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Study Finds Obese People Might Have Alzheimer’s-Like Brain Atrophy

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Obesity may put you at risk for cognitive decline. (Creativa Images/Shutterstock)

Obesity may put you at risk for cognitive decline

Obesity has long been linked to many health conditions, including cardiovascular disease, Type 2 diabetes, and some cancers. New research adds another concern: cognitive decline.

The study, published in the Journal of Alzheimer’s Disease, found obesity was associated with decreased brain mass similar to that seen in Alzheimer’s disease patients.

Obesity Causes Similar Changes to Brain as Alzheimer’s Disease

Researchers compared patterns of brain atrophy and amyloid-β/tau protein accumulation (hallmarks of Alzheimer’s) in patients with obesity and Alzheimer’s disease. They used a sample of over 1,300 individuals from four groups—Alzheimer’s disease patients, healthy people, obese but otherwise healthy people, and lean people.

The study was conducted using two large cohorts: the UK Biobank and the Alzheimer’s Disease Neuroimaging Initiative (ADNI).

Researchers used PET brain scans to investigate what mechanisms might be responsible for similarities between obesity-related brain atrophy and Alzheimer’s-related amyloid-beta accumulation. They also looked for overlapping areas among patients with these conditions.

The scans showed these groups experienced similar brain thinning in areas associated with learning, memory, and judgment.

Additional data were included from a previous study involving over 20,000 participants, which showed that increased body mass index (BMI), body fat percentage, and waist-to-hip ratio were associated with worse fluid intelligence (ability to solve problems) and working memory.

Earlier research also found that obesity can change the body in ways that are linked to increased Alzheimer’s risk, particularly damage to blood vessels in the brain and accumulation of abnormal proteins in the brain.

Obesity is related to many health problems, such as Type 2 diabetes, hypertension, and high cholesterol.

“All those affect the brain in a negative way,” study author Filip Morys, who holds a doctorate in cognitive neuroscience and who is a postdoctoral researcher at McGill University in Montreal, Canada, told The Epoch Times. “For example, through changes in the brain’s vascular system or the blood-brain barrier, this might in turn lead to neuronal loss.”

How Obesity Increases Risk for Neurodegenerative Diseases

Obesity rates have increased alarmingly in the last decades, reaching global epidemic levels.

Obesity has tripled worldwide since 1975. World Health Organization (WHO) data from 2016 show that nearly 40 percent of adults 18 years and older were overweight, and 13 percent were obese.

From 1999 to 2000, through 2017 to March 2020, obesity prevalence in the United States rose from almost 31 percent to about 42 percent. 

In the same period, the prevalence of severe obesity also nearly doubled.

Obesity is believed to increase neurodegenerative disease risk by two means—“promoting insulin resistance and the production of inflammatory molecules in the body called cytokines,” said Dr. Jonathan J. Rasouli, director of complex and adult spinal deformity surgery at Staten Island University Hospital, part of Northwell Health in New York.

The combination of these factors can mean an increased risk of cardiovascular, pulmonary, musculoskeletal, and neurologic diseases, he continued.

There’s evidence showing insulin plays a role in brain health, and insulin resistance, which is associated with overweight and obesity, is significantly associated with Alzheimer’s risk.

A study published in Frontiers in Neuroscience shows that in addition to metabolic functions, insulin also modifies neuronal activity that improves memory in mammals and promotes the health of synapses in the brain.

When the brain can’t use insulin properly, cognition can become impaired.

A recent study stated that insulin signaling is impaired in the brains of Alzheimer’s patients, and brain insulin resistance appears to be an early and common feature of Alzheimer’s disease.

‘An Ounce of Prevention Is Worth a Pound of Cure’

Can weight loss reverse or prevent cognitive decline; is it ever too late? The impact of weight loss on cognitive function in older adults, specifically, is still not understood fully, and it’s likely that more research will be needed.

However, there is encouraging evidence that it may help.

A recent study finds that even modest weight loss can lead to improved cognitive function in older adults. Furthermore, lifestyle changes, like exercise and a healthy diet, will likely have a positive impact on cognitive function and overall health at any age.

When it comes to cognitive decline, “an ounce of prevention is worth a pound of cure,” said Rasouli.

Although the progression of cognitive decline—including memory loss—can be slowed or temporarily stopped, he warned that as soon as the process starts, it is very difficult to fully “return to normal” afterward.

Reducing sources of inflammation is one of the things Rasouli encourages patients to do.

Normal aging is associated with increased and prolonged inflammation throughout the body—and the brain.

There is evidence that persistent, increased levels of inflammation are strongly associated with neurodegeneration, impaired neuron growth (neurogenesis), and chronic diseases.

Metaflammation is a metabolic inflammatory state associated with obesity that directly contributes to insulin resistance, metabolic syndrome, and Type 2 diabetes. Evidence shows that losing weight can reverse this process.

