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    @alansonbrown This is a terribly unscientific post—there is no mechanistic evidence (ie. mouse studies) to support their claim. To address their clinical data, you cannot use randomized controlled trials to investigate the effects of vitamin (including vitamin D) and mineral supplementation. When you begin with a population of people, these individuals have varying concentrations of vitamins D due to varying degrees of sun exposure and diet. You cannot just randomly assign these individuals into two groups and give them a vitamin/mineral supplement without measuring the concentrations of these vitamin D at baseline (before the trial). You want to make sure that the individuals both groups start with similar levels of whatever particular micronutrient you are investigating or multiple micronutrients if you are interested in a specific effect of vitamin D.

    One of the studies that was used to show that vitamins have no effect on cancer incidence was vitamin D. Postmenopausal women were given only 400 IU of vitamin D and 1,000 mg of calcium a day for 6 years and colon cancer incidence was determined. After two years of supplementation the women talking the vitamin D/calcium were still deficient in D they had levels of 23ng/ml compared to the placebo which was 12ng/ml. You need vitamin D levels of 30 ng/ml just to maintain normal bone homeostasis. Neither of these groups even met that requirment and you are going to make a conclusion that vitamin D has no effect on colon cancer incidence just because your treatment group had slightly high D levels than your placebo, even though they were still deficient? Why not make the conclusion, 400 IU per day after 2 years was not an adequate dose to raise vitamin D levels to an adequate status. Therefore, no conclusion can be made on the effect of vitamin D supplementation on colon cancer incidence…because we did not give these women an adequate dose! It has been shown that supplementing with 400 IU per day on average only raises serum vitamin D levels by 5ng/ml. That is not very much particularly for a person that is vitamin D deficient. If you want to determine the potential benefits of vitamin D supplementation on different disease outcomes, don’t you think it would be more effective to give people a dose of vitamin D that will ensure they have adequate levels?

    If we look at other studies with higher vitamin D supplementation we see that a daily dose of 1500 IU of vitamin D resulted in a 17% reduction in total cancer incidence, a 29% reduction in total cancer mortality, a 43% decrease in cancer of the digestive system (including colon cancer) as well as a 45% decrease in cancer mortality associated with digestive system cancers. Research from UCSD found that women supplementing with 2000 IU/day and had serum levels of 52ng/ml was associated with a 50% reduction in breast cancer incidence.

    This article repeatedly and emphatically states: “correlation does not equal causation."This is true and is WHY WE TURN TO MOUSE MODELS TO INVESTIGATE THE MECHANISMS BY WHICH VITAMIN D HORMONE PREVENTS DISEASES OF AGING. They do not cite one paper using mouse models. There are thousands of well-done mechanistic studies that have been done on mice demonstrating the protective effect of vitamin D hormone on inflammation, DNA damage, mitochondrial function, metabolism, bone homeostasis, brain function and behavior, lipid metabolism, immune function and more.