Ultra-Processed Food and Depression

Where to find the key brain nutrients that can reverse the effects of junk food on mental health

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We are collectively anxious and depressed about so much these days. Climate change, endless war, saying the wrong thing and offending everyone, and the fact that artificial intelligence is poised and programmed to kill us all off.

Never mind all that. Never mind that the robots are coming up over the hill. Hiding in plain sight is, I would argue, the greatest existential threat to humanity: ultra-processed food (UPF). It can make us ill, it can make us depressed, and it may well kill us off before the robots get to us.

Even so, nobody seems too bothered. UK prime minister Rishi Sunak has just shelved plans to ban two-for-one junk food sales, supposedly because of concerns about the cost-of-living crisis. Bearing in mind that junk food is designed by food scientists to create an insatiable desire to keep eating even when full (for details of this, see How to Control Your Food Cravings), UPF can be an expensive way of managing said crisis.

Not to mention depressing. Big in the news recently was the finding of Australian research, published in the Journal of Affective Disorders, that risk of depression “jumps markedly” among those whose diet consists of over 30% UPF. This study found that people who ate the most UPF had approximately 23% greater risk of suffering from depression than those who ate the least.

“The research suggests an association between high consumption of ultra-processed food and a higher risk of depression, even after accounting for factors like smoking, lower education, income, and physical activity.”

Observational studies like this one do not provide us with evidence of cause-and-effect, but they are worthy of further investigation, especially when the same results are regularly reproduced elsewhere.

And they are. A quick trip around the world shows us just how similar we all are in response to bad food. In 2020, a Spanish study of almost 15,000 students found that those with the highest consumption of UPF were more likely to experience depression than those who ate the least. A French study in 2019 found that.. “Overall, UPF consumption was positively associated with the risk of incident depressive symptoms.” The more the UPF, the greater the risk.

Across the Atlantic, we find that a US study of almost 14,000 adults revealed that those who ate more than 73% of their calorie intake in the form of UPF had a 35% greater risk of depression than those with a low intake.

Let’s head south to Brazil now. In May this year (2023), research that set out to evaluate the link between UPF and depression found that in over 2,500 adults, those who were the biggest consumers of junk food were also those most likely to develop depression. As the authors note, this is not good for Brazil, which has the highest prevalence of depression in Latin America.

The whole world is consuming ever more UPF, and we’ve never been so depressed.

BY 2030, it is expected that mental ill-health, mainly depression, will be the leading cause of mortality and illness across the globe. Suicide is currently the fourth main cause of death among 15-29 year olds, according to the World Health Organization.

Young people today eat more ultra-processed food and less real food than ever before. In 2018, people aged 2-19 consumed around 67% of their calories from UPV. In 2022, a UK study revealed that more than 75% of the calories in school lunches came from UPFs, mainly in the form of bread, snacks, puddings and soft drinks.

Junk defined

The definition of UPF is based on the NOVA classification system. According to this system, a processed food is something recognisable, something you could make in your own kitchen. Bread and cheese, for example, or fermented vegetables and drinks. Ultra-processed foods, on the other hand, are on a whole different level, because they are not really foods at all, they just look and taste (arguably) like the real thing.

Made in factories to industrial formulations that only a food scientist could understand, these products are intensely processed, using emulsifiers, dyes, stablizers, defoaming agents (don’t ask me), flavour enhancers, and artificial sweeteners. These are the products that meet the requirement for “super palatability”.

How do they link to depression? It’s probably two-fold: the chemical concoctions they contain, and the absence of key brain nutrients that protect against depression and poor cognitive function.

So, for the sake of our collective sanity, below are some of the most important nutrients that keep your brain functioning at optimal level, and your mood on an even keel.