As I've remarked before the two supplements that I routinely recommend to my patients most are Krill Oil and Vitamin D3. Studies on Vitamin D in particular have really increased in frequency over the last year. So, I thought I would do a quick review of some that caught my eye!
First, is a study that over six months looked at Vitamin D 3 supplementation at 2000 iu a day in patients with Type II Diabetes. There were several metabolic improvements. Most notably, significant decreases in LDL (commonly called "bad cholesterol") and LDL/HDL ratio. Given our current accepted understanding of cholesterol (which may be changing, but that's a conversation for another day) and risk for coronary artery disease, you would expect to see decreased risk for cardiac events. Problems with this study are the relative small size and lack of placebo arm for comparison.
Secondly, a recent meta-analysis looked at Vitamin D supplementation and prevention of dental caries. This did show a positive association with Vitamin D supplementation and decreased dental caries up to the age of 13, at which the association did not continue. Unfortunately, this study did not break out traditional Vitamin D supplements with Vitamin D3 supplementation and as noted this was not a causal relationship but an association. Certainly, more study is warranted.
Third, a large study looked at Vitamin D levels and risk for development of diabetes. It did confirm a large relationship between Vitamin D levels and likelihood of developing diabetes. I found the following quote interesting (it does make sense):
"As the researchers explain, worldwide rates of type 1 diabetes vary by latitude, with annual age-standardized incidences ranging from a low in the tropics (0.5 per 100,000 in Venezuela) to a high near the Arctic Circle (60/100,000 in Finland). "
Another study showed a link between low Vitamin D levels and severe mental disease in adolescents. This study showed a link between development of seasonal allergies and asthma and low Vitamin D levels. Also, Low Vitamin D Linked to Alzheimer's.
These are just some highlights from the last couple of months. The bottom line is that low Vitamin D levels are highly correlated with numerous disease and metabolic abnormalities in the human body, but is it causative or associative? Which came first the chicken or the egg? Does Diabetes or Alzheimer's cause changes in the human body which inhibit Vitamin D levels? Also, does absolute level matter or does source of Vitamin D (artificial supplementation versus sun exposure)?
We need more "good" (double blind placebo controlled trials) to answer these questions. For now, I continue to recommend Vitamin D3 supplementation (dose depending on what patient's levels are found to be - usually 2000-5000 units a day). But also, get out in the sun a little. Some some exposure daily is good for us! Just don't overdo it!