Ultra-processed foods (UPF) and the negative impact they can have on our health have been a big topic lately. Now, a new study has linked consuming higher amounts of UPF (typically convenience foods, sugary cereals and soft drinks) with poorer mental health.
The research, published in The BMJ, suggested that consuming higher amounts of these types of foods, which are often high in fat, sugar, salt and chemical colourings, sweeteners and preservatives, was associated with a higher risk of anxiety and depression.
Academics in Australia analyzed 14 review articles over the past three years that associated UPF with poor health outcomes, using data from 9.9 million people.
Among the findings, there was “compelling evidence” that higher UPF intake was associated with a 48-53% increased chance of developing anxiety, and “highly suggestive” evidence of a 22% increased risk of developing depression.
So how exactly does junk food affect your mental health? Health experts share everything you need to know…
Why do we like ultra-processed and junk food?
“These ultra-processed foods lack nutritional value, but are full of instant satisfaction,” says Dr Ishani Rao, NHS GP and Physician at Plant-Based Health Professionals UK.
“These foods often trigger an immediate dose of dopamine, but this has the consequence of increasing future cravings and fueling addiction.”
However, the feeling of satisfaction may be short-lived. Rao says people can experience a “crash” after eating junk food, a neurochemical process similar to a “crash.”
“Studies have shown that this can cause irritability, brain fog and fatigue, and can trigger inflammatory pathways that affect the brain, in addition to triggering physical conditions,” he explains. “These foods often fill us up quickly, so it can be easy to ignore the fact that we need to eat fruits and vegetables and healthy carbohydrates, too.”
Children's mental health concerns
According to Dr Amelia Lake, professor of public health nutrition at Teesside University, a recent study found a wide range of risks linked to children's consumption of energy drinks, especially when it comes to their mental health. .
“Drinking energy drinks is linked to an increased risk of anxiety, stress, depression, suicidal thoughts and psychological distress among children. Its consumption also showed an increased risk of poor academic performance, sleep problems and unhealthy eating habits,” says Lake. “Energy drinks are marketed to children and young people as a way to improve energy and performance, but our findings suggested they are doing more harm than good.”
The gut is the 'second brain'
Rao says the relationship between the gut and the brain is “absolutely fascinating” and researchers are discovering more and more about the role our diet plays.
“We've all heard the terms 'gut instinct,' 'go with your gut,' and 'something to think about,' so it's no surprise that the digestive system has been described as our second brain,” Rao says. “One theory, in addition to neurotransmitter dysregulation and increased inflammation, is that there is a direct link between the vagus nerve and our brain.
“The vagus nerve is the nerve responsible for regulating the parasympathetic nervous system, known as the 'rest and digest' system. This pathway calms and relaxes us, the opposite of the sympathetic nervous system, known as the “fight or flight” system.
About 80% of our serotonin is produced in the intestine…
“This direct link between the vagus nerve and the brain is really exciting and we should not ignore the benefits of feeding our gut with healthy, colorful and nutritionally complete foods to improve our mental health,” he adds.
“It is also worth noting that around 80% of our serotonin, one of the key mediators of well-being in regulating our mental health, is produced in the gut. Look for healthy foods that give you long-term energy, make you feel light and calm, and don't exacerbate any physical or mental symptoms.”
The gut microbiome also influences
Rao adds: “The gut microbiome also plays a key role here. It is made up of trillions of microbes that are active in the intestine and help digest food and strengthen the immune system. We know that having a wide diversity of microbes in the gut can improve our overall physical and mental health. Those who eat a varied diet, consisting of many fruits, vegetables, whole grains and spices, have a more diverse gut microbiome.
“Conversely, highly processed foods can be harmful to good microbes and lead to inflammation of the gut. Therefore, consuming them in moderation is really important to protect the health of your digestive system.”
The shame factor
Experts often say that balance is key when it comes to a healthy diet, and indulging occasionally is nothing to worry about. But for some people, junk food can also be linked to binge eating.
“Binge eating brings with it feelings of shame, lack of control, and subsequent mental health problems in response to changes in the body,” says Dr. Catherine Carney, a psychiatrist and addiction expert at Delamere.
“Most of the time, this action is done in secret, which is burdensome and likely leads to additional feelings of stress and anxiety. In some cases, binge eating can lead to self-medication to mask feelings of sadness and, eventually, substance addiction.”
Losing the good things
Eating a diet predominantly composed of ultra-processed foods may also increase the risk of becoming deficient in essential nutrients, such as iron, calcium, magnesium, selenium, vitamin B12, and zinc.
“Low levels of these can cause neurological deficits and can even mimic symptoms of mental health problems such as burnout or depression,” Rao says. “We also know that unhealthy diets can increase the risk of physical conditions, such as high blood pressure, high cholesterol, obesity, inflammatory conditions such as joint problems, and more.
“People who suffer from chronic physical health conditions suffer double the rate of mental health problems compared to the general population. “So not only is there a direct link between poor food quality and mood, but there is also an indirect link as a result of poor physical health, which can cause mental health problems.”
