The mouse equivalent of a diet of cheeseburgers and fries causes inflammation in the male mouse brain. But would it do the same for females? No one had bothered studying that until Deborah Clegg, Ph.D. came along. What Clegg discovered may have profound implications for the human brain — and for how we eat.
“We knew that a junk food diet causes inflammation in the male mouse brain. We wanted to find out if the same was true for females. In humans, women are less affected in their overall health by weight gain than are men and we were hoping to discover something about this difference,” says Clegg, research scientist and assistant professor, the Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center in Los Angeles.
But female rodents are more challenging to work with in the lab, because they go through hormonal cycles every three-to-four days. “Females are rarely used in research because of their fluctuating hormones,” said Clegg, in an interview with BetterBrainBetterLife.com. “But we controlled for this and gave them exactly the same diet as the males. Both sexes gained exactly the same amount of weight.”
When Clegg submitted her research to a peer-reviewed publication she was asked to further explore why these differences exist. “We went back to the lab and dissected the brain tissues and discovered that the fatty acid composition in brain tissue is different for the sexes. Even down to individual neurons, we found a distinct and different response to diet in the male and female brains, independent of sex hormones,” says Clegg.
Inflammation was found in virtually all parts of the male mouse brain as well as in the liver, body fat and muscle tissues. Males also suffered from reduced cardiac function. These far-reaching differences between males and females in response to the junk food diet are related to the presence of the hormone estrogen and estrogen receptors within brain cells.
“This is really striking,” says Clegg. “Our research suggests that males and females process nutrients differently. If this proves to be true in humans then it is really amazing and should affect what we put on our plates.”
Clegg is currently considering how to study the relationship between a junk food diet and the fatty acid composition of human brains. Her current research was funded by the American National Institutes of Health (NIH) and was published in the Cell Press journal Cell Reports on Oct. 16, 2014.