Obesity can mess up the brain for good; here's how

Those extra pounds, which may seem harmless, could be really messing with your mind. And it's not what you think. Obesity may do more than harm physical health, it could also contribute to anxiety and cognitive dysfunction. A new study found that obesity contributes to anxiety and cognitive impairment

A study, led by Desiree Wanders, PhD, of Georgia State University, looked at how diet-induced obesity affects behavior and brain function.

Obesity and Anxiety

Obesity and anxiety rates are rising, especially among younger Americans, and the new research suggests that the two conditions are connected. The research conducted in mice linked diet-induced obesity with anxiety-like symptoms, alterations in brain signaling, and differences in gut microbes that may contribute to impaired brain functioning.

“Several studies have pointed to a link between obesity and anxiety, though it is still unclear whether obesity directly causes anxiety or if the association is influenced by societal pressures. Our findings suggest that obesity can lead to anxiety-like behavior, possibly due to changes in both brain function and gut health,” Desiree Wanders, PhD, associate professor and chair of nutrition at Georgia State University, said in a statement.

What obesity does to the brain

Though it is known that obesity can lead to conditions like type 2 diabetes and heart disease, the potential impacts on brain health are less clear. To understand the connections between obesity, cognitive function, and anxiety, the researchers designed a series of experiments in 32 male mice. During the 6 to 21 weeks of age (equivalent to adolescence into early adulthood in humans), half of the mice were fed a low-fat diet and half were fed a high-fat diet. The researchers found that the mice fed a high-fat diet weighed significantly more and had significantly more body fat than those fed a low-fat diet, towards the end of the study.

They also found that the obese mice displayed more anxiety-like behaviors, such as freezing (a defensive behavior mice exhibit in response to a perceived threat), compared with lean mice. Interestingly, these mice also showed different signaling patterns in the hypothalamus, a region of the brain involved in regulating metabolism, which could contribute to cognitive impairments.

The researchers also observed distinct differences in the makeup of gut bacteria in obese mice compared with lean mice.

“These findings could have important implications for both public health and personal decisions. The study highlights the potential impact of obesity on mental health, particularly in terms of anxiety. By understanding the connections between diet, brain health and gut microbiota, this research may help guide public health initiatives that focus on obesity prevention and early intervention, particularly in children and adolescents,” Wanders said.
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“While our findings suggest that diet plays a significant role in both physical and mental health, it is important to remember that diet is just one piece of the puzzle. Environmental factors, genetics, lifestyle choices and socioeconomic status also contribute to the risk of obesity and its associated health outcomes. Therefore, while these results are important, they should be considered in the context of a broader, multifactorial approach to understanding and addressing obesity-related cognitive impairments and mental health issues,” Wanders added.