Morys said the “key takeaway” is that obesity is a major risk factor for Alzheimer’s disease and other types of dementia.

“In line with this, we think that obesity prevention and weight loss might play a very important role in decreasing the risk for Alzheimer’s disease,” he concluded.

Compounds In Citrus Fruit May Prevent Heart Disease, Fatty Liver, And Diabetes In Obese People

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Adding oranges, limes, and lemons into your diet may be the health trick we’ve been looking for to fight off the steady increase ofobesity-related diseases in America. A new study, presented at the American Chemical Society’s 252nd National Meeting & Exposition, has revealed the previously underestimated benefits citrus fruits could have for the roughly 80 million obese people in the United States.

Knowing that citrus fruits are packed with heart-healthy antioxidants, a team of researchers from the Universidad Estadual Paulista tested how far its benefits could go. For one month they fed a group of 50 mice a standard diet, a high-fat diet, or a high-fat diet mixed with flavanones, which are a class of antioxidants found in oranges, lemons, and limes. Compared to the standard diet, the mice that were fed a high-fat diet experienced an increase damage in the blood by 80 percent and the liver by 57 percent. However, the mice that were fed flavanones decreased damage in the blood by about 48 percent and liver damage between 50 and 64 percent.

Even though the research team did not observe any weight loss as a result of the citrus flavanones, the mice didn’t need to lose any weight in order to experience the health benefits. They had lower levels of stress, liver damage, blood lips and blood glucose, drastically decreasing their risk for disease.

Ultimately, the flavanones were able to decreases the risk of obesity-related diseaseslike heart disease, fatty liver, and diabetes associated with eating a high-fat, western diet. But the benefits may not be limited to obese people alone. According to researchers, a normal, healthy body is capable of fighting off molecules that cause cell damage known as oxidative stress. But when people consume high-fat diets they accumulate fat cells in their bodies. In turn, those fat cells produce a large amount of reactive oxygen cells that make it difficult to prevent damage, which increases the risk for disease. Because of this, researchers believe it matters more on how many fat cells you have and less on how much you weigh.

Researchers said for people to get a similar disease-fighting effect at home, it may be as easy as a glass of lime juice or, in the future, a pill with concentrated flavanone compounds.

“In the future we can use citrus flavanone to prevent or delay chronic diseases caused by obesity in humans,” said the study’s co-author Paula S. Ferreira, a graduate student at the Universidad Estadual Paulista, in a statement. “This study also suggests that consuming citrus fruits probably could have beneficial effects for people who are not obese, but have diets rich in fats, putting them at risk of developing cardiovascular disease, insulin resistance and abdominal obesity.”

Obese People Sometimes Protected Against Diabetes, Heart Disease Due To Lack Of Metabolic Problems

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Some Obese People Aren't At Risk
Contrary to popular belief, not all obese people are at risk for disease. 

Obesity contributes to more than 60 different unhealthy conditions, including diabetes, heart disease, and stroke. Knowing that more than one-third of adults in the United States are obese, researchers from Washington University School of Medicine decided to study the risk these people faced. They published their findings in The Journal of Clinical Investigation.

“This research demonstrates that some obese people are protected from the adverse metabolic effects of moderate weight gain, whereas others are predisposed to develop these problems,” said the study’s senior investigator Dr. Samuel Klein, director of Washington University’s Center for Human Nutrition, in a press release. “This observation is important clinically because about 25 percent of obese people do not have metabolic complications. Our data shows that these people remain metabolically normal even after they gain additional weight.”

Klein and his research team studied 20 obese participants, who were asked to gain approximately 15 pounds over the course of several months in order to determine how the extra weight would affect their risk of disease. Before they started, the subjects’ blood sugar, liver fat, and other risk factors were measured. And then under the supervision of a dietician, subjects ate extra food from fast-food restaurants.

“Our goal was to have research participants consume 1,000 extra calories every day until each gained six percent of his or her body weight,” said the study’s co-author Dr. Elisa Fabbrini, assistant professor of medicine at Washington University School of Medicine, in the press release. “This was not easy to do. It is just as difficult to get people to gain weight as it is to get them to lose weight.”

Test subjects who were in relatively healthy ranges to begin with weren’t harmed by the weight gain and none of their risk increased. However, those who were already at risk to begin with had significantly worsened once they gained extra weight. Once the study was completed, the test subjects were enrolled in a weight-loss program designed to make sure they lost all of the weight they gained.

Researchers found answers in the type of fat inside participants’ liver, which helped the researchers determine whether an obese person was protected or at risk of disease. Another factor was that some people, despite being obese, had normal metabolisms. They were able to metabolize the extra weight in a healthier way than those who had slow or abnormal metabolisms. The research team’s next step is to analyze types of fat, muscle, and liver more closely in order to see why certain obese people are protected from harm’s way.

