Vitamin A, E, D intake linked to lower prevalence of respiratory complaints

Consuming more of vitamins A, E and D may help lower respiratory complaints, according to research published in BMJ Nutrition, Prevention & Health.

“Nutrition is known to play a critical role in the prevention of a number of infectious diseases, while malnutrition is known to contribute to increased morbidity and mortality from such diseases,” Suzana Almoosawi, PhD, a public health nutritionist and a nutritional epidemiologist at the Imperial College London’s School of Public Health, and colleagues wrote. “Although the mechanisms by which nutrition affects immunity are complex, optimal nutritional status is known to contribute to the maintenance of the immune system.”

They said evidence suggests that unhealthy Western diets can promote chronic inflammation and lower the immune system’s defense to viruses. Recent findings highlighted by the American Nutrition Association have been consistent with this evidence and show the benefit of vitamins A, E, C and D in the prevention of respiratory complaints, the researchers wrote.

Almoosawi and colleagues evaluated a cross-sectional association between vitamins A, E, C and D consumed through diet or supplements and occurrence of respiratory complaints, including both infectious and noninfectious sources such as colds, COPD and asthma.

The researchers collected data from participants in the United Kingdom’s National Diet and Nutritional Survey Rolling Programme from 2008 to 2016. Those included in the study were aged 19 years and older and had completed at least 3 days of diet diaries.

A total of 6,115 participants were included in the study, 33 of whom had respiratory complaints.

According to the researchers, those who reported respiratory complaints were typically older. In the initial analysis, these patients were less likely to report taking vitamins A, E, C or D dietary supplements, and had lower dietary intake of vitamins A and E compared with those who did not report respiratory complaints.

Almoosawi and colleagues found these associations remained after adjusting for multiple factors, including age, sex, BMI, smoking status and income.

However, they found that continuous exposure of vitamin A and E through dietary intake remained significantly associated with lower respiratory complaints. The association between vitamin D and lower respiratory complaints remained only with supplements.

The findings suggest consuming more vitamins A and E through food and supplements and vitamin D through supplements was associated with a lower prevalence of respiratory complaints, the researchers said.

They noted that as the respiratory complaints stemmed from both infectious and noninfectious sources, the findings may not be generalizable to COVID-19.

“These findings provide some basis for further research into the value of vitamin intake up and beyond recommended dietary intake,” the researchers wrote. “Further research is required to assess the implications of the current study in the context of the current coronavirus disease 2019 pandemic using data from longitudinal cohorts.”