Mushrooms provide as much vitamin D as supplements, study reveals

Ah, vitamin D. It seems we can't go a day without hearing about how important it is to our health. Previous research has linked a lack of vitamin D to various health problems including depression, osteoporosis and pregnancy complications.

But why is getting enough of it such a challenge?

Also known as the "sunshine vitamin," vitamin D naturally occurs in very few food sources, but is produced in abundance when ultraviolet rays strike the skin and trigger vitamin D synthesis.

For this reason, Canadians suffer from chronically low levels of vitamin D from October to April when there is very little sunlight. Consequently, doctors and medical associations have long recommended taking vitamin D supplements to ensure we get enough.

But now, new research from the Boston University School of Medicine suggests that eating mushrooms containing vitamin D2 can be as effective at increasing and maintaining vitamin D levels as taking supplements of vitamin D2 or vitamin D3.

"These results provide evidence that ingesting mushrooms that have been exposed to ultraviolet light and contain vitamin D2 can improve the vitamin D status of healthy adults," says lead researcher Dr. Michael F. Holick.

While it is not news that mushrooms contain vitamin D, this study is one of the first to suggest that eating mushrooms is as effective as taking supplements for vitamin D.

The study -- to be presented Monday at the annual meeting of the American Society for Biochemistry and Molecular Biology -- examined 30 healthy adults divided into three groups. Those who took a supplement containing 2000 IU of vitamin D2, those who took a supplement of 2000 IU of vitamin D3 and those who took mushroom powder containing 2000 IU of vitamin D2.

After 12 weeks, there was no statistically significantly difference in vitamin D levels between those who took either supplement and those who ingested the mushroom powder.

The mushrooms used in the experiment made vitamin D using a process similar to what occurs in human skin after sun exposure.

"Although it has been previously reported that mushrooms have the ability to produce both vitamin D2 and vitamin D4, through our research we were able to detect vitamin D3, which is also made in human skin," Holick says.