Consuming fast food and other ultra-processed foods has a negative impact on brain function. In particular, such food can lead to a decrease in the hippocampus region of the brain. She spoke about this in an interview with The Guardian Alice Jacka is a leading researcher in nutritional psychiatry, co-director of the Center for Nutrition and Mood at Deakin University in Australia, and president of the International Society for Research in Nutritional Psychiatry.
What are ultra-processed foods?
Ultra-processed products are products intended to be consumed ready-made (sometimes they require the addition of milk) or heated. They usually contain salt and other preservatives, as well as various flavor enhancers, flavorings and coloring agents that shape dietary habits. Ultra-processed foods include bread, cookies, biscuits, ice cream, chocolate, candy, breakfast cereals, cereal bars, chips, sugary soft drinks, and fast food (burgers, hot dogs, nuggets, etc.).
What is the hippocampus?
The hippocampus is a brain structure that is involved in the mechanisms of emotion formation, the transition of short-term memory to long-term memory, spatial memory necessary for navigation, and is also responsible for the process of maintaining attention. This area of the brain is one of the first to be affected in Alzheimer’s disease and other forms of dementia.
The hippocampus is the only area of the brain that can grow and shrink throughout life. As Alice Jacka explained, patients with severe depression have a smaller hippocampus on average than healthy people. Moreover, in case of recovery from depression, the hippocampus begins to grow again.
“And then, of course, the hippocampus is very important for various aspects of learning and memory. This is really important for children in school, for example, although any of us who want to preserve our brains and avoid cognitive decline as we age want to do everything we can to keep our hippocampus nice, thick and healthy,” the expert noted.
How do fast food and ultra-processed foods disrupt brain function?
Jacka explained that what we eat directly affects the composition of our gut microbes. And the gut microbiome, in turn, affects almost every aspect of health: metabolism, blood glucose levels, body weight, the amount of serotonin in the brain, the stress response system, the functioning of mitochondria in our cells, etc.
According to an expert in nutritional psychiatry, there is research showing that people who eat less healthy diets have smaller hippocampuses, while people who eat healthier diets have larger ones. Another study demonstrated that young adults who typically eat a fairly healthy diet and were given Western fast food for a week began to experience cognitive impairment in the hippocampus.
According to another study Jacka shared, the brain or gut microbes do not process ultra-processed foods in the same way as minimally processed whole foods. Moreover, this also happens if the packaging of finished products indicates that they contain vitamins, minerals or a large amount of protein.
Another 2021 study found that there is a link between pregnant women’s consumption of unhealthy foods and attention deficit disorder in their children. According to Jack, this is consistent with animal studies, which have demonstrated that the gut microbiota of a pregnant woman and a child after birth influence not only the formation of the child’s immunity, but also the development of brain function.