Mushrooms are a much-loved ingredient in cuisines around the world. They are nutritious and especially rich in antioxidants, which protect cell health. Researchers are now asking whether mushrooms can also protect against cognitive decline.

Mushrooms are fascinating. Although some are edible and grocery stores sell them in their "vegetable" aisles, they aren't actually vegetables.

They are actually fungi, a kingdom all of its own, alongside those of plants and animals in biological classifications.

Edible mushrooms — both cultivated and wild species — contain a high amount of dietary fiber, antioxidants, and protein, as well as vitamins and minerals.

New research has found that people who integrate mushrooms into their diets — even if they only consume them in small portions — appear to have a lower risk of mild cognitive impairment (MCI), which often precedes Alzheimer's disease.

In MCI, a person may experience some symptoms characteristic of Alzheimer's disease — such as poor memory and issues with language and spatial orientation — but in a much subtler way that does not prevent them from continuing to lead a fully functional life.

Researchers at the National University of Singapore (NUS) near Clementi hypothesized that eating mushrooms could help preserve cognitive function in late adulthood. So, they conducted a new study to see whether they could find any evidence in this respect.

Their findings — which now appear in the Journal of Alzheimer's Disease — suggest that the mushrooms common in Singaporean cuisine may help reduce the risk of MCI.

MCI: A subtle form of cognitive decline

The study lasted 6 years, from 2011 to 2017, and it included 663 participants aged 60 and older at baseline. The researchers recruited them through the Diet and Healthy Aging project.

The investigators focused on the consumption of some of the most common mushrooms that people in Singapore eat:

• golden mushrooms
• oyster mushrooms
• shiitake mushrooms
• white button mushrooms
• dried mushrooms
• canned button mushrooms

The team defined mushroom portion sizes as three-quarters of a cup of cooked mushrooms per portion, weighing about 150 grams, on average.