AsianScientist (Mar. 25, 2019) – Mushrooms could help reduce the risk of cognitive impairment in old age, say scientists in Singapore. They published their findings in the Journal of Alzheimer’s Disease.
Mild cognitive impairment (MCI) is typically viewed as the stage between the cognitive decline of normal aging and the more serious cognitive decline of dementia. Seniors afflicted with MCI often display some form of memory loss or forgetfulness and may also show deficit in other cognitive functions such as language, attention and visuospatial abilities.
In the present study, researchers led by Assistant Professor Feng Lei at the National University of Singapore (NUS) found that increased ergothioneine (ET) intake through mushroom consumption was associated with a reduction in MCI symptoms. The six-year study, which was conducted from 2011 to 2017, saw data collected from more than 600 Chinese seniors over the age of 60 living in Singapore.
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. The researchers also took into account demographic information, medical history, psychological factors and dietary habits of study participants. In addition, they measured the participants’ blood pressure, weight, height, handgrip and walking speed, and performed a simple screen test on cognition, depression and anxiety.
The team found that seniors who consume more than two standard portions of mushrooms weekly may have 50 percent reduced odds of having MCI. 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, the researchers found that even one small portion of mushrooms a week may still be beneficial to reduce chances of MCI.
“This correlation is surprising and encouraging. It seems that a commonly available single ingredient could have a dramatic effect on cognitive decline,” said Feng.
The researchers believe the reason for the reduced prevalence of MCI in mushroom eaters may be down to a specific compound—ET—found in almost all mushroom varieties. Prior studies have shown that plasma levels of a compound called ET were lower in individuals with MCI as compared to age-matched healthy individuals.
“ET is a unique antioxidant and anti-inflammatory compound which humans are unable to synthesize on their own. But it can be obtained from dietary sources, one of the main ones being mushrooms,” said Dr. Irwin Cheah of NUS who co-authored the study.
Other compounds contained within mushrooms may also be advantageous for decreasing the risk of cognitive decline, said the researchers. Bioactive compounds in mushrooms may also protect the brain from neurodegeneration by inhibiting the production of beta-amyloid, phosphorylated tau and acetylcholinesterase.
Going forward, the team may want to perform a randomized controlled trial with the pure compound of ET and other plant-based ingredients, such as L-theanine and catechins from tea leaves, to determine the efficacy of such phytonutrients in delaying cognitive decline. Such interventional studies will lead to more robust conclusions on the causal relationships between dietary habits and MCI.
Source: National University of Singapore; Photo: Pexels.
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