Too Much Fat, Sugar Linked to Decline in Brain Function

Too much fat and sugar can affect more than one’s waistline or likelihood of developing diabetes, according to new research from Oregon State University in Corvallis.

The study of young lab mice adds to growing evidence that the typical high-fat, high-sugar Western diet can impact brain function via a roundabout path.

The study findings, published in the August issue of the journal Neuroscience, suggest that high-fat and high-sugar diets alter gut bacteria.

Those changes are linked to what an OSU press release describes as a “significant loss” in cognitive flexibility, which is essentially the ability to adapt and adjust to changing situations.

The study’s lead author, Kathy Magnusson, says in the press release that it’s becoming increasingly clear that the bacteria that occur naturally in the gut, called “microbiota,” can communicate with the human brain:

“Bacteria can release compounds that act as neurotransmitters, stimulate sensory nerves or the immune system, and affect a wide range of biological functions. We’re not sure just what messages are being sent, but we are tracking down the pathways and the effects.”

Magnusson is a principal investigator at OSU’s Linus Pauling Institute and a professor in the university’s College of Veterinary Medicine.

The findings are consistent with previous studies about the impact of fat and sugar on cognitive function, the press release states.

Magnusson says the results could be even more pronounced for older animals or humans with compromised intestinal systems.

The mice were assigned to one of three groups, with each group fed a different diet:

• High-fat (42 percent fat, 43 percent carbohydrates)
• High-sugar (12 percent fat, 70 percent carbohydrates — primarily sucrose, which is table sugar)
• Normal (13 percent fat, 62 percent carbohydrates)

After four weeks, the mice on the high-fat or high-sugar diet started performing more poorly on various tests of mental and physical function than those on a normal diet.

Magnusson states:

“We’ve known for a while that too much fat and sugar are not good for you. This work suggests that fat and sugar are altering your healthy bacterial systems, and that’s one of the reasons those foods aren’t good for you. It’s not just the food that could be influencing your brain, but an interaction between the food and microbial changes.”

Do studies like this concern you? Would you change your diet because of them? Share your thoughts with us in a comment below or on Facebook.