Mediterranean Diet Improves Asthma

Researchers in Portugal found that high adherence to the Mediterranean diet reduced by 78% the risk of out-of-control asthma.

Other recent studies have associated the Mediterranean diet with 1) lesser incidence of asthma-like symptoms and allergies in children of women who followed the Mediterranean diet while pregnant, and 2) reduced risk of chronic obstructive pulmonary disease in men who eat Mediterranean-style.

The Mediterranean diet is famous for prolonging life and reducing rates of cardiovascular disease, cancer, and dementia.  Type 2 diabetes mellitus was recently added to the list of diseases prevented by the Mediterranean diet.  We have to consider adding lung disease to the list next.

In my capacity as a hospitalist, I see lots of poorly-controlled asthmatics.  The standard therapeutic approach is avoidance of allergens when possible, and administration of multiple drugs with multiple potential adverse effects.  So the following study involving diet and asthma caught my eye.

Scientists in Portugal studied 174 asthmatics with an average age of 40.  They administered an Asthma Control Questionnaire and measured lung function and exhaled nitric oxide.  Food intake was determined with a food frequency questionnaire, and a diet score was used to determine conformity to the Mediterranean diet.

Asthmatics felt to be under good control comprised 23% of the participants.  Were there dietary factors associated with good control?

I’m glad you asked.  The answer is , “Yes”:

  • high adherence to the Mediterranean diet
  • higher intake of fresh fruit
  • lower intake of ethanol (alcohol)

The researchers note that “the traditional Mediterranean diet is claimed to possess antioxidant and immune-regulatory properties in several chonic diseases.  Typical Mediterranean foods have recently been associated with improvement of symptoms of asthma and rhinitis [runny nose, often allergy-related] in children” in Crete and Spain.

This study is good news for people with asthma.  But association of well-controlled asthma with the Mediterranean diet does not prove that the diet is causing the improvement.  Next, we need a study that educates people with asthma on the Mediterranean diet, monitors adherence, and follows them over time while checking for improvement in asthma and comparing to a control group on a standard diet.

Steve Parker, M.D.

Reference:  Barros, R., et al.  Adherence to the Mediterranean diet and fresh fruit intake are associated with improved asthma control.  Allergy, vol. 63 (2008): 917-923.