Alzheimer’s: Causes and How to Prevent It

As human life expectancy has grown longer, it has led to the emergence of disease that were once quite rare. One of these is Alzheimer’s. At the beginning, Alzheimer’s manifests as a decrease in overall everyday activity. It becomes more apparent as mental functions decrease and cognition weakens. In advanced stages, it leads to senility, a tragic condition induced by the deterioration of neurons.

Memory loss is a leading symptom that emerges at the onset of the disease. At first, past memories remain intact and little memory lapses occur. Then mental abilities gradually disappear. Speaking and hand gestures, which are primarily controlled by the frontal and temporal lobes of the brain, start to fail, accompanied by problems with recognition.

Although the underlying pathological processes in the brain tissues are not completely identified, it is known that there are disconnections between the limbic system and the frontal and temporal lobes. The intensive deterioration of the side cortical regions (the temporoparietal cortex) becomes visible in the amyloid plaques and the coiling nerve fibers as neurons degenerate and advance toward death.

Causes of Alzheimer’s

The exact cause of the disease is not known. It is in 2-4% of people over 65, and this rises to 20% of people over 85, indicating the relationship of the disease with advanced age. 1-5% of the cases are known to arise from genetic factors. A dominant mutation was identified in three different genes in a few cases diagnosed in the early stages of disease. A gene called ApoE was identified to be oversensitive in patients diagnosed with the more common type of Alzheimer’s at later ages.

One of the hypothesized causes is prions, proteins 100 times smaller than viruses that became known thanks to mad cow disease. Neither a virus nor a bacterium, prions are pathogens formed by the mutation of normal proteins produced in neural cells. Prions can be contagious. It is believed that prions can pass from person to person during a blood transfusion or dental treatment through unsterilized tools.

Dementia might be a single disorder for the layperson, but in medicine it refers to several disorders with different underlying causes. Alzheimer’s dementia is one of the neurodegenerative diseases in which neurons are destroyed; it is classified separately from frontotemporal dementia, dementia with Lewy bodies, dementia from Parkinson’s disease, vascular dementia, and dementia originating from Multiple Sclerosis (MS) or a metabolic disorder.

Demographic studies have identified several factors that increase the risk of Alzheimer’s disease. The energy source of neurons can be disrupted because of a decrease in blood flow into the brain resulting from circulatory damage, especially in patients who have high blood pressure and are overweight. Therefore, recommendations for a healthy way of life hold true for this disease.

The disease, which gradually destroys the neurons and the brain, severs the connections between cells. A typical symptom of the loss of neurons in Alzheimer’s begins with the loss of the sense of smell. The death of the cells spreads slowly to regions associated with memory and then to the entire brain surface. One-fifth of brain mass might be lost as a result.

The olfactory (smell) center and the bottom part of the brain are affected at an earlier stage. The Meynert basal nucleus in the central nervous system produces a substance (neurotransmitter) required for communication between neurons. The presence of this substance is important for retrieving memories from the archives – that is, for remembering. An apparent decrease in acetylcholine levels prevents processing of information, and because short-term memory is negatively affected, it may become very hard to remember events that have only recently happened.

As losses increase, the acetylcholine produced in the basal nucleus decreases. A remarkable finding about Alzheimer’s is the protein buildup in neurons and gaps in certain regions of the brain. Some doctors believe that this protein buildup causes the disease, while others argue that it is the body’s response to the disease. The result is the same: protein plaques act like poison that damage the metabolism of neurons, and the patient’s cognitive performance decreases because neurons cannot communicate with each other.

Increasing risk for relatives

Kinship seems to be an important risk factor for almost a third of Alzheimer’s patients. The probability that an Alzheimer’s patient’s siblings and children will have the disease is four times higher than for other people. The genes that indicate genetic factors have been identified in some families. For example, the epsilon-4 allele is found in 40% of Alzheimer’s patients, while it is present only in 10% of the healthy population. Yet this finding does not necessarily mean that everyone who has this gene will get sick. As researchers put it, the highest risk factor for Alzheimer’s is age. The older a person gets, the greater the risk of developing Alzheimer’s. Although the effect of gender is not exactly known, women have been found to be twice as likely to have the disease.

Among factors that increase the risk of Alzheimer’s are nicotine, alcohol, obesity, high cholesterol levels, diabetes, thyroid function disorders (hypo- or hyperthyroid), frequent concussions, unhealthy diet, heart attack, and paralysis. It is also interesting that depression, anxiety, and increased nervousness may develop at the onset of the disease.

Alzheimer’s and loneliness

In Alzheimer's as well as other types of dementia, dementia is found to be triggered by lack of mental activity, which is in part connected to loneliness and isolation from people. In fact, loneliness is considered to be a preliminary symptom of Alzheimer's. A study performed with 79 older people (43 female and 36 male) who had symptoms of dementia found that the amount of amyloid plaque was seven times higher in the brains of the participants with a greater decline in mental abilities. In addition, these patients suffered from severe cases of loneliness.

