Cognitive abilities decline naturally with age even in the healthiest of individuals. Lifespans are increasing around the globe, and the population 65 years and older is projected to triple by 2050. Many diseases such as diabetes, heart disease, high blood pressure and sleep apnea can increase the risk of severe memory loss and create a detrimental environment in the brain that helps lead to memory loss. Although the process is not fully understood, it is clear that this detrimental environment and negative processes go on for many decades before memory loss occurs. Many different causes come together to result in severe memory loss or dementia, but 4 key processes are involved: inflammation, oxidation (free radicals), high blood sugar and insulin insensitivity, and high blood cholesterol.
Inflammation in the brain (called neuroinflammation) can be caused by toxicities, diseases, brain injury and other detrimental environmental factors. There is increasing scientific evidence that ongoing high levels of inflammation in the brain can damage neurons and lead to neuronal death and memory loss. Neuroinflammation is seen with every type of dementia.
Free radicals (also called oxidation) are also found in every type of dementia. These free radicals cause tissue damage, can alter DNA and can seriously damage the brain.
The brain is not equipped to deal with high blood sugar levels that result from ongoing high sugar or high carbohydrate diets. The brain has very similar issues with these ongoing blood sugar levels as the body does. Diabetes the result of sustained high blood sugar levels in the body. Alzheimer’s disease is often referred to as type 3 diabetes (or diabetes of the brain) because it is so similar to diabetes (type 2 diabetes or ‘diabetes of the body’). Diabetics have more memory loss and higher rates of dementia and Alzheimer’s disease that those who do not have diabetes. The brain shows the same insulin resistance that occurs with diabetes of the body. Brain sugar metabolism decreases 10-15% during normal aging and the extent of memory loss correlates with the degree of loss of sugar metabolism. Thus it is very important to manage blood sugar levels and address insulin insensitivity and diabetes that prime the brain for memory loss and dementia.
High blood cholesterol has been linked to higher risk of dementia in many clinical studies. This is especially true for high blood cholesterol levels in ones’s 40s and 50s.
These 4 key causes are correlated with the depositing of beta amyloid plaques on neurons and tau tangles inside the neurons. These result in damage to neurons, reduced connections between neurons and reduced number of neurons, As this process continues, the brain actually shrinks in size. The hippocampus, which is primarily responsible for memories, often shrinks the most. Neuron death, neuronal plaques and shrinking of the brain happen many decades before the first memory loss symptom. So this is a long, chronic pathology that typically is present for many, many years before symptoms occur.
This pathology and memory loss typically continues for an average of 3-5 years before dementia and Alzheimer’s occur. Since this is a long, prolonged process before symptoms occur, it is important to address the causes of memory loss early in the process. It is estimated that changes in lifestyle and addressing the causes of memory loss could result in avoiding half of all cases of dementia!!