The food-mood connection

Scientists often refer to the gut as the second brain and, with more than 95% of serotonin (the ‘happy hormone’) manufactured by the gut, it’s no surprise that our ‘gut feelings’ are often correct.

Woman holding spoon with cake on

The impact our food choices have on our mood can be profound. After all, neurotransmitters sending messages to the brain travel along a direct chemical pathway, from the gut to the central nervous system. Some studies even suggest that people who don’t eat enough oily fish – rich in omega 3 – are more likely to have depression.

Why is the gut significant?

The gut-brain connection is heavily influenced by the gut microbiome (GM) – trillions of bacteria that create a unique ecosystem in our guts. Specific species of healthy bacteria produce serotonin, which is closely linked to our mood, and it’s been found that low levels of this happy hormone may be linked to mental health conditions such as depression and anxiety.

While 2020 has been a tough year for many of us, there has been some good news to come from it too, as it could be the year to revolutionise the importance of gut health for overall well-being, with many studies suggesting that the health of our gut microbiome is key to positive mental health. So, if your gut bacteria is out of balance, you may struggle to regulate your mood.

Gut health is a critical aspect of our mental well-being, with 95% of our serotonin being produced in the gut by our gut bacteria

“It’s important to maintain a healthy gut flora through eating a healthy balanced diet, rich in prebiotic and probiotic foods,” says Dr Kirstie Lawton, registered nutritional therapist and director of You Nutrition Clinic, who specialises in brain health.

Your gut microbiome is fragile and, with modern-day stressors and busy lifestyles encroaching on our health, sometimes the gut microbiome can fall out of equilibrium. But you can proactively nurture your gut health to regain that balance through introducing fermented foods such as kefir and sauerkraut into your diet.

Jar of yoghurt with raspberries
Kefir is a probiotic food, known to help balance gut bacteria

What foods support positive mental health?

In an ideal world, we could just eat bowls of food containing serotonin but, unfortunately, this happy hormone is not directly found in food. Instead you can prompt this hormone production through exercise or exposure to bright lights. But it’s also believed that foods containing the amino acid tryptophan could help to release serotonin – so you could try foods such as turkey, salmon, spinach, seeds and nuts.

Another good option is to pay attention to foods that are naturally high in B vitamins, such as liver, eggs and leafy greens, as Kirsty notes that those who struggle with mild depression, anxiety or high levels of pain can find this beneficial. Vitamin B6 is needed to make the key neurotransmitters in positive mental health, and Kirstie stresses the important roles they perform.

“Serotonin and GABA help to keep our mood calm and stable, and dopamine, which is linked to pleasure, is essential for mental well-being. Each of these requires a range of amino acids and micronutrients for their development.”

Kirstie also advocates adopting a traditional Mediterranean diet. “Following a nutrient-rich, Mediterranean-style diet, high in olives, omega-3 containing foods such fatty fish, nuts, seeds and avocado, zinc-rich meat and seafood, and a wide range of antioxidant and nutrient-rich fruits and vegetables (including cruciferous, dark green and brightly coloured choices) can have a positive effect on mood by improving gut health. It provides us with the nutrients and protein building blocks (e.g. tryptophan and tyrosine) that we require for neurotransmitter production, reducing inflammation and oxidation, and supporting overall brain function.”

Research also suggests that both magnesium and vitamin D can kick start the parasympathetic nervous system – the rest and digest state that enables optimum cognitive function. Kirstie adds L theanine (found in green tea) to the list, as it has shown to help with anxiety. Adaptogenic herbs are also worth investigating, as tulsi, chamomile and turmeric help the body react positively to sudden stressors, and support relaxation. 

Unhelpful foods for low mood

If you struggle with low mood, it can be helpful to avoid refined carbohydrates, poor quality meats and, sadly, sugar. It’s common to turn to sugary snacks as a form of comfort but, although it might hit the spot at the time, the aftermath of the sugar hit can send your mood plummeting even further.

Glass cup of chamomile tea
Chamomile tea has soothing qualities

A nutritional therapist specialising in mood and energy, Clare Backhouse, explains that sugar can upset the equilibrium of your mood in three significant ways. “Sugary foods disrupt our blood glucose levels. We might experience an initial, brief boost to our mood, but it will be followed by an unpleasant slump. Firstly, you eat some sugar and get a rush of energy as your blood glucose spikes. Then, the hormone insulin steps in to get the glucose out of your blood and into other cells in your body. 

The more sugary your food, the more insulin is produced, so that you actually become a bit too low in blood glucose after all – and, therefore, your mood dips. You feel so low that you crave a quick fix, which generally means more sugar.

Clare notes that sugar prompts the production of inflammatory cytokines, which have been shown to trigger symptoms of depression, and can have a significant impact on the delicate ecosystem of your gut bacteria. She says, “We also know that sugary foods may predispose the gut to dysbiosis, or an imbalance of beneficial bacteria.”

But it’s not just sugar that’s the bad guy here. Kirstie suggests avoiding inflammatory foods too. “Gluten, alcohol, processed and packaged foods, poor quality vegetable and seed oils, and chemicals such as pesticides should also be avoided, as they can negatively impact our brain chemistry, and therefore our mood.”

While there is a growing theory that food can be used as medicine (studies certainly show positive results), the jury’s still out on a definitive answer, and one size doesn’t fit all. It’s always best to consult your nutrition professional for guidance and further support to make the most of what’s on your plate.

This piece was originally published in the 2021 February edition of Happiful magazine, to purchase your copy, visit

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Written by Katie Hoare
Katie is a writer for Nutritionist Resource.
Written by Katie Hoare
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