Are Your Brain and Muscles Getting Enough Vitamin D?
While experts may wonder how much vitamin D is enough, new research finds increased risk of developing Alzheimer’s diseases and dementia if vitamin D status is low. In a meta-analysis with 10 studies published between 2010-2015, Sheng and Ji report 21% and 63% increased risk of developing Alzheimer’s disease and dementia, respectively, in subjects with serum 25(OH)D concentrations < 50nmol/L (vs >50 nmol/L).
In addition, a British expert committee reaffirms the importance of never allowing serum 25(OH)D concentrations to fall below 25 nmol/L to protect musculoskeletal health. The Scientific Advisory Committee on Nutrition (SCAN) issued its “Draft Vitamin D and Health report” for review.
The report confirms that the active metabolite of vitamin D, namely 1,25(OH)2D, shouldn’t be used as an indicator of vitamin D exposure because of its short half-life (<4h) and the fact that the concentration is regulated in blood. Because of its 2-3wk half-life, serum 25(OH)D is a much better indicator of total vitamin D exposure from diet and sunlight, although it does decrease in acute inflammation. Serum 25(OH)D concentrations may also be affected by body fat content and genetic variation.
This statement by SCAN reinforces the validity of the EFSA health claim submitted by DSM, based on 5 randomized, controlled trials (RCT) showing a benefit of vitamin D in the reduction of falls in subjects consuming 800-1,000 IU daily (in combination with calcium compared to calcium alone). In September 2011, the EFSA Panel on Dietetic Products, Nutrition and Allergies approved the following claim – “Vitamin D may reduce the risk of falling. Falling is a risk factor for bone fractures.” Both the US and EU have approved vitamin D health claims.
The SCAN target population is men and women 60 y of age and older. In order to obtain the claimed effect, the Panel considered that 800 IU should be consumed daily.
For more on vitamin D choices see “Vitamin D3 More Effective than D2 in Maintaining Optimal Status”.
Sheng L, Ji H-F. Vitamin D deficiency is associated with increased risk of Alzheimer’s disease and dementia: evidence from meta-analysis. Nutrition J doi: 10.1186/s12937-015-0063-7
Scientific Advisory Committee on Nutrition. Draft Vitamin D and Health report: Scientific Consultation: 22 July to 23 September, 2105.
Scientific opinion on the substantiation of a health related to vitamin D and risk of falling pursuant to Article 14 of Regulation (EC) No 1924/2006 – Scientific opinion of the Panel on Dietetic Products, Nutrition and Allergies. 2011 EFJSA J doi: 10.2903/j.efsa.2011.2382