Odds are that most people reading this have leftovers sitting in their refrigerator in a plastic container and plan to reheat them in a microwave. But, maybe that is not such a great idea. A new study shows that microwaving food in those plastic containers, as well as plastic stretch wrap, cosmetics and other products, may lead to an increased risk for developing diabetes and high blood pressure. Before throwing out that Tupperware or Rubbermaid, however, read on.

Reheating food in a plastic storage container has been shown to unleash toxic chemicals into the food. Some of those chemicals were shown to cause insulin resistance and high blood pressure. Both of those risks are factors that are known to lead to diabetes. They do leech a small amount of chemicals sitting in the containers without reheating, but the study did not show a significant impact on the body when the containers are used for the intended purpose of storage.

It is when heating food in plastic containers in the microwave, and to some degree using hot water in the dishwasher, that chemicals in the plastic escape. “Heating enhances contamination,” according to Dr. Leonardo Trasande, a New York University (NYU) Langone Medical Center professor involved with the study, which was published in the American Heart Association publication Hypertension.

Focusing on the impact on children and teens, the population that would clearly have the longest “lifelong effects” from exposure going forward, the research team studied two of the compounds in plastics, di-isononyl phthalate (DINP) and di-isodecyl phthalate (DIDP), that were introduced into the production process within the last 10 years.

For their study, the NYU team examined blood and urine samples collected between 2008 and 2012 from 356 children and adolescents who were 12- to 19-years old. The blood was measured and evaluated for phthalates and glucose based on urinary levels of the substances. Diet, ethnicity, gender, levels of physical activity, family income and other factors known to affect risk for insulin resistance and hypertension were also factored into the analysis. They also quantified exposure to common phthalates, particularly dietary contamination from them as shown in the kids’ urine.

It should be noted that they were introduced because the previous chemical, di-2-ethylhexylphlatate or DEHP, manufacturers used was found to be dangerous too. Many products are not tested for health issues until something warrants the investigation. As Trasande noted. “Our study adds further concern for the need to test chemicals for toxicity prior to their broad and widespread use, which is not required under current federal law.”

This is not the first NYU study published to show issues or diabetes ties with the replacement chemicals. A study released in May in the Journal of Clinical Endocrinology and Metabolism also demonstrated a “significant association” between high blood pressure and the chemicals. Trasande noted that the studies indicate potential health risks from the DEHP replacements and still indicate concerns with plastics used in food preparation.

The researchers emphasize that further longitudinal studies are needs to delve deeper into the associations uncovered. In the meantime, to minimize exposure to phthalates, they suggest avoiding use of plastic containers with the numbers 3, 6 or 7 located in the recycle symbol on the bottom. In addition, to ensure that leftover food may not eventually lead to diabetes, or at least increase the risk factors, avoid microwaving it in the plastic container or putting the plastic in a hot dishwasher.

Dyanne Weiss