International Symposium on Health Aspects of Magnesium and Calcium in Drinking Water will address whether consumption of hard water provides health benefits to consumers. The symposium will be held April 24 to 26, 2006 in Baltimore, Md.

WQP: Please give us a brief overview of the issue.

Stan Hazan: As the WHO Collaborating Centre in drinking water safety and treatment, NSF International has frequently addressed emerging issues as a support for WHO, often in the form of a symposium or conference. This particular issue began to attract attention about four years ago when WHO’s Eastern Mediterranean Regional Office in Rome initiated development of Guidelines on Health and Environmental Aspects of Desalination. Given the rapidly expanding use of desalination technology around the world, this was a timely issue.

Dr. Joe Cotruvo, a consultant for NSF, and Dr. Suzanne Harris, executive director of the International Life Sciences Institute, attended the Rome meeting. Cotruvo and Harris recognized the need for a follow-up meeting to gain worldwide expert input on the topic, hence a three-day symposium, followed by a two-day WHO expert meeting.

One of the questions brought up was whether long-term consumption of desalinated water might have a negative effect on consumers’ health. Although this wasn’t likely, it was worth addressing the question.

Desalinated water must be stabilized to control its corrosivity, and one of the common methods is the addition of lime. The conference aimed to explore the possibility that there could be benefits beyond corrosion control from lime, and whether it would be better if the water contained some magnesium and calcium.

Numerous epidemiological studies of varying quality have suggested that communities that consumed “hard water” had lower incidences of some types of heart disease. A WHO committee reviewed the nutrients issue and concluded in its recently released report that the “hard water benefits hypothesis” was plausible (see, and that a follow-up review should be undertaken.

The upcoming symposium is the response to that recommendation to dig more deeply into the issue before decisions are made in desalinated water treatment. Of course, soft and softened water raise the same questions. Reduced osteoporosis as well as cardiovascular disease and other effects have been postulated for calcium and magnesium in the scientific literature.

WQP: What are some of the main issues that will be addressed at the NSF/WHO/ILSI symposium?

Hazan: Some of the issues include:

  • How reliable are those hypothesized hard water consumption epidemiological studies?
  • Do the water epidemiology and controlled dietary studies provide a basis for hypothesizing benefits in populations consuming calcium and/or magnesium in drinking water?
  • Are there measurable health benefits from relatively small incremental contributions of calcium and/or magnesium to total diet from drinking water?
  • Is there an optimum amount of calcium and/or magnesium in drinking water in each world region based on diet and nutritional needs? If so, what would those amounts of calcium and magnesium be?
  • What is the health significance of life-long hard water consumption?
  • Does the mineral composition of cooking water affect the mineral composition of cooked food?

    WQP: How would the symposium’s conclusions impact the water industry?

    Hazan: There will be a WHO expert meeting after the symposium to discuss the issues listed above. If the conclusions are positive, and depending on how conclusive they are, they could have an impact on all aspects of the water industry, including desalination practices, membrane filtration, central softening in water supplies, corrosion control, home treatment systems (ion exchange, RO, distillation), bottled water choices and perhaps even beverages. The effects would be mostly positive for the affected industries, with only small adjustments needed in most cases.

    WQP: Why is the water industry’s participation essential at the event?

    Hazan: The water industry needs to be present to hear what the state-of-the-science is on these important matters and to contribute to the discussions so that there will be balanced perspectives. This is where the experts will be, and networking with this group will be important down the road. If there is an impact on health, then water suppliers will want to know that information sooner rather than later.

    WQP: Where can our readers receive more information about the symposium and sign up to attend the event?

    Hazan: The symposium is being organized by NSF International, the NSF/WHO Collaborating Centre for Drinking Water and the International Life Sciences Institute, with the assistance of Dr. Joe Cotruvo. A conference registration form can be downloaded at, which also contains program and hotel information. Questions should be directed to Diane Dalisera of ILSI at 202.659.0074, or by e-mail at [email protected].

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