Fat vs. Fiber in Breathing Flow

Asthma patients consumed more fat and less fiber than healthy individuals

(RxWiki News) Allergies, sports, cold and a number of conditions can stir up problems for people with asthma. A fatty diet with little fiber may add to the problems.

Asthmatics with trouble breathing had diets that were lower in fiber and richer in fat compared with non-asthmatic individuals, a new study found.

The findings suggest that fiber may have a protective role against asthma, according to researchers.

"Eat more fiber and less fat."

Bronwyn Berthon, PhD, clinical trial research assistant from the Centre for Asthma and Respiratory Disease at Hunter Medical Research Institute in New South Wales, Australia, and colleagues examined how diet was linked to asthma severity, lung function and use of inhalers and corticosteroids.

The study included 137 adults with asthma and 65 healthy individuals who were recruited from the John Hunter Hospital Asthma Clinic in Australia and through advertisements, respectively.

Participants were required to be non-smokers. They completed a questionnaire on the kinds of food they consumed and how often they consumed those foods, as well as the kinds of medication they took for their asthma and the severity of their symptoms.

Researchers also noted patients' inflammation levels and leptin levels in the blood. Leptin is a hormone that regulates energy intake and how much energy is spent.

Using a spirometer, researchers measured how well patients could breathe. Patients also underwent a hypertonic saline challenge, which measures how well the lungs function.

Patients with severe, persistent asthma consumed less fiber and more fat compared to healthy patients, researchers found.

Aligned with previous research on fiber's tie to chronic pulmonary disease, the findings suggested that the nutrient "has a protective role in asthma," according to researchers.

"Dietary fiber exerts anti-inflammatory effects due to the production of butyrate, a short-chain fatty acid, by microbiota in the gut that ferment soluble fiber," researchers wrote in their report.

Gut microbiota consist of organisms and bacteria living inside the stomach. They help break down and modify food to be digested.

Higher fat and lower fiber was also linked with a weaker ability to exhale among asthmatics. For both asthmatic men and women, leptin levels were higher compared to the healthy individuals.

"High dietary fat intake has been associated with airway hyper-responsiveness and asthma diagnosis," researchers wrote.

"Furthermore, plasma triglyceride levels have been reported to be elevated in subjects with adult onset wheeze; trans polyunsaturated fatty acids have been associated with increased asthma prevalence and margarine intake, a source of trans fats, has been related to increased asthma risk," they wrote.

Fiber-rich foods are often sources of antioxidants and micronutrients that could counteract oxidative stress in asthma, researchers said.

The authors noted that the ties between asthma and diet do not mean that one causes the other.

The study, funded by a grant from the National Health and Medical Research Council of Australia Project, was published online March 21 in the journal Respirology, the official journal of the Asian Pacific Society of Respirology.

Review Date: 
March 30, 2013