The pathogenesis of Alzheimer's disease is still unsolved. However, based on what we know, it can be concluded that in most cases it has a metabolic basis, i.e. its development is directly influenced by diet and physical activity (or lack of it), and not, as previously thought - genetic load, which statistically may influence the development of the disease in 3-5% of patients. It is suspected that cholesterol may have a significant influence on the development of dementia, including Alzheimer's disease.

The most commonly diagnosed form of dementia is Alzheimer's disease. It is a loss of memory and other intellectual disorders, leading to reduced performance in the elderly. The disease leads to premature death usually 3 to 9 years after diagnosis.

Mild Cognitive Impairment (MCI), on the other hand, is the most common preclinical form that does not yet have clear symptoms characteristic of AD. MCI allows you to function normally, but it contributes to a decline in cognitive functions and may be associated with the development of AD in the near future.

Early detection of MCI allows for an intervention that can significantly reduce the risk of developing the disease to its full extent.

Cholesterol plays a very important role in the brain, which stores 20% of the total amount of cholesterol in the body. In 70-80% it is used as the myelin sheaths of neurons.

Acting like electrical tape, it allows faster data transfer (up to 150 m / s) between brain cells. It is also essential for synaptic development and formation, dendrite differentiation, axon elongation, and long-term enhancement of the synaptic signal.

Cholesterol metabolism in the brain is independent of that in peripheral tissues. In other words, the cholesterol molecule is too large to cross the blood-brain barrier from the blood system to the brain.

How does cholesterol contribute to the development of Alzheimer's disease?

Abnormalities in cholesterol metabolism lead to structural and functional damage to the central nervous system, leading to diseases such as Niemann Pick, Huntington, Parkinson's and… Alzheimer's disease!

How is this possible when cholesterol is unable to cross the blood-brain barrier? The answer isoxidized form of cholesterol, i.e. oxycholesterol.

If there is an excess of cholesterol in the brain, then the appropriate enzyme oxidizes its molecules so that it can freely leave the skull structure without causing damage.

Studies show that excessive amounts of oxycholesterol in the bloodstream (often associated with poor diet, dyslipidemia, or liver disease) can also enter the brain by accumulating there. Excess oxysterols are toxic and induce apoptosis (death) in nerve cells.

Studies of people with MCI show significantly elevated levels of oxysterols in the blood. This level is even higher in people diagnosed with AD. In addition, the increase in the amount of oxysterols in the blood is also associated with a number of other metabolic diseases.

Atherosclerotic plaques in people with coronary artery disease contained 20 times more cholesterol than its concentration in cell membranes. However, the level of oxidized cholesterol there was as much as 45 times higher.

Small particles of oxidized choleterol not only easily penetrate the blood-brain barrier. They can also pass freely from the gastrointestinal tract into the blood. Hence, it only takes a few heartbeats to reach the brain, causing inflammation and inducing the deposition of amyloid plaques characteristic of Alzheimer's disease. Such a situation may take place even years before the first memory damage.

Accumulation of oxysterols can be cytotoxic, mutagenic, atherogenic and possibly carcinogenic.

The most commonly diagnosed form of dementia is Alzheimer's disease. It is a loss of memory and other intellectual disorders, leading to reduced performance in the elderly. The disease leads to premature death usually 3 to 9 years after diagnosis.

Mild Cognitive Impairment (MCI), on the other hand, is the most common preclinical form that does not yet have clear symptoms characteristic of AD. MCI allows you to function normally, but it contributes to a decline in cognitive functions and may be associated with the development of AD in the near future.

Early detection of MCI allows for an intervention that can significantly reduce the risk of developing the disease to its full extent.

Cholesterol plays a very important role in the brain, which stores 20% of the total amount of cholesterol in the body. In 70-80% it is used as the myelin sheaths of neurons.

Acting like electrical tape, it allows faster data transfer (up to 150 m / s) between brain cells. It is also necessary for the development and formation of synapses, dendrite differentiation, and elongationaxon (elongation), long-term amplification of the synaptic signal.

Cholesterol metabolism in the brain is independent of that in peripheral tissues. In other words, the cholesterol molecule is too large to cross the blood-brain barrier from the blood system to the brain.

How does cholesterol contribute to the development of Alzheimer's disease?

Abnormalities in cholesterol metabolism lead to structural and functional damage to the central nervous system, leading to diseases such as Niemann Pick, Huntington, Parkinson's and… Alzheimer's disease!

How is this possible when cholesterol is unable to cross the blood-brain barrier? The answer is the neutralized form of cholesterol, i.e. oxycholesterol.

If there is an excess of cholesterol in the brain, then the appropriate enzyme oxidizes its molecules so that it can freely leave the skull structure without causing damage.

Studies show that excessive amounts of oxycholesterol in the bloodstream (often associated with poor diet, dyslipidemia, or liver disease) can also enter the brain by accumulating there. Excess oxysterols are toxic and induce apoptosis (death) in nerve cells.

Studies of people with MCI show significantly elevated levels of oxysterols in the blood. This level is even higher in people diagnosed with AD. In addition, the increase in the amount of oxysterols in the blood is also associated with a number of other metabolic diseases.

