Dementia and Alzheimer's disease

Dementia is a collective term for a group of diseases that lead to the gradual deterioration of cognitive functions. It is not a specific disease but a syndrome resulting from various pathological processes in the brain. A common feature is a decline in mental abilities significant enough to disrupt everyday functioning. [1]

Typical symptoms include memory disorders (particularly short-term), deterioration in thinking and judgement, difficulties with time-space orientation, disruptions in speech, and changes in behavior and personality. The affected person may have trouble planning and solving everyday tasks, gradually losing independence, and often experiencing emotional changes (apathy, irritability, anxiety).

Natural aging brings with it a mild slowing of thinking and occasional forgetfulness, which does not impede independent living. In contrast, in dementia, the loss of abilities is more pronounced, progressive, and in most cases irreversible. In other words, dementia is not a normal part of aging but a severe disorder that significantly affects a patient's self-sufficiency.

The most common cause of dementia is Alzheimer's disease, accounting for approximately 60-70% of all cases. It is a neurodegenerative disorder that develops slowly, with the first symptoms often being subtle for a long time. Typically, memory first deteriorates (especially the ability to store new information), and only over time do speech, thinking, orientation disorders, and more significant behavioral changes appear. [2]

In the brains of patients with Alzheimer's disease, beta-amyloid plaques accumulate, and neurofibrillary tangles (aggregates of the tau protein) form. [3] These pathological changes disrupt neuron functioning—impairing their mutual communication and leading to the gradual demise of nerve cells. The brain tissue damage spreads to other areas, hence why the disease is progressive, and symptoms worsen over time.

Risk Factors for Dementia

The development of dementia is influenced by a combination of non-modifiable and modifiable factors. The main risk factors include:

• Advanced age—the most significant risk factor (the risk of dementia significantly increases with age),

• Genetic predisposition—hereditary factors can increase the likelihood of the disease, but alone usually are not enough to cause the illness,

• Chronic diseases—particularly high blood pressure, diabetes, high cholesterol, and obesity. These conditions damage blood vessels (including those in the brain) and thus increase the risk of cognitive decline and vascular dementia,

• Lifestyle—lack of physical activity and smoking are modifiable risk factors for dementia. Long-term excessive stress and chronic fatigue (likely through hormonal and inflammatory changes in the body) can also have a negative impact. [4]

A healthy lifestyle has a protective effect. Regular physical activity, mental stimulation (brain training), and an overall healthy way of life can reduce the risk of developing dementia. Physical exercise, in particular, is associated with better cognitive function in old age and a lower incidence of dementia. [5] Maintaining these healthy habits throughout life can support the brain's cognitive reserve and delay the onset of dementia.

The Impact of Diet on Alzheimer's Disease and Dementia

Long-term dietary habits can influence the risk of developing Alzheimer's disease and other dementias, primarily through their impact on the vascular system, inflammatory processes, and brain metabolism. An inappropriate diet composition is not a direct cause of dementia, but it creates an environment that can accelerate cognitive decline over the years. An unhealthy diet can thus, through its impact on overall brain health, expedite the pathological changes that lead to dementia. [6]

The Negative Impact of an Inadequate Diet:

A diet high in saturated fats, trans fats, industrially processed foods, and added sugar is associated with an increased incidence of obesity, diabetes, high blood pressure, and lipid metabolism disorders. These conditions significantly contribute to vascular damage (including in the brain) and indirectly promote cognitive decline and some forms of dementia. [7]

Excessive intake of simple sugars further burdens the regulation of blood glucose levels and, in the long term, can negatively affect the energetic metabolism of brain cells (Alzheimer’s disease is sometimes metaphorically referred to as “Type III diabetes” due to its association with insulin resistance in the brain). [8] Such an unhealthy diet is also associated with chronic low-grade inflammation in the body, considered a contributing factor to neurodegenerative changes in the brain. Persistently elevated inflammation and oxidative stress can damage neurons, disrupt synaptic communication, and accelerate the formation of amyloid plaques and tau proteins in the brain, typical pathological phenomena for Alzheimer's disease.

The Benefits of a Healthy Diet for the Brain:

A protective effect is associated with a well-balanced diet based on natural, minimally processed foods (whole grains, fruits, vegetables...). Such a diet provides the body with many bioactive compounds (vitamins, minerals, antioxidants, flavonoids, and other phytonutrients) that support the function of nerve cells and help protect brain tissue from oxidative stress. [9] At the same time, it contributes to maintaining healthy blood supply to the brain.

Sources of omega-3 fatty acids are significant, as they support the structure of neuronal cell membranes and regulate inflammatory processes. [10]

Whole grain foods (cereals, legumes, etc.) help stabilize blood sugar levels, which is important given the established link between glucose metabolism disorders (such as diabetes) and cognitive decline.

Vegetables and fruits are rich in antioxidants, which reduce oxidative stress and inflammatory processes in nervous tissue. This can help protect brain cells from damage.

It is crucial to emphasize that no diet on its own will prevent or cure dementia. However, it represents an important component of long-term prevention. In combination with regular exercise, mental training, and an overall healthy lifestyle, a balanced diet can significantly contribute to maintaining good brain function and cognitive abilities throughout life. Current research suggests that up to a third of dementia cases could be preventively influenced by improving lifestyle, which includes nutrition, physical activity, intellectual and social engagement, or managing cardiovascular risk factors. [11] A healthy lifestyle is thus a key pillar in brain health care.