Ultra-Processed Foods Lead to Alzheimer's Disease

For years, scientists have known that poor diets, particularly ones high in fat and sugar, can create negative changes in the brain and lead to cognitive impairment. Many factors that contribute to cognitive declines, such as heredity and socioeconomic conditions, are beyond a person's control. However, continuing research indicates that a poor diet is a risk factor for memory deficits during normal aging, as well as an increased risk of acquiring Alzheimer's disease.

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Good Nutrition is Important Brain Function

However, when assessing how certain diets may deteriorate brain function as we age, research on the impact of ingesting minimally processed versus ultra-processed foods has been limited - until now.

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Eating Ultra-Processed Foods Increases Risk of Dementia

According to two recent large-scale research, eating ultra-processed meals may accelerate age-related cognitive decline and raise the likelihood of developing dementia. In contrast, another recent study found that eating ultra-processed foods was not connected with poor cognition in persons over the age of 60.

Although additional research is needed, as a neuroscientist who studies how diet affects cognition later in life, I feel that these early studies provide a new dimension to understanding how important nutrition is to brain health.

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What are Ultra-Processed Foods

When compared to unprocessed or minimally processed foods, ultra-processed foods are lower in nutrients and fiber and higher in sugar, fat, and salt. Soda, packaged cookies, chips, frozen dinners, flavored almonds, flavored yogurt, distilled alcoholic beverages, and fast foods are examples of ultra-processed foods. Because of the additives and preservatives they include, even packaged bread, particularly those high in healthful whole grains, qualify as ultra-processed in many circumstances.

Another way to look at it is that you are unlikely to find the components that comprise the majority of these delicacies in your kitchen.

But don't confuse ultra-processed with processed foods, which keep most of their natural properties despite being treated in some way, such as canned vegetables, dried pasta, or frozen fruit.

Food Habits Influence Cognitive Performance

Researchers assessed the rate of cognitive impairment over nearly eight years across groups of persons who consumed varying amounts of ultra-processed foods in a December 2022 study.

Over 10,000 Brazilian participants reported their food habits during the preceding 12 months at the start of the study. The researchers then assessed the participants' cognitive performance over several years using conventional assessments of memory and executive function.

Those who consumed more ultra-processed foods at the outset of the trial experienced slightly higher cognitive deterioration than those who consumed little to no ultra-processed foods. The difference in the rate of cognitive deterioration between experimental groups was rather minor. It is unclear if the minor variation in cognitive deterioration related to increased consumption of ultra-processed meals would have a relevant effect at the individual level.

The second study, which enrolled over 72,000 people in the United Kingdom, looked at the link between eating ultra-processed foods and dementia. Over 10 years, nearly 1 out of 120 participants in the group eating the most ultra-processed meals were diagnosed with dementia. This number was 1 out of 170 for the group who consumed little to no ultra-processed meals.

The NOVA classification, which is a categorization system based on the type and intensity of industrial food processing, is used in research evaluating the association between health and ultra-processed foods. Some nutritionists have criticized the NOVA categorization for lacking specific definitions of food processing, potentially leading to misclassification. They also claim that the potential health hazards associated with ultra-processed foods may be explained by low amounts of fiber and nutrients in the diet, as well as excessive levels of fat, sugar, and salt, rather than the amount of processing.

Many ultra-processed foods contain a high concentration of chemicals, preservatives, or coloring agents, as well as other characteristics of an unhealthy diet, such as a lack of fiber and nutrients. As a result, it is uncertain whether eating more processed foods has a detrimental influence on health in addition to poor diet quality.

For example, you could consume a fast food burger and fries that are heavy in fat, sugar, and salt, as well as being ultra-processed. You might prepare the same dish at home, which would be rich in fat, sugar, and salt but not as processed. More research is required to establish whether one is superior to the other.

Even when the dementia-causing mechanisms are not taking place, the aging brain suffers biochemical and anatomical changes that are associated with declining cognition.

Mediterranean and Ketogenic Diets are Brain-Healthy Diets

A healthier diet, on the other hand, may boost the likelihood of preserving superior brain function in persons over the age of 55. The Mediterranean and ketogenic diets, in particular, have been linked to improved cognition in old age.

The Mediterranean diet emphasizes plant-based meals and healthy fats such as olive oil, seeds, and nuts. The ketogenic diet is high in fat and low in carbohydrates, with vegetables serving as the principal source of fiber. Sugar consumption is reduced or eliminated in both diets.

According to our findings and the findings of others, both diets can reverse some of these alterations and improve cognitive performance, possibly by reducing detrimental inflammation.

Consuming Excess Sugar and Salt Leads to Brain Inflammation

Although inflammation is a necessary immunological response to injury or illness, it can be harmful to the brain over time. Excess sugar and fat have been proven in studies to contribute to chronic inflammation, and ultra-processed diets may further promote detrimental inflammation.

Ultra-Processed Foods Alter Gut Microbiome

Another way that nutrition and ultra-processed foods may affect brain health is through the gut-brain axis, which involves communication between the brain and the gut microbiome, or the community of bacteria that live in the digestive tract.

The gut microbiome not only aids digestion but also regulates the immune system and produces hormones and neurotransmitters that are essential for brain function.

According to research, ketogenic and Mediterranean diets alter the composition of bacteria in the gut in beneficial ways. Consumption of ultra-processed foods is also connected with changes in the type and number of gut microbes that have greater detrimental consequences.

Studying the Effect of Food on the Human Body

Disentangling the particular effects of individual foods on the human body is challenging, in part because it is difficult to keep strict control over people's diets to study them over long periods. Furthermore, randomized controlled trials, the most trustworthy type of investigation for demonstrating causality, are too expensive to conduct.

Most nutritional research, including these two, has only found links between ultra-processed food consumption and health. However, they cannot rule out other lifestyle factors that may influence cognitive performance, such as exercise, education, financial status, social relationships, stress, and many more.

This is where animal-based laboratory research come in handy. Rats experience cognitive deterioration similar to humans as they age. In a laboratory, it is simple to regulate mouse diets and activity levels. Furthermore, rats age from middle to elderly age in months, reducing study duration.

Animal trials in the lab will allow researchers to evaluate whether ultra-processed meals play a role in the development of cognitive deficits and dementia in humans. As the world's population ages and the number of dementia patients grows, this understanding cannot arrive soon enough.

Source-Medindia