The foods that you eat don’t only impact your physical health. Just like the body, your brain runs on fuel from your diet – and there’s a strong connection between the quality of that diet and the way your brain’s function, particularly when it comes to mood.

Mental illness is incredibly common in the US, with one out of five adults living with a mental, behavioural, or emotional illness such as depression, anxiety, bipolar disorder, or attention deficit disorder (ADD).

And, while there are a variety of causal factors behind these disorders – including genetics and chemical imbalances – researchers have established that there’s also a link between the high rate of mental health conditions in the US and a Western diet high in processed and refined foods.

You are what you eat

In a systematic review of 12 epidemiological studies, researchers found evidence that diet plays a vital role in regulating mental health.

Looking at diet quality among children and adolescents, researchers observed ‘consistent trends’ between high-quality diets and better mental health outcomes, as well as evidence for the reverse.

Some of the key findings were that children with poor dietary habits suffered from higher rates of depression and anxiety, as well as higher rates of behavioural conditions like ADD and hyperactivity.

These results echo similar studies done in adults which found a link between Western diets and depression and anxiety in adult women, and others which suggest the inverse – that a Mediterranean diet high in lean protein, whole grains, and healthy fats decreases the risk of depression, as well as other neurological conditions such as stroke and Parkinson’s disease.

So, why does some foods lead to improved mental health outcomes and others don’t?

Food as fuel

When scientists talk of food fuelling the brain, it’s not about just the basic nutrient required to keep the brain operating. It’s about providing the brain with the right type of fuel.

The fuel that comes from processed, sugary, and fried foods can lead to cognitive decline, primarily through increased inflammation and disruptions in cellular pathways.

These types of neural impairments can lead to imbalances, including mood disorders.

From the opposite perspective, diets high in premium fuel nourish and protect the essential features of the brain, in turn supporting better cognitive function.

There is also a reduction in the risk factors that can lead to depression, anxiety, and other mental illnesses.

Instead of looking at diet as the end-all-be-all when examining triggers for mental disorders, it helps to examine the role that food plays in relation to other risks.

While diet alone might not be the sole cause of a mental disorder, maintaining a healthy diet is a critical part of protecting one’s ability to regulate mood.

Likewise, an unhealthy diet sets the stage for the opposite effect and can be a key contributor to poor mental health.

Moods and foods

A well-balanced, mental health-driven diet is one that focuses on both variety and nutrition, with a limited intake of sugar, salt, and saturated fat.

To do this, look at the major food groups and the role that each plays in providing the right type of brain fuel.

• Vegetables and legumes: try to eat the “rainbow” whenever possible, meaning colourful veggies and lots of dark, leafy greens.

Vegetables and legumes (black beans, garbanzo beans, and soybean products) are rich in fibre, folate, potassium, and vitamin A, and high daily intakes are related to reduced levels of psychological distress and depressive symptoms.

• Fruits: Fruits high in antioxidants and vitamins A, C, and E help regulate neural functions and help combat stress-induced psychiatric disorders like depression and anxiety.
• Grains: Whole grains, rice, oats, and barley provide the body with iron and vitamin B, healthy grains that help control blood sugar levels and gut function, both of which can support equilibrium in the body and brain.
• Protein: These include meats, seafood, poultry, eggs, and plant-based proteins like nuts and seeds. Quality counts since all protein sources are not equal.

The types of protein that have the most profoundly positive effect on mental health are lean proteins like fish, chicken, whole-fat yoghurt, and high-protein nuts and seeds, which help produce natural chemicals in the brain that improve mood.

The benefits of nuts, in particular, are often cited since they offer a quick, healthy, and convenient protein source combined with brain-boosting omega-3s.

• Dairy: Notably whole-fat dairy products like milk and cheese. Dairy has been linked to lower stress levels and is a natural source of feel-good vitamin D.

Eating a healthy diet means finding a balance between these major food groups, getting in more of the good stuff and less of the stuff outside of these groups, such as sweets, fried foods, and empty calorie beverages like soda and fruit juice.

Not only is this type of diet important for maintaining prime physical health, but it’s also instrumental in achieving better mental health.

Again, food alone isn’t necessarily the cause (or the cure) for mental health conditions.

But diet is linked to mental health in a myriad of ways, making it all the more essential to make diet part of an action plan for dealing with or preventing a mental disorder.

Life happens, and it’s often unpredictable, but eating right can go a long way towards mitigating the risks of mental distress and putting both body and brain in the right space to take on whatever happens.

Dennis Relojo-Howell is the founder of Psychreg and host of The DRH Show. You can connect with him on Twitter @drelojo_howell