A new study published in the Journal of the American Medical Association (JAMA, September 9th issue) brings up the concern that many have about the effects of bisphenyl A (BPA) in our food supply. This time it concerns childhood obesity.
BPA exposure is ubiquitous in the U.S. population with 92.6 percent of persons over the age of 6 years having detectable BPA levels in their urine. A study of indoor and outdoor air, solid and liquid food in preschool-aged children suggested that dietary sources constitute 99% of BPA exposure.
In the JAMA study, researchers examined the association between urinary BPA concentrations and body mass in children. They studied 2,838 children, ages 6 through 19 years in a randomly selected sample from the 2003-2008 National Health and Nutrition Examination Surveys.
The BPA concentrations of the participants were divided into four groups (quartiles). Controlling for race, age, caregiver education, poverty to income ratio, sex, serum cotinine level (a bio marker for tobacco smoke exposure), caloric intake, television watching and urinary creatinine level, children in the lowest urinary BPA group had a lower estimated prevalence of obesity (10.3%) than those in quartile 2 (20.1%), quartile 3 (19.0%), and 4 (22.3%). Further analyses showed this association was only statistically significant in 1 subpopulation, white children and adolescents.
The FDA has recently banned BPA in baby bottles and sippy cups, but last year the FDA failed to ban BPA in aluminum cans and other food packaging.
A new theory of obesity has emerged called the “obesogen” theory.. Obesogens are chemicals that disrupt the function of hormonal system; many researchers believe they lead to weight gain and contribute to of numerous diseases we face today including fertility problems, behavioral disorders, impaired immune function, various cancers, and heart disease.
In addition to BPA, obesogens come from a variety of sources including soy-based infant formulas, phthalates (used in plastics), PCBs (found in coolant and electrical equipment, DDE (a pesticide), fungicides, and atrazine (a common pesticide). They can often mimic human hormones such as estrogen; miss-program stem cells to become fat cells, and possibly alter the function of genes. They can affect early development and affect obesity risk later in life. A study reported that prenatal exposure to obesogens in mice was associated with weight gain later in life. In another study, the adult daughters of women who had the highest level of DDE in their blood during childbearing years were found to be 20 pounds heavier, on average, than daughters of women who had the least.
Can the obesity epidemic merely be blamed on just calories in/ calories out or too much fast food and too little exercise? It’s obvious that obesity is caused by a complicated interwoven set of theories, not just one or two or even three. And it’s possible that things will get worse.
The Robert Wood Johnson Foundation and the Trust for America’s Health released a new report a couple of days ago projecting America’s obesity rates through 2030. The report states that If current obesity rates continue, every state could have an obesity rate above 44 percent by 2030, and most states could have rates higher than 50 percent.
That means the prevalence of health problems like type 2 diabetes, heart disease and hypertension could increase 10 times by 2020 — and double by 2030. And in 20 years, the report finds, medical costs for treating obesity-related diseases like these in the United States will be increasing by $48 billion to $66 billion every year.
The obesogen theory may also contribute to the fact that many people are not losing the weight easily by following the old advice (eat less, move more). However, there is still a multitude of studies that support the energy balance model (calories in = calories out). This debate will continue.
What to do?
1. Organic produce is healthier. The recent headlines say they are no more nutritious than conventional produce; however, there are other aspects of health to be considered. Simply choose organic especially when buying the big 12 (highest in pesticide use) – peaches, apples, bell peppers, celery, kale, lettuce, imported grapes, carrots, pears.
2. Cut down the use of plastic – avoid plastic-wrapped meat – try to visit supermarkets with unwrapped meats counters. Don’t put plastic in the microwave – the heat can damage the plastic and release the chemicals into the foods.
3. Cut down on canned foods – buy frozen or fresh when possible.
4. Organic beef has none of the growth hormones or weight-promoting steroids of conventional beef. The same goes for organic milk.
As with all studies, there are alternative explanations for these results. Obese children may drink more canned or bottled beverages or eat more canned foods accounting for the higher urinary BPA levels. Although they adjusted for excessive calorie intake and television watching, it may be sedentary children consume foods that are high in BPA. Obese children may also have higher BPA levels due to BPA storage and release from adipose tissue.
The Bottom Line: This is a theory that certainly needs more investigation. The food industry will more than likely discredit this research and fund studies that produce positive results (for them), thus casting doubt on the science. Any organization that is funded by the food industry will fight the obesogen theory.