There is new evidence coming to light which suggests that vitamin D could be useful to those suffering with asthma although more evidence is necessary before firm conclusions can be drawn. It does not surprise me greatly that low vitamin D levels are implicated in asthma severity since studies over the last two years are showing just how crucial this vitamin is to the efficient functioning of the body and prevention against disease. Here in the UK most individuals have low levels of the vitamin in their blood, increasing bodily levels of this vitamin could be incredibly useful for disease prevention, though experts are still in conflict over what optimal levels are and how much an individual should supplement.
A recent study (1) with 54 adult asthmatics found that low levels of vitamin D were associated with impaired lung function, higher vitamin D levels were associated with better lung function “suggesting that supplementation of vitamin D levels in patients with asthma may improve multiple parameters of asthma severity and treatment response”(1). There is a need for supplementation trials in order to discover what kind of impact vitamin D supplementation could have in asthma sufferers, what level of supplementation is optimal and how the vitamin D is working in the body to product positive effects. Recent research (2,3,4) suggests that vitamin D could be working by boosting the immune system so that it functions more effectively and efficiently.
Vitamin D could also be important in asthma prevention. A recent(4) study which looked at the diet of pregnant women found that higher vitamin D intake during pregnancy may be protective against childhood wheeze and eczema, though this was just an association study it paves the way for further, specific research which may be useful in asthma prevention.
What is known, as mentioned in my previous posts, is that most people in the UK do not get enough vitamin D and have insufficient/deficient blood levels. 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. For children under the age of 18 lower doses would be necessary and I would suggest speaking to a medical practitioner about how much vitamin D would be needed. 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.
Please read my other posts relating to asthma since there are some very useful nutritional strategies that can be employed to help asthma sufferers. In particular two posts ‘Can dietary change help asthmatics to breathe easier’ part 1 and part 2 contain lots of helpful ideas.
(1) Sutherland ER et al. 2010. Vitamin D Levels, Lung Function and Steroid Response in Adult Asthma. Am J Respir Crit Care Med. 2010 Jan 14. [Epub ahead of print]
(2) Maruotti N & Cantatore FP. 2010. Vitamin d and the immune system. J Rheumatol. 37(3):491-5.
(3) Lange NE et al. 2009. Vitamin D, the immune system and asthma. Expert Rev Clin Immunol. 5:693-702
(4)Rode von Essen M et al. 2010. Vitamin D controls T cell antigen receptor signaling and activation of human T cells. Nature Immunology (7 March 2010) doi:10.1038/ni.1851 Article
(5) Miyake Y et al. 2009. Dairy food, calcium, and vitamin D intake in pregnancy and wheeze and eczema in infants. Eur Respir J. 2009 Oct 19. [Epub ahead of print]
Written by Ani Kowal
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