The study is the most recent to suggest that obesity leads to alterations in brain function in the area that regulates memory.
The list of health risks associated with obesity keeps growing—and now poor memory may be added to the list, based on a study just published in BMJ.
Diabetes, hypertension, certain cancers, and heart disease are all more common among those with an excessive body mass index (BMI); in the United States, obesity is defined by CDC has having a BMI of 30 or above, with overweight having a BMI between 25 and 29.9.
Studies showing the ties between obesity and poor cognitive function are more recent. Being excessively heavy apparently alters the function of the brain, causing changes in the frontal lobes that control intelligence and the hippocampus that regulates memory. This second area is the subject of the study just published.
Researchers at the University of Cambridge asked 50 participants of varying sizes, with BMI from 18 (underweight) to 51 (extremely obese) to perform memory tests that involved moving items around a computer screen; the test required subjects to recall where certain items were hidden to retrieve them, as well as the order things had been hidden in the scenes.
Those with higher BMI performed poorly on this test; they struggled to combine the elements of the “what” (the items) the “where” (the location where hidden) and the “when” (the order when things were hid). The findings confirmed tests carried out on other humans, as well as tests on animals, that cognitive deficits associated with obesity show up early and last.
The researchers said the test would need to be repeated to ensure that it is obesity, and not an associated health condition such as hypertension, that causes the impaired mental function.
Cheke LG, Simons JS, Clayton NS. Body mass index is associated with episodic memory deficits in young adults. Q. J. Exp. Psychol. DOI:10.1080/17470218.2015.1099163.