Bisphenol-A (BPA) is widely spread in the plastic we use every day. It may be toxic even at low doses, and has been associated with various human diseases. Differences in the susceptibility of people to the adverse effects of BPA depend on the different amount of BPA consumed, and on personal ability of an individual to effectively excrete BPA.

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Routes of exposure

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BPA is mainly found in toys, drinking containers, dental sealants, water pipes, and food containers. The primary route of exposure to BPA is through oral intake, but exposure can also occur via dermal contact or through inhalation.

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Health effects of BPA

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BPA is an environmental endocrine disruptor, mimicking the action of human estrogen. It is considered a health threat due to its widespread exposure and the potential for toxicity at low doses. BPA has been associated with various human diseases including breast cancer, prostate cancer, polycystic ovary disease, cardiovascular disease, diabetes, obesity, asthma and thyroid maladies.

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​Metabolism

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After ingestion, BPA is taken up by the body and must be metabolized to enable efficient excretion. The main route of metabolism of BPA in humans is glucuronidation, which occurs primarily in the liver and is mediated by the UDP-glucuronosyltransferase (UGT) enzymes.

The UGT2B15 enzyme acts mainly in the liver, and is responsible for 50-80% of total BPA metabolism.

The UGT1A1 enzyme contributes to BPA metabolism mainly in breast tissue.

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The GSTP1 gene plays a significant role in antioxidant defense mechanisms. It may be responsible for conjugation of BPA metabolites with glutathione, which could increase BPA excretion.

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How to reduce the risk from exposure to BPA

These following precautions should help reduce a genetic sensitivity to BPA: 

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• Minimize consumption from canned foods. Linings of cans contain BPA may leak into the food. Eat more fresh food.

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• Check for the type of plastic. Polycarbonate containers that contain BPA are usually marked on the bottom of the package with a number 7 recycling code, or as “PC”. Containers marked by the number 3 recycling code may also contain BPA. Prefer cardboard, stainless steel or glass containers or bottles.

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• Do not microwave polycarbonate plastic food containers. Polycarbonate plastic is used in packaging for many microwaveable foods, and may break down at high temperatures to release BPA.

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• Avoid pouring hot water or storing hot food into plastic containers. 

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• Freezer temperatures can cause plastics to deteriorate, which increases the leaching of chemicals into the food when you take containers out of the freezer to thaw or reheat. Note that there is still a debate over the level of exposure from heated or frozen plastic containers, but you may want to be extra cautious.

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• BPA is fat soluble. Oily or acidic food items absorb more BPA, so be extra cautious with such foods.

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• Many cash/credit register receipts are coated with (a lot of) BPA. Heat-activated paper receipts (“thermal papers”) are widely used and are laden with BPA, making up to 3% of the weight of the paper. That’s hundreds of times more than the BPA that may leach from food packages. This BPA powder is readily absorbed through skin and mouth. Therefore, if you don't need a receipt, leave it. If you need the receipt, ask the cashier to place it in the bag. When you get home, remove receipts from all bags, place them in a drawer or space on your desk just for the receipts, and avoid further unnecessary contact. Be sure to wash your hands well after handling receipts. Use soap, since hand sanitizers (and lotion creams) speed up the uptake of BPA through the skin. Do not place receipts in bags with food items, especially items you eat raw. 

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