If you haven't already caught the news, it's time to eliminate canned foods and exposure to plastics that contain the chemical, bisphenol A (BPA). A worrisome and unexpected association with heart disease and diabetes has been found.
This issue has been debated for some years ever since scientists at the NIH detected BPA in the blood samples of 93-95% of Americans, with consumer protection advocates calling for more research or even the outright banning of BPA , while industry representatives have argued that the data fail to conclusively prove adverse health effects.
Well, the argument has been tilted heavily in favor of increased consumer protection with the publication of a study in the Journal of the American Medical Association by Dr. Iain Lang and associates at the University of Exeter, UK, and the University of Iowa. Their study, released Sept. 17, 2008, Association of urinary bisphenol A concentration with medical disorders and laboratory abnormalities in adults, persuasively demonstrated a 40% increased incidence of coronary heart disease, heart attack, and diabetes with increasing exposure to BPA (as judged by urine levels) among the nearly 1500 adults aged 18-74 years. People with coronary heart disease had double the blood level of BPA compared to those without.
In addition, higher urine levels of BPA were associated with abnormalities of two liver tests, GGT and alkaline phosphatase.
Interestingly, although much of the debate over adverse health effects of BPA have centered around concern over cancer and reproductive risks, an association with cancer did not hold. (No analysis for reproductive issues was conducted in these adults, since most of the concern is for children exposed through polycarbonate baby bottle use. Some BPA critics have raised questions like low birth weight developing from exposure.) No relationship to thyroid disease was identified, also.
The editorial accompanying the study added some sharp commentary:
"Subsequent to an unexpected observation in 1997, numerous laboratory animal studies have identified low-dose drug-like effects of BPA at levels less than the dose used by the US Food and Drug Administration and the Environmental Protection Agency to estimate the current human acceptable daily intake dose (ADI) deemed safe for humans. These studies have shown adverse effects of BPA on the brain, reproductive system, and--most relevant to the findings of Lang et al--metabolic processes, including alterations in insulin homeostasis and liver enzymes. . . For example, when adults rats were fed a 0.2 microgram/kg per day dose of BPA for 1 month (a dose 250 times lower than the current ADI), BPA significantly decreased the activities of antioxidant enzymes and increased lipid peroxidation, thereby increasing oxidative stress. When adult mice were administered a 10 microgram/kg dose of BPA once a day for 2 days ( a dose 5 times lower than the ADI), BPA stimulated pancreatic beta cells to release insulin."
This study, piled on top of the worrisome literature that precede it, are enough for me: No more tin cans (which are lined with BPA), no more hard plastics labeled with recycling code #7 or #3, no more polycarbonate water bottles (the hard ones, often brightly colored). Microwaveable-safe may also mean human-unsafe, as highlighted by this damning assurance from the Tupperware people that BPA is not a health hazard.
The National Toxicology Program also issued these advice in response to the Lang study to reduce BPA exposure (reported by the Washington Post) �:
· Don't microwave polycarbonate plastic food containers. Polycarbonate may break down from overuse at high temperatures and release BPA. (Manufacturers are not required to disclose whether an item contains BPA, but polycarbonate containers that do usually have a No. 7 on the bottom.)
· Reduce use of canned foods, especially acidic foods such as tomatoes that can accelerate leaching of BPA from plastic can linings. Opt for soups, vegetables and other items packaged in cardboard "brick" cartons, made of safer layers of aluminum and polyethylene plastic (labeled No. 2).
· Switch to glass, porcelain or stainless-steel containers, particularly for hot food or liquids.
· Use baby bottles that are BPA-free; in the past year, most major manufacturers have developed bottles made without BPA.