Published: Oct 14, 2013
Author: BioCeuticals - Editor
International vitamin D experts maintain that vitamin D supplementation is recommended for the maintenance of healthy bones, despite a controversial meta-analysis finding that vitamin D supplements have no beneficial effect on bone density.
The study Effects of Vitamin D Supplements on Bone Mineral Density: A Systematic Review and Meta-Analysis, was published late last week in The Lancet and analysed data from 23 studies involving 4000 healthy people. The study researchers, led by Professor Ian Reid from the University of Auckland in New Zealand, concluded that “Continuing widespread use of vitamin D for osteoporosis prevention in community-dwelling adults without specific risk factors for vitamin D deficiency seems to be inappropriate.”
According to a statement from the United States’ peak body the Council for Responsible Nutrition (CRN) Vice President of Scientific and Regulatory Affairs, Duffy MacKay, N.D. says “one of the serious limitations of this meta-analysis was the lack of consideration of studies that looked at how vitamin D and calcium work together.
“For populations that are most vulnerable to vitamin D deficiencies and insufficiencies – especially older adults – getting vitamin D from food alone is particularly challenging, and so supplementation may be warranted”.
A number of global public health and nutrition experts have also warned that the study, which was published this week in the Lancet, is being misinterpreted by mainstream, non-expert media outlets, who have reported the findings outside of their wider scientific context.
The Complementary Healthcare Council agrees with the CRN, saying in a statement issued today “this meta-analysis looks at the effects of vitamin D supplementation without co-administration of calcium on the effects of fracture prevention. This is a serious limitation as the scientific literature supports that vitamin D and calcium work together to provide a protective effect for helping to prevent osteoporosis.
“A further limitation is that the meta-analysis only looks at the effect of vitamin D supplementation on bone health. A large body of scientific literature shows that vitamin D plays an important role in other areas, such as cardiovascular health, immune health and diabetes”.
World-renowned vitamin D specialist, Professor Michael Holick, PhD MD, says “Vitamin D is important for maintenance of bone health, improved muscle performance as well as reducing the risk of many serious chronic illnesses later in life including osteoporosis, cardiovascular disease, common cancers and infectious diseases.
“For children, we now know that if they don’t get enough vitamin D then they wont be able to achieve their genetically pre-programmed maximum bone density and height. For young and mid-age adults [a lack of vitamin D] cannot only reduce their bone density but cause a bone disease known as osteomalaysia, which is associated with symptoms that mimic fibromyalgia. And many patients that are diagnosed with fibromyalgia are in fact vitamin D deficient,” says Prof. Holick.
In his book, The Vitamin D Solution, Prof. Holick recommends a three-step process consisting of eating foods that are fortified with vitamin D, taking vitamin D supplementation and sensibly exposing skin to the sun for a few minutes between the prime hours of 10am to 3pm.
“Simply trying to get vitamin D from dietary sources is not adequate. The Australian Cancer Council as well as dermatology associations are now realising that some sensible sun exposure is really important for getting adequate vitamin D. If you do that, in my opinion, you’re not at increased risk of skin cancer, but you will be taking advantage of the beneficial effects of sunlight,” says Prof. Holick.
According to data from the meta-analysis, vitamin D supplements were taken for an average of two years by the study participants.
The trials took place in a number of different countries including the UK, the US, Australia, Holland, Finland and Norway.
The authors found that vitamin D supplementation over the two years resulted in no change in bone mineral density at four major skeletal sites (spine, total hip, radius and total body), with a significant increase only at the femoral neck (0.8%, 95% CI 0.2-1.4).
According to the authors, this effect is unlikely to be clinically significant and they concluded that their findings showed that healthy adults did not need to take vitamin D supplements.
"Our data suggest that the targeting of low-dose vitamin D supplements only to individuals who are likely to be deficient could free up substantial resources that could be better used elsewhere in healthcare," they wrote.
But a criticism of the research, published on The New Hope website, says that the average vitamin D status in the data was about 20ng/ml, which is the amount recommended the US institute of Medicine, “but far less than the 35-60ng/ml that’s recommended by vitamin D savvy researchers and medical practitioners.
“In 10 studies individuals were given less than 800 IU/day, which is the official recommended amount to take – but far less than the 2,000 IU vitamin D researchers were recommending to the [Food and Drug Administration] before it issued its recommendations.
According to New Hope “what we have is too little vitamin D given, and not in combination with calcium”.
A position statement published in the Medical Journal of Australia in 2012 titled “Vitamin D and health in adults in Australia and New Zealand: a position statement” concurs with the Council for Responsible Nutrition statement that diet is not always a reliable way to get adequate vitamin D.
“Most adults are unlikely to obtain more than 5%–10% of their vitamin D requirement from dietary sources. The main source of vitamin D for people residing in Australia and New Zealand is exposure to sunlight,” the MJA papers states.
According to the authors of the position statement, led by Vitamin D expert, Professor Caryl A Nowson, the Chair in Nutrition and ageing from Deakin University in Melbourne,”Vitamin D status has emerged as a significant public health issue in Australia and New Zealand.
“An estimated 31% of adults in Australia have inadequate vitamin D status (serum 25-hydroxyvitamin D [25-OHD] level < 50 nmol/L), increasing to more than 50% in women during winter–spring and in people residing in southern states.
The paper states:
Dr MacKay from the CRN warns “we have concerns that the Lancet paper’s author’s broad-based advice will do nothing but cause potentially dire consequences if people, particularly those at-risk for fracture, fail to obtain the recommended daily intake of vitamin D”.
Department of Health, Victoria, Adult Dosing Schedule
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