Plastic May Lower Vitamin D Levels

The research denouncing BPA, a chemical commonly used in plastics, seems to be building up all the time. BPA is now one of the most widely known endocrine disruptors, named as such because of their documented negative effects on our hormones. Another type of endocrine disruptor is the phthalates, which are found in many cosmetics and children's products, as well as medical tubing and food packaging. These seem to be less well-known, maybe because of the hard-to-remember name. Now, a new study is showing a link between these chemicals and low levels of vitamin D.

"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 the study's first author, Lauren Johns. Vitamin D plays a key role in the maintenance of muscle and bone health; a severe deficiency in childhood can cause rickets, a disease that results in soft, weak bones and associated deformities. Inadequate sun exposure and nutritional deficiencies are the main causes of rickets, which is rare in Australia but on the rise. Less severe deficiencies have been linked with cardiovascular diseases, some cancers, diabetes and autoimmune conditions. Higher levels of vitamin D may also protect the independence of the elderly. A study of over 2,000 people found that those with vitamin D levels under 50nmol/L had a 29% higher risk of mobility limitation, and a 93% higher risk of mobility disability, than people with levels higher than 75nmol/L. Volunteers whose levels were between 50 and 75nmol/L had a 27% higher risk of limitations and a 30% higher risk of disability.

This study examined data from 4,667 adult volunteers in the National Health and Nutrition Examination Survey (NHANES), from 2005 to 2010. This is a cross-sectional study aiming to collect health and nutrition data from a sample of US adults meant to represent the general population. Information on vitamin D levels were taken from blood test results, and endocrine disruptor exposure was measured by urine samples. The study found a link between the level of phthalates, another type of endocrine disruptor, and low levels of vitamin D in both sexes, although the link was stronger in women. The link between higher BPA levels and low vitamin D was only significant in women. While more research is needed, these endocrine disruptors are thought to alter the active form of vitamin D, possibly by the same mechanisms that they use to interfere with thyroid and reproductive hormones.