The University of Auckland performed a study, headed by Associate Professors Robert Scragg and Peter Black from the Faculty of Medical and Health Sciences, suggesting that supplementing with vitamin D could improve lung function.
Both professors analyzed information from the United States National Health and Nutrition Examination Survey, conducted from 1988 to 1994, and performed lung volume tests with 14,000 people. While studying their subjects, the team found that healthy lung patients had remarkably 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 a much larger lung capacity.
Regardless of warnings about the sun, vitamin D has been involved in many studies that prove the benefits of getting daily sun, without sunscreen, which blocks the absorption of vitamin D. Many doctors recommend that ten to twenty minutes of direct sunlight a day, depending upon skin color, is enough to keep vitamin D levels healthy. Vitamin D can also be found in oily fish, eggs, butter and some leafy greens.
Vitamin D deficiencies have been linked to MS, osteoporosis, high blood pressure, various cancers, hypertension and diabetes, to name a few conditions.
Although the Auckland study showed that vitamin D has an association with lung health, they could not conclude that supplements could help those with chronic respiratory diseases, such as asthma. The team found that vitamin D was distinguished from other vitamins in that it was associated with obesity levels, declined with age and was higher in men than woman. They also found that vitamin D was lowest in those who smoked more than a pack a day.
Although the researchers are unsure as to why vitamin D has an effect on lung health, they have noted evidence that vitamin D repairs lung tissue, is essential for the body to absorb calcium, and also affects cell growth. The evidence suggests that vitamin D is needed to develop strong bones and that strong bones could effect the size of the lungs. Some authorities think that vitamin D may be needed for the development of the rib cage, instead of the lung tissue. More research is needed for this hypothesis.
More research is also needed to determine whether dietary supplements can improve lung function.