The University of Auckland conducted a study, led by Associate Professors Robert Scragg and Peter Black from the School of Health and Medical Sciences, suggesting that vitamin D supplementation might improve lung function.
Both professors analyzed information from the United States National Health and Nutrition Examination Survey, conducted between 1988 and 1994, and performed lung volume tests with 14,000 people. While studying their subjects, the team found that healthy lung patients had markedly higher levels of vitamin D, while those with low levels of vitamin D had weaker lungs. The tests measured the amount of air that can be forced in one second after taking a deep breath and the amount that is expelled after taking a deep breath. Those with the highest levels of vitamin D showed much higher lung capacity.
Regardless of the sun warnings, vitamin D has been involved in many studies proving the benefits of sunbathing every day, without sunscreen, which blocks the absorption of vitamin D. Many doctors recommend that ten to twenty minutes of direct sunlight a day, depending on skin color, is enough to keep vitamin D levels healthy. Vitamin D can also be found in oily fish, eggs, butter, and some green leafy vegetables .
Vitamin D deficiencies have been linked to MS, osteoporosis, high blood pressure, various types of cancer, hypertension, and diabetes, to name a few conditions.
Although the Auckland study showed that vitamin D has an association with lung health, they were unable to conclude that supplements can help people with chronic respiratory diseases, such as asthma. The team found that vitamin D was distinguished from other vitamins because it was associated with obesity levels, decreased with age, and was higher in men than women. They also found that vitamin D was lower in those who smoked more than one pack a day.
Although researchers are not sure why vitamin D has an effect on lung health, they have observed evidence that vitamin D repairs lung tissue, is essential for the body to absorb calcium, and also affects cell growth. Evidence suggests that vitamin D is necessary for building strong bones and that strong bones may affect the size of the lungs. Some authorities think that vitamin D may be necessary for the development of the rib cage, rather than lung tissue. More research is needed for this hypothesis.
More research is also needed to determine if dietary supplements can improve lung function.