Is poor sleep a risk factor?

Observations in sleep laboratories indicate that prolonged periods of poor sleep increase the risk of Alzheimer's. Even a single restless night without deep sleep can increase the beta-amyloid concentration, or Alzheimer's protein, in the brain fluid. In case of several subsequent nights of restless nights, an increase is observed in the levels of tau protein, a second protein associated with the illness. The findings obtained by a team of specialists led by David M. Holtzman from Washington University Department of Medicine show that sleep disorders that are untreated for a long time increase the risk of Alzheimer's.

The brain may not be cleaned sufficiently without deep sleep, hence the increase in the levels of protein particles. Yet it has been found that the amounts of beta-amyloid return to normal after a few days of sound sleep. The risk increases after a prolonged lack of deep sleep. It is thus believed that the risk of Alzheimer's increases in people with sleep apnea who wake up repeatedly during the night because of problems breathing.

Yet it is not clear whether the increase in the amounts of tau and beta-amyloid proteins is related with the onset of the disease and how the findings should be interpreted. The reason for the confusion is that the two proteins also change shape and cause buildups in healthy people, not just in patients. It is therefore not known whether risk of Alzheimer's can be lowered with a night of sound sleep.

We can say that warning signs can be found in sleep. Neuroscientists at the University of Toronto have discovered one of the early signs of sleep behavior. They have found that people who beat or kick themselves in their dreams are 80-90% more likely to develop a neurodegenerative disorder such as Parkinson's and dementia at a later age, and this condition, also known as REM sleep disorder,[1] could be early signs of a brain disorder that may emerge within fifteen years.

Another study by Boston University researchers has revealed a correlation between REM sleep and Alzheimer’s. The researchers have found that a reduction in REM or dream-sleep phase increased the risk of disease. On the other hand, not every nightmare is a symptom of the disease. The predictive factor is the desire to move taking place during REM sleep. We spend about a quarter of our sleep in the REM phase.

The more efficient the sleep, the less the amyloid plaques

How long we sleep at night might predict how well our memory will work when we get older. According to Dr. Yo-Elju, sleep disorders seem to contribute to the formation of amyloid plaques. A two-week study conducted at the Faculty of Medicine at Washington University in St. Louis collected data from about 100 people aged 45-80. Researchers used sleep behavior surveys and machine measurements. A quarter of the participants had signs of amyloid plaques.

The participants spent eight hours a night in bed. They were disturbed by being woken at different intervals. It was seen in the end that those who were woken more often had greater amyloid plaques. Interestingly, those who slept more than 6.5 hours had the same condition. The correlation between poor sleep and amyloid plaques is striking, yet the findings in this study do not provide evidence for a cause-effect relationship. Therefore, longitudinal studies are needed to find out whether sleep disorders contribute to formation of plaques in the brain. To sum up, these studies indicate that quality of sleep matters more than length of sleep. It seems more important to have a shorter sleep with a complete REM phase than a ten-hour sleep without REM sleep.

An important advice

It is important for families to take care of their elderlies in their old age. It is worth noting that the Qur’an refers to weakness of mental faculties in old age followed by an advice to give in charity and reminding of His favors including spouses, children, and good, healthy sustenance:

God has created you, then He causes you to die. And among you are those who are deferred to the age of senility so they do not know, of what they once knew, anything at all. Surely God is All-Knowing, All-Powerful. And God has favored some of you above others in provision. And yet (while it is We Who provide them), those who are more favored do not consent to share their provision with those (slaves) whom their right hands possess, so that they might be equal with them in this respect. How then do they deny God's grace and bounty (and associate partners with Him)? God has made for you, from your selves, mates (spouses), and has made for you from your mates children and grandchildren, and has provided you with good, wholesome things. Do they, then, believe in falsehood and deny the blessings of God? (16:70-72)

This allusion to family as a favor makes much sense thinking of the huge difference in the quality of life and health the elderlies have depending on the company of children and grandchildren and the lack thereof. As an example, I can cite my own father who lived to the age of 102 with his six children and fifteen grandchildren in the same apartment building. He never felt loneliness thanks to his many visitors, who conversed with him every day. He never became senile. 

Another interesting point to note is that this chapter of the Qur’an is Nahl, which means “honeybee.” Considering the fact that the main nutrition for our brain is glucose, consumption of honey and other food mentioned in the same chapter, like dates and grapes, may be considered useful to prevent mental diseases like Alzheimer’s.

References

Nancy J. Donovan ve ark. (2016): Association of Higher Cortical Amyloid Burden with Loneliness in Cognitively Normal Older Adults. JAMA Psychiatry, 2016; DOI: 10.1001/jamapsychiatry.2016.2657.

[1] REM (rapid eye movement) sleep is the period of sleep that starts 30-90 minutes after falling asleep in which one has dreams. This phase of deep sleep takes up about 20% of one’s overall sleep. It is the most refreshing period of sleep during which muscles are completely relaxed, eyelids move rapidly, and noradrenalin and serotonin are absent.

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