Scientists have known for years that unhealthy foods – especially those high in fat and sugar – can cause it Harmful changes in the brain And They lead to cognitive impairment.
Many factors that contribute to cognitive decline are beyond a person’s control, e.g Genetics And Socio-economic factors. But ongoing research is increasingly showing that a Poor nutrition is a risk factor Normal aging increases the risk of memory impairment The development of Alzheimer’s disease.
But considering how certain diets can erode brain health as we age, research on the effects of consuming minimally processed foods versus highly processed foods has been scarce—that is, until now.
Two recent large-scale studies suggest that eating highly processed foods May worsen age-related cognitive decline. And add Risk of dementia. In contrast, another recent study reported that consumption of highly processed foods was unrelated Worse cognitive impairment in people over 60 years old.
Although more research is needed, as a Neuroscientist Who will investigate how Diet can affect cognition. Later, I realized that these early studies added a new layer to our understanding of how fundamental nutrition is to brain health.
More nutrients, less nutrition
Highly processed foods tend to be lower in nutrients and fiber and higher in sugar, fat, and salt compared to non- or minimally processed foods.
some Examples of highly processed foods They include soda, packaged cookies, chips, frozen meals, flavored nuts, flavored yogurt, refined alcoholic beverages, and fast food. Although packaged breads, including those found in Almi Whole Grains, qualify as highly processed in many respects due to the additives and preservatives they contain.
Another way to look at it: You won’t find the ingredients that make up most of these foods in your home kitchen.
But don’t confuse them with highly processed foods, though, such as canned vegetables, dried pasta or frozen fruit that retain many of their natural qualities.
In the year In a December 2022 study, researchers compared the rate of cognitive decline between groups of people over approximately eight years. He took highly processed foods in varying amounts.
At the start of the study, more than 10,000 participants living in Brazil reported their eating habits over the past 12 months. Then, for the following years, the researchers evaluated the cognitive performance of the participants with standard memory and executive tasks.
At the start of the study, people who ate a diet high in processed foods showed slightly greater cognitive decline compared to those who ate little or no ultra-processed food. This was a relatively small difference in the rate of cognitive decline between the experimental groups.
It is not yet clear whether the small differences in cognitive decline associated with eating highly processed foods have meaningful effects on the individual level.
The second study, involving nearly 72,000 participants in the United Kingdom, measured the relationship between Eating highly processed foods and memory loss. For the group that ate the most highly processed foods, about 1 in 120 people were diagnosed with dementia within 10 years. For the group that ate little to no ultra-processed foods, that number was 1 in 170.
Research examining the relationship between health and highly processed foods Classification of NOVAIt is a classification system based on the type and size of industrial food processing.
Some nutritionists have He criticized the classification of NOVA Because there is no clear description of food processing, it can be They lead to misclassification. They also argue that the health risks of eating highly processed foods can be explained by the low levels of fiber and nutrients and the high levels of fat, sugar and salt in the diet rather than the processing itself.
Many highly processed foods are high in additives, preservatives or coloring agents and have other unhealthy nutritional characteristics, such as being low in fiber and nutrients. Therefore, it is not clear that eating more processed food has additional negative effects Health over low nutritional quality.
For example, you may eat burgers and fries from a fast food chain, which are high in fat, sugar, and salt and highly processed. You can do the same at a restaurant, which may be high in fat, sugar, and salt, but it won’t be super processed. More research is needed to determine whether one is worse than the other.
A healthy diet for the brain
Even when the processes leading to dementia do not occur, the aging brain undergoes biochemical and structural changes. Associated with cognitive impairment.
But for adults over age 55, a healthy diet increases the likelihood of maintaining better brain function. in particular, Mediterranean diet And ketogenic diet They are associated with better cognition in old age.
The Mediterranean diet focuses on the consumption of plant-based foods and healthy fats such as olive oil, seeds and nuts. The ketogenic diet is high in fat and low in carbohydrates, with the main source of fiber coming from vegetables. Both foods reduce or eliminate sugar consumption.
Our research and the work of others show that both foods can Reversing some of these changes And Improving cognitive function – maybe by Reducing harmful inflammation.
Although inflammation is a normal immune response to injury or infection, chronic inflammation can damage the brain. Research shows that excess sugar and fat It can contribute to chronic inflammation, And they can be highly processed foods It also aggravates harmful inflammation.
Another way diet and ultra-processed foods affect mental health. through the gut-brain axisThis is the connection between the brain and The gut microbiomeor a community of microorganisms living in the digestive tract.
The gut microbiome not only affects digestion, but also the immune system, produces hormones, Neurotransmitters important for brain function.
Studies show that ketogenic And Mediterranean diet Change the composition of the microbial community in the gut in a way that benefits the person. Highly processed food consumption is also related to this. Changes in type and quantity Intestinal microorganisms with more harmful effects.
Disentangling the specific effects of individual foods on the human body is difficult, as it is difficult to study people’s diets over a long period of time. Moreover, in the year Randomized controlled trialsThe most reliable form of research to establish causality, They are expensive to carry out.
So far, most nutrition studies, including these two, have only shown a correlation between highly processed food consumption and health. But you can’t avoid it Other living conditions Such as exercise, education, socioeconomic status, social relationships, stress and many other variables can affect cognitive function.
This is where laboratory-based studies using animals are incredibly useful. Rats show Cognitive decline similar to humans in old age. It is easy to control the feeding and activity levels of rats in the laboratory. And mice go from middle-aged to old in months, which shortens the study period.
Laboratory-based studies in animals suggest that highly processed foods are playing a key role in the development of cognitive impairment and dementia in humans. According to the age and size of the world population Elderly people with dementia are increasingThis knowledge cannot come quickly.
Sarah N. BurkeAssociate Professor of Neurobiology and Cognitive Aging, University of Florida
This article was reprinted from The conversation Under a Creative Commons license. Read Original article.