Ultra-processed, fried, or poor-quality carbohydrates are some of the foods to avoid for good cognitive function.

Diet is essential for the proper functioning of the body. Vitamins and minerals feed muscles, help regenerate tissues, and protect the body from oxidation and the action of free radicals. The functioning of the brain, like the rest of the organs, depends on a correct diet and, just as this can be beneficial for its maintenance, there are foods that can have just the opposite effect.

It is possible that, throughout the day, you consume foods that can alter and compromise your cognitive ability, explains Uma Naidoo, author of the book This is your brain on food (What food does to your brain) and director of Psychiatry Nutritional at Harvard Medical School.

This scientist has spent years studying how changes in diet affect mental health and the human brain in general. Specifically, she has focused on intestinal bacteria and how they can trigger metabolic processes and even episodes of brain inflammation, which negatively affect concentration and reasoning. “Some current studies support the idea that we can reduce the chance of dementia by avoiding certain foods that compromise our gut bacteria and weaken our memory,” she explained in a column for CNBC. Here are some of them:

A diet loaded with sugary foods is linked to memory problems and less plasticity of the hippocampus, the part of the brain that controls memory. For this reason, Naidoo advises against its consumption, pointing out processed foods as a common source of these additives.

“Industrial pastries and soft drinks are products with a lot of added sugars that we also usually keep in mind in our daily diet. Among their many drawbacks is the risk of suffering from type 2 diabetes or weight gain. In addition, they cause an inflammation process in the organism, which in turn is related to diseases such as obesity”, highlights Concepción Martínez, a dietitian-nutritionist specializing in obesity.

Different studies have shown that excessive consumption of these types of sugars can contribute to inflammation, which in turn can lead to mental health problems such as depression and anxiety. It also affects memory and learning ability, as well as general cognitive function.

As recommended by the World Health Organization (WHO), the consumption of this type of sugar should not exceed 10% of total caloric intake. He even adds as a suggestion to reduce your intake to less than 5% of the total calories of the day, that is, about 25 grams a day. Taking into account that some soft drinks can have between 11 and 35 grams of sugar, moderating the consumption of these or even eliminating their intake would be the most advisable.

ultra-processed foods

A greater consumption of ultra-processed foods is associated with a greater risk of suffering from Alzheimer’s and vascular dementia, as revealed by a study published in Neurology. These conclusions were obtained after the evaluation of more than 72,000 patients during about ten years of follow-up. Specifically, a 10% increase in ultra-processed foods in daily intake was associated with a 25% chance of suffering from dementia.

During this investigation, it was related to replace these ultra-processed foods with minimally processed products or fresh foods, thus discovering that the risk of suffering from memory problems decreased. Also an analysis published in the Journal of Nutritional Science links processed foods with lower scores on cognitive tests.


How we cook food can also influence how it affects our brain. Fried food has a negative impact on this organ for several reasons. The first is that it contains a high amount of saturated fat, which has been linked to the development of cardiovascular disease and increased risk of stroke. This is because excess of this type of fat increases cholesterol and triglyceride levels in the blood, making it difficult for blood to circulate to the brain.

Additionally, fried food can also contain high levels of arachidonic acid, which is an essential fatty acid linked to inflammation and neuronal damage. This can affect cognitive function and memory, which can contribute to short-term memory loss and long-term decline in cognitive function.

Finally, foods cooked this way are high in trans fats, which have been linked to increased risk of cardiovascular disease and impaired brain health. These fats can affect the normal functioning of neurotransmitters, which can lead to cognitive problems.


Carbohydrates, endowed with a bad name for years, are actually a key element of a healthy diet. However, there are different types, divided by their chemical structure and each one has a different effect on the body.

Depending on their structure, we find two types of carbohydrates: complex or slow absorption (starches and fiber) and simple or fast absorption, called free or simple sugars (glucose, fructose and lactose). Within the simple ones, there are the monosaccharides (a unit of sugar) such as fructose, galactose and glucose; and disaccharides (two units), such as fructose, sucrose (or table sugar), and maltose.

Taking into account that it is advised that between 45 and 65% of the calories we eat each day come from carbohydrates, it is vital to consume them during daily food intake. “It is advisable to consume good quality carbohydrates, such as those provided by fruit, avoiding poor quality ones, such as industrial pastries,” explains Martínez.

So where is the problem? While complex carbohydrates, made from whole grains, provide fiber and vitamins and minerals, those made from refined grains or flour have been stripped of nutrient-dense parts. The consequence is that its intake causes spikes in blood sugar that can lead to different diseases, such as type 2 diabetes, and can also affect the brain, since they interfere with cognitive function and mental performance.


Drinking alcohol excessively can be harmful to the brain. This substance can damage brain cells, affecting memory, learning, coordination, judgment, and the ability to make decisions. In addition, it also influences the production of hormones.

There are different investigations that have measured its harmful effects, such as the one carried out by the University of Oxford and published in the British Medical Journal, which has shown how the intake of alcoholic beverages, even moderately, is related to a lower amount of gray matter . Another study points out that people who consume more than 14 drinks per week have a higher risk of dementia, compared to those who drink alcohol in moderation.

Categorized in: