Food and mood

Just as sleep and exercise are key to feeling good, food also affects your mood. Like the rest of your body, your brain needs fuel to function. And just like filling up your car, putting in the right kind of fuel is key to how well your brain performs – including how well you are mentally and emotionally. 

A recent study showed that the more people improved their food choices, the more their depression improved. Food is linked to the hippocampus, a key area of your brain involved in learning, memory and mental health. People with healthy diets have more hippocampal volume than those with unhealthy diets.

As well as your brain, your gut is the other part of your body that plays a key role in your mood. Everything you eat passes through your intestine (gut). Your gut is home to billions of bacteria and other mircroorganisms (bugs), known as your gut microbiome. These bugs are involved in many functions critical to your health and wellbeing. Therefore, eating foods that support your gut microbiome will support your mental health. Read more about gut health and mental health in the section below. 

Although we don’t yet know exactly which bugs are needed for the optimal mix of gut bacteria, we do know that greater diversity of bugs is associated with better health outcomes(external link). And what promotes a greater variety of gut bugs? The simple answer is fibre-rich whole-foods(external link).

Video: How to manage your mood with food | 8 tips

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(Mind, the mental health charity, UK, 2018)

Food choices that meet the Eating and activity guidelines for NZ Adults(external link), as well as Mediterranean eating patterns, can reduce the risk of getting depression. What does that look like in terms of food? To quote food author Michael Pollan: “eat food, not too much, mostly plants”.

Eat food, mostly plants

“Eat food” means to eat real food – vegetables, fruits, nuts and seeds, whole grains, fish and meat – and avoid highly processed foods. People who eat a diet high in whole foods are up to 35% less likely to develop depression than people who eat less of these foods. A University of Otago study found that young adults who ate more fruit and vegetables for just 2 weeks increased their feelings of vitality and wellbeing.

Rather than only eating cooked fruit and vegetables, each day have some of them raw.

An eating pattern that includes a wide range of foods includes the following:

• vegetables (eg, carrots, dark leafy greens, cucumber)
• fruits (eg, bananas, apples, citrus, berries)
• legumes (eg, lentils, chickpeas, beans)
• wholegrains (eg, rice, oats, breads)
• nuts and seeds
• oily fish and lean meats
• good oils (eg, most plant-based oils).

If you eat a wide range of foods the nutrients should take care of themselves, including the main nutrients associated with depression:

• Omega 3 fatty acids – because of its anti-inflammatory properties and effects on transmitting the hormones dopamine and serotonin, omega 3 has a role in brain development and functioning. If you don’t have enough omega-3, it can contribute to mental health problems.¹² These are found in oily fish (salmon, tuna, sardines and anchovies, plant-based oils, walnuts, flax and chia seeds and dark green leafy veggies, as well as some fish oil supplements.
• B group vitamins – these help regulate neurotransmitters and immune function. They can be found in green leafy veggies, legumes and whole grains. B12 is in fish, beef, lamb, poultry, eggs and milk and some fortified breakfast cereals.
• Vitamin D – for optimal brain function, mood and critical thinking – and present in fatty fish, eggs, dairy foods and sunlight! 

Not too much

• Cut down on sugar, salt and highly processed foods (eg, takeaway meals, packaged snack foods and processed or smoked meats).
• Limit caffeine (which may cause or exacerbate anxiety).
• If you drink alcohol, reduce your long-term health risks by drinking no more than:
  • 2 standard drinks a day for women and no more than 10 standard drinks a week
  • 3 standard drinks a day for men and no more than 15 standard drinks a week.
  • This should include at least 2 alcohol-free days every week.
  • Read more about alcohol and low-risk drinking.

Your gut microbiome also activates a neural pathway that travels directly between your gut and your brain, called the gut-brain axis. Because of this pathway, the food you digest in your gut affects the messages sent to your brain. This means that what is happening in your digestive system affects your emotional and mental wellbeing.

How does gut health affect mental health?

Everything you eat passes through your intestine (gut). Your gut is home to billions of bacteria and other micro-organisms (bugs), known as your gut microbiome. These bugs are involved in many functions critical to your health and wellbeing. A healthy gut microbiome:

• provides a strong barrier against toxins and “bad” bacteria
• aids absorbtion of nutrients from your food (digestion)
• supports the functioning of neurons (nerve cells) that line your gut wall
• helps reduce inflammation.

Your gut microbiome also activates a neural pathway that travels directly between your gut and your brain, called the gut–brain axis. Because of this pathway, the food you digest in your gut affects the messages sent to your brain. This means that what is happening in your digestive system affects your emotional and mental wellbeing. Therefore, eating foods that support your gut microbiome will support your mental health.

What foods support a healthy gut microbiome?

Although it's not yet known exactly which bugs are needed for the ideal mix of gut bacteria, it is known that greater diversity of bugs is associated with better health outcomes. And what promotes a greater variety of gut bugs? The simple answer is fibre-rich whole-foods.  

• Fibre-rich whole foods help support a healthy gut. These include plant foods such as vegetables, fruit, whole-grains, legumes, nuts and seeds.
• You can also promote a healthy gut by eating bacteria itself in the form of fermented food such as kimchi, kefir and sauerkraut.
• The benefits of eating fibre-rich food or fermented food only last for as long as you are eating them (or shortly thereafter).
• This means that if you want to get their health-benefiting rewards, you need eat them every day and ideally with every meal.
• Simple ways to increase dietary fibre intake include swapping white bread or white rice for wholegrain bread or brown rice, or snacking on fruit or adding a cup of mixed vegetables with lunch or dinner.

A day-to-day diet lacking in fibre starves the gut microbiome and can lead to them eating the mucus that lines and protects your gut wall. Evidence suggests that if your gut microbiome consume too much of your gut wall, damaging inflammatory processes may kick in.