I have long wondered why vitamin D deficiency is becoming so common these days. When I was in Seattle, the near epidemic level of vitamin D deficiency seemed easily explained by the lack of sunshine, but I started seeing similar patterns in Arkansas, where we have no shortage of sunshine. This pattern could be explained by the fact that many individuals spend very little time outdoors and use sun protection when outside. When I began seeing vitamin D deficiency in people who get a substantial amount of sun, I wondered what else could be playing a role.
A recent study on pesticides and vitamin D levels offers one possible answer. When over 1000 study participants were tested for both vitamin D and particular pesticides known as organochlorine pesticides, the people with higher levels of these pesticides had lower vitamin D levels on average. Though this inverse correlation could be a coincidence, there are two different means by which pesticides could be interfering with vitamin D levels. These organochlorine pesticides are known to disrupt the endocrine system, and vitamin D is considered to be one of the endocrine hormones. Another possibility is that the pesticides are causing faster breakdown of vitamin D by increasing certain liver detoxification enzymes that remove vitamin D and other substances from the body.
The specific organochlorine pesticides that were associated with lower vitamin D were Lindane and DDT, which unfortunately still persists in our environment despite being banned decades ago. Of course, there are many other reasons for us to try to avoid and eliminate these pesticides from our bodies. DDT has been linked to diabetes, cancer, endocrine issues, and nerve damage. Lindane is neurotoxic, possibly carcinogenic, and associated with developmental defects in babies. Vitamin D deficiency has been associated with decreased immune function and increased risk for osteoporosis, colon cancer, and possibly cardiovascular disease. This new study is only showing us a possible link between pesticides and low levels of vitamin D, but it still gives us further reason to minimize the use of pesticides and consider vitamin D testing for those who experience higher pesticide exposure.