Study suggests melatonin may be detrimental for asthmatics - NutraIngredients-usa.com

With asthma affecting an estimated 330 million people in the world, researchers are hoping to gain a better understanding of the condition—and why it intensifies at night. 

Many asthma sufferers experience a worsening of pulmonary function and asthmatic symptoms at night, called "nocturnal asthma." Several causes have been hypothesized—activation of the parasympathetic nervous system in the evening, alveolar tissue inflammation and reduced pulmonary function, to name a few. However, "​The precise mechanisms regulating this asthma phenotype remain obscure,"​ explained Kentaro Mizuta, DDS, PhD, a professor at the Tohoku University Graduate School of Dentistry.  The university is located in Sendai City, Japan.

According to Mizuta, who led the research published in the American Journal of Physiology Lung Cellular and Molecular Physiology​, melatonin is the likely culprit. He explained that the sleep hormone actually worsens asthma.

First of its kind 

The study investigated the expression of melatonin receptors in native human and guinea pig airway smooth muscle and primary cultured human airway smooth muscle cells. 

When it comes to melatonin and asthma, there is a lot of conflicting data. Some research suggests melatonin improves asthmatic airway remodeling​, and other studies suggest elevated serum melatonin is associated with the nocturnal worsening of asthma​. 

While previous several studies have been conducted on melatonin's relationship with asthma, the focus was often on the antioxidative ​and anti-inflammatory​ effects of melatonin—not airway smooth muscle contraction through the melatonin MT2 receptor.  Mizuta explained that his team, for the first time, showed that the functional melatonin MT2 receptor is expressed on human airway smooth muscle.