A new study conducted by the researchers of Iowa State University has found that having more abdominal fat and less muscle could greatly affect mental flexibility, especially in older people.
The researchers analyzed data from over 4,000 middle-aged to older men and women and examined their muscle mass, belly fat, subcutaneous fat, and their “fluid intelligence” for over six years.
Fluid intelligence is your mental ability to reason and think flexibly.
The study found that most people in their 40s and 50s, who had higher amounts of belly fat, had worse fluid intelligence. However, greater muscle mass seemed to have a protective factor.
The association between high belly fat and worse mental flexibility remained the same even after taking chronological age, level of education, and socioeconomic status into consideration.
Lead study author Dr. Auriel Willette said, “Chronological age doesn’t seem to be a factor in fluid intelligence decreasing over time. It appears to be biological age, which here is the amount of fat and muscle.”
After attaining a certain age, people often start gaining fat and losing muscle mass, which continues as the age progresses. So, it is important to engage in some physical activities to lose fat and maintain muscle mass.
Researcher Brandon Klinedinst said, “Exercising, especially resistance training, is essential for middle-aged women, who naturally tend to have less muscle mass than men.”
The researchers also looked at whether there are any changes in the immune system activity, which could explain the association between fat or muscle and fluid intelligence.
It was found that, in women, the association was explained by changes in lymphocytes and eosinophils, which are the types of white blood cells (WBCs). And in men, a completely different type of WBC, basophils, explained the association between high belly fat or less muscle mass and fluid intelligence.
Although the study was able to explain the association between fat/muscle and fluid intelligence, it is unclear whether it could increase the risk of Alzheimer’s.
Klinedinst said, “Further studies would be needed to see if people with less muscle mass and more fat mass are more likely to develop Alzheimer’s disease, and what the role of the immune system is.” “If you eat alright and do at least brisk walking some of the time, it might help you with mentally staying quick on your feet,” said Dr. Willette.
