Can Dieting Minimize Asthma Symptoms?
Asthma has long been linked to obesity, and researchers have shown over the years that not only does obesity increase the chances of developing asthma, but asthma also increases the chances of developing obesity. According to the U.S. Centers for Disease Control and Prevention (CDC), nearly 40% of adults who suffer from asthma are also obese. The relationship between these two conditions is therefore complex but deep.
A new study conducted by researchers at Johns Hopkins University has shown that a low-calorie diet can prevent asthma symptoms. Interestingly, low calorie diets appear able to improve asthma symptoms regardless of the fat content or sugar content included in the diets. This study was published in Scientific Reports.
To delve deeper into the link between calories and asthma symptoms, the researchers looked not only at the impact of low-calorie diets on asthma symptoms but also on the impact of high-calorie diets. Consistent with their findings on low-calorie diets, the researchers observed that high-calorie diets were associated with asthma symptoms and that these symptoms were mediated by increased lung inflammation. When a drug that blocks the lung inflammation was implemented, the asthma symptoms associated with high-calorie diets were avoided.
To test their questions about the impact of calories on asthma symptoms, the scientists provided mice with 1 of 4 separate diets: a low-calorie diet, a high-calorie diet with more calories and fat per gram, a high-calorie diet with more calories and sugar per gram, or a high calorie diet that was high in transfat and also supplemented with sugar. After 8 weeks of this feeding schedule, the mice on each of the 3 high-calorie diets had gained at least 7 grams more weight than the mice on low-calorie diets. In addition, the mice on high-calorie diets experienced higher rates of airway constriction than did those on low-calorie diets. This constriction, however, was reduced if anti-inflammatory drugs were administered.
These results show the potential for high-calorie diets to exacerbate asthma symptoms. Future research will need to further clarify the links between obesity, diet, inflammation, and asthma. Given findings that traditional therapies like steroid inhalers do not work as well in asthma sufferers who are also obese, it will be important to determine the factors that contribute to therapy responsiveness and to develop evidence-based protocols for specific populations of asthma patients in order to optimize their outcomes.