Most people have food in their fridges and cupboards that they know aren’t the healthiest choice.
A box of chocolate chip cookies you grab for a bedtime snack. Instant noodles for when you can’t be bothered to make dinner. Or that bag of ketchup chips you grabbed on a late night stroll home from the bar.
But it’s not just guilty pleasures. Nearly half of the calories Canadians consume — 45.7 per cent on average, according to Statistics Canada — comes in the form of ultra-processed foods (UPFs) and includes everything from breakfast cereals to frozen meals.
Over the years, research has shown that UPFs can negatively impact everything from our weight to our cardiovascular health, and could even be linked to some types of cancer.
But a new study co-authored by two professors at Hamilton’s McMaster University, published Thursday by JAMA Network Open, signals that our brains could also suffer as a result of consuming too many foods produced to be cheap and ready-to-eat.
The authors say that the people with the highest intake of UPFs in their diets may face an increased likelihood of experiencing changes to the brain that could serve as precursors for stroke, dementia and cognitive decline.
People wouldn’t necessarily be aware of these potential harms, says study co-author Russell de Souza, an associate professor at McMaster’s Mary Heersink School of Global Health and Social Medicine.
But he says the findings could encourage people to shift their eating habits now, before experiencing serious consequences later in life.
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Feeding the furnace
De Souza and co-author Dr. Sonia Anand, a vascular medicine specialist, examined the diets and brain MRI scans of more than 8,700 Canadian adults, with a median age of about 58, and broke them down into four groups, from those with the lowest intake of UPFs to those with the highest.
The latter cohort was made up of people who consumed nearly 45 per cent of their calories from UPFs, or the equivalent of 16 servings a day, which they self-reported in a survey listing 150 to 170 food items consumed in the past year.
By comparison, the group with the lowest consumption got 15 per cent of their daily calories from UPFs, equal to three servings.
Anand, a professor of medicine and epidemiology at McMaster, says they analyzed the scans of higher-risk participants and found that their UPF-heavy diets were associated with increased body fat and visceral fat — the kind stored deeper in the body and around organs.
“Fat tissue in the wrong places can be almost like a furnace spewing out a whole bunch of inflammatory proteins that then affect our brains,” she said.
Ultra-processed foods like instant noodles are mostly or entirely made from substances derived from plant and animal sources and combined with additives, preservatives, stabilizers, dyes and artificial flavours, rather than minimally-processed ingredients. (Dan Kitwood/Getty Images)
Anand says the MRIs of the higher-risk group showed changes to the brain similar to silent strokes, a type of stroke that doesn’t present any noticeable symptoms but damages the tissue.
These injuries add up over time and make it more likely that people could develop neurological problems, such as vascular dementia, says Dr. Michael Hill, a neurologist and professor at the University of Calgary who is not affiliated with the study.
“The more injuries you accumulate, the more likely you are to have neurological problems later in life, most commonly vascular dementia,” he said.
While the damage a UPF-heavy diet may do can’t be reversed, Hill says dietary changes can reduce further progression.
“Feed your brain,” he said. “It’s not just about your gut, right? It’s about your whole body.”
He says the findings are consistent with a growing body of evidence about the health impacts of UPFs.
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‘Eat foods that rot, not rotten foods’
De Souza notes that not all processed foods are ultra-processed and, in fact, many processed products in grocery stores have a lot of nutritional value.
“Some degree of processing is absolutely necessary in the food supply,” he said. “It helps keep food safe and shelf stable.”
But a can of beans, a bag of frozen vegetables or a container of yogurt are all different from a fast-food meal or a box of sugar-coated cereal.
Foods are classified using what’s known as the NOVA system, where foods are determined to be ultra-processed if they are mostly or entirely made from substances derived from plant and animal sources and combined with additives like salt, sugar, fats and oils, as well as preservatives, stabilizers, dyes and artificial flavours.
They also tend to be lower in fibre, vitamins and minerals that benefit overall health, de Souza says.
Hill says that while “one Snickers bar isn’t going to hurt you,” ultimately, ultra-processed food isn’t going to benefit your health — especially if you’re eating it regularly.
And even when people want a sugary or salty treat, he says it’s going to be better if they make it at home from whole or minimally-processed foods.
“Eat foods that will rot, but not rotten food,” he said.
Anand and de Souza note that their study doesn’t provide the full picture of the potential toll UPFs can have on brain health and say more long-term research is needed to determine if dietary changes later in life can make a difference.
The next phase of their research will see 2,000 people who took part in the first round of scans receive a second round to determine if reducing the amount of UPFs in their diets results in changes or improvements to brain health.
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Research shows that pre-prepared, packaged, highly processed food (UPF) is linked to weight gain and obesity, some cancers, dementia and more. It’s also highly delicious and convenient. Dr. Chris van Tulleken offers 5 tips for reducing how much UPF you eat. For more information on ultra-processed foods, how they affect our health and what we can do about it, watch Foodspiracy on CBC Gem and The Nature of Things YouTube channel.
Improving health literacy
Anand notes that not everyone has the time or money to prepare high-quality food, which she says is a systemic issue that would require government intervention to reduce the amount of UPFs available and make healthy food more affordable.
It’s also a matter of improving health literacy, which she says would increase awareness about the repercussions of consuming too many UPFs.
Canada, she says, could follow the lead of other countries that have successfully minimized the consumption of UPFs. One such country, Chile, implemented mandatory front-of-package labels for UPFs that are high in sugar in an effort to curb childhood obesity.
She says there are things individuals and governments can do “and we need both to happen to make Canadians healthier.”
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