Researchers have identified an association between vitamin D intake and poor lung function in people with asthma.
The study, carried out by scientists at National Jewish Health in Denver, found that asthma sufferers with higher levels of the vitamin in their bloodstream had stronger lungs than those with lower concentrations.
According to the team, vitamin D levels were also inversely related to BMI, meaning that overweight and obese patients tended to have less of the vitamin in their blood.
Dr E Rand Sutherland, the lead author of the study, which was published in the American Journal of Respiratory and Critical Care Medicine, said: "Our findings suggest that vitamin D levels influence a number of important features of asthma, including lung function, bronchospasm and therapeutic response to steroids.
"The next question to answer is whether giving supplemental vitamin D will lead to clinical improvements in patients with asthma, highlighting the need for clinical trials in this area."
Independent advice on private healthcare