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For years natural health and nutrition experts (other than here at Steady Health) have been telling us that the right dosage of vitamin D is more, more, more. Recently, however, researchers have begun to realize that low concentrations of vitamin D in the bloodstream may be the result of diseases rather than their cause.
The Reality of the Relationship of Vitamin D and Disease Not in Doubt
When French researchers did a meta-analysis of 290 published scientific studies of the relationship of vitamin D concentrations in the bloodstream and various diseases, they found strong evidence that low levels of vitamin D are related to cardiovascular disease, type 2 diabetes, infections, and psychiatric disorders.
Cause and Effect Relationships of Vitamin D and Disease in Question
The findings of decades of research, however, only shows that there is a correlation, a relationship, between vitamin D levels and various diseases. Almost no research has been designed to answer the question of whether low vitamin D levels cause disease (and therefore supplemental vitamin D might cure them), or diseases deplete vitamin D.
Dr. Philippe Autier, MD, MPH, PhD, vice president of population studies at the International Prevention Research Institute in Lyon, France, was able to locate interventional studies of the use of vitamin D as a treatment in studies involving 2,805 people who had low test levels of vitamin D. These studies showed no benefit when people who were already sick were given supplemental vitamin D.
Vitamin D Apparently Does Not Improve Type 2 Diabetes
When the statistically robust relationship between low vitamin D levels and type 2 diabetes was discovered about 20 years ago, many natural health enthusiasts, including some doctors who wrote books, assumed that they had stumbled across a safe, inexpensive, natural cure for diabetes. Over the following 20 years, however, these same doctors and researchers failed to have any patients who actually went into remission as a result of taking vitamin D. (If you are a diabetic who did, of course, please feel free to comment below.)
When Dr. Autier and his associates looked at a subset of 16 studies in which researchers used vitamin D as a treatment for type 2 diabetes, they found taking the vitamin did not result in lower glycosylated hemoglobin (HbA1c). Since HbA1c is the standard measurement of diabetes control, any treatment that does not lower this number cannot be said to treat diabetes. After all, diabetes is a condition in which one really does "treat the number," controlling blood glucose levels to prevent the effects of high blood sugar levels, although there are subtle differences in the effects of high blood sugar levels from diabetic to diabetic.
Vitamin D Not a Cure for Cancer, Either
Autier and colleagues also looked for evidence to support the frequent claim that vitamin D supplementation helps cancer patients go into remission. Overall, there was some evidence that higher vitamin D levels may be associated with a lower risk of colorectal cancer, but no other forms of cancer. Two of the studies, however, found that there was no benefit of vitamin D in the prevention or treatment of any form of cancer.