Vitamin D is known to help our bodies to build bones and muscles, as well as playing a suspected role in preventing chronic diseases, but too much vitamin D can prove ineffective. That’s the conclusion of a study about super doses of vitamin D; too much vitamin D does not appear to reduce the risk of falling or suffering fractures in elderly women.

Our bodies produce vitamin D naturally when exposed to UV radiation, but due to an increased concern over skin cancer and increased use of sunscreens, vitamin D deficiency has become a worrying trend. Much research is now being done to ascertain the ‘right’ amount for vitamin D supplementation; mostly among the elderly, who are at increased risk of falls and fractures, which are a major cause of death.

In a recent study lead by Professor Geoffrey Nicholson (and Professor Kerrie Sanders), 2,256 women aged 70 or higher were randomly assigned to receive 500,000 IU of cholecalciferol (a form of vitamin D) or placebo once a year for up to 5 years.

To the researchers’ surprise, the group of women who received megadoses of vitamin D actually experienced 15% more falls and 26 % more fractures.

According to studies with animals, in rats, for example, the body may perceive the sudden influx of vitamin D as a foreign substance. The body wants to rid itself of what it believes to be a toxin, and so the enzyme responsible goes into overdrive. This results in converting active forms of the vitamin into inactive forms, which leaves the body vitamin D deficient.

While the researchers may have been disappointed with their findings, at least, according to Prof Nicholson, the results are “useful in actually defining that the megadosing regime is unsafe, and that high annual doses need to be considered with some caution.”

Reference:

http://www.barwonhealth.org.au/research/keyresearchprojects/default.aspx

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Tags: about, discussion, health, megadose, research, skin, sunlight, the vitamin d debate, UV, vitamin d, vitamin d debate

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