It is the most baffling and mysterious disease. Since its discovery in 1906 by Aloise Alzheimer, a German neurologist and psychiatrist, billions have been spent on research, but we still don't know what causes it or how to treat it. Alzheimer Disease (AD) is becoming one of the most predominant reasons of death in the last decades in Western society, (second in Australia (Becker, Ma Fat et al 2006)), and, sadly, it is becoming more and more prevalent in many other countries. It is predicted that it will rise to about 981,000 in Australia by 2050 (Cappai 2012). That presents society and policymakers with quite a few financial and social challenges and fuel more and more funding and researches.
What is AD, anyway?
AD is a neurological form of disease and the leading form of dementia (other types are Parkinson's disease or vascular dementia). It happens when your brain starts slowly to die; despite common belief, this is not a part of a normal aging.
The first signs of AD are memory loss and inability to learn new information, as AD usually affects the part of the brain that is responsible for learning. With time, the whole brain shrinks and as a result, the connection between the brain's cells get lost too. Usually, people with AD don't recognise that they are having problems even as it becomes obvious to family and friends. As AD progresses, it leads to more severe symptoms such as disorientation, changes of behaviour, hallucinations, inability to carry out day to day tasks and in the end, difficulty speaking, swallowing and immobility. This can lead to malnutrition and very often to pneumonia, resulting in death.
Why do we get it?
Scientists are not sure what causes AD, however, the main suspects are two deformities in brain, neurofibrillary tangles and senile plaques (Bethune 2010). Plaques are deposits of protein fragment called beta – amyloid that build up in the spaces between nerve cells. Tangles are twisted fibres of another protein called tau that build up inside cells.
Experts agree that like most of other neurological conditions, AD is developed as result of many causes and numerous factors and among them age, genetics, diet, environment, high blood pressure, life style etc.
The greatest risk of getting AD is older age. Most cases of AD are seen in older adults even though, the average is getting younger and younger every year. Between the ages of 65 and 74, approximately 5% of people are having AD. For those over 85, the risk increases to 50% (Bhushan, Kour et al 2018).
In less than five percent cases AD is caused by specific genetic changes that virtually guarantee the development of the disease.
However, we can theorise that genetics are not contributing factor in developing AD as more cases of AD were recorded in Europe and North America than in Asia, Japan, India or Africa. Yet, the rate of people who moved from Japan or India to live to Western countries and adopted their lifestyle is close to western people. Studies also show that in the countries where Western diet become more and more popular (Japan, for example, where the consumption of their staple food rice has dropped, and intake of animal products increased) the incidence of AD has sky-rocketed.
Although we can't change the main factors as age or genetics, the others as life style, diet, management of health problems as high blood pressure or diabetes can greatly reduce the risk.
There is strong evidence that development of AD appears to be increased by a multiple health conditions such as high blood pressure, high level of cholesterol, diabetes, stroke and heart decease. Some autopsy studies reveal that as many as 80% of individuals with AD also have cardiovascular disease. This connection make sense as the heart is responsible for pumping the blood through the thousands of blood vessels and nourishing the brain. Cardiovascular diseases are causing damage to blood vessels in the brain, resulting in less blood flow and possible brain tissue death.
Type 2 diabetes is also associated as a contributing factor of development of AD. Inefficiency of insulin to convert blood sugar to energy may cause higher levels of sugar in the brain, causing sever harm.
There is a strong connection between the strong head injury, especially that involve loss of consciousness and development of dementia.
A higher prevalence of dementia in individuals with fewer years of education has suggested that education may protect against AD (Stern et al. 1992). Several mechanisms have been implied to explain this association. The exact case of this relationship is still debatable, however, most of researches suggest that educational level leads to the formation of more synaptic connections in the brain. This creates a “synaptic reserve” in the brain, enabling patients to compensate for the loss of neurons as disease progress (Mayo Clinic 2010).
Keeping mentally and socially active throughout the life might lower at some degree the development of AD or lower cognitive decline of AD. Scientists are not certain about the cause of this association, it has been suggested that it is due to the mechanism through which social and mental stimulation strengthen connections between nerve cells in the brain (Gatz 2005).
Current research suggests that certain diets can protect the brain from development of dementia. Mediterranean diet and DASH (Dietary Approaches to Stop Hypertension) were considered the most beneficial for this purpose. Mediterranean diet emphasises plant food such as vegetables, fruits, cereals and legumes, olive oil, fish and shellfish and relatively low intake of meat and dairy products and low intake of alcohol. A DASH diet involves whole grains, fruits and vegetables, low fat dairy products, nuts, seeds, legumes, vegetables and oils. It suggests avoiding sodium, sweets and red meat.
Both of these diets were created to reduce or prevent high blood pressure, diabetes and heart disease. However, there were none to address brain health, till in September 2015 Martha Morris published her article “MIND Diet Associated with Reduced Incidence of Alzheimer’s Disease” (Morris et al 2015), where she and her colleges from Rush University Medical Centre proposed a new diet that was developed especially to promote cognitive health. MIND stands for the Mediterranean-DASH Intervention for Neurodegenerative Delay. It combined two diets that are regarded as a the healthiest by many dietitians around the world with emphases on food that can promote brain health. For example, both diets promote eating a lot of fruits, however the MIND don't recommend any fruits apart from berries as they promote brain health.
MIND diet encourages to eat the following food:
Find time to exercise
It is world widely accepted by all researches that exercise can lower the risk of developing AD, delay its development and possibly improve thinking among people with vascular cognitive impairment, yet, exactly how this occurs and how to take advantage of it therapeutically has remained elusive.
Current evidences suggest that physical exercises help to flow the blood into the brain and increasing chemical that protect the brain. Also, exercise protects against AD and other types of dementia by stimulating the brain’s ability to maintain old connections that are naturally reducing with aging.
Several studies indicate that the individuals aged 65 and above should engage in 150 minutes of moderate-intensity aerobic exercise every week. Most of the studies report on the effects of aerobic exercise done several times a week and maintained for at least a year. Yet, exercising, doesn't mean just jogging or swimming, it also implies other physical activities: gardening, walking or cleaning the house.
Maintaining active social life
Many scientists share the believe that having an active social interaction one of the pillars of preventing or slowing down AD. Like with everything else in AD researchers are not certain what happens in the brain to produce the positive effects seen among the more socially engaged. Currently, it appears clear that close relationships and large social networks have a beneficial impact on memory and cognitive function as people age. If we consider countries with low AD prevalence (India, Georgia, Cambodia, Singapore) we'll see that older people live there with the families in the “extended type of family” model and those countries are mostly agricultural, where people live in the community.
Although the pathogenesis of AD is not fully understood and there is no curative treatment is available, the scientific research provides significant evidence that primary prevention and protective factors seems possible.
Some prevention and or risk management strategies may include control of cardiovascular health and disorders, certain lifestyles choices as being physically active and have a healthy diet, encouraging children's high educational achievements and staying socially and intellectually active throughout the life.