Question: I have heard that we should avoid storing food in plastic containers because they contain dangerous chemicals known as endocrine disrupters. Can you explain what these are and what the concern is?

Dr. Brownstein's Answer:

If you look closely at most plastic products — including containers — you will find a triangle with a number in the middle. These numbers indicate what the plastic is made of, and whether or not the product is “safe” to recycle.

But they also tell you if the plastics contain endocrine disruptors. These are chemicals we are exposed to every day that have been linked to breast and prostate cancer, widespread thyroid disorders, and problems with fertility. Endocrine disrupters, such as bisphenol A (BPA), triclosan, and phthalates, have a similar chemical structure to the body’s own hormones, and research has shown that they can interfere with the body’s signaling pathways by binding to hormone receptors.

Recycling codes 3 and 7 are more likely to contain phthalates and/or bisphenoyl A. Plastics coded 1, 2, or 5 may be safer. However, there may be other components that are endocrine disrupters.

It is best to avoid food in a plastic container, if possible. Glass or ceramic containers are much safer. It is also important that you never heat food in a container labeled with a 3 or 7, because it will cause more phthalates to be released. In fact, you should never heat any food in a plastic container.