“We need more studies to try to understand why obesity causes specific diseases in some people but not in others,” Klein said. “Could it be genetics, specific dietary intake, physical lifestyle, emotional health, or even the microbes that live in the gut?”

Source: Klein S, Fabbrini E, Yoshino J, et al. Metabolically normal obese people are protected from adverse effects following weight gain. Journal of Clinical Investigation. 2015.

Not all obese people develop metabolic problems linked to excess weight .

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Obesity does not always go hand in hand with metabolic changes in the body that can lead to diabetes, heart disease and stroke, according to new research. In addition, obese people who didn’t have these metabolic problems when the study began did not develop them even after they gained more weight.
Samuel Klein, MD, and colleagues at Washington University School of Medicine in St. Louis found that a subset of obese people are protected from developing unhealthy metabolic profiles linked to diabetes and heart disease even when they gain additional weight.

New research demonstrates that obesity does not always go hand in hand with metabolic changes in the body that can lead to diabetes, heart disease and stroke.

In a study at Washington University School of Medicine in St. Louis, researchers found that a subset of obese people do not have common metabolic abnormalities associated with obesity, such as insulin resistance, abnormal blood lipids (high triglycerides and low HDL cholesterol), high blood pressure and excess liver fat.

In addition, obese people who didn’t have these metabolic problems when the study began did not develop them even after they gained more weight.

The findings are published Jan. 2 in The Journal of Clinical Investigation.

The study involved 20 obese participants who were asked to gain about 15 pounds over several months to determine how the extra pounds affected their metabolic functions.

“Our goal was to have research participants consume 1,000 extra calories every day until each gained 6 percent of his or her body weight,” said first author Elisa Fabbrini, MD, PhD, assistant professor of medicine. “This was not easy to do. It is just as difficult to get people to gain weight as it is to get them to lose weight.”

All of the subjects gained weight by eating at fast-food restaurants, under the supervision of a dietitian. The researchers chose fast-food chain restaurants that provide rigorously regulated portion sizes and nutritional information.

Before and after weight gain, the researchers carefully evaluated each study subject’s body composition, insulin sensitivity and ability to regulate blood sugar, liver fat and other measures of metabolic health.

After gaining weight, the metabolic profiles of obese subjects remained normal if they were in the normal range when the study began. But the metabolic profiles significantly worsened after weight gain in obese subjects whose metabolic profiles already were abnormal when the study got underway.

“This research demonstrates that some obese people are protected from the adverse metabolic effects of moderate weight gain, whereas others are predisposed to develop these problems,” said senior investigator Samuel Klein, MD, the Danforth Professor of Medicine and Nutritional Science and director of Washington University’s Center for Human Nutrition.

“This observation is important clinically because about 25 percent of obese people do not have metabolic complications,” he added. “Our data shows that these people remain metabolically normal even after they gain additional weight.”

As part of the study, the researchers then helped the subjects lose the weight they had gained.

“It’s important to point out that once the study was completed, we enrolled all subjects in our weight-loss program to make sure they lost all of the weight they had gained, or more,” said Klein, who also directs the Division of Geriatrics and Nutritional Science and the Atkins Center of Excellence in Obesity Medicine.

The researchers identified some key measurements that distinguished metabolically normal obese subjects from those with problems. One was the presence of fat inside the liver. Those with abnormal metabolism accumulated fat there.

Another difference involved gene function in fat tissue. People with normal metabolism in spite of their obesity expressed more genes that regulate fat production and accumulation. And the activity of those genes increased even more when the metabolically normal people gained weight. That wasn’t true for people with abnormal metabolism.

“These results suggest that the ability of body fat to expand and increase in a healthy way may protect some people from the metabolic problems associated with obesity and weight gain,” said Klein.

He noted that obesity contributes to more than 60 different unhealthy conditions.

“We need more studies to try to understand why obesity causes specific diseases in some people but not in others,” Klein said. “Could it be genetics, specific dietary intake, physical lifestyle, emotional health or even the microbes that live in the gut?”

As they look for answers, Klein and his colleagues plan to more closely analyze fat, muscle and liver tissue and to include lean people in future studies so that the researchers can learn more about how and why some individuals are protected from metabolic problems while others are vulnerable.

While the study was underway, it was featured in the HBO documentary “Weight of the Nation.” A 10-minute segment of the program that focuses on the study begins at 42:10 in the HBO video: https://www.youtube.com/watch?v=-pEkCbqN4uo

Story Source:

The above story is based on materials provided by Washington University School of Medicine. Note: Materials may be edited for content and length.

Journal Reference:

  1. Elisa Fabbrini, Jun Yoshino, Mihoko Yoshino, Faidon Magkos, Courtney Tiemann Luecking, Dmitri Samovski, Gemma Fraterrigo, Adewole L. Okunade, Bruce W. Patterson, Samuel Klein. Metabolically normal obese people are protected from adverse effects following weight gain. Journal of Clinical Investigation, 2015; DOI: 10.1172/JCI78425