New Clinical Metastudy Finds Vitamin D No Help to Middle Age Bones
If you think about it, it’s not hard to believe that the bones of a seventy-year old are different from those of a forty-year old. From there it’s also understandable that a vitamin that helps the bones of a seventy-year old might not have the same effect for a forty-year old.
That’s why a new study based on the results of 23 clinical trials shows that vitamin D might be of some help for the elderly, but has almost no effect for the middle aged.
The study, conducted in New Zealand, examined the results of various vitamin D clinical trials involving more than 4,000 people. This was a typical metastudy, combining the results of many studies and submitting them to statistical analysis and interpretation. The main goal of the study was to probe the ongoing research into the effect of vitamin D on bone health and development, especially in combination with calcium.
For more than a decade, the popular notion of vitamin D approaches that of a wonder drug. It’s seen as beneficial, especially in large daily doses, for prevention of cancer, heart disease and many other chronic illnesses. The connection between vitamin D and bone health predates even the latest trends.
There’s no doubt that vitamin D is an important vitamin with a very complicated utilization by the body. At this point, none can claim full understanding of what it does, much less, how it works. It’s also rather unique in that while it is one of the vitamins produced by the human body, it’s a product of sunlight on the skin.
As should be obvious, that’s a variable. In some places, in some seasons it would be quite easy for people to have insufficient sunlight to produce adequate quantities of vitamin D, Scandinavia, for example. Ditto for people who stay indoors all the time.
Consequently, between people with one degree of vitamin D deficiency or another and the rampant touting of vitamin D for all sorts of health reasons, vitamin D supplements are a hot topic and a multi-million dollar piece of the vitamin industry.
This new study, published in the journal The Lancet, focused on the bone health property of vitamin D, which is mainly that it aids in the absorption of calcium through the intestines. Calcium is still the key factor, as that’s primarily what bones are made of, but vitamin D is linked to the process of making bone through its dietary role. The working hypothesis for most of the clinical trials was that taking a daily vitamin D supplement (for two years or more) would be beneficial for bones.
What the review study found, however, was for middle-aged people (women and men) the vitamin D regime had no effect on the bone density in the spine, hip, arms and general skeleton. There was some increase in density for the femur (leg bone). The review also found that adding a calcium supplement also had no effect on bone density and health – for middle-aged people.
There were two exceptions to the study’s generally negative findings, both of them somewhat obvious. One was that people with a vitamin D deficiency were clearly helped by taking supplements. The other was that elderly people (65+) were generally helped by taking vitamin D and calcium supplements.
It’s well known that as we reach old age, bone mass and density decreases. Diseases such as osteoporosis are also more common in the elderly.
What seemed to be a common factor in both exceptions to the general results was that taking vitamin D in combination with calcium helped only when a person is low on either, or both. Put another way, if you have enough calcium circulating in your body, more vitamin D has no effect. Since most middle-age adults get more than enough calcium through food (e.g. dairy products, fatty fish, some vegetables), additional vitamin D is of no benefit.
These results are in general agreement with the U.S. Preventative Services Task Force, which said that there is no evidence taking calcium supplements and up to 400 International Units of vitamin D a day are beneficial for the bones of healthy people. They qualified their recommendation by adding that this does not apply to people who already have osteoporosis or for people over 65.