Although rising rates of obesity and low levels of physical activity are often held responsible for the dramatic increase in the diagnosis of Type 2 diabetes worldwide, new research reinforces the role of the widespread chemical bisphenol A, or BPA, in causing the condition.
BPA is a plasticizer (a substance that is used to promote plasticity and reduce brittleness) used in a wide variety of products, including dental sealants, food-can liners, toilet paper, cash register receipts, pesticides, and bottles and other containers made with plastic that has a number 7 or number 3 recycling code. In research conducted by the Centers for Disease Control and Prevention (CDC) in 2004, 93% of study participants were found to have detectable levels of this chemical in their bodies.
BPA is an endocrine disruptor, or a substance “that may interfere with the body’s endocrine system and produce adverse developmental, reproductive, neurological, and immune effects in both humans and wildlife,” according to the National Institutes for Health. Studies have linked BPA to health conditions such increased risk for cardiovascular disease, reproductive dysfunction, breast and prostate cancer, and metabolic conditions such as insulin resistance and diabetes.
To determine how BPA might increase the risk of diabetes, Angel Nadal, PhD, a BPA expert at the Miguel Hernandez University in Spain, and colleagues, studied the effects of the chemical in both mice and in human pancreatic cells. The researchers found that, by tricking a hormone receptor into thinking that it is estrogen, a small amount of BPA can cause the release of almost twice as much insulin as necessary to metabolize food. As little as a quarter of a billionth of a gram of BPA was sufficient to cause a reaction. The results served to remove doubts about the link between diabetes and BPA by pinpointing the mechanism by which BPA interferes with metabolism.
According to Nadal, “When you eat something with BPA, it’s like telling your organs that you are eating more than you are really eating.”
Representatives from the plastics industry contend that BPA has been thoroughly studied and deemed safe. But in a reversal of the usual “dose makes the poison” scenario, scientists suggest that lower doses of BPA may actually be more damaging than higher doses, because higher doses may effectively overwhelm the relevant receptors, shutting them off. Frederick vom Saal, an endocrine disruptor expert at the University of Missouri-Columbia noted that, “People are seeing effects of BPA down to 1000-fold below [Nadal's threshold]… It takes so little of this chemical to cause harm.”
Dr. Nadal suggests that the risk of this chemical may be highest in pregnant women, whose fetus may be exposed not only to BPA, but to high levels of insulin as well, potentially programming the baby for weight gain later in life.
With the use of BPA so widespread, it is hard to avoid this chemical completely, but there are ways that you can reduce your exposure. According to an article on About.com, steps you can take include reducing your consumption of canned foods; choosing cardboard and glass containers in place of cans; using glass, porcelain, or unlined stainless steel containers for hot foods and beverages; and avoiding microwaving food in plastic that has a number 7 recycling code, which is the most likely type to contain BPA. To reduce your baby’s exposure to this substance, be sure to choose bottles that are free of BPA (typically soft or cloudy plastic does not contain the chemical) and use powdered formula mixes in place of liquid mixes, which have been found to contain higher levels of BPA.