Atherosclerotic plaques in people with coronary artery disease contained 20 times more cholesterol than its concentration in cell membranes. However, the level of oxidized cholesterol there was as much as 45 times higher.

Small particles of oxidized choleterol not only easily penetrate the blood-brain barrier. They can also pass freely from the gastrointestinal tract into the blood. Hence, it only takes a few heartbeats to reach the brain, causing inflammation and inducing the deposition of amyloid plaques characteristic of Alzheimer's disease. Such a situation may take place even years before the first memory damage.

Accumulation of oxysterols can be cytotoxic, mutagenic, atherogenic and possibly carcinogenic.

What products are oxysterols in?

What can we do to lower blood cholesterol? One of the ways to lower your blood cholesterol levels, prescribed by doctors, is by taking statins. However, research shows that this has no impact on the development of Alzheimer's disease.

Another way is to exclude products containing oxidized forms of cholesterol from your diet.

Where can I find sources of oxysteroli in the diet? The highest values ​​of these lipoprotein fractions can be found in clarified butter (ghee). It is a product that has undergone a heat treatment which involves heating regular butter to separate the fats from the proteins in it.

This process significantly increases the oxidation of cholesterol particles. Its value increases tenfold! This may explain why Hindus have a very high percentage of heart disease despite the fact that a significant percentage of citizens are vegetarians (vegetarians tend to have a lower percentage of cardiovascular disease incidence than the general public).

The sources of large amounts of oxycholesterol are also products such as butter, cheese, red meat or highly processed products such as fast-food dishes and sweets.

What contributes to the increase in the amount of oxidized cholesterol in food products?

Thermal treatment comes to the fore. It is difficult to assess the effect of a particular food preparation method on the content of oxidized cholesterol as it will differ from one food product to another. It is certainly worth emphasizing that the shorter the heating time, the less oxycholesterol will be. This also applies to cooking and steaming. However, by systematizing the information, it is possible to determine the average which of the heat treatment increases the oxycholesterol content the most: These are:

  • microwaves
  • frying
  • baking
  • grilling
  • cooking

The freshness of the products is also important. Storing a frozen product, such as fish, increased the amount of oxidized cholesterol up to 10 times over 4 months.

What products are oxysterols in?

What can we do to lower blood cholesterol? One of the ways to lower your blood cholesterol levels, prescribed by doctors, is by taking statins. However, research shows that this has no impact on the development of Alzheimer's disease.

Another way is to exclude products containing oxidized forms of cholesterol from your diet.

Where can I find sources of oxysteroli in the diet? The highest values ​​of these lipoprotein fractions can be found in clarified butter (ghee). It is a product that has undergone a heat treatment which involves heating regular butter to separate the fats from the proteins in it.

This process significantly increases the oxidation of cholesterol particles. Its value increases tenfold! This may explain why Hindus have a very high percentage of heart disease despite the fact that a significant percentage of citizens have itvegetarians (vegetarians generally have a lower percentage of cardiovascular disease incidence than the general public).

The sources of large amounts of oxycholesterol are also products such as butter, cheese, red meat or highly processed products such as fast-food dishes and sweets.

What contributes to the increase in the amount of oxidized cholesterol in food products?

Thermal treatment comes to the fore. It is difficult to assess the effect of a particular food preparation method on the content of oxidized cholesterol as it will differ from one food product to another. It is certainly worth emphasizing that the shorter the heating time, the less oxycholesterol will be. This also applies to cooking and steaming. However, by systematizing the information, it is possible to determine the average which of the heat treatment increases the oxycholesterol content the most: These are:

  • microwaves
  • frying
  • baking
  • grilling
  • cooking

The freshness of the products is also important. Storing a frozen product, such as fish, increased the amount of oxidized cholesterol up to 10 times over 4 months.

Worth knowing

Certainly, all products that are a source of oxidized sterols cannot be completely excluded from the diet. Even plant sources containing sterols are prone to oxidation and, albeit to a lesser extent, are absorbed from the digestive tract.

To keep the balance, it is worth adding vegetables rich in antioxidants on a regular basis (preferably with each meal). A serving of fruit or two a day will also have a positive effect on your he alth.

The right diet for the brain is so complicated that changes will not be noticed on the weight, as in the case of slimming diets. It takes years for the brain to change. The first symptoms usually appear when it is too late.

Worth knowing

Certainly, all products that are a source of oxidized sterols cannot be completely excluded from the diet. Even plant sources containing sterols are prone to oxidation and, albeit to a lesser extent, are absorbed from the digestive tract.

To keep the balance, it is worth adding vegetables rich in antioxidants on a regular basis (preferably with each meal). A serving of fruit or two a day will also have a positive effect on your he alth.

The right diet for the brain is so complicated that changes will not be noticed on the weight, as in the case of slimming diets. It takes years for the brain to change. The first symptoms usually appear when it is too late.

About the authorMikołaj Choroszyński,dietitian and gastrocoach Master of Human Nutrition and Dietetics, Psycho-dietician, Youtuber. Author of the first book on the Polish market about a diet counteracting neurodegenerative diseases "MIND Diet. A Way for a Long Life". He fulfills himself professionally, running his Bdieta diet clinic, because nutrition has always been his passion. She helps her patients by telling them what to eat to stay he althy and look good.

Category:

Neurology