People who eat as little as one eighth to one fourth of a cup of mushrooms daily are 45% less likely to develop cancer compared with those who eat no mushrooms, according to a new observational study published in the journal Advances in Nutrition. While observational studies cannot establish cause and effect, the researchers believe that the evidence suggests a protective effect.

Pennsylvania State College of Medicine researchers conducted a systematic review of 17 studies on the correlation published between January 1, 1966 and October 31, 2020. They reviewed data on more than 19,500 participants. They found a statistically significant link between higher mushroom consumption and a lower risk of cancer. The strongest site-specific link was between mushroom intake and breast cancer, which kills an estimated 40,900 women every year in the United States.

About 25 species of mushrooms are edible and widely cultivated, and they tend to be an excellent source of certain vitamins, minerals and antioxidants. “Mushrooms are the highest dietary source of ergothioneine, which is a unique and potent antioxidant and cellular protector,” the study’s coauthor, Djibril M. Ba, a graduate student in epidemiology at Pennsylvania State College of Medicine, told Penn State News. “Replenishing antioxidants in the body may help protect against oxidative stress and lower the risk of cancer.”

However, while some mushroom species, including the shiitake, oyster, maitake and king oyster, are richer in ergothioneine than others, such as the cremini, white button and portobello, the researchers did not find significant differences in cancer risk reduction between people who preferred one class over another. Eating any kind of mushroom on a regular basis was associated with reduced risk.

“Overall, these findings provide important evidence for the protective effects of mushrooms against cancer,” said coauthor John Richie, a professor of public health sciences and pharmacology at Penn State. “Future studies are needed to better pinpoint the mechanisms involved and specific cancers that may be impacted.”

Not a fan of fungi? Fortunately, the researchers note, evidence suggests that other fruits and vegetables might confer similar health benefits.

For more on mushrooms and site-specific cancer risk, read “Can Mushrooms Lower Prostate Cancer Risk?” And to learn about a decidedly less legal mushroom variety and its applications for cancer care, read “First, Marijuana. Are Magic Mushrooms Next?” and “New Legal Push Aims to Speed Magic Mushrooms to Dying Patients."