Long-term exposure to nitrates through food and water may increase a woman's risk of thyroid disease, finds a study of older women in Iowa. Public water supplies contaminated with nitrates increased the risk of thyroid cancer in the women. Eating nitrates from certain vegetables was linked to increases in thyroid cancer and hypothyroidism, one type of thyroid disease.

This is the first study to show a link between nitrates and thyroid cancer in people, although nitrates have been shown to cause thyroid tumors in animal studies.

Thyroid cancer is the eighth most common cancer among women. In the United States, the incidence of thyroid cancer has increased steadily since 1980.

Nitrate is a common contaminant of drinking water, particularly in agricultural areas where nitrogen fertilizers are used. High rates of fertilizer application may also increase the natural nitrate levels found in certain vegetables, such as lettuce and root crops.

Full article:  http://www.environmentalhealthnews.org/ehs/newscience/nitrates-in-water-food-may-increase-thyroid-disease-risks