It is recommended to dry mushrooms in the sun before eating

Mushrooms can provide ample vitamin D as supplements - provided you have to dry them in the sun before eating.

Researchers recommend that people remove mushrooms from their pockets and dry them in the sun for half an hour before cooking. That's because, like human skin, fungi metabolize ultraviolet rays in the sun into vitamins and continue to do so even when people have harvested.

In the study, 30 adults were given oral vitamin D capsules each day containing 2,000 units, used for 12 weeks, or fed nutrient-rich mushroom powder.

At the end of the trial, there were no significant differences in vitamin D levels between participants.

"This result provides evidence that eating sun-dried mushrooms is a good source of vitamin D, which can improve vitamin D levels in healthy people," said lead researcher Michael Holick.

The findings were presented at the meeting of the American Society of Biochemistry and Microbiology, held in Boston, and published in the journal Dermato-Endocrinology.