Testing of the level is a bit “controversial” and insurance often doesn’t cover it. I remember when I was practicing and I would test patient’s levels, many times those levels would come back on the low side. Normal range for most labs is 30-80. I always wanted to see that level in the 50-80 range. The lowest level I ever saw in a patient was 4. She was having severe fatigue and joint pains. All other labs came back normal. We supplemented with high dose Vitamin D and she came back 2 months later saying her symptoms were gone and her level came up to the 30’s.
Low Vitamin D levels have been associated with cardiovascular disease, severe asthma in children, cancer, cognitive impairment in adults, and more recently a link with pregnant women having low levels having children with autistic traits by the age of 6.
The cause of Vitamin D deficiency is quite broad including a diet deficient in Vitamin D, lack of sunlight (sunscreen blocks the absorption), malabsorption of Vitamin D (due to leaky gut), and obesity.
This morning I came across an article in The Journal of Clinical Endocrinology & Metabolism discussing the possibility that phthalate exposure has a role in low Vitamin D levels. Once again phthalates are causing trouble. As a refresher, phthalates are plasticizers used to make plastic pliable and scents stick to the skin.
What can be done? Eat a well balanced diet making sure to get a wide variety of vegetables, be mindful of how often you wear sunscreen, if you aren’t going to be outside for more than a few minutes skip the sunscreen, supplement with Vitamin D3 (I usually recommend 1000-2000IU/day), avoid plastic, avoid products containing fragrance.
Article on phthalates and Vitamin D deficiency- http://press.endocrine.org/doi/10.1210/jc.2016-2134