Study links ultra-processed food to cognitive decline. Here's what some experts say

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We may often turn to meals like frozen pizza, burgers, French fries and instant soups since they're quick and easy meals. But what these foods lack is sufficient amounts of key nutrients.

Highly processed foods are loaded with sodium, sugar and saturated fat which, in large quantities, can lead to high blood pressure, heart disease, obesity and, in some cases, certain types of cancer.

Now, new research out of Brazil is highlighting how ultra-processed foods can also significantly accelerate a person’s cognitive decline.

In an interview with NBC News, Claudia Suemoto, author of the study and geriatrics professor at the University of São Paulo's medical school, says it’s imperative to look at more than just calories when choosing your meals.

“Independent of the amount of calories, independent of the amount of healthy food you try to eat, the ultra-processed food is not good for your cognition,” she says. “I know that sometimes it’s easier to open a package and throw it in the microwave, but in the long term, it’s going to cost you some years of life.”

In the study, researchers analyzed more than 10,000 people over a nine-year follow-up. A little more than half of the people who took part in the study were white women and the average age of participants was 51. Cognitive performance was evaluated using a "standardized battery of tests," including immediate recall, late recall, recognition and verbal fluency.

The findings, presented at the Alzheimer’s Association International Conference in San Diego, show people who eat high amounts of ultra-processed foods have a 28 per cent faster decline in global cognitive scores, including memory and executive function, which is part of the brain that helps us plan, monitor and successfully execute our goals.

In this case, high consumption was defined as someone who consumed more than 20 per cent of daily calories from ultra-processed food.

Devon Peart, a registered dietitian with Cleveland Clinic Canada, says she was impressed by the sheer size and length of the study, but not surprised at the findings. She stresses the importance of eating whole foods that provide our body and mind with the nutrients we need to stay healthy.

“One thing that we understand much better now than we used to is the connection between gut health and brain health, there is a connection there that we didn't really realize or appreciate, and we're learning more about that as research continues and science evolves,” she says.

What are processed and ultra-processed foods?

According to the Heart and Stroke Foundation, Canadians consume almost 50 per cent of their daily calories from ultra-processed foods, which the organization defines as foods that have been significantly changed from their original state.

Foods become ultra-processed when they have salt, sugar, fat, additives and preservatives added to them, like hot dogs, breakfast cereals, candy and soft drinks.

Peart says there has been a proliferation of packaged processed foods over the past 50 years.

“The thing about ultra-processed foods is they bear really little resemblance to actual food. They might taste like food, they might smell like food, but they bear little nutritive similarities to whole foods,” she adds. “If we're consuming foods that are really low in nutrients, what we call nutrient-poor, then I'm not at all surprised that it affects health and brain health.”

Compared to ultra-processed food, processed food is not all bad.

Processed food may have oil, sugar, salt or other ingredients added to it before it’s packaged, like cheese, tofu, yogurt, and canned tuna. The Heart and Stroke Foundation says these foods have been altered, but not in a way that’s detrimental to our health.

Ultra-processed food may cause systemic inflammation

While inflammation is normal and a natural part of our body’s immune system, systemic inflammation can lead to diseases and chronic conditions.

Peart says one of the main concerns with ultra-processed food is that it can cause systemic inflammation.

“If we have too much fast food, if we have too much alcohol, too much saturated fat, that increases inflammation, because the body essentially recognizes those things as foreign and it creates inflammation to try to deal with it,” she explains during an interview with Yahoo Canada.

Can ultra-processed food lead to diseases?

Dr. Joshua Armstrong, a researcher with the Alzheimer Society of Canada who was not part of the study, also says he wasn’t surprised by the research.

When asked if eating certain foods can increase a person’s risk of brain diseases, like Alzheimer’s disease, Armstrong says the findings presented in the study are associations only and do not provide “evidence of causation.”

“Food influences our brain health in a wide variety of ways. Many researchers are now focusing on this topic, along with studying the interactions between food, the brain, and the human microbiome,” he tells Yahoo Canada. “Evidence exists that suggests that nutrients like certain vitamins, flavonoids and omega-3 fatty acids have the potential to improve brain health and cognition.”

The researcher also notes that when we link certain foods to the risk of Alzheimer’s disease, we need to recognize that eating unhealthy meals doesn’t happen in isolation.

“They [unhealthy foods] are often accompanied with other negative health behaviours, such as a sedentary lifestyle, overconsumption of sugary products and further, higher rates of consumption of UPF [ultra-processed foods] may also be associated with other dementia risk factors such as socioeconomic status, heart health and a range of other factors which have been demonstrated to be associated with increased dementia risk,” he explains.

Armstrong says no matter what your age is, you can improve your brain health and reduce your risk of dementia by engaging in physical activity every day, not drinking excessively, getting a good night’s sleep and staying socially active.

“Make healthy food choices. Not only will it improve your general health, eating a healthy diet will help maintain your brain function as you get older,” he adds. “The Alzheimer Society of Canada has several helpful resources available to educate people about the need for healthy, balanced eating.” 

Food recommendations change upon age

As people get older, Peart says there should be a focus on foods that are strongly associated with brain health, such as lean protein, vegetables and even blueberries, which she says have “brain-protective properties.”

The registered dietitian also highly recommends whole grains like quinoa, brown rice and barley, as well as legumes and herbs like ginger, turmeric and garlic.

Oily fish, like salmon, sardines and mackerel, should be eaten at least a couple of times a week.

“Those are the richest source of omega-three fats. Omega-three fats are good for heart health because they help lower LDL cholesterol, the "bad" cholesterol, and they're really good for brain health because the body uses omega-three fats to make anti-inflammatory compounds,” she says. “Omega-three fats help reduce inflammation in the body.”

Limit ultra-processed foods as much as you can

The Canada Food Guide urges people to limit highly processed foods and drinks and has suggestions on how to do that.

Recommendations include replacing sugary drinks with water, trying not to keep highly-processed foods in the house and making healthier choices when eating out.

Peart says if someone regularly eats at restaurants, they should make sure they still include whole foods in other meals and snacks throughout the day.

“The more we have of foods with a lot of added sugar or a lot of added salt, the more 'tolerance' we have for sweet and salty, so it takes more for us to be satisfied from it,” she adds. “Overall, ultra-processed foods potentially contribute to cognitive decline in terms of memory, in terms of mental processing and in terms of increasing your risk for brain diseases."

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