Diets High in Sugar and Fat Can Hurt Cognitive Health

DoughnutsIt is widely known that a healthy, balanced diet promotes not only physical health but brain health too. Researchers at Oregon State University conducted a study to further understand how diet affects the brain and found that high-fat and high-sugar diets induce bacterial changes in the gut, which can cause a decline in cognitive flexibility.

The trial was conducted on lab mice, which were given one of three diets: high-fat, high-sugar or normal. After being on the diets for four weeks, the mice underwent a series of tests to assess their behavior and cognitive function. They were also tested before and after the trial to look at each diet’s impact on bacteria in the gut.

The researchers found that the mice on the high-fat and high-sugar diets declined the most in their abilities to be cognitively flexible. Strong cognitive flexibility means that an individual can adapt quickly to new situations without too much added stress. For example, if you drove home via the same route every day and one day a road was closed for construction, someone with cognitive flexibility would determine an alternate route to get home and remember to take the new route the next day. Someone with declining cognitive flexibility may be slower at determining a new route and the added difficulty could cause increased stress and frustration. Decline in performance was most notable in mice given the high-sugar diet, which was found to also impair early learning for short- and long-term memory.

The food we eat affects our microbiome, a complex mixture of over 100 trillion microorganisms that make up the digestive system. Microbiota, bacteria from the gut, can affect brain health by acting as neurotransmitters, stimulating sensory nerves or the immune system and affecting biological functions that relay messages to the brain. A microbiome analysis of the mice found a higher percentage of “bad” microbiota and lower amounts of healthy bacteria in the mice that had eaten a high-fat or high-sugar diet, which directly correlated with their cognitive flexibility performance. The way our diet impacts our minds brings a whole new meaning to the phrase “you are what you eat”.

Instead of a high-fat, high-sugar snack like a donut, try a healthy alternative like dark chocolate or blueberries, which both promote the removal of toxins and increase blood flow to the brain. By incorporating a variety of nutrient-rich foods into your diet, you can promote brain health and stave off symptoms of cognitive decline.