In developing nations with limited infrastructure, obtaining and storing vitamin supplements can be difficult. With that in mind, German scientists are now suggesting that people in such regions could fight tuberculosis (TB) by ingesting something else – oyster mushrooms that have been sitting in the sun.

It's important for people who have TB to take vitamin D, as the vitamin forms a compound that attacks the bacteria which causes the disease. Exposure to the sun causes our skin to produce some vitamin D naturally. If you require more, it's generally done by taking commercially-prepared supplements.

That said, University of Hohenheim doctoral fellow Tibebeselassie Seyoum Keflie believes that oyster mushrooms may be an alternative supplement that could be grown onsite in impoverished countries. In their fresh form, the mushrooms have little vitamin D. Like us, though, they produce the vitamin – a lot of it – when exposed to sunlight.

In a controlled test, Keflie and Hohenheim's Prof. Hans Konrad Biesalski administered 146 micrograms of mushroom-derived vitamin D to a group of 32 TB patients every morning for four months. The volunteers consumed the vitamin within fortified bread, plus they were also receiving a traditional anti-TB drug.

When the test subjects were assessed after the four-month period, almost 97 percent of them were found to have the lowest-possible TB severity score on a five-point rating system. By contrast, 21.5 percent of the people in a 32-patient control group – who received the drug but not the bread – saw a similar improvement. The bread group also had much higher vitamin D levels, plus they showed marked improvements in immunological responses.

The scientists are now trying to determine which mushroom-drying methods allow for the greatest vitamin D concentrations, and are planning on conducting another test utilizing a larger and more diverse group of patients.

"TB is becoming more difficult to fight due to the emergence of drug-resistant strains, creating an urgent need for new treatments that can support first-line drugs," says Keflie. "This source of vitamin D is ideal for low-income countries because mushrooms can easily be distributed and administered in a safe, low-cost, easy-to-replicate manner."

The research is being presented this week in Baltimore, Maryland, at the American Society for Nutrition annual meeting.