Adding mushrooms to your diet may reduce cognitive decline, researchers say

Seniors who ate more than 300 grams of cooked mushrooms a week may have 50 percent reduced odds of developing mild cognitive impairment (MCI), according to new research from the Department of Psychological Medicine and Department of Biochemistry at the Yong Loo Lin School of Medicine at the National University of Singapore (NUS). The study was published yesterday in the Journal of Alzheimer’s Disease.

The six-year study, which was conducted from 2011 to 2017, collected data from more than 600 Chinese seniors over the age of 60 living in Singapore. The research was carried out with support from the Life Sciences Institute and the Mind Science Centre at NUS, as well as the Singapore Ministry of Health's National Medical Research Council.

Six commonly consumed mushrooms in Singapore were referenced in the study—golden, oyster, shiitake, and white button mushrooms, as well as dried and canned mushrooms. A portion was defined as three quarters of a cup of cooked mushrooms with an average weight of around 150 grams. Two portions would be equivalent to approximately half a plate. While the portion sizes act as a guideline, researchers found even one small portion of mushrooms a week may still be beneficial to reduce chances of MCI, according to an announcement published by the university.

MCI is typically viewed as the stage between the cognitive decline of normal ageing and the more serious decline of dementia. Seniors afflicted with MCI often display some form of memory loss or forgetfulness and may also show deficit on other cognitive function such as language, attention and visuospatial abilities. However, the changes can be subtle, as they do not experience disabling cognitive deficits that affect everyday life activities, which is characteristic of Alzheimer's and other forms of dementia.

As such, the researchers conducted extensive interviews and tests with the senior citizens to determine an accurate diagnosis. After this, a two-hour standard neuropsychological assessment was performed, along with a dementia rating. The overall results of these tests were discussed in depth with expert psychiatrists involved in the study to get a diagnostic consensus.

The researchers believe the reason for the reduced prevalence of MCI in mushroom eaters may be down to a specific compound found in almost all varieties, according to the study.

An earlier study by the team on elderly Singaporeans revealed that plasma levels of ET in participants with MCI were significantly lower than age-matched healthy individuals. The work, which was published in the journal Biochemical and Biophysical Research Communications in 2016, led to the belief that a deficiency in ET may be a risk factor for neurodegeneration, and increasing ET intake through mushroom consumption might possibly promote cognitive health.

Other compounds contained within mushrooms may also be advantageous for decreasing the risk of cognitive decline. Certain hericenones, erinacines, scabronines, and dictyophorines may promote the synthesis of nerve growth factors. Bioactive compounds in mushrooms, researchers say, may also protect the brain from neurodegeneration by inhibiting production of beta amyloid and phosphorylated tau, and acetylcholinesterase.