People with asthma who eat a diet low in fat and high in fiber may be better off than those who eat less healthfully, a new study suggests.
In the study, people with severe asthma consumed five grams more of fat daily, and five fewer grams of fiber daily, compared with healthy people without the condition.
The data also showed that for every 10-gram increase in daily fat consumption, the odds of having severe asthma increased by 48 percent, even after the researchers took into account the total calories consumed.
The findings show that "people with asthma may benefit from improving their diet to reduce fat and increase fiber intake," said study researcher Bronwyn Berthon, who studies medical biochemistry at the University of Newcastle in Australia.
Berthon cautioned that the study revealed an association, not a cause-and-effect relationship between diet and asthma. But animal studies have suggested that a higher fiber intake is beneficial for those with asthma, and randomized controlled trials should be done in people to see whether the findings hold up, she said.
Exactly how the link between diet and asthma may work remains unclear, but researchers are working toward a better understanding of it, Berthon said. Severe asthma is linked with an increased risk of life-threatening asthma attacks.
In the new study, the researchers looked at 137 people with asthma, and 65 people without the condition. Participants completed questionnaires about their diets, and the researchers also ran blood tests, including tests looking for markers of inflammation.
The researchers found that people who consumed more fat had increased airway inflammation, which is related to asthma symptoms. "Fat intake is important in people with asthma as it is pro-inflammatory, and can reduce the response to bronchodilator (rescue inhaler)," Berthon told LiveScience in an email.
Higher intake of fiber also seemed to be beneficial, according to the study. "Lower fiber intake was related to poorer lung function and increased airway inflammation in people with asthma," Berthon said.
The new findings may also hold clues for the close link researchers have observed between asthma and obesity. The new findings show that it is not just how much food is eaten, but what types of food are eaten that may affect asthma, Berthon said.
The findings were detailed in the April issue of the journal Respirology.