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In the news: Vitamin D & Asthma: ‘Med’ Diet for a healthier life

Can Vitamin D Help Fight Asthma?

In children and adults with asthma, low blood levels of vitamin D have been linked to poorer lung function, airways that narrow instead of relax, more frequent asthma attacks, and less responsiveness to the corticosteroid medications used to treat symptoms. Two recent studies have looked further at the relationship between this vitamin and asthma.

The first, a clinical study (1) called the VIDA trial, looked at whether giving very large doses of vitamin D could improve the clinical response to inhaled corticosteroids in adult asthmatics already using bronchodilators. These patients had symptoms and low blood levels of the vitamin.

vitamin D treatment did not significantly reduce initial treatment failures compared to placebo. However, they saw a 12% decrease in overall treatment failures and a 20% reduction in the overall rate of asthma attacks for each 10 ng/mL increase in vitamin D levels.

In the second study (2), researchers examined some 300,000 people whose vitamin D blood levels had been measured. Over 21,000 of those people were found to have asthma.

While blood levels of vitamin D were not associated with an initial diagnosis of the disease, low levels were associated with the number of asthma attacks and the severity of those attacks. The lower the level of vitamin D, the greater the chance of having recurring asthma attacks. Among those with poor vitamin D levels, the odds for having an asthma attack were 25% higher than people with levels in the normal range.
 
What’s the take home message? Preventing low vitamin D levels is no magic bullet for those with asthma, but it can give them a better chance of controlling symptoms and managing their disease.

Benefits of the Med Diet are Long Lasting

Overall, those who adopt the Mediterranean style of eating (‘Med diet’) are likely to have a much lower risk of developing life-threatening and chronic disease than those who don't. Scientific evidence for the health benefits of the Med diet continues to grow, with the latest study from UK-based researchers showing that the benefits can be long lasting (3).

The endothelium is a thin membrane that lines the inside of the heart and blood vessels, and a healthy endothelium can fully dilate when needed. Having good endothelial function and healthy small blood vessels (micro-vascular integrity) is thought to reduce the risk of cardiovascular disease. The function of the endothelium and small vessels declines as we age.

In a previous study, the authors looked at healthy people 50+ for an 8-week period. One group was given a moderate exercise regimen and encouraged to follow a Med- style diet by consuming more fruit, vegetables, nuts, olive oil and oily fish. Participants in the other group were assigned to exercise alone.

At study’s end, the Med diet plus exercise group was found to have more vascular health improvements than those exercising only and, in fact, the age-related decline in endothelial and small vessel function was reported to be reversed in the combination group.

In the new study, a subgroup of participants from the original study again underwent tests to assess endothelial and small vessel function one year later. The original improvements seen with the 8-week exercise and Med diet were still evident, a year after the initial study.

This suggests that a brief intervention combining a Med-style diet with exercise promises long-term health benefits. It also suggests that adopting and sticking with this style of eating and exercising – even walking – can pay big dividends over a lifetime.

References

1. Castro M, et al. Effect of vitamin D3 on asthma treatment failures in adults with symptomatic asthma and lower vitamin D levels: The VIDA Clinical Trial. JAMA; 311:2083-91, 2014.
2. Confino-Cohen R, et al. Vitamin D, asthma prevalence and asthma exacerbations: a large adult population-based study. Allergy; Epub Oct 3, 2014.
3. Klonizakis M, et al..Long-term effects of an exercise and Mediterranean diet intervention in the vascular function of an older, healthy population. Microvasc Res; Epub Aug 7, 2014.