Mushrooms: Alzheimer’s disease (AD) is a neurodegenerative disease that gets worse over time and damages memory and other important mental abilities. It’s the main reason people get dementia, and there’s no fix yet.
In Alzheimer’s disease, both the links between brain cells and the cells themselves break down. This makes memory and thinking skills get worse over time. In the worst cases, AD can leave people in a state of confusion that lasts for a long time and causes big changes in their personality and behavior.
AD mostly affects people over 65, but early-onset AD in people in their mid- to late-30s is becoming a bigger problem. About one in nine people over the age of 65 is thought to have some form of AD.
Pathologically, AD is mostly identified and defined by the buildup of too many tau tangles and diffuse beta-amyloid (Aβ) plaques. Even though study into the pathology of AD is still going on, no one knows how the disease progresses and there is currently no cure for it. Studies have found that genetic, environmental, food, age, and sociodemographic factors all play a role in the development and occurrence of AD.
So, while most research into possible therapeutic interventions focuses on ways to stop AD from happening or slow it down, there is more and more evidence that diet and lifestyle choices can affect how the disease shows up and how people who already have it deal with it.
Health behaviors and dietary changes can strongly predict the risk of AD in adults. For example, the Mediterranean diet, the Dietary Approaches to Stop Hypertension (DASH) diet, and the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet have all been linked to better memory retention and cognition in older people.
Some healthy habits, like intermittent fasting for a long time and eating fresh, selenium-rich foods, have been shown to delay or even cure the symptoms of AD. These effects may be caused by limiting calories and using antioxidant and anti-inflammatory systems, respectively. Researchers have also found that drinking tea, which is the most popular drink in the world, can successfully slow the progression of AD when done in moderation.
“Whole plant foods, such as mushrooms, berries, garlic, and turmeric, were found to effectively prevent and improve cognitive deficit via regulating the main pathway of neuroinflammation, lipoxin A4 (LXA4)-nuclear factor-kappa B (NF-κB), and mitogen-activated protein kinases (MAPK). These beneficial effects were mainly attributed to their high contents of functional macromolecules, including polysaccharides, bioactive peptides, and polyphenols; therefore, whole-plant foods can be part of a dietary plan to prevent the progression of AD.”
Li et al. (2023)
One meat, one vegetable, and mushrooms
Studies have shown that bad health habits have the opposite effect on cognitive function. For example, a Korean cohort of 3,933,382 people who drank a lot of alcohol had a higher chance of dementia.
There is also a link between how much food is processed and cognitive decline. A 10-year study found that eating ultra-processed (high in sugar, fat, and energy density) foods was linked to a higher risk of dementia.
Researchers have found that the Western diet, which is high in simple sugars and heavy fatty acids, is one of the main causes of memory loss in Alzheimer’s disease (AD). This is because it damages the blood-brain barrier (BBB).
So, it’s very important to eat healthy foods, especially ones that are high in bioactive substances that are known to improve brain function. This review is an overview of the research that has been done on the effects of eating mushrooms on Alzheimer’s disease. It includes notes on the biochemical qualities that make mushrooms a great early dietary intervention in the disease.
The fleshy, spore-bearing fruiting body of macrofungi is what mushrooms are. They usually grow above ground on dirt or their food source.
In addition to their unique umami flavor, mushrooms have been a staple in people’s meals around the world for hundreds of years because they are good for you and can help with health problems.
Recent studies in vitro and in vivo have found biomolecules in mushrooms to have anticancer, antioxidant, antimicrobial, and neuroprotective properties. This suggests that eating mushrooms may help delay or even prevent cognitive impairment (CI) linked with Alzheimer’s disease.
Cohort studies on Japanese and Singaporean people over 65 have shown that eating mushrooms often greatly lowers the risk of getting dementia. One Singaporean cohort study found that eating as few as two or three mushrooms a week, or 300 grams, cut the chance of mild cognitive impairment (MCI) by half.
The lion’s mane mushroom, Hericium erinaceus, has been studied and its biomolecules and extracts have been shown to improve cognitive and behavioral problems in both experimental animal tests and, surprisingly, clinical human tests.
This study looked at how different parts of mushrooms, such as polysaccharides, terpenoids, proteins, lipids, and phenolic compounds, can help protect neurons from AD.
One way that medicine is used to help is to block the acetylcholinesterase (AChE) receptor, which stops the chemical acetylcholine from working in the brain.
The polysaccharide extracts from the shaggy mane mushroom (Coprinus comatus) and the truncorum mushroom (Coprinellus truncorum) were high in β-glucans, which stopped AChE from working without the usual side effects that come with synthesis medicines.
In vitro studies using polysaccharide extracts from Grifola frondosa (Maitake mushrooms), Pleurotus eryngii (king trumpet mushrooms), and H. erinaceus all showed that these mushrooms could help protect neurons and fight free radicals in aging rats. The rats’ thinking got a lot better, which suggests that neurodegeneration stopped.
One of the most well-studied causes linked to Alzheimer’s disease and dementia is inflammation, which is supported by glial cell activity. Surprisingly, mushrooms have a lot more protein than most other veggies and fruits. These proteins are made up of new peptides, and some of them have been shown to be very good at reducing inflammation.
“Novel selenium peptides obtained from selenium-enriched Cordyceps militaris showed protective effect in H2O2-injured PC12 and alleviated the cognitive impairment in lipopolysaccharide (LPS) injured mice through its antioxidative, anti-inflammatory, and regulating properties on gut microflora.”
Li et al. (2023)
Even though mushrooms only have a small amount of lipids (0.1 to 16.3%), the oleic and linolenic acids they contain have been shown to be just as good at reducing inflammation as their peptides. It was found that alpha linoleic acid successfully protected mouse neurons from Aβ-induced glial cell-mediated neuroinflammation. In an Aβ-infused rat model, the test group of mice that ate the alpha-linoleic acid had much less neuronal cell loss than the control group.
The chemicals melatonin, ergosterol, terpenoids, and phenolic substances that are taken from mushrooms have been shown to help fight AD in many different ways, mainly by protecting neurons in the brain and reducing inflammation. There is evidence that brain inflammation is the main cause of neurological diseases like Alzheimer’s.
Eating these mushrooms or extracts from them could lead to new treatments and therapies that replace synthetic chemicals with cheap, healthy, and naturally occurring options. This would help the fight against Alzheimer’s disease and other age-related cognitive conditions.