Like all organs in the human body, the structure and function of the brain gradually deteriorate with age. This aging is completely normal and, in the majority of cases, does not have a major impact on a person’s quality of life.
In some cases, however, the decrease in brain performance can become more significant and lead to the appearance of “mild cognitive deficits”, i.e. episodes where cognitive functions are subtly altered and cause unusual problems with memory, attention, language or visual-spatial functions (orientation, driving, etc.).
Over time, these deficits can progress to greater loss of cognitive functions and, eventually, to the onset of dementia. With the aging of the population, this deterioration in cognitive health is likely to have serious consequences: according to recent estimates made by the World Health Organization (WHO), it is predicted that the number of people with dementia could triple over the next 30 years, with disastrous consequences for the quality of life of those affected and their loved ones.
The neuroprotective effect of foods rich in polyphenols
The WHO report emphasizes the importance of preventing the onset of dementia by adopting a healthy lifestyle, including regular physical activity, body weight control and good nutrition ( the Mediterranean diet, for example).
It is also interesting to note that several studies suggest that certain foods rich in antioxidant and anti-inflammatory polyphenols (olive oil, dark chocolate, turmeric, blueberries) seem to exert a positive effect on brain function, raising the interesting possibility that including these foods in dietary habits may enhance the neuroprotective potential associated with healthy eating.
Even if a proportion of dementias are of genetic origin and are therefore inevitable, it is however necessary to be aware that it is quite possible to prevent many of them by modifying the way of life.
Two servings of mushrooms a week halves the risk of cognitive decline
Mushrooms are another category of foods that may help prevent cognitive decline. For example, studies have reported that regular mushroom consumption was associated with better cognitive performance in Norwegians aged 70-74, as well as a significant (20%) decrease in the risk of dementia in elderly Japanese. 65 and over. This neuropreventive potential of mushrooms is also highlighted by the results of a recent study carried out in Singapore among 663 people aged 60 and over. Compared to people who rarely ate mushrooms (less than once a week), those who ate them regularly (2 or more servings a week) had a 56% lower risk of experiencing mild cognitive deficits such as memory loss.
The neuroprotective effect of mushrooms scientifically explained
As the authors point out, this protective effect of fungi is biologically explainable. On the one hand, mushrooms contain several specific molecules (hericones, erinacins, scabronins and dictyophorin) known to promote the synthesis of neuronal growth factor (NGF), a molecule involved in the survival of neurons. On the other hand, mushrooms are a very important source of L-ergothioneine (ET), a molecule which has very strong antioxidant activity and which can accumulate in the brain and protect neurons from oxidative stress.
Moreover, a study has shown that ET levels are significantly reduced in people with mild cognitive impairment, suggesting that ET deficiency could represent a risk factor for neurodegeneration. By increasing ET levels in the brain, regular consumption of mushrooms could therefore prevent or at least attenuate the processes involved in the deterioration of cognitive functions linked to aging and its progression towards neurodegenerative diseases such as dementia.
World Health Organization. Adopting a healthy lifestyle helps reduce the risk of dementia (www.who.int).
Feng et al. The association between mushroom consumption and mild cognitive impairment: a community-based cross-sectional study in Singapore. J. Alzheimer’s Disease 197-203.
Cheah I et al. Ergothioneine levels in an elderly population decrease with age and incidence of cognitive decline; a risk factor for neurodegeneration? Biochem. Biophys. Res. Common. 478: 162-167.