As Sustainable Living includes both living in harmony with Earth and our quality-of-life experience, how our brains are working is a vital consideration. Here’s some new research linking our daily food consumption to the health of our brain.
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The Link Between Highly Processed
Foods and Brain Health
Roughly 60 percent of the calories in the average American diet come from highly processed foods. We’ve known for decades that eating such packaged products — like some breakfast cereals, snack bars, frozen meals and virtually all packaged sweets, among many other things — is linked to unwelcome health outcomes, like an increased risk of diabetes, obesity and even cancer. But more recent studies point to another major downside to these often delicious, always convenient foods: They appear to have a significant impact on our minds, too.
Research from the past ten or so years has shown that the more ultraprocessed foods a person eats, the higher the chances that they feel depressed and anxious. A few studies have suggested a link between eating UPFs and increased risk of cognitive decline.
What’s so insidious about these foods, and how can you avoid the mental fallout? Scientists are still working on answers, but here’s what we know so far.
What qualifies as an ultraprocessed food?
In 2009, Brazilian researchers put food on a four-part scale, from unprocessed and minimally processed (like fruits, vegetables, rice and flour) to processed (oils, butter, sugar, dairy products, some canned foods, and smoked meats and fish) and ultraprocessed.
“Ultraprocessed foods include ingredi-
ents That are rarely used in homemade
recipes — such as high-fructose corn
syrup, hydrogenated oils, protein
isolates and chemical additives” like
colors, artificial flavors, sweeteners,
emulsifiers and preservatives,
… said Eurídice Martínez Steele, a researcher in food processing at University of Sao Paulo, Brazil. This classification system is now used widely by nutrition researchers.
UPFs make up a majority of the packaged foods you find in the frozen food aisles at grocery stores and on the menu at fast-food restaurants — 70 percent of the packaged foods sold in the United States are considered ultraprocessed. They’re increasingly edging out healthier foods in people’s diets and are widely consumed across socioeconomic groups.
“Ultraprocessed foods are carefully
formulated to be so palatable and sa-
tisfying that they’re almost addictive.
“The problem is that in order to make
the products taste better and better,
manufacturers make them
less and less like real food,”
… said Dr. Eric M. Hecht, an epidemiologist at the Schmidt College of Medicine at Florida Atlantic University.
What effect do ultraprocessed foods have on mental health?
Recent research has demonstrated a link between highly processed foods and low mood. In one 2022 study of over 10,000 adults in the United States, the more UPFs participants ate, the more likely they were to report mild depression or feelings of anxiety. Dr. Hecht, the study’s author, said …
“There was a significant increase in
mentally unhealthy days for those
eating 60 percent or more of their
calories from UPFs. This is not proof
of causation, but we can say that
there seems to be an association.”
New research has also found a connection between high UPF consumption and cognitive decline. A 2022 study that followed nearly 11,000 Brazilian adults over a decade found a correlation between eating ultraprocessed foods and worse cognitive function (the ability to learn, remember, reason and solve problems).
“While we have a natural decline in
these abilities with age, we saw that
this decline accelerated by 28 percent
in people who consume more than 20
percent of their calories from UPFs,”
… said Natalia Gomes Goncalves, a professor at the University of São Paulo Medical School and the lead author of the study.
It’s possible that eating a healthy diet may offset the detrimental effects of eating ultraprocessed foods. The Brazilian researchers found that following a healthy eating regimen, like the MIND diet — which is rich in whole grains, green leafy vegetables, legumes, nuts, berries, fish, chicken and olive oil — greatly reduced the dementia risk associated with consuming ultraprocessed foods. Those who followed the MIND diet but still ate UPFs “had no association between UPF consumption and cognitive decline,” Dr. Goncalves said, adding that researchers still don’t know what a safe quantity of UPFs is.
Why might ultraprocessed foods have this effect?
It’s unclear. Melissa Lane, a researcher at the Food & Mood Centre at Deakin University in Australia, said …
“Many high-quality, randomized
studies have shown the beneficial
effect of a nutrient-dense diet on
depression, but we still do not
fully understand the role of food
processing on mental health.”
However, there are some clues. Much of the research has focused on how poor gut health might affect the brain. Diets that are high in ultraprocessed foods are typically low in fiber, which is mostly found in plant-based foods like whole grains, fruits, vegetables, nuts and seeds.
Fiber helps feed the good bacteria in the gut. Fiber is also necessary for the production of short-chain fatty acids, the substances produced when it breaks down in the digestive system, and which play an important role in brain function, said Wolfgang Marx, the president of the International Society for Nutritional Psychiatry Research and a senior research fellow at Deakin University.
“We know that people with depression
and other mental disorders have a less
diverse composition of gut bacteria
and fewer short-chain fatty acids.”
Chemical additives in UPFs might also have an impact on gut flora. Dr. Marx said …
“Emerging evidence — mostly from animal
studies, but also some human data — sug-
gests that isolated nutrients (like fructose),
additives such as artificial sweeteners (like
aspartame and saccharin) or emulsifiers (like
carboxymethylcellulose and polysorbate-80)
can negatively influence the gut microbiome.”
Poor gut microbiota diversity — as well as a diet high in sugar — may contribute to chronic inflammation, which has been linked to a host of mental and physical issues, Dr. Lane said.
“Interactions between increased
inflammation and the brain
are thought to drive the de-
velopment of depression.”
It’s also worth considering the possibility that the link between highly processed foods and mental health works in both directions. Dr. Frank Hu, a professor of nutrition and epidemiology at the Harvard T.H. Chan School of Public Health, said …
“Diet does influence mood, but
the reverse is also true. When
you Get stressed, anxious or
depressed, you tend to eat more
unhealthy foods, in particular
ultraprocessed foods that are high
in sugar, fat and chemical additives.”
How to recognize ultraprocessed foods
The best way to identify ultraprocessed foods is to read product labels.
“A long list of ingredients, and especially
one that includes ingredients you
would never use in home cooking,”
… are clues that the food is ultraprocessed, said Whitney Linsenmeyer, an assistant professor of nutrition at Saint Louis University in Missouri and a spokeswoman for the Academy of Nutrition and Dietetics. Chemical names, unpronounceable words, and anything you would be unlikely to find in a kitchen cabinet are often signs that a food is in the ultraprocessed category.
You can still use convenience foods to make cooking easier without resorting to ultraprocessed foods. Products such as canned beans, frozen vegetables, precooked brown rice or canned fish are all shortcut ingredients that fit well within the scope of a healthy diet, provided there aren’t any industrial items on the ingredient list. Dr. Linsenmeyer said …
“If the added ingredients are ones
you would use yourself, like herbs,
spices, salt or cooking oils, that’s an
indication that the food, while pro-
cessed, is not inherently bad for you.”
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As my expertise is neither in chemistry nor nutrition, I turned to D for comments …
“Foods in their natural state – as in grown without artificial chemicals – are the best foods to be eaten by humans. They have the most micronutrients to help keep your bodies healthy. The closer you can eat foods that are in this natural state, the more you’ll increase your ability to fight off disease.
“This article speaks specifically about the brain. It also includes the connection between gut health and brain health, proving that all systems within a body are connected. Eating is your means for fuel. This article speaks of the MIND diet; we would also recommend the Mediterranean diet. As food is fuel, use the best possible fuel for your body … so your ‘human engine’ will hum!”