FOOD is a sensitive issue for many women in the west, not least because of pressure to diet, and the way food advertising is targeted. Now it seems this may be showing up in how women’s brains react to food.

Rudolf Uher and his colleagues at King’s College London Institute of Psychiatry used functional magnetic resonance imaging (fMRI) to test reactions to food in the brains of 18 men and women after they had either eaten normally or fasted for 24 hours. When the volunteers were shown photographs of food or given food to taste, a part of the brain that processes visual information about food reacted more strongly in the women than in the men, whether they were hungry or not – a difference that did not occur when non-food pictures were shown.

The strongest activity was in the occipitotemporal cortex, a region that monitors and reflects how other areas of the brain – such as those processing hunger and feelings of pleasure - react to food. This suggests that the women were engaging in more conscious thought and decision-making in response to the stimulus.

Uher says this could be related to biological differences between men and women, but he believes the more likely explanation is that women have a more complicated reaction to food because of social pressure. “My personal bet would be to set more store by learning processes,” he says.

Confirming Uher’s speculations will need specific testing, cautions Angelo del Parigi of the John B. Pierce Laboratory in New Haven, Connecticut. His research echoes Uher’s finding, but looking at Fmri alone cannot confirm whether this is due to innate differences or a learned process, he says.

Uher’s team is now applying its findings to patients with eating disorders, 9 out of 10 of whom are women. Compared to healthy women, those with anorexia or bulimia show greater activity in the occipitotemporal cortex when shown pictures of food, possibly reflecting their negative perception and heightened awareness of food. “We found a reaction even in motivational areas that are very difficult to pick up with fMRI,” Uher says. He also plans to explore how obese people react to similar pictures.

For more information read New Scientist, issue 29 April 2006 at www.newscientist.com

To view related articles on the EUFIC website go to Food For All Ages and Eating Disorders.