Eating more mushrooms could prevent gastric cancer, says researchers
Key Takeaways
A new study suggests eating more mushrooms may prevent gastric cancer.
Doctors and dietitians say mushrooms contain many functional nutrients, but it's unclear whether these have a direct impact on gastric cancer prevention.
A recent review found that eating mushrooms may reduce the risks of gastric cancer, and benefits may come from functional properties within the fungi.[]
The review analyzed the results of a meta-analysis of previously published studies and the Stomach Cancer Pooling (StoP) Project to investigate the relationship between mushroom consumption and gastric cancer risk and found that “higher mushroom consumption was associated with a lower risk of gastric cancer.”[]
The StoP Project contained 11 studies with a total of 3,900 gastric cancer cases and 7,792 control cases. Study participants’ mushroom was measured through food frequency questionnaires. The relative risk (RR) of gastric cancer for participants with the highest mushroom consumption vs. lowest mushroom conception was recorded as 0.82; 95%, with a confidence interval (CI) of 0.71-0.95.[]
Researchers also conducted a geographic subgroup analysis, where they found that people in Western Pacific countries who consumed mushrooms had an even lower risk of gastric cancer than those in other countries—which may reflect that mushrooms native to Asia may have higher levels of antioxidants, the researchers wrote.
“While interesting and hypothesis-generating, there's a lot of limitations that are inherent with that study design,” says Aasma Shaukat, MD, MPH, gastroenterologist and director of outcomes research for the division of gastroenterology and hepatology at NYU Langone Health. “You don't know if it's the mushrooms or a whole host of other factors associated with somebody that eats mushrooms or mushrooms themselves that might be contributing to [gastric cancer risk reduction].”
More research is needed to confirm if eating mushrooms truly reduces gastric cancer risks and, if so, why, adds Shaukat. However, the researchers present a plausible hypothesis, she says. And if or when that confirmation comes, the results could have a profound impact—as gastric cancer is the 5th most common cancer nationwide.[]
Benefits of mushrooms
Led by the same researchers, a review of research studies from 1999 to 2020 found that eating about 18 grams of mushrooms daily (or about two medium-sized mushrooms) could lower cancer risks as a whole by up to 45%. The Food and Drug Administration’s (FDA) listed serving size for raw mushrooms is about five medium mushrooms per serving.[][]
One quality that makes mushrooms so powerful is their abundance of antioxidants and amino acids. Among others, mushrooms are a good source of ergothioneine, which has been shown to prevent or slow cellular damage. Ergothioneine cannot be created by the human body and is rare in other foods. Mushrooms are also a good source of fiber, Vitamin D, Vitamin B6, and selenium—another antioxidant that helps the body make antioxidant enzymes to protect against cell damage.[][]
“There's some good pilot data that these compounds have antioxidant properties, but it's unclear if that’s sufficient—and if the quantity is sufficient—to translate into chemo prevention,” says Shaukat.
How to add mushrooms to your diet, safely
In lieu of the study findings, some doctors may want to recommend patients incorporate more mushrooms into their diet—particularly if they have a family history of gastric cancer. Still, it’s important not to over-promise what mushrooms can do for a patient or to encourage unhealthy dietary patterns. (For example, make sure they’re not only eating mushrooms.)
“I recommend including a variety of mushrooms in your diet, as well as a wide range of other fruits, vegetables, whole grains, and lean proteins,” says Melissa Baker, RD, a registered dietitian nutritionist and founder of Food Queries. “This balanced approach ensures that you are getting a diverse array of nutrients and phytochemicals that can help support overall health and potentially reduce cancer risk.”
“You can certainly consume more than this if you enjoy mushrooms and find them to be a tasty and nutritious addition to your diet,” says Baker.
She adds that “there is no one-size-fits-all answer,” but people wanting to increase their mushroom intake could aim to eat one or two servings a week. How closely people want to match this baseline is an individual choice, which may depend on how much they feel they are benefiting from eating mushrooms and, importantly, how much they enjoy the food, she says.
Some of the many varieties of mushrooms that people can incorporate into their diet include:
Button mushrooms
Shiitake mushrooms
Portobello mushrooms
Oyster mushrooms
Cremini mushrooms.
“Each of these types of mushrooms has a unique nutrient profile, so incorporating a variety of mushrooms can help ensure that you are getting a diverse array of nutrients,” says Baker.
For maximum nutritional benefit, people may want to diversify the types of mushrooms they are eating, and how they prepare the food, too, she adds.
People who are allergic, or suspect they are allergic to mushrooms, should not follow this advice and instead talk to a doctor, allergist, or dietitian about how to proceed.
“The take-home shouldn't be to suddenly start eating large amounts of mushrooms,” says Shaukat. “But, this generally points to the fact that diets high in vegetables—particularly raw vegetables—are generally good for us, not just for gastric cancer risk but for other cancers too.”