By David Liu

Eating one serving of canned soup per day for only five days would increase urinary levels of a toxic chemical called bisphenol A or BPA by more than 1,200 percent, according to a new study published online in the Nov 22, 2011 issue of JAMA.

Jenny Carwile of Harvard School of public Health and colleagues conducted the study and found subjects who consumed a serving of canned soup per day for five days raised their urinary levels of BPA to 22 micrograms per liter, compared to 1 to 2 mcg/L in the urine of those who did not eat canned soup.

The researchers detected BPA in 77 percent of the urine samples from subjects who did not eat canned soup and 100 percent of samples from subjects who consumed canned soup.

Bisphenol A is a known endocrine-disruptor, which is widely used in the lining of metal food and beverage cans.   The chemical is known to interfere with reproductive development in animal models among other things and has been associated with cardiovascular disease, diabetes, and obesity in humans.

A. Shankar and S. Teppala of West Virginia University School of Medicine in Morgantown, West Virginia reported in Sept 28, 2011 issue of Journal of Clinical Endocrinology and Metabolism that urinary BPA levels were inversely associated with risk of diabetes mellitus.

The researchers conducted an analysis of data from participants in the National Health and Nutritional Examination Survey (NHANES) 2003-200 and found that compared to men and women whose urinary levels of bisphenol A were in the lowest quartile, those who had their urinary levels of BPA in the highest quartile were at 50 percent higher risk for diabetes mellitus.

The association was independent of body weight status. That is, it was found among normal weight, overweight and obese subjects.

Canned food is not the only consumer product that carries bisphenol A.   Plastics used in polycarbonate bottles with the recycling number 7, dentistry composites, sealants and printed thermal paper recipes from stores also contain this toxic chemical.