Alzheimer’s disease is the most frequent type of dementia, characterized by a progressive loss of cognitive abilities, including memory, thinking, and behavior. Researchers believe that there is no single cause for this disease, but rather it’s the result of a set of genetic, lifestyle, and environmental risk factors. Even sleep can shape the risk of developing dementia: recent data has shown that people who sleep six or fewer hours a night have a 30% higher risk in comparison to those who get seven hours of sleep. But scientists are just now starting to understand the relationship between sleep and Alzheimer’s.
Our brain is composed of billions of neurons that communicate with each other, originating our thoughts, feelings, and actions. However, in Alzheimer’s disease, brain connections and basic cell processes are often disrupted by the abnormal accumulation of proteins. Two proteins are involved in this pathological process: amyloid-beta (Aꞵ), which forms plaques around neurons, and tau, which forms tangles inside them. Once brain connections and the transport of nutrients and other essential supplies within neurons are lost, these cells die. The brain shrinks and brain function suffers.
Luckily, our bodies have a system that allows these toxic proteins to be cleared out from the brain. Here’s how it works: surrounding the brain, and in close contact with the brain’s blood vessels, there is fluid – the cerebrospinal fluid (CSF) – which collects waste products from the brain and drains them out. This clearance system seems to be most active during sleep, but scientists do not yet fully understand why. It is also known that the clearance of brain waste and sleep quality decline with age, suggesting a causal relationship between sleep and the progression of neurodegenerative diseases. In agreement with this, a recent study provided new evidence supporting the role of sleep-related brain activity in the clearance of toxic protein buildup. In this study, functional magnetic resonance imaging (fMRI) tests and behavioral data from 118 participants, including patients presenting cognitive decline, patients with Alzheimer’s disease, and healthy people, were evaluated.
fMRI measures the activity of different parts of the brain based on the fact that oxygenated blood rushes to the most active regions. The increase in oxygenated blood in a given region causes a signal change that can be seen during the brain scan. Using this imaging technique, the researchers found that activity occurring in the brain during sleep coincides with CSF passing through to clear waste from the brain.
Interestingly, the coupling between brain activity and CSF flow was decreased in Alzheimer’s patients and tended to decrease with disease severity. This association also seemed to be weaker in participants at higher risk of developing Alzheimer’s, including older individuals and females. These findings are very promising since the coupling between brain activity and CSF flux could be used as an imaging marker for the diagnosis of this neurodegenerative disease.
But there is more to it than that. The researchers also found that patients presenting a weaker relationship between brain activity and CSF flow had more buildup of Aꞵ in their brains and a larger decline in cognitive performance in the following two years. This study confirmed that the coupling between brain activity and CSF movement was stronger during resting states. Thus, a lack of sleep could affect the flux of CSF, which is essential to clear out toxic proteins, such as Aꞵ, from the brain, causing the Alzheimer’s-disease related pathology.
Although there is no effective treatment for this disease, there are lifestyle interventions that could optimize the removal of brain waste and prevent neurodegeneration. Here are 4 things you can do to improve the quality of your sleep and help this process:
Supplement your diet with Omega-3 fatty acids
Omega-3 supplementation has been shown to promote the clearance of Aꞵ and to improve cognitive function. Oily fish are rich in omega-3 polyunsaturated fatty acids (n3-PUFAs), which reduce the risk of neurodegenerative diseases like Alzheimer’s and help the brain get rid of harmful proteins while you sleep. Enjoy some salmon, mackerel, oysters, or caviar. Nuts like flax seeds and walnuts also are high in omega-3 fatty acids.
Practice intermittent fasting – Eat an early dinner
Intermittent fasting causes protective changes in the brain. Allowing your gut to rest for a few hours before you fall asleep can help you sleep better, ensuring the proper functioning of your brain’s clearance system.
Exercise
Exercise is well known for its neuroprotective effects. Running, for example, boosts fluid flow through the brain, reducing inflammation and protein deposition, and improves memory and cognition. Aim for at least 150 minutes of moderate or 75 minutes of vigorous exercise a week to improve brain health.
Sleep in the right lateral position
Fluid flow through the brain is influenced by several factors, including gravity and the stretch of nerves and vessels on the neck. That is why the position in which we sleep is so important. Sleeping on your right lateral side might improve the efficiency of brain waste clearance, compared to lying on your back or stomach.
