Vitamin D prevents flu

A study published this month in The American Journal of Clinical Nutrition has demonstrated that Vitamin D3 is more effective than antiviral drugs in preventing children from contracting influenza A, which caused last year’s swine flu epidemic.

The randomised, double blind study, carried out in Japan by Dr Urashima and colleagues, gave children 1200IU/day vitamin D3 supplements or a placebo for 3 months. Influenza A occurred in 18 out of 167 (10.8%) children in the vitamin D3 group compared with 31 of 167 (18.6%) children in the placebo group. In children who also had asthma, attacks following flu ocurred in only 2 children in the vitamin D3 group compared to 12 children receiving placebo.

Antiviral drugs reduce the risk of flu infection by 8% in children who have been exposed to flu. These drugs are expensive and potentially toxic. This research shows, however, that vitamin D3 reduces the risk of infection by 50%, and it is believed to carry other benefits, such as strong bones and a reduction in cancer, heart disease, diabetes and depression.

Vitamin D3 is made from cholesterol when the skin is exposed to sunshine. In Britain, the sun is only strong enough for this to occur from March to September. During the winter, vitamin D3 is stored in the liver, but levels are depleted as the winter progresses. It is suspected that low blood levels explain why flu epidemics generally peak between December and March.

Vitamin D boosts immunity by activating the innate immune system, whereas vaccines enhance acquired immunity. The researchers suggest that both interventions may assist each other. Dr John Oxford, professor of virology at Queen Mary School of Medicine, London supports this view, suggesting that vitamin D may be given at the same time as the vaccine in the future.

Vitamin D3 is also gained in the diet from oily fish and eggs. Many foods such as cereals and butter substitutes are fortified with vitamin D3. Some individuals , especially vegetarians, may benefit from supplements, particularly during the winter months. However, as vitamin D is a fat soluble vitamin, high levels can be toxic. To find out more about vitamin D or to order a test to establish your vitamin D status, click here. Alternatively, to speak to someone at Smart Nutrition about vitamin D call 01273 775480 or click here  to book a consultation online.