U.S. researchers have discovered another reason to reduce alcohol consumption, finding that adults who drink excessively have less nitric oxide in their exhaled breath than adults who don't drink. The findings are significant as nitric oxide, a colorless gas produced by the body during respiration, is one of the molecules that protects against certain harmful bacteria, including those that cause respiratory infections.

The study, which is the first to reveal an association between nitric oxide and an excessive intake of alcohol, was carried out by a team from Loyola Medicine and Loyola University Chicago, USA using data from the US Centers for Disease Control and Prevention's National Health and Examination Survey (NHANES).

NHANES is a program of studies which uses interviews and physical examinations to assess the health and nutritional status of adults and children in the United States, and gave the researchers access to data from 12,059 adults who had participated between 2007 and 2012.

Questionnaires were used to define put the participants into the following alcohol groups: never drinkers, nonexcessive drinkers, excessive drinkers, and former excessive drinkers.

Excessive drinkers were defined in the study as those who consumed more than one drink per day on average for women and more than two drinks per day for men, and people who binge drink at least once per month, with binge drinking defined as four or more drinks per drinking session for women and five or more drinks for men.

From their sample of data 26.9 percent were found to be excessive drinkers.

After taking into account factors such as asthma, smoking, and diet, the results showed that nitric oxide levels decreased across the groups as alcohol consumption increased, with excessive drinkers showing the lowest level of nitric oxide in their exhaled breath when compared to adults who never drink.

In addition, the team also found that the more alcohol consumed by an excessive drinker, the lower the level of nitric oxide, with the researchers also adding the results also suggest that alcohol disrupts the healthy balance in the lung.

Commenting on the findings, which were published in the journal Chest, lead author of the study Dr Majid Afshar noted that the results could be of particular significance for those with asthma, as amount of exhaled nitric oxide in a breath test is used as an indicator of how asthma medication is working.

The research suggests that excessive consumption of alcohol could affect these results, with Dr. Afshar advising that doctors may need to take this into consideration when carrying out tests.

The team also noted that the association between exhaled nitric oxide levels and alcohol consumption should be investigated further in order to better understand the relationship between the two.