High fat diet linked to exacerbation of asthma

By Dr. Ananya Mandal, MDMay 17 2010

In a new study researchers have found a connection between exacerbation of bronchial asthma and high calorie burgers and fries. Diet and lifestyle have been linked to asthma for some time now but this is the first real evidence. With the advent of unhealthy diets the incidence and prevalence of asthma is on the rise. In 2007, about 34.1 million Americans had asthma, according to the American Academy of Allergy, Asthma and Immunology. From 1980 through 1994, the prevalence of asthma increased by 75 percent.

Asthma is a disease where the hyperactive immune system causes increased inflammatory responses in the airways. The common symptoms include breathlessness, wheezing and cough. Those prone to asthma attacks may react to various irritants and triggers like air pollution, smoke and allergens, such as pollen and animal dander. Extreme emotion, exercise and laughter may also precipitate an attack.

Study researchers have found that asthmatics who ate a high fat meal did not respond well to treatment when compared to those who ate a healthier diet. The results of the study suggest that cutting down fats may help asthmatics.

Study researcher Lisa Wood, of the University of Newcastle says, “If these results can be confirmed by further research, this suggests that strategies aimed at reducing dietary fat intake may be useful in managing asthma.” She would be presenting the results of the study at this year's American Thoracic Society's International Conference, held May 14-19 in New Orleans.

Wood and her colleagues studied 30 non-obese asthmatics and 16 obese asthmatics. They made them eat either a high-fat meal, consisting of burgers and hash browns, or a low-fat meal of yogurt. The high-fat meal was 1,000 calories (52 percent of calories from fat), and the low-fat meal was 200 calories (13 percent from fat). At the end of the study sputum from all patients was analyzed. Those who had had burgers had more immune cells called neutrophils in their bronchial secretions. These can trigger an asthma attack. These patients were also not responsive to asthma medication like Albuterol or Ventorlin three to four hours after their meal. Researchers say that the fats in the diet could be the reason why this drug was not working.

Lung function tests were also carried out on all patients. In patients on high fat meal asthma medication by inhaler caused only 1% improvement whereas those on low-fat meal saw a 4.5 percent increase in their lung function after using their medication.

“Further work is needed to understand the clinical relevance of these observations. Nonetheless, a difference of 3 to 4 percent [in lung function] is approaching a level which can be perceived by patients,” said Wood.

Expert opinion

Dr. Thomas Leath, division director of allergy and immunology at Scott & White Healthcare in Round Rock, Texas, said, “I wouldn't have thought that the food itself would cause the inflammation. Eating that way can lead to obesity, and fat cells can definitely cause quite a bit of inflammation, but I'm surprised one meal could do this.”