We are suffering an epidemic of iodine deficiency in this country. Over the last 40 years, iodine levels have fallen more than 50 percent, according to the National Health and Nutrition Examination Survey (NHANES). And the consequences of low iodine levels are severe.

Nearly 60 percent of pregnant women in the United States are low in iodine — many severely low. Low iodine levels during pregnancy can cause low IQ in children.

Iodine deficiency is also associated with an increase in cancers of the glandular tissues, including the breasts, ovaries, thyroid, uterus, prostate, and pancreas — precisely the same cancers that are growing most rapidly in the U.S. One in seven American women currently suffer from breast cancer. One in three men have prostate cancer.

In 2011, the Obama administration announced a plan to regulate perchlorate — a toxic compound that contaminates water supplies and has been linked to fetal and infant brain damage — for the first time. I was thrilled, as far too many municipal water supplies are known to be contaminated with perchlorate.

In fact, the entire lower Colorado River — which irrigates more than 1.8 million acres of land that produces more than 15 percent of the nation’s crops and 13 percent of the nation’s livestock — is contaminated with perchlorate. More than 20 million Americans also get their drinking water from the Colorado River.

Because perchlorate inhibits iodine intake to the thyroid gland, it makes sense that ingesting perchlorate would lead to thyroid issues. Newborns living in areas where the lower Colorado River supplies drinking water were compared to infants drinking water not contaminated with perchlorate.

After studying 1,500 children, scientists reported that infants who drank perchlorate-contaminated water had significantly lower thyroid function than those who didn’t. Because the lower Colorado is used to irrigate food crops, those food sources can be predicted to have elevated perchlorate levels.

Research shows that up to 70 percent of the U.S. fall and winter lettuce supplies are irrigated by perchlorate-contaminated water from the lower Colorado River. Unfortunately, that includes organic as well as non-organic lettuce.