Daily sunshine helps to keep lungs healthy

Get out in the sun - it may be good for your lungs, a new study has found.

Auckland University researchers discovered that people with very low levels of vitamin D had less healthy lungs than those with higher levels of the vitamin.

After decades of warning that too much sun can cause melanoma, health authorities last month formally acknowledged that too little sun is also a health risk. Exposure to the sun's ultraviolet rays produces vitamin D.

The university study by Associate Professors Peter Black and Robert Scragg recommended that pale-skinned people get 10 minutes of sun daily without sunscreen, while people with darker complexions need double the dosage, as their skin takes longer to absorb the sun's rays.

The study found substantial differences in lung function between those with the highest and lowest levels of vitamin D.

Dr Black said it was even more pronounced than the difference in lung function between former smokers and non-smokers. The difference would be distinctly noticeable for someone already suffering from shortness of breath, he said.

The pair analysed data from the United States National Health and Nutrition Examination Survey, comparing the lung health of 14,000 participants with different levels of vitamin D. Participants were given a lung function test which measured the volume of air they could exhale. Lower levels of Vitamin D were associated with lower lung volumes.

"We were a little surprised, but that's how it came out," said Dr Black.

Dr Black said the effect was more pronounced in Caucasians and African Americans than Hispanics.

"From that we can assume it would very likely apply to New Zealand Caucasians and is probably relevant to other ethnicities such as Maori and Pacific people."

Further research was needed to determine just what its role was, and whether increases in the vitamin would actually benefit patients with chronic respiratory diseases such as asthma and emphysema.

Dr Scragg, who has been researching vitamin D since the 1980s, said other studies have shown the vitamin's positive effects against cancer - in particular cancers of the breast, prostate and bowel - and cardiovascular diseases.

He said researchers were still unsure of the reasons for vitamin D's qualities, but cited evolutionary factors as a possible explanation.

"From an evolutionary perspective, humans arose from a sun-rich environment in East Africa and so a certain level of vitamin D is vital for good health and also reproduction."

While people must be conscious of the dangers of spending too much time in the sun, it was still the best source of vitamin D.

Supplements could provide the vitamin as well, but could be costly, said Dr Scragg.

"It doesn't cost anything to get out into the sun." 

 
Cost-free tonic

Vitamin D is a fat-soluble vitamin that is found in food and can also be made in your body after exposure to ultraviolet (UV) rays from the sun.

Sunshine is a significant source of vitamin D because UV rays from sunlight trigger vitamin D synthesis in the skin.