We are all familiar with the saying "you are what you eat," but can what you eat also interfere with your mood? The simple answer is yes. Those are the findings of nutritionists and researchers who have investigated whether what you eat can increase or decrease the risk for or symptoms of depression.

Researchers at El Camino Hospital, California say diet may have a significant effect on preventing and treating depression. They found that depression can either increase or decrease appetite and negative mood states have been shown to stimulate a preference for foods high in sugar, fat and/or salt.

The Brain-Gut Connection

Studies have shown that the bacteria that lives inside the gut and contribute to overall health is significantly different in healthy people than it is in depressed people.

Your body needs adequate supplies of lots of nutrients to help support its ability to manufacture neurotransmitters such as serotonin, also sometimes called the feel-good chemical. Neurotransmitters are chemicals that carry messages between neurons.

Serotonin is a neurotransmitter that helps regulate sleep, appetite, moods and inhibits pain and is primarily produced in the gastrointestinal tract, which is lined with millions of nerve cells, or neurons. This means that our digestive systems don’t just help us digest and absorb our food, but also play a significant role in how we feel.

How well your neurons function and produce serotonin, is influenced by your gut microbiome, which thrives on 'good' bacteria. That good bacteria, in turn, thrives on whole foods that are high in fibre and full of nutrients, including leafy greens, healthy fats and whole grains.

Is there a best diet for Depression?

When someone has depression, what they eat might improve or worsen symptoms. The idea is that eating a diet rich in high-quality foods that provide significant nutrition, including vitamins, minerals and antioxidants, may help nourish the brain and protect it from free radicals, or oxidative stress.

Generally, it is recommended we eat a diet that includes fruits and vegetables, whole grains, nuts and seeds, fish, low fat dairy and olive oil. This type of diet is described as the 'Mediterranean Diet.' Studies have shown that the risk of depression is 25% to 35% lower in those who eat this diet.

The compounds within these foods that have been studied appear to have a positive effect on depressive symptoms. These include:

• Omega 3 fatty acids, which are found in fatty fish like salmon, sardines and mackerel;
• B vitamins, found in meat, poultry, fish, eggs, dairy, legumes, nuts, seeds and dark leafy greens;
• Vitamin D, which is also known as the "sunshine vitamin" because your body makes vitamin D in the skin when it's exposed to ultraviolet light;
• Magnesium not only supports brain health but also supports healthy neurons and the manufacture of neurotransmitters the brain needs, so those cells can relay messages to each other;
• Folic acid which is a B vitamin that’s critical to brain health, especially in developing babies;
• Zinc, which is also an important nutrient that supports normal neural function; and
• Antioxidants, which are found in fruits and vegetables.

Foods can't do it all

A dietary regimen alone isn't sufficient to promote good health and you should adopt other "good living habits" that can help keep depression in check, such as a good sleep regime, reducing stress and exercising for at least 30 minutes per day.