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Hard Water May Protect Against Heart Attacks

Fluoride in Water May Reduce the Risk of Heart Attack

Medically Reviewed by Michael W. Smith, MD on January 14, 2004
From the WebMD Archives

Jan. 14, 2004 -- The harder the water, the fewer the heart attacks? That's what a new Finnish study suggests.

Researchers found that the higher the concentration of minerals, otherwise known as the "hardness" of the water, the lower the risk of heart attack and heart disease across different regions in Finland.

Although the study can't pinpoint exactly which minerals were responsible for these effects, researchers say analyses suggest that higher fluoride levels were protective but higher levels of iron and copper in the water had the opposite effect.

Hard Water Helps Hearts

For years, researchers have been puzzled by seemingly unexplainable differences in the frequency of heart disease across Finland. For example, heart disease rates have been 40% higher in the eastern part of the country than in the western part for the last 50 years.

In this study, published in the January issue of the Journal of Epidemiology and Community Health, researchers analyzed water hardness in several sections of Finland as well as heart disease and death in nearly 19,000 men.

Researchers found that for every one-unit increase in water hardness, there was a corresponding 1% decrease in the risk of heart attack.

Specifically, each increase in fluoride in household drinking water was associated with a 3% decrease in the risk of heart attack. But each increase in copper and iron was associated with an increase in heart attack risk of 4% and 10%, respectively.

Researchers say water hardness can't account for all geographical differences in heart attack rates because factors like lifestyle, genetic disposition, and environmental also play a role. But some trace and mineral elements may be more readily absorbed through water than in food and have an impact on the development of some chronic disease, such as heart disease.

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SOURCE: Kausa, A. Journal of Epidemiology and Community Health, January 2004; vol 58: pp 136-139.

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