Fasting, especially intermittent fasting, is becoming popular among researchers and the public. It has been proposed to prevent and treat various diseases, including neurodegenerative diseases, such as dementia. Alzheimer's disease is the most common type of dementia with no known cure. Therefore, interventions to improve lifestyle and manage behavioral symptoms are primary approaches to prevent or delay the onset of the disease. This article will evaluate the potential of intermittent fasting in improving Alzheimer's.
What is Alzheimer's disease?
Alzheimer's disease is the most common cause of dementia, which is an age-related neurodegenerative disorder characterized by the loss of memory and other cognitive and physical abilities. Fourteen million people are expected to have Alzheimer's disease by 2060. The risk of disease increases with age, especially after 60.
The causes of Alzheimer's disease are still being researched. Age, genes, lifestyle, and environment are hypothesized to contribute to it.
Unfortunately, there is no cure for Alzheimer's yet. Therefore, treatment consists of interventions to maintain brain health and manage behavioral symptoms to delay the onset of dementia.
What is fasting?
Fasting is a caloric restriction achieved by periodic eating. In fasting, intervals of eating without restrictions are followed by fasting. There are various types of fasting; the most popular is 16/8 intermittent fasting, which is 16 hours of daily fasting followed by an 8-hour eating window.
Fasting benefits are associated with ketones, produced when the body lacks glucose. Fasting intervals allow the body to break down fat. Fat is broken down to produce ketones, which organs (including the brain) use as an energy source when enough glucose is unavailable.
How fasting may improve brain health
Fasting may improve brain health by altering insulin production, decreasing oxidative stress and inflammation, and increasing vascular integrity, all of which you'll learn about in a minute.
1. Fasting may alter insulin production
Although accumulation of certain molecules (Aβ plaque) is often hypothesized to cause Alzheimer's disease, 1 in 3 patients does not show accumulation of Aβ plaque in the brain. These findings suggest that there could be different causes underlying the diseases, and one of them could be metabolic problems, such as insulin resistance.
Abnormal glucose and insulin metabolism in the brain are linked to Alzheimer's disease. A cohort study of more than 5,000 patients with poor glycemic control and type 2 diabetes has shown a significantly faster decline in memory, reading, and global cognitive score compared to patients with normal blood glucose levels.
Insulin is a hormone that carries blood glucose to the cells. When insulin is insufficient or inefficient, glucose can't enter the cells, causing high blood glucose, insulin resistance (decreased insulin sensitivity), and diabetes in the long term.
Intermittent fasting has been shown to improve insulin sensitivity, which is associated with diabetes and cardiovascular diseases. Healthy insulin production and function are crucial for optimal metabolism and vascular health, which affects brain health and diseases.
3. Fasting may reduce oxidative stress
Oxidative stress is caused by the accumulation of reactive oxygen species (ROS) and free radicals, resulting from physiological and environmental factors, including metabolism, chemicals, air pollution, and smoking.
Increased oxidative stress can damage cells, affecting their functions. The brain is rich in lipids and requires lots of oxygen, making brain cells more susceptible to oxidation. In animal studies, intermittent fasting has been shown to reduce oxidative stress by several mechanisms, including enhancing antioxidant defenses and autophagy in neurons.
4. Fasting may reduce inflammation
Systemic inflammation is hypothesized to cause dementia in Alzheimer's disease. Some studies suggest improving inflammation can delay the onset of dementia. There could be many causes behind chronic inflammation, such as aging, infections, and chronic diseases.
5. Fasting may improve the brain's vascular structure
Vascular health is essential for the brain because blood carries all the nutrients and molecules needed for proper function. The brain's vascular (neurovascular) structure consists of several units, including a blood-brain barrier (BBB), which is responsible for transporting nutrients and molecules from the blood to the brain's fluid.
Accumulation of β-amyloid plaques is hypothesized to be one of the causes of Alzheimer's disease. The blood-brain barrier helps remove β-amyloid from the brain. Dysfunctions in vascular structure disturb BBB's function, possibly affecting the clearance of β-amyloid plaques.
Fasting may improve vascular integrity by improving endothelial cells, which are the lining of cells in blood vessels that control the exchange of molecules. A study on healthy middle-aged male subjects showed that intermittent fasting can improve endothelial function.
Adverse effects of fasting
The evidence showing the long-term effects of fasting in humans is limited. Although intermittent fasting can benefit brain health, a qualified healthcare provider must carefully examine a patient's physical and psychological health.
Adverse effects, such as headaches, difficulty concentrating, lack of energy, bad temper, and constipation, have been reported.
Fasting may involve health risks in specific populations, such as older people and patients with diabetes. Since Alzheimer's disease is generally recognized in older adults who also have a higher probability of having chronic diseases, the pros and cons of fasting must be carefully examined by a doctor.
Loss of muscle mass due to caloric restriction can pose a risk for older adults. Still, studies investigating fasting effects in the older population showed improved body composition, decreased blood inflammation markers, and increased cognitive functions.
Fasting can also pose a risk for diabetes patients because of the alteration in insulin and glucose levels.
The degree of dementia can also determine the achievability of intermittent fasting. Fasting may cause malnutrition, which is generally already a problem in the late phase of dementia.
Fasting and Alzheimer's: the final words
In conclusion, fasting without malnutrition may prevent or delay the onset of Alzheimer's disease; however, the long-term effects of fasting on Alzheimer's disease are limited. It's harmful and risky to practice fasting without a doctor's approval, especially if you have chronic diseases.
Therefore, a qualified healthcare professional must evaluate an individual's physiological and psychological health and decide if fasting can improve Alzheimer's disease for that patient. Remember to consult your doctor before adopting any dietary interventions.
Fasting may improve brain health by altering insulin production, decreasing oxidative stress and inflammation, and improving the brain's vascular structure.
Fasting can cause adverse effects, such as headaches, difficulty concentrating, lack of energy, bad temper, and constipation.
Fasting can be risky, especially in older adults and patients with chronic diseases, such as diabetes. Therefore, the supervision of a qualified healthcare professional is a must.
Some studies suggest that fasting without malnutrition may prevent or delay the onset of Alzheimer's disease; however, strong evidence is lacking.
A qualified healthcare professional must evaluate the feasibility and potential benefits of fasting regarding an individual's physiological and psychological health.
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