Patients With Asthma Should Avoid High-Fat Meals

People with asthma may be well advised to avoid heavy, high-fat meals, according to new research presented at the American Thoracic Society’s international conference. Individuals with asthma who consumed a high-fat meal showed increased airway inflammation just hours after the binge, according to Australian researchers who conducted the study. The high-fat meal also appeared to inhibit the response to the asthma reliever medication Ventolin (albuterol).

“Subjects who had consumed the high-fat meal had an increase in airway neutrophils and TLR4 mRNA gene expression from sputum cells that didn’t occur following the low-fat meal,” said Lisa Wood, PhD, a research fellow at the University of Newcastle. “The high-fat meal impaired the asthmatic response to albuterol. In subjects who had consumed a high-fat meal, the post-albuterol improvement in lung function at three and four hours was suppressed.”

Researchers recruited 40 subjects with asthma who were randomized to receive either a high-fat, high-calorie “food challenge” consisting of fast-food burgers and hash browns containing about 1,000 kcals, 52% of which were from fat; or a low-fat, low-calorie meal consisting of reduced-fat yogurt, containing about 200 kcals and 13% fat.

Sputum samples were collected before the meal and four hours afterward, and analyzed for inflammatory markers.

Subjects who had consumed the high-fat meal had a marked increase in airway neutrophils and TLR4 mRNA gene expression. TLR4 is a cell surface receptor that is activated by nutritional fatty acids; it “senses” the presence of saturated fatty acids and prompts the cell to respond to the fatty acids as if they were an invading pathogen, releasing inflammatory mediators. While the study didn’t definitively distinguish between high fat and high energy, this increase in TLR4 activity suggests that dietary fat is important to the effects.

Subjects who had consumed the high-fat meal also had reduced bronchodilator response as measured by FEV1% predicted and FEV1/FVC% compared with those had consumed the low-fat meal.

“This is the first study to show that a high-fat meal increases airway inflammation, so this is a very important finding,” said Wood. “The observation that a high-fat meal changes the asthmatic response to albuterol was unexpected as we hadn’t considered the possibility that this would occur.”

Source: American Thoracic Society