Braininvat, I took the opportunity to have a close look at the article on vitamin D that you cited on the following website -
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356951/ My motivation for doing so was to check on all of the other benefits of vitamin D apart from being a transporter of calcium throughout the body.
I'm a bit embarrassed because I don't like to be negative but I saw what I thought to be many flaws in the paper. In a way, I would like to be proven wrong in what I found.
Also, in a way, this reference supports my comments in an earlier post about the ‘iffy’ and ‘butty’ nature of the vitamin D research.
The Introduction refers to the role of poor exposure to sunlight -
“This pandemic of hypovitaminosis D can mainly be attributed to lifestyle and environmental factors that reduce exposure to sunlight, which is required for ultraviolet-B (UVB)-induced vitamin D production in the skin. Black people absorb more UVB in the melanin of their skin than do white people and, therefore, require more sun exposure to produce the same amount of vitamin D.[4]”This was not so important, but if there is a pandemic, I would have thought that the authors would suggest more possibilities. I could be wrong, but I imagine that the cholesterol toxicity myth of the last 6 or 7 decades, may be playing a role. Is there a possibility that we’ve all been eating less fats and therefore taking in less fat-soluble vitamins? Could a low blood vitamin D concentration indicate low vitamins A, E and K, as well as essential fatty acids by association?
This is the first statement that took my eye –
“Vitamin D influences the bones, intestines, immune and cardiovascular systems, pancreas, muscles, brain, and the control of cell cycles.[63]” I took the opportunity to check on the full text of reference 63. I have no idea how the above conclusion was drawn from that study and it’s difficult to understand how the editor’s referees did not question THIS entire paper before publication. Reference 63 has been grossly misquoted. The authors found low blood vitamin D concentrations in more than 50% of seriously ill in-patients in a hospital and recorded the following conditions associated with those low concentrations.
I have no idea how anyone could interpret this list to be able to say
“Vitamin D influences the bones, intestines, immune and cardiovascular systems, pancreas, muscles, brain, and the control of cell cycles.[63]"
There were many other possible factors that they did not check.
A list of the
Clinical benefits of vitamin D was provided. It included the following
Cancer
Heart disease
Hypertension
Obesity
Type 2 diabetes
Depression
Cognitive impairment
Parkinson's disease
Fractures and falls
Autoimmune diseases
Influenza
Bacterial vaginosis
Pelvic floor disorders
Age-related macular regeneration
I didn't see 'Ingrown Toenails' listed, but I can see why the term 'Vitamin D Religion' has been coined.
The list looks impressive and virtually too good to be true. In view of the misinterpretation of reference 63, I decided to check on the supportive evidence for the items in this impressive list.
I began with the first -
Cancer The claim here is that "
Vitamin D decreases cell proliferation and increases cell differentiation, stops the growth of new blood vessels, and has significant anti-inflammatory effects.[71,72]"The conclusion of ref 71 states
"The findings of this large prospective study do not support the hypothesis that vitamin D is associated with decreased risk of prostate cancer; indeed, higher circulating 25(OH)D concentrations may be associated with increased risk of aggressive disease." How does this support the above statement - "
Vitamin D decreases cell proliferation and increases cell differentiation, stops the growth of new blood vessels, and has significant anti-inflammatory effects?[71,72]"Similarly, the conclusion of ref 72 states "No associations were found between overall vitamin D or calcium intake and breast cancer risk. Vitamin D from supplements was independently associated with reduced breast cancer risk. Further research is needed to investigate the effects of higher doses of vitamin D and calcium supplements." The statement that Vitamin D from supplements was independently associated with reduced breast cancer risk prompted me to check on the 'supplements'.
This was the official Result wording on this - "No significant ORs (Odds Ratio) were observed between milk, margarine, dairy, or fish intake and breast cancer risk (Table 2). However, OR point estimates increased with milk intake (P for trend = 0.04). Single-product vitamin D supplements or
cod liver oil were used by only 13% of cases and 14% of controls, and, although no categories of frequency or duration of use were significantly associated with breast cancer risk, a significant inverse dose-response relation was observed between frequency of supplement use and breast cancer risk (P for trend = 0.04)."
I’m not sure of the ‘single-product vitamin D supplement’, but the
cod liver oil also possesses a high vitamin A content. And milk contains much more than vitamin D.
I didn't check any further, but I am embarrassed at finding so much bad science in this paper.