Obesity, Asthma, and Dietary Intake: Paying Attention Can Reduce Morbidity

Patients who have asthma and who are also obese carry a heavy burden. Officials with the CDC indicate that among the general population of patients who do not have asthma, prevalence of obesity is 26.8%. However, prevalence of obesity is almost 39% among patients who do have asthma.

Obesity and its effect on patients with asthma is the subject of a paper published in Critical Reviews in Food Science and Nutrition. The systematic review tries to determine diet's effects on asthma treatment.

The researchers identified more than 12,000 studies that evaluated the effects of diet in adults who have asthma, and included 21 studies in the review. The findings indicate that clinicians need to encourage obese patients to lose weight and do so aggressively.

Weight loss of 7.5% or more from baseline appeared to improve asthma control quality of life and pulmonary function. For the most part, the most successful diets seem to be those that restricted caloric intake as opposed to those that used a specific dietary approach or increased exercise alone.

The authors looked at studies that examined dietary intake of antioxidant-containing foods, but found no clinical significance of this intervention. By definition, high intake of antioxidant was defined as daily intake of at least 5 servings of vegetables and 2 servings of fruit.

However, supplementation with antioxidants did seem to improve asthma. One study indicated that patients who took magnesium supplements improved their asthma control. Vitamin C supplementation was associated with less lung function decline and a smaller drop in FEV1 compared to usual diet or placebo.

Fatty acid supplementation was associated with greater weight loss and improved asthma control. Studies used various fatty acid supplements including eicosapentaenoic acid, perilla oil, and conjugated linoleic acid.

Additionally, the researchers noted that clinicians need to advise patients to reduce their dietary salt intake. Elevated levels of salt were associated with lung function decline.

Reference

Forte GC, da Silva DR, Hennemann ML, et al. Diet effects in the asthma treatment: A systematic review. Crit Rev Food Sci Nutr. 2017 Mar 31; doi:10.1080/10408398.2017.1289893. [Epub ahead of print]