The hidden link between what we eat and our mental health

We all know that what we eat affects our body, but what if it’s also affecting our mind? We spoke with Dr Mohammad Abu Al Izz, a psychiatrist with a deep passion for nutritional psychiatry, adolescent psychiatry, and taking a holistic approach to patient care. His work explores the powerful connection between the food we consume and our mental health – an area that’s becoming increasingly crucial in today’s fast-paced, processed-food world.

Dr Al Izz explained to us how certain foods – especially ultra-processed foods – are not just linked to physical ailments like diabetes or heart disease, but can also play a significant role in conditions like depression, anxiety, and brain fog. So, what’s going on behind the scenes in our body when we choose processed snacks over whole, nutritious foods? Let’s dive in.

The journey from nature to your plate: what are ultra-processed foods?

Imagine you’re walking through a field. The corn on the cob is fresh, unadulterated, and full of natural goodness. Now, imagine that same corn, but after it’s been stripped of its original form, deep-fried, and covered with artificial flavourings and preservatives. This is the difference between minimally processed foods and ultra-processed foods.

Dr Al Izz shares a food classification system called NOVA, which helps us understand this difference. In the world of food, NOVA breaks down foods into four categories:

1. Unprocessed or minimally processed foods: Think fruits, vegetables, and meats in their natural form, like a washed corn on the cob.
2. Processed culinary ingredients: These include oils, salts, and sugars – things we add to foods to enhance flavour.
3. Processed foods: A mix of the first two categories, like canned vegetables or salted nuts.
4. Ultra-processed foods (UPFs): These are foods that have been so altered by industrial processes that they barely resemble their original form. These include packaged snacks, ready-to-eat meals, and fizzy drinks – foods engineered for convenience, taste, and shelf life, but lacking in the nutrients that nourish both the body and mind.

Ultra-processed foods are packed with additives, preservatives, and refined ingredients, often with a long list of things you can’t pronounce. They’re engineered to taste delicious, but at what cost?

How ultra-processed foods affect our mental health

Here’s the thing: mental health isn’t just in your head – it’s deeply connected to your body. Dr Al Izz emphasizes that when he assesses a patient’s mental health, he looks at the entire person, considering both the biological and physiological factors. Physical health issues like obesity, diabetes, and heart disease often come hand-in-hand with mental health challenges like depression and anxiety. But how does food fit into this picture?

Dr Al Izz explains that ultra-processed foods can set off a chain of events in the body that ultimately impacts the brain. For example:

• Inflammation: The additives and preservatives in UPFs can cause an inflammatory response in the body, which has been linked to mental health conditions like depression.
• Blood sugar fluctuations: These foods cause rapid spikes and crashes in blood sugar, leading to cravings, overeating, and insulin resistance – all of which are linked to mood swings and weight gain.
• Gut health: The gut is often called the “second brain” because it plays a key role in mental well-being. Ultra-processed foods disrupt the gut microbiome, which is crucial for mood regulation and overall mental health.
• Nutrient deficiency: UPFs are often low in essential vitamins and minerals, like magnesium and B vitamins, which are vital for brain function. Without these nutrients, the brain can’t function optimally, and this can contribute to mental health problems.

The bottom line? The foods we eat directly impact how our body functions—and that includes the brain. For example, the chemicals in ultra-processed foods can increase inflammation and disrupt our gut microbiota, which can then affect serotonin production (the chemical that helps regulate mood). When serotonin levels drop, we often feel the effects in the form of depression, anxiety, and even brain fog.

The science behind ultra-processed foods and depression

It might sound alarming, but the evidence is clear. A recent meta-analysis found that for every 10% increase in ultra-processed foods consumed, there was an 11% increase in the risk of depression. And it’s not just a theory—studies have shown that when people reduce their intake of ultra-processed foods and eat more whole, minimally processed foods, their depression levels significantly decrease.

The biological mechanisms behind this are fascinating. For one, ultra-processed foods elevate inflammation markers in the body, which have been strongly linked to mood disorders like depression. They also affect serotonin production in the gut – where about 90% of serotonin is made. Without enough of the right nutrients (like tryptophan), serotonin production is impaired, and that leads to a greater risk of depression.

But it’s not just about the chemical imbalance – ultra-processed foods also affect the brain’s reward system. They are designed to stimulate the release of dopamine, the “feel-good” chemical in the brain. Over time, this can desensitize the brain, reducing its ability to experience pleasure from natural rewards like exercise, relationships, or even food that’s nourishing.

A personal story: how diet can make a difference

Dr Al Izz recalls a patient from his early career who had a profound impact on him. A 33-year-old woman came to his clinic with symptoms of severe depression. After assessing her mental and physical health, Dr Al Izz prescribed antidepressants and began working with her on a holistic approach. But it wasn’t just the medication that made a difference. The woman told Dr Al Izz that in addition to taking the medication, she had also started taking B12 and folic acid supplements. Within weeks, she felt better – her depression lifted, and she returned to her vibrant self.

This experience sparked Dr Al Izz’s interest in nutritional psychiatry. Over the years, he’s seen how dietary improvements can transform mental health. Many of his patients – especially those struggling with depression—see massive improvements when they adopt healthier eating habits. Even children with ADHD-like symptoms have shown significant behavioral improvements when they reduce their intake of ultra-processed foods and replace them with whole, nutrient-dense options.

How to improve your mental health through diet

f you’re ready to take charge of your mental health through your diet, Dr. Al Izz has some practical advice:

• Aim for 80% whole, minimally processed foods: Incorporate a variety of fruits, vegetables, whole grains, lean proteins, and healthy fats into your daily meals.
• Batch cook: Preparing meals in advance over the weekend can save time during the week and ensure you always have healthy options on hand.
• Snack smarter: Swap out chips and candy for nuts, seeds, and fruits like apples or berries.
• Stay hydrated: Drink plenty of water and avoid sugary drinks like sodas and sweetened juices.
• Read labels: If the list of ingredients seems like a science experiment, put it back. Fewer ingredients are better.

Who needs to pay extra attention?

Dr. Al Izz notes that certain groups are particularly vulnerable to the effects of poor diets:

• Children and adolescents: Their brains are still developing, making them more sensitive to the effects of nutrient deficiencies.
• Pregnant and postpartum women: Hormonal fluctuations during and after pregnancy can make women more prone to diet-related mood swings.
• People with gut disorders: Those with digestive issues may already struggle with serotonin production or absorption, increasing the risk of mental health problems.

The takeaway

What you eat isn’t just fuel for your body – it’s fuel for your mind, too. By making simple changes to your diet, like eating more whole, minimally processed foods and cutting back on ultra-processed options, you can make a significant impact on your mental health. As Dr Al Izz puts it, nourishing your body with the right foods is a powerful way to nourish your mind.

Your mental well-being is worth the effort, and small, consistent changes can make a world of difference. Let food be your medicine, and take the first step toward a healthier mind today.

About Dr Mohammad Abu Al Izz

Dr Mohammad Abu Al Izz is a psychiatrist with over eight years of experience. He completed his residency at the National Center for Mental Health (NCMH) in Jordan and received the Jordanian Board in Psychiatry. After working with the Ministry of Health, he joined Dr Nasri Jacir’s Clinic in Amman, where he focused on evidence-based practices and psychodynamic psychotherapy.

Dr Abu Al Izz specialises in cognitive behavioural therapy (CBT), supportive psychotherapy, and psychoeducation. His interests include nutritional psychiatry, adolescent psychiatry, and a holistic approach to mental health care. He is also involved in training and advocacy to improve mental health services.