Excess Weight Affects Your Brain Health

Over time, being overweight can impact more than your waistline and cardiovascular system. Extra pounds may affect brain function and increase risk of dementia.

Being significantly overweight and even obese has become such a significant health concern in the U.S. that the Centers for Disease Control and Prevention (CDC) has declared it an epidemic. Over 73 percent of Americans who are age 20 or older are overweight, and almost 44 percent of them are obese, according to research from the CDC. Those are worrisome facts because carrying around extra pounds increases your risk of several significant medical problems affecting multiple areas of the body, including the brain.

In fact, being significantly overweight is associated with the leading causes of death in the U.S. — including diabetes, heart disease, stroke, and some types of cancer. And associations between obesity and risks to brain health are increasingly being documented.

For example, the CDC notes obesity is linked with poorer mental health outcomes. Being overweight raises the risk for brain-injuring strokes, too. What’s more, researchers are also finding evidence being overweight may directly impact your brain over time, potentially upping the odds of developing dementia, including Alzheimer's disease.

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The weight connection to brain health

A study, published in the Journal of Alzheimer's Disease, used high-tech neuroimaging scans to study the blood flow and brain activity of 17,000 people. The results found those who were overweight or obese had reduced blood flow and brain activity — raising their risk for Alzheimer's disease as well as other psychiatric conditions and cognitive difficulties, according to Daniel G. Amen, MD, the study's lead author and founder of the brain-centered mental health Amen Clinics.

Now, a research team from the University of Sheffield’s Neuroscience Institute and the University of Eastern Finland has found an association between excess pounds and tissue changes in a specific area of the brain that can impact thinking abilities and may play a role in the progression of Alzheimer’s disease.

The scientists studied the brains of 47 patients diagnosed with mild Alzheimer's disease dementia, 68 patients with mild cognitive impairment, and 57 cognitively healthy volunteers. They looked at brain anatomy and blood flow and measured the concentration of brain tissue in certain areas to assess the volume of gray matter (which degenerates as Alzheimer’s develops and progresses). The results, published in the Journal of Alzheimer’s Disease Reports, revealed a link between obesity and shrinking gray matter tissue.

Specifically, even in patients with mild dementia symptoms, a positive association was found between obesity and decreased gray matter volume around the right temporoparietal junction, an area of the brain involved in the processing of information and ability of a person to pay attention.

Bottom line? Controlling weight can help protect mental and physical health

While the researchers emphasized this doesn’t prove being obese will cause Alzheimer’s or other dementia, it does suggest obesity may play a role in making your brain more vulnerable to these diseases.

The research team concluded their findings highlight the negative impact being overweight in mid-life could have on brain health in older age. That’s a reason to pay extra attention to that “spare tire” around your waist you might find yourself acquiring as you hit middle age.

"More than 50 million people are thought to be living with Alzheimer's disease, and despite decades of ground-breaking studies and a huge global research effort, we still don't have a cure for this cruel disease,” researcher Annalena Venneri, a University of Sheffield's Neuroscience Institute professor, said.

"Prevention plays such an important role in the fight against the disease. It is important to stress this study does not show that obesity causes Alzheimer's, but what it does show is that being overweight is an additional burden on brain health, and it may exacerbate the disease."

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