A new mouse study sheds light on how chemicals from plastic may increase obesity risk.

Drinking-Water From Bottle

What the heck is BPA?  BPA is a chemical found in a variety of plastic food containers, water bottles, and can linings. BPA is employed to make certain plastics and epoxy resins. BPA is a clear, tough plastic that is made into a variety of everyday consumer goods, such as water bottles, sports equipment, CDs, and DVDs.  In epoxy resin, it has been used in water pipes.  You can quickly see why it is found in the urine of many Americans.  

What does BPA do to us?  We don’t really know.  There is research that suggests ties, but we don’t have definitive studies of their effects on people. The U.S. Food and Drug Administration (FDA) previously said that BPA was safe, but in 2010 the agency altered its position. Now, the FDA maintains that studies using standardized toxicity tests have shown BPA to be safe at the current low levels of human exposure.  But based on assertional evidence, obtained largely from animal studies, the FDA expressed concerns about the potential adverse effects of BPA.

A new study published in the February issue of Endocrinology adds to the mounting evidence that continues to highlight the evils of BPA[1].  It has been linked to decreasing hormone levels in women by reducing estrogen production and many other illnesses in both males and females.  BPA appears to interfere with the endocrine system by disrupting the production, secretion, transport, action, function, and elimination of natural hormones such as estrogen and testosterone.  BPA can imitate or reduce the function of our body’s hormones in a way that could be hazardous to our health.  Babies fetuses and young children are more sensitive to the effects of chemicals such as BPA.

What are the possible health effects of bisphenol A (BPA) on humans[2]?

1. 

   Water bottle in fitness

   Asthma.  There has been a reported link between increasing asthma rates and a particular threshold of BPA.

2. Reproductive disorders.  BPA exposure may affect egg maturation in humans.
3. Hormone levels.  Some experts believe that BPA could theoretically act like hormones in our bodies.  Because of this hormone-like activity, BPA disrupts normal hormone levels and development in fetuses, babies, and children.
4. Male impotence.  BPA exposure may raise the risk of erectile dysfunction. Sexual desire issues and problems with ejaculation were also linked to BPA exposure among men.
5. Female fertility.  Exposure to BPA may reduce fertility and affect the quality of a woman’s eggs retrieved for in vitro fertilization (IVF).
6. Heart disease.  BPA can cause heart disease in women.  We know that BPA affects estrogen activity or production and estrogen is cardioprotective so it would make sense that BPA would increase the risk of heart disease.  
7. Cardiovascular disease in all adults.   Another US study linked BPA exposure to diabetes and heart disease in adults.  However, the higher incidence could be unrelated to BPA.
8. Sex hormones in men.   BPA exposure may cause changes in sex hormones in men.
9. Type 2 diabetes.  Higher levels of urinary BPA may be linked to type 2 diabetes, cardiovascular disease, and liver enzyme abnormalities.
10. Brain and behavior problems. After a review of the evidence, the National Toxicology Program at the FDA has expressed concern about BPA’s possible effects on the brain and behavior of infants and young children.  BPA exposure may be associated with loss of connections between brain cells in primates, potential problems with memory and learning, as well as depression.
11. Chemotherapy.  Scientists believe that BPA exposure may reduce chemotherapy treatment efficacy.
12. Cancer.  Some animal studies have shown a possible link between BPA exposure and a later increased risk of cancer.  In particular, there may be a link to an increase in breast cancer risk among females exposed to BPA and DES in the womb. 
13. Increased risk to children. Some studies suggest that the possible effects of BPA could be most pronounced in infants and young children. Their bodies are still developing, and they are less efficient at eliminating substances from their systems.

How big is the problem?

The CDC (Centers for Disease Control and Prevention) reports that urine samples in 95% of adult humans and 93% of children contain bisphenol-A.  Experts say the primary source of human exposure is BPA leached from the plastic lining of canned foods.

The Bottom Line:  Although this list of possible BPA risks is frightening, keep in mind that nothing has been fully established.  The concern about BPA risks stems primarily from studies in animals, and there is very little evidence of ties to disease in humans.  There are a few studies in humans that have found a correlation between BPA and a higher incidence of certain health problems, but there is no direct evidence that BPA is the cause of the problems. To be honest, other studies contradict some of these results and some experts doubt that BPA is the problem at the exposure levels.  That being said, I would recommend taking precautions against BPA exposure and limiting the number of plastic containers you use.