BPA thought to cause Obesity

Bisphenol A (BPA) is a chemical that is in plastics that lines cans to protect the food from metal contamination. It is also used in some plastic food containers. some of the BPA leaks out of the plastic into our foods. Governments around the world have refused to ban BPA saying that animals studies are weak and that levels of BPA in the human body are low.

According to the WHO (World Health Organization), over 700 million people with obesity exist worldwide and about 2 billion people are overweight. Endocrine disruptors, like bisphenol A can influence regulation of genes involved in obesity.BPA mainly works by imitating the natural hormone 17B-oestradiol BPA has been shown to alter glucose and lipid metabolism in animal studies, causing weight gain in some cases. A recent study found an association between urinary concentrations of the endocrine disruptor BPA and body mass indexes of children and adults aged 6–19 years. Interestingly, obesity was not correlated with exposure to any other environmental phenols such as those found in soaps or sunscreens. This finding strengthens the association between BPA and obesity.

An increasing number of researchers focus on prenatal and perinatal exposure because developing organisms are extremely sensitive to chemicals that have hormone-like activity. In developing organisms, effects can occur at concentrations of the chemical that are much lower than those that would cause harmful effects in the adult. Studies have indicated that perinatal exposure to BPA at very low concentration feminizes activity and spatial memory of male offspring. This tendency toward feminization has led to a gender difference in sweet and salty taste preference. One study discovered that mature female rats prefer sweeter tastes compared to mature males. Another study exposed rats perinatally to BPA and tested their sweet preference for varying levels of saccharin and sucrose. They found that the correlation discovered previously where mature female rats tend to prefer sweeter tastes compared to mature males was reversed by perinatal exposure to BPA. This finding implies the feminization of males (increased preference for sweet tastes) and masculinization of females upon exposure to BPA.

There are potential effects of BPA exposure during different stages of development. During adulthood, BPA exposure modifies insulin sensitivity and insulin release without affecting weight. Exposure during pregnancy has effects on both mother and offspring later in life. During pregnancy and lactation BPA exposure induces metabolic alterations, including weight gain.

This effect on pancreatic B-cells is significant because its function is to store and release insulin, the main hormone involved in maintaining blood sugar levels. A recent study demonstrated a link between environmental estrogens and insulin resistance. Mice were injected with BPA to replicate plasma concentrations found in late pregnancy. They concluded that BPA imitates the sex hormone 17B-estradiol which leads to a rise in insulin and eventually resistance. This resistance can lead to type 2 diabetes and hypertension.

It is obvious that we are having an obesity epidemic. Obesity may not be a disease but it is a health problem. We need to stop ignoring research and ban BPA in food containers.