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study links ultra-processed foods to increased risk of stroke and cognitive decline

foods, including soft drinks, pizza, and candy, contain minimal or no nutritional value, but they can be even worse for your health than you think.

by angelica bottaro

may 24 2024

6 minute read

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when people consume more ultra-processed foods than anything else, their bodies do not get the nutrients needed to function. getty images

it’s generally well-known that eating a diet rich in nutritious whole foods is best for you to ward off diseases, such as obesity. however, new research shows just how important it is to watch what you eat, and not just for your waistline.

a study conducted by a team of researchers at massachusetts general hospital (mgh) found a direct correlation between an ultra-processed diet and adverse health reactions.

the study looked at foods with the highest levels of additives and preservatives, which are often the go-to for people living in the western world, and their power to negatively affect a person’s health when consumed long-term.

those eating more of these foods experienced higher levels of cognitive decline compared to those who didn’t, as well as an increased risk of life-threatening events, such as stroke.

the breakdown of food processing and what it means

according to the heart and stroke foundation of canada , roughly half of what canadians consume in a day is considered processed or ultra-processed. these foods are altered from their original state using additives and preservatives to help maintain their shelf life and sugar, salt, and fat to improve flavour.

these foods, including soft drinks, pizza, and candy, contain minimal or no nutritional value. when people consume more of these foods than anything else, their bodies do not get the nutrients needed to function. without adequate nutrition, bodily processes designed to keep you healthy cannot operate adequately.

there are three main food categories: unprocessed or minimally processed, processed, and ultra-processed. these foods are split into groups based on how altered they are from their original state.

for example, a bag of potato chips is considered ultra-processed because by the time the potatoes used to make the chips are ready for sale, they have been tweaked and changed so much from their original state that they no longer nutritionally resemble the potato they once were.

in the same vein, unprocessed foods are barely, if at all, modified—think fresh produce, nuts, legumes, eggs, and milk. to improve a person’s diet, they must consume more of the latter to get the nutrients they need to thrive both physically and mentally.

how the study was conducted

the study, “associations between ultra-processed food consumption and adverse brain health outcomes,” was published in the journal neurology . the researchers, led by w. taylor kimberly, md, phd, of the mass general brigham healthcare system, followed a group of 30,000 people over the last two decades.

during that time, the cognition and medical records of the participants were randomly assessed as they related to their dietary food intake using detailed questionnaires to see who was eating what and what that meant for their health.

kimberly and the mgh research team wanted to assess and understand just how big of an impact food can have on a person’s overall health, especially as they age. they chose to focus on the “two most common neurological conditions that lead to impaired brain health” as a way to see how diet contributes to the widespread development of cognitive decline and stroke.

“we were interested in the broader question of understanding risk factors that can impact brain health over one’s lifespan, and especially interested in risk factors that are potentially modifiable,” kimberly said in an email to healthing.

the reasoning behind studying processed and ultra-processed foods

there is a vast collection of studies and literature on diet as it pertains to health, and the widespread knowledge that eating a healthy diet correlates with healthier living isn’t news. however, many of the studies people have conducted focus on specific types of diets.

for example, there are many research articles available that look at healthier diets, including the mediterranean diet and the dash and mind diets. instead of a specific diet, kimberly and the researchers wanted to examine how food processing, specifically, affects health.

“there was less known about the role of food processing on these outcomes. we reasoned that it’s not only the type of food that matters, but also how it’s processed,” kimberly said.

the results and what they mean for canadians

the findings of the study, conducted in the united states with american participants, showed both sides of the same coin: those who ate more ultra-processed foods were likelier to experience cognitive decline and an increased risk for stroke, and those who consumed less managed to reduce that risk. this shows a direct correlation between these foods and brain and cerebrovascular health over time.

when it comes to how much of an increased risk was found, those who ate more of these harmful foods were 12 per cent more likely to experience accelerated cognitive decline and nine per cent more likely to have a stroke.

ultra-processed food isn’t ideal as a main dietary source for anyone, but the group that was most affected by the association were black participants. they experienced an increased risk of stroke by 15 per cent.

while there is already a well-known correlation between a bad diet and the development of diseases, the researchers also found that higher levels of stroke risk and cognitive decline were still present in the absence of comorbid conditions, potentially outlining a direct link between the brain and cerebrovascular health and processed food.

“when thinking about how to preserve and maintain brain function throughout our life, it’s important to identify factors that we can change – in other words, modifiable risk factors – that can alter that risk. understanding how ultra-processed foods impair brain function can inform a strategy to hopefully reduce that risk,” kimberly said.

using the results in preventative care

in canada, someone has a stroke every five minutes. while there are many other risk factors associated with stroke, many canadians don’t adhere to a healthy diet as well as they avoid smoking, alcohol consumption, and living sedentary lifestyles.

the increase in availability and consumption of ultra-processed foods has a significant impact on why: they are “convenient, they tend to have a longer shelf-life, and are designed to appeal to our sense of taste.” that’s often why many canadians reach for these foods over whole foods.

however, due to the severe and potentially disabling effects of these foods, knowing just how damaging they can be is the first step in making real change that can effectively reduce a person’s risk of early brain and cerebrovascular health decline.

“our study provides a reason to be mindful of the food we eat. not only should we aim to increase the amount of healthy foods, such as leafy greens, nuts, and fish-based protein, but we should also aim to reduce the amount of pre-packaged foods and sweet and salty snacks,” kimberly said.

being mindful of diet is an excellent way to practice preventative care, essentially stopping the development of diseases before they start. people who wish to reduce their risk don’t necessarily have to cut out all processed foods altogether. the research shows that even reducing intake minimally and incrementally over time can mitigate risk.

“the good news is that our study showed that even incrementally lower consumption of ultra-processed foods was associated with a better brain health profile,” kimberly said. “because diet patterns and brain health are a long-term relationship, it may make sense to aim for small changes that are sustainable over time, rather than dramatic changes that can be harder to maintain.”

the researcher’s next steps involve understanding the “biological mechanisms that link” the consumption of ultra-processed foods and brain health in the hopes of finding a new way to create personalized medicine plans that help individuals in their quest for optimal health and longevity.

angelica bottaro

angelica bottaro is the lead editor at healthing.ca, and has been content writing for over a decade, specializing in all things health. her goal as a health journalist is to bring awareness and information to people that they can use as an additional tool toward their own optimal health.

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study links ultra-processed foods to increased risk of stroke and cognitive decline

foods, including soft drinks, pizza, and candy, contain minimal or no nutritional value, but they can be even worse for your health than you think.

the breakdown of food processing and what it means

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