Mushrooms as brain food

Relation

Feng L, Cheah I, Ng M, et al. The association between mushroom consumption and mild cognitive impairment: a community-based cross-sectional study in Singapore.J Alzheimer's Dis. 2019;68(1):197-203.

Study objective

Investigating the Association Between Mushroom Consumption and Mild Cognitive Impairment (MCI)

Draft

A community-based cross-sectional observational study

Participant

The study involved 663 participants (all 60 years of age or older) from the Diet and Healthy Aging (DaHA) study in Singapore, which collected a wide range of data using a cross-sectional study design at the start of the study from 2011 to 2017. The participants who had not been diagnosed with dementia or psychiatric disorders.

Study parameters assessed

Researchers used personal questionnaires to assess mushroom consumption. In the interview they asked the question: “How often do you eat the following?” One serving was ¼ plate, ¾ cup or approximately 150 grams. There were 4 different mushrooms in 6 different shapes.

Primary outcome measures

To assess cognitive status, researchers administered the Singapore Modified Mini-Mental State Examination (SM-MMSE) and a local version of the Clinical Dementia Rating (CDR) scale. They conducted further assessment with cognitive domains through a clinical assessment involving 2 consultant psychiatrists.

Key insights

Participants who consumed more than 2 servings of mushrooms per week were less likely to have MCI (OR = 0.43; 95% CI, 0.24-0.75,P= 0.003) compared to those who consumed less than 1 serving per week and those who consumed 1-2 servings per week; this remained statistically significant even after adjusting for demographic characteristics (age, gender, education), lifestyle (physical activities, social activities, cigarette smoking, alcohol consumption) and other medical conditions (hypertension, diabetes, heart disease and stroke).

Practice implications

Mushrooms have been used for food and medicine for centuries, with positive effects on human health well documented in studies. Many components of mushrooms have been shown in cell and rodent studies to promote brain health against neurodegenerative diseases. For example, a medicinal mushroom from Taiwan,Antrodia camphorataBeta-amyloid 1-42 (Aß1-42) has been shown to prevent Aß peptides from being deposited in the hippocampus, a known side effect of memory impairment in Alzheimer's patients.¹

shiitake (Lentinula edodes) show properties that improve intestinal health with beta-glucans, naturally occurring polysaccharides. These beta-glucans can act as the main source of energy (carbon) for microbiota (such asBifidobacterium spp. andLactobacillus spp.) by stimulating their growth as they produce short-chain fatty acids (SCFAs). The role of SCFAs in the intestine is to maintain osmotic pressure in the intestine, which allows the normal function of the distal intestine along with the colonic epithelium.²Reports have shown that mushroom-derived beta-glucans can alter the gut microbiome and potentially reverse gut microbiota composition, such as: B. the reduced ratio of Firmicutes/Bacteroides.^3.4This shift may help older adults with cognitive function, according to a 2017 study that found higher levels of Bacteroidetes are not beneficial and may be harmful.⁵

The well-known onesPorcini mushroomsCommonly called Porcini in the USA, it is said to contain the highest amount of ergothioneine.

But researchers in this Singapore study suggest that a compound found in most mushrooms, ergothioneine, is responsible for an associated reduction in MCI. Ergothioneine is named after the ergot fungus (Claviceps purpurea), from which it was first isolated in 1909. It is a sulfur-containing amino acid found in non-yeast fungi (mainly basidiomycetes) and some bacteria (Actinomycetales and cyanobacteria including spirulina,Arthrospira maxima⁶), but neither plants nor mammals.⁷Plants absorb ergothioneine from symbiotic associations with fungal mycelia and soil bacteria.⁸Humans and other mammals absorb it from these plants.⁷Once consumed, it has a transport protein, OCTN1,⁹and occurs in many human cells.

In vitro studies have suggested that ergothioneine is a powerful antioxidant, similar to glutathione, and may play a role in mitochondrial protection.¹⁰In contrast to glutathione, ergothioneine does not oxidize as easily and is therefore considered more stable.¹¹Several studies report a protective effect on neurological tissue, and ergothioneine appears to be able to cross the blood-brain barrier.⁷In humans, a study has shown that ergothioneine is at its highest concentration at a young age and in teenagers¹²but decreases with increasing age. It is not known why older individuals have lower levels; it could be changes in food intake in older people or changes in expression of the transport protein gene.¹³Ergothioneine has also been shown to be lower in people with MCI.¹⁴In a transgenic nematodeCaenorhabditis elegansModel of amyloid-induced toxicity, ergothioneine added to the growth medium extended lifespan and resulted in less oxidative stress compared to those without ergothioneine (P<.0001).^fifteenIn his article “Prolonging Healthy Aging: Vitamins and Proteins for Long Life”¹⁶Bruce Ames includes ergothioneine on a list of putative longevity vitamins, substances that are not needed for survival but that instead reduce the accumulation of long-term oxidative damage.

Researchers in Singapore are conducting a Phase 3 clinical trial in which participants will take a placebo or 25 mg of ergothioneine three times weekly for a total of 52 weeks. The process will be completed in 2021,¹⁷and should provide more details about the effectiveness of this compound. But until then, there are a variety of mushrooms that can be added to the dietary recommendations. The well-known onesPorcini mushroomsCommonly called Porcini in the USA, it is said to contain the highest amount of ergothioneine.¹⁸Non-mushroom foods with some ergothioneine (but still lower than the mushrooms) include pork liver; kidney, black and red beans; and oat bran.

Here is a list of edible and common medicinal mushrooms in order of ergothioneine content from highest to lowest, approximated according to the reports of some studies.^19.20The use of these mushrooms as food offers many benefits and should be encouraged. However, production of ergothioneine in the nutraceutical industry is probably not far off using synthesisSaccharomyces cerevisiaeYeast.⁹

Note: Ergothioneine has been abbreviated “ESH,” “ERG,” “LE,” and “Ergo” in various articles.

*Studies have reported mixed amounts of shiitake; For example, in a 2007 report, the values ​​were very low to non-existent.