Scientists say the brains of overweight and obese people can appear 10 years older than those of healthy lean people.
Obesity is already linked to conditions such as diabetes, cancer, and heart disease. Now, scientists are beginning to look at how obesity may affect our brains, which naturally shrink with age. Scientists are increasingly recognizing that obesity may affect the onset and progression of brain aging, but studies to support this theory have been lacking.
New research, led by the University of Cambridge, found that from middle age people, the brains of overweight and obese people display differences in the amount of white matter that are similar to those in lean people who are 10 years older. White matter is the tissue that connects different areas of the brain, and allows for information to be communicated between regions. The results are published in the journal, Neurobiology of Aging.
The research team studied data from 473 healthy individuals between the ages of 20 and 87 years old who were recruited from the Cambridge Centre for Aging and Neuroscience.
The team divided the participants into two categories based on weight: lean and overweight/obese. Underweight people were excluded from the study. MRI imaging scans of the participants' brains along with special computer software for cortical reconstruction, were used to generate measures of whole brain cerebral white matter volume, cortical thickness, and surface area.
When the researchers analyzed the data, they found striking differences in the volume of white matter as overweight and obese people had a widespread reduction of white matter when compared to lean people.
The researchers then calculated how white matter volume related to age across the two groups. Subsequently, the team discovered that an overweight or obese person had a similar amount of white matter as a lean person 10 years younger. For example, a 40-year-old obese person has a similar amount of white matter as a 50-year-old lean person. This observation was noted especially in middle age (approximately 40 years old) participants, suggesting that our brains may be particularly vulnerable during this period of aging.
The researchers are unsure why overweight and obese people have a greater reduction in white matter. Dr. Lisa Ronan, first author and from the Department of Psychiatry at the University of Cambridge, says in a statement, "We can only speculate whether obesity might in some way cause these changes or whether obesity is a consequence of brain changes."
Professor Paul Fletcher, senior author and also from the Department of Psychiatry, added: "We're living in an aging population, with increasing levels of obesity, so it's essential that we establish how these two factors might interact since the consequences for health are potentially serious... It will also be important to find out whether these changes could be reversible with weight loss, which may well be the case."
Although there were distinct differences in the volume of white matter between lean and overweight people, the researchers did not find any connection between being overweight or obese and a person's cognitive abilities, which were measured using a standard test similar to an IQ test.
Professor Sadaf Farooqi, co-author of the study and from the Wellcome Trust–Medical Research Council Institute of Metabolic Science at Cambridge, says: "We don't yet know the implications of these changes in brain structure. Clearly, this must be a starting point for us to explore in more depth the effects of weight, diet, and exercise on the brain and memory."
Source: Theresa Bebbington, WebMD UK Health News
Medically Reviewed by DR. Sheena Maredith
