Tuberculosis (TB) remains one of the deadliest infectious diseases in low-income countries, where 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 TB by ingesting something else – oyster mushrooms that have been sitting in the sun.

Studies have shown that it’s important that those diagnosed with TB take vitamin D as part of their treatment as the vitamin induces the body to form an antimicrobial compound that attacks the bacterial cause of TB. Although sun exposure can boost a person’s vitamin D levels, it must be obtained through commercially-prepared supplements when sun exposure is scarce.

That said, the researchers believe that oyster mushrooms may be an alternative supplement that could be grown onsite in impoverished countries. Although fresh oyster mushrooms contain almost no vitamin D, the fungus produces it after exposure to sunlight, much like the human body.

For the study, the researchers gave a group of TB patients fortified bread containing 146 micrograms of vitamin D from sun-exposed oyster mushrooms every morning during the first four months in which they received an anti-TB drug. At the end of the four months, 97 percent of patients receiving the fortified bread were classified with the lowest TB severity score on a five-point rating system. The treatment group had significantly higher vitamin D levels compared to patients not receiving the bread, and also showed marked improvements in immunological responses.