Cancer is the second leading cause of death following cardiovascular disease. For many cancers, the risk may be reduced by consumption of a healthy diet rich in plant-based foods because many plants contain anticancer compounds. One team of researchers aimed to determine the role of mushroom consumption in reducing cancer risk.

Mushrooms are rich in bioactive compounds, including phytochemicals (plant chemicals such as flavonoids and carotenoids), fiber, selenium, vitamins, and antioxidants, such as ergothioneine and glutathione, which may help prevent cancer. While laboratory studies have shown the ability of mushroom compounds to inhibit cancer growth, epidemiological evidence is mixed, with some studies reporting a link between mushroom consumption and decreased cancer risk and others reporting no link.

The current report is a systematic review and meta-analysis, meaning the authors searched the existing literature on mushroom consumption and cancer risk, selected studies based on a set of criteria meant to select for relevant studies of high quality, and combined the risk data from each trial to calculate a new set of risk estimates. They selected observational studies of mushroom intake and cancer incidence that included at least two doses of mushroom intake and were published between January 1966 and October 2020.

The authors identified 17 studies that met their selection criteria. Pooled data from these studies showed that higher mushroom consumption was associated with lower risk of total cancer, with participants in the highest consumption group having a 66 percent lower risk of all cancers than participants in the lowest consumption group. Higher mushroom consumption was associated with an 80 percent lower risk for non-breast cancers and a 65 percent lower risk of breast cancer specifically. When the authors calculated risk for specific cancers (lung, breast, prostate, colon, etc.), only breast cancer was significantly associated with mushroom consumption, but they noted this could be due to the small number of studies conducted with non-breast cancers. Finally, the data revealed a significant dose-response association between mushroom consumption and the risk of total cancer with a 45 percent lower risk at high intake (about a quarter cup of sliced mushrooms per day) compared to the lowest intake of zero grams per day.

The results show a significant benefit of mushroom consumption in preventing breast and non-breast cancers. The authors noted that there are limitations to their study including variation in study design among trials.

• Link to full study.