When looking into the risk factors of Alzheimer’s disease (AD), researchers have been paying close attention to the relationship between obesity and Alzheimer’s.
Alzheimer’s Association reports that over 5 million people in the US are living with AD. Unfortunately, we expect this number to rise to almost 14 million by 2050.
Does Obesity Increase Alzheimer’s Risk?
Alzheimer’s is a progressive brain disorder that results in loss of memory, cognitive skills, and also causes changes in behavior.
The increasing rate of this progressive illness means that it is important to identify the biomarkers that tell when a person is at high risk of developing AD.
Early diagnosis can lead to the development of treatment and prevention strategies with a positive impact.
What is obesity?
We can describe obesity as a complex condition that involves too much body fat according to Mayo Clinic.
This increases the risk of a person suffering other health problems like diabetes, heart diseases, certain cancers, and high blood pressure.
Experts also state that obesity is one of the risk factors for developing AD.
This is because obesity often leads to insulin resistance. Data suggests that in middle age, insulin resistance can increase the risk of Alzheimer’s disease through numerous pathways.
These include dysfunctional brain insulin and decreased brain glucose metabolism which can result in increased amyloid deposition as well as reduced brain volume.
Results from human and animal studies show that subjects with AD have increased brain insulin resistance.
Worth noting is that excessive insulin in a person’s bloodstream ends up interfering with the energy supply in the brain. This is primarily because it lowers the amount of glucose or fuel that reaches the brain.
Obesity can contribute to Alzheimer’s
Over the years, research has revealed that obesity and related comorbidities as potential contributors to Alzheimer’s disease pathophysiology.
This suggests that conditions like poor-quality diet, diabetes, and a sedentary lifestyle may be part of AD’s modifiable risk factors.
A study published in Obesity Reviews examined possible mechanisms in the relationship between AD and obesity.
This also included recommended treatment strategies that may play a role in the development as well as the progression of Alzheimer’s.
Reports from numerous animal and human studies suggest that there is a link between obesity and Alzheimer’s.
Obesity and higher body mass index (BMI) have been linked to reduced white matter, brain atrophy, cognitive decline, the integrity of the blood-brain barrier, and an increased risk for late-onset Alzheimer’s.
The calculated effect size of obesity for the neurodegenerative disease was 1.54 according to various results from longitudinal epidemiological studies.
Strong evidence points to midlife obesity as a risk factor for Alzheimer’s.
A cross-sectional study that was published in Obesity revealed that there is an inverse relationship between cognitive function and BMI among healthy middle-aged adults.
Several observational studies have also reported that obesity in mid-life increases the risk of dementia later in life.
Weight loss can occur later in life due to the disease
Even though there seems to be a connection between obesity and Alzheimer’s, this association tends to shift later in life.
According to the statistics about 20%-45% of patients with Alzheimer’s tend to experience weight loss as the illness progresses.
There may be a possibility that a decline in BMI that goes before AD diagnosis may be related to the neurodegeneration sections of the brain that are responsible for homeostatic weight regulation.
Several factors can contribute to weight loss including decreased motivation for self-care, https://readementia.com/why-do-dementia-patients-stop-eating/, paying less attention to mealtime, social withdrawal, and altered metabolism amongst others.
At times, genetic factors might also come into play.
For instance, there have been reports on a connection between increased weight loss in AD and the presence of the APOE gene.
Inappropriate diet has a degenerating impact on the body and mind
Another study on the association between obesity and Alzheimer’s suggests that when HFS (high-sugar and high-fat) diet linked to obesity is paired with normal aging, it can lead to the development of AD.
You can find the details of this study in Physiological Reports. The study was conducted by researchers from Brock University in Ontario, Canada.
They chose to look at the effects of an obesity-inducing diet on insulin signaling which is the process that lets the body know how to use sugar as well as markers of cellular stress, and inflammation.
These are some of the factors that play a role in the progression of Alzheimer’s during the aging process in mice.
There were two groups of mice one on a normal diet and the other on HSF.
The researchers measured the animals’ stress and inflammation levels in the prefrontal cortex and hippocampus areas of the brain after 13 weeks of the allocated diets.
The prefrontal cortex oversees complex cognitive, behavioral, and emotional functions. The hippocampus deals with long-term memory.
Obesity affects aging and brain functioning
After comparing the two groups of mice, the experts found that the HFS had higher markers for insulin resistance, inflammation, and cellular stress in the hippocampus region.
This is thought to play a role in the progression of Alzheimer’s disease. Their prefrontal cortex region also showed more signs of insulin resistance.
On the other hand, there were no alterations in cellular stress and inflammation markers.
The researchers concluded that the region-specific differences between the hippocampus and prefrontal cortex in regards to aging with an HFS diet shows that the pathology of the disease is not uniform in all section of the brain.
When compared to baseline readings, the control group also recorded an increase in inflammation levels.
The results according to this study indicate that although age plays a role in the progression of AD, obesity also worsens the effects of aging on the function of the brain.
The research team acknowledged that their study offers fresh details to the mechanistic link between obesity and Alzheimer’s.
This is regarding the pathways that lead to the early progression of AD and the negative effects that the HFS diet has on the hippocampal and prefrontal cortex regions of the brain.
Obesity and Alzheimer’s Conclusion
After talking about the link between obesity and Alzheimer’s, it is important for people to manage their weight well especially during mid-life or better yet earlier to reap the benefits later in life.
A healthy diet and proper exercise are key to reducing the risk of a myriad of health problems including Alzheimer’s disease.
