A study published in the Journal of Clinical Endocrinology and Metabolism(1) has found that low vitamin D levels are linked to an increased accumulation of fat in muscle tissue and reduced muscle strength.
The study involved 90 young Californian women aged between 16-24. 59% of the group had insufficient vitamin D levels, with 24% exhibiting serious deficiencies(1). This is surprising since in California there is ample opportunity for sunshine exposure, needed for vitamin D production. One of the study authors comments (1) “We are not yet sure what is causing Vitamin D insufficiency in this group“. It could be that young people are spending less time outside being active, or that sunscreens are blocking vitamin D production, or for numerous other reasons which would need to be further investigated. The worrying point is that so many individuals seem to have insufficient vitamin D levels which has now been linked to an increased risk of many health problems.
In a press release(2) Dr Richard Kremer one of the study scientists says “Vitamin D insufficiency is a risk factor for other diseases,” “Because it is linked to increased body fat, it may affect many different parts of the body. Abnormal levels of Vitamin D are associated with a whole spectrum of diseases, including cancer, osteoporosis and diabetes, as well as cardiovascular and autoimmune disorders.”
The study(1), is the first to show a clear link between Vitamin D levels and the accumulation of fat in muscle tissue which is a factor associated with muscle strength and overall health. Lower levels of vitamin D were associated with higher levels of fat in the muscle tissues of the women. It is not yet known whether increasing the levels of vitamin D could help to reduce muscle fat and overall body fat levels – further research with vitamin D supplementation would be necessary in order to elucidate this. In the press release (2) Dr Kremer says: “Obviously this subject requires more study,” “We don’t yet know whether Vitamin D supplementation would actually result in less accumulation of fat in the muscles or increase muscle strength. We need more research before we can recommend interventions. We need to take things one step at a time.”
What is known now is that many individuals in the UK and USA have insufficient levels of vitamin D in their bodies. In the introduction of the study mentioned above, the authors write “Vitamin D insufficiency has now reached epidemic proportions”. Despite all the evidence for the importance of vitamin D there is no current consensus about the amount of daily vitamin D intake necessary to maintain blood levels at around 40-50nmol/l (which is currently seen as optimal by many medical practitioners). I would suggest most adult (age 18 and over) individuals in the UK would require a supplement of around 2000iu vitamin D daily. Higher doses (up to 5000iu daily) may well be useful but I would not recommend such a regimen unless under the supervision of a medical doctor who can monitor blood levels regularly. When looking for vitamin D supplements two forms are generally available. Cholecalciferol, known as vitamin D3, and ergocalciferol or vitamin D2. Cholecalciferol is generally taken to be the more potent, easily absorbed and preferred form of vitamin D. Unfortunately vitamin D is also difficult to obtain from dietary sources, with oily fish and egg yolk being the biggest providers.
As mentioned in my previous blog posts, vitamin D is called the sunshine vitamin, though technically vitamin D is a hormone, as it is produced in the body when the skin is exposed to the UVB rays in sunlight (for more information on the importance of sunlight for health please visit the SUNARC centre website). In the past it was thought that spending just 10-15 minutes in the sun everyday would supply all the vitamin D that we need. However this is now estimated not to be nearly enough and many of us in the UK do not get enough sun on our skin to generate adequate amounts of vitamin D especially in the autumn and winter months.
(1) Gilsanz V et al. 2010. Vitamin D Status and Its Relation to Muscle Mass and Muscle Fat in Young Women. Journal of Clinical Endocrinology & Metabolism, 2010; DOI: 10.1210/jc.2009-2309 E-Pub
(2)Press release. McGill University Health Centre (2010, March 6). Low levels of vitamin D linked to muscle fat, decreased strength in young people. ScienceDaily. Retrieved March 8, 2010, from http://www.sciencedaily.com/releases/2010/03/100305112157.htm
Written by Ani Kowal
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