A simple way to protect the brain from the harmful effects of fatty foods has been identified

A diet rich in fruits and vegetables can protect the brain from the harmful effects of fatty foods. This is the conclusion scientists reached in a preclinical study showing that memory was preserved in mice on a "Western" diet when their feed was supplemented with a mixture of plant products. The work was published in the journal Nutritional Neuroscience.

The rise in obesity worldwide parallels the increase in cognitive impairments among elderly people. Obesity is considered a risk factor for dementia, and one of the causes is high consumption of calorie-dense food with high saturated fat content. Such a diet enhances oxidative stress - an imbalance between free radicals and the body's antioxidant defenses, which over time damages tissues, including neural tissues.

A team led by Weimin Guo decided to test whether a combination of plant products, rather than individual ingredients, could mitigate these effects.

The experiment used male C57BL/6 mice. The animals were divided into five groups: one received a standard low-fat diet, while the others received a high-fat "Western" diet that causes obesity. Additionally, lyophilized fruit and vegetable powder was added to their feed at 0, 5, 10, or 15% of the diet by weight. The mixture included apples, bananas, berries, grapes, citrus fruits, spinach, carrots, broccoli, and tomatoes. The maximum dose roughly corresponded to 8-9 servings of fruits and vegetables per day for humans.

After 20 weeks, scientists assessed the animals' memory using the novel object recognition test - a standard method for studying learning and memory in rodents. Mice on the low-fat diet confidently distinguished new objects from familiar ones. In animals on the fatty diet without supplements, this ability deteriorated. However, in mice receiving the plant mixture, memory indicators improved as the dose increased. With the 15% supplement, the results were almost the same as in the control group.

Interestingly, supplements at 5 and 10% did not prevent the development of obesity, whereas at 15%, the weight gain was less than in mice without the plant powder. This suggests that memory preservation was not solely related to weight control.

To understand the mechanism of the effect, researchers measured the level of malondialdehyde in the liver - a marker of oxidative stress. The high-fat diet sharply increased its level, whereas the fruit and vegetable supplement reduced these indicators, pointing to a decrease in systemic oxidative stress. The authors believe that this could have protected neuronal pathways and cognitive functions.

In the future, scientists plan to study specific brain regions, including the hippocampus, and verify whether the protective effect persists in humans in clinical studies.