Per the Centers for Disease Control and Prevention (CDC) the prevalence of asthma has steadily risen since the 1980s. According to a handful of preliminary studies, there may be a connection between dairy consumption, especially in early childhood development, with a reduced risk of developing this respiratory condition, which usually results from hypersensitivity or an allergic reaction.
 
A new large-scale analysis strengthens the case that milk contains nutritional and/or bioactive compounds which may support healthy lung function. 
 
“Dairy products contribute a major share of the food supply, but surprisingly little research has been conducted to evaluate the direct effects of milk consumption and fat content on health outcomes like inflammation,” the authors of the study wrote. “Dairy consumption may be protective against asthma, and has also been associated with improvement in lung function and inflammatory biomarkers in the ECLIPSE cohort of individuals with COPD. Low fat, but not high fat, dairy intake has also been associated with a decrease in emphysema, improved lung density measured by computed tomography (CT) images, and a potential inverse relationship between high-fat dairy and [forced expiratory volume].
 
Using data pooled from 1,542 adults with asthma, and a parallel group of non-asthmatic adults, the researchers determined that self-reported milk consumption, either varied or regular, was associated significantly with improvements in forced vital capacity (the maximum amount of air one can breathe out with maximal effort, a standard measurement of lung function).
 
The researchers found that, depending on which milk type was reported, milk had variable influence and significance in this marker of lung function among the asthmatic population. The pattern of dairy consumption which had the most significant effect, not just on forced vital capacity but also on forced expiratory volume, were those who consumed low-fat milk regularly starting at an early life period.
 
“We identified a potential protective association for exclusive consumption of low fat milks including reduced likelihood of current asthma or higher lung function measurements in both the general and asthmatic populations. Together, these data from NHANES support additional findings in the literature on the effects of dairy consumption and lung health, particularly in the case of low-fat milks,” the authors wrote.
 
There were a number of properties present in milk that the authors posited as potential reasons for the protective effect it had on lung function in this analysis, such as the potentially anti-inflammatory short-chain fatty acids, immunoglobulins, and diet-derived small RNAs. However, the treatment of the milk (raw vs. pasteurized, the level of heat used in the pasteurization process, etc.) could have a huge influence on the efficacy of dairy compounds in reducing the risk of asthma symptoms.