Obesity leads to poor memory

Obesity leads to poor memory

Obesity has become a significant health crisis: More than 300 million people worldwide are considered obese and more than a billion people are classified as overweight. To make it worse, new research from the University of Cambridge has stated that overweight young adults may have poorer episodic memory, the ability to recall past events, than their peers.

An earlier study had established a link between obesity and mental health. It seems that along with increased risk for health problems such as type 2 diabetes and heart disease, obesity is bad for your brain: we have linked it to shrinkage of brain areas that are also targeted by Alzheimer s, said Cyrus A. Raji, a medical student at the University of Pittsburgh School of Medicine.

In a preliminary study published in The Quarterly Journal of Experimental Psychology, researchers from the Department of Psychology at Cambridge found an association between high body mass index (BMI) and poorer performance on a test of episodic memory.

Although only a small study, its results in particular state, obesity has been linked with dysfunction of the hippocampus, an area of the brain involved in memory and learning, and of the frontal lobe, the part of the brain involved in decision making, problem solving and emotions, suggesting that it might also affect memory; however, evidence for memory impairment in obesity is currently limited.

Research suggests that consuming between 2,100 and 6,000 calories per day may double the risk of memory loss, or mild cognitive impairment (MCI), among people age 70 and older.

Understanding what drives our consumption and how we instinctively regulate our eating behaviour is becoming more and more important given the rise of obesity in society, says Dr Lucy Cheke.

It turns out that Obese people have 8% less brain tissue than people of normal weight. Overweight people have 4% less brain tissue than people of normal weight. According to Dr. Paul Thompson, a UCLA professor of neurology, This represents severe brain degeneration, that s a big loss of tissue and it depletes your cognitive reserves, putting you at a much greater risk of Alzheimer s and other diseases that attack the brain. But you can greatly reduce your risk for Alzheimer s, if you can eat healthy and keep your weight under control.

The researchers tested 50 participants aged 18-35, with body mass indexes (BMIs) ranging from 18 through to 51 - a BMI of 18-25 is considered healthy, 25-30 overweight, and over 30 obese. The participants took part in a memory test known as the 'Treasure-Hunt Task', where they were asked to hide items around complex scenes (for example, a desert with palm trees) across two 'days'.

They were then asked to remember which items they had hidden, where they had hidden them, and when they were hidden. Overall, the team found an association between higher BMI and poorer performance on the tasks.

The researchers say that the results could suggest that the structural and functional changes in the brain previously found in those with higher BMI may be accompanied by a reduced ability to form and/or retrieve episodic memories. As the effect was shown in young adults, it adds to growing evidence that the cognitive impairments that accompany obesity may be present early in adult life.

This was a small, preliminary study and so the researchers caution that further research will be necessary to establish whether the results of this study can be generalised to overweight individuals in general, and to episodic memory in everyday life rather than in experimental conditions.

Dr Cheke believes that this work is an important step in understanding the role of psychological factors in obesity.

Co-author Dr Jon Simons adds, By recognising and addressing these psychological factors head-on, not only can we come to understand obesity better, but we may enable the creation of interventions that can make a real difference to health and wellbeing.

Obesity leads to poor memory