Exposure to endocrine-disrupting chemicals, including bisphenol A (BPA) and phthalates, has been linked to a wide array of health problems, including infertility, diabetes, obesity and neurological problems, according to a scientific statement by the Endocrine Society.
Endocrine disruptors are chemicals that mimic or disrupt the action of hormones in the body. Because hormones control so many delicate bodily functions, the health implications of such disruption are enormous.
Now a study conducted by researchers from the University of Michigan, and published in the Journal of Clinical Endocrinology & Metabolism, has demonstrated another potential effect of endocrine disruption: lower vitamin D levels.
“Nearly every person on the planet is exposed to BPA and another class of endocrine-disrupting chemicals called phthalates, so the possibility that these chemicals may even slightly reduce vitamin D levels has widespread implications for public health,” said first author, Lauren Johns.
“Vitamin D plays a broad role in maintaining bone and muscle health. In addition, low vitamin D levels have been implicated in outcomes of numerous conditions such as cardiovascular disease, diabetes and cancer.”
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The new study focused on two separate classes of EDCs: the chemical BPA, found in everything from plastics to food cans; and phthalates, which are found in medical tubing, soft plastics, food packages and even cosmetics and children’s products.
The study was conducted on 4,667 adults who had participated in the National Health and Nutrition Examination Survey (NHANES) between 2005 and 2010. The researchers tested the participants’ urine for metabolites of BPA and phthalates, and compared these results with blood tests for vitamin D levels.
The researchers found that people with higher exposure to phthalates had significantly lower levels of circulating vitamin D. This effect was even stronger in women than in men.
The researchers found that women with higher BPA exposure also had lower vitamin D levels.
“More research is needed into why an association exists, but it is possible that EDCs alter the active form of vitamin D in the body through some of the same mechanisms that they use to impact similar reproductive and thyroid hormones,” senior author John D. Meeker said.
Although it is called a vitamin, vitamin D is technically a hormone. It can be produced naturally by the body from sunlight exposure or absorbed through the diet.
Sunlight more important than ever
Globally, low levels of vitamin D are considered a major public health problem; that’s because vitamin D plays a critical role in regulating several bodily systems, particularly the immune system.
Previously, scientists thought that vitamin D was only good for helping to build strong bones and teeth. But they now know that levels of vitamin D high enough to maintain bone health can still be low enough to cause autoimmune diseases, cancer, susceptibility to infection, cardiovascular disease and diabetes. Low vitamin D levels have also been linked to dementia and even schizophrenia.
According to a 2010 study, between 50 and 90 percent of a person’s vitamin D is produced by their own body. In fact, it is relatively easy for the body to generate 10,000 IU of the vitamin per day, given only moderate exposure to the sun.
The greatest factors contributing to vitamin D deficiency are insufficient time spent outside, ultraviolet (UV)-blocking behaviors such as use of sunscreen or heavily covering clothing, and living at a latitude far from the equator. People with darker skin – which blocks UV radiation – are also at higher risk, particularly if they have another risk factor.
All it takes to get enough vitamin D though is less than an hour of (sunblock-free) sun on your face and hands each day. For very pale-skinned people, it may take only 15–30 minutes – significantly less time than it takes to burn.
Sources for this article include:
H/t reader kevin a.