As relayed by MedPageToday.com, researchers from Boston University (BU) found that people who supplemented with a daily intake of mushroom extract experienced elevated blood levels of 25-hydroxyvitamin D [25(OH)D] similar to the levels obtained from taking vitamin D supplements.
In a randomized trial involving 30 healthy adults, BU researchers administered either capsules of vitamin D2, vitamin D3, or mushroom powder containing vitamin D2 once a day during the winter months when natural sunlight exposure, the optimal source of vitamin D, is limited. Each dose in every category measured the equivalent of 2,000 international units (IU) of vitamin D, which is higher than the government's recommended daily allowance (RDA) for vitamin D but much closer to the legitimate therapeutic dose required for optimal health.
All participants regardless of group assignment had roughly the same baseline levels of serum vitamin D at the beginning of the study, and all participants were observed to experience similar increases in serum vitamin D levels throughout the course of the study. For the first seven weeks, serum vitamin D levels increased across the board, eventually reaching a plateau. And for the final five weeks of the study, serum vitamin D levels were maintained, according to the researchers.
After the 12 weeks were complete, researchers tested the blood levels of 25(OH)D in all participants and found that those taking vitamin D supplements had roughly the same vitamin D levels as those taking the mushroom extract. In other words, eating large amounts of mushrooms or taking concentrated mushroom extract daily appears to be at least equally as effective at boosting vitamin D levels as taking vitamin D supplements, which are sometimes unsuitable for vegetarians as they are commonly made from animal materials.
"These results provide evidence that ingesting mushrooms that have been exposed to ultraviolet (UV) light and contain vitamin D2 are a good source of vitamin D that can improve the vitamin D status of healthy adults," says Michael Holick, M.D., Ph.D., one of the study's authors.
UV-exposed mushrooms contain extra vitamin DInterestingly, the researchers observed that mushrooms exposed to just a few seconds of UV light contain significantly higher levels of vitamin D than regular mushrooms, which means they have the potential to be far more potent for therapeutic purposes. Thus, it is believed that UV-infused mushrooms may be the key for some people to maximize their vitamin D intake naturally.
"Mushrooms are one of the few food sources where the precursor to vitamin D occurs naturally," explains a report compiled by the Beltsville Human Nutrition Research Center in Maryland for the U.S. Department of Agriculture (USDA). "(And) the amount of vitamin D2 in mushrooms can be significantly increased by exposing mushrooms to ultraviolet (UV) light; UV-treated mushrooms are now entering some retail markets."
Commenting on the research, Kurt Kennel, M.D., from the Mayo Clinic in Minnesota, notes that there still may be a difference between the type of vitamin D found in mushrooms and the type of vitamin D found in natural sunlight and supplements. Though it has been shown scientifically to help promote calcium and bone metabolism, vitamin D2 is not typically the preferred type of vitamin D for human health.
"We don't want to look at one or the other as ineffective, but there probably is a difference," said Dr. Kennel to MedPageToday.com. "We wouldn't want to say that this is an equivalent way of treating vitamin D deficiency."