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Mental Health Awareness Week: Food to help brain function

We consult our nutritional lifestyle coach, Marta Decarli, to explore what foods and diet can do to help our mind, mood, and positive thought processes.

This week is Mental Health Awareness Week in the UK. And whilst mindfulness practices and exercise are at the forefront of advice for maintaining a positive outlook, we are looking at how food impacts mental health.

After all, what we put in our bodies influences mood, cognition, and even the production of neurotransmitters that regulate emotions, so it’s pretty important! Spotlighting a balanced diet – rich in nutrients and healthy fats – is a vital factor in how we improve mental wellbeing and support brain function.

There is a current TikTok diet trend, taken from ‘75 hard’ (75 days of fitness and health rules), which is now gaining popularity in its own right. This is the ‘No Sugar Diet’, which entails a long list of foods you cannot eat – including any processed sugar from bread to cereal to electrolyte drinks. Now, whilst this doesn’t sound too bad, sticking to this for two weeks can have a significantly negative impact on your brain.

Dietary deficiencies or excesses can contribute to mood disorders and cognitive decline, as found in this study by the National Institute of Health. In one video where a woman shows off her no-sugar results, the comments are bombarded with differing opinions. Most comments are asking how to start this diet, but others are pointing out how “healthy you looked before” and why “you need sugar because it's food that your brain uses for energy! You might look less bloated, but how did you feel?”

And that’s kind of the point, surely? Deficiencies in vitamins like B12 and B9 can lead to mental health issues; inconsistent blood sugar levels can trigger anxiety and depression; dehydration can affect mood and concentration; Omega-3 fatty acids can regulate mood and reduce the risk of depression; and a balanced protein intake can produce neurotransmitters to regulate thoughts and feelings. Too much or too little of anything can have a major impact on how we function.

Mental Health Awareness Week has coincided with the rise of these TikTok diet fads, as everyone is preparing for summer, but we are missing out on some essential nutritional information on how food fuels our brains. What’s the point in having the goal summer body if you are miserable in the process? With Gen Z in a mental health crisis, perhaps we look to little nutritional changes that can fuel our brain to combat this, and the more education around it, the better we can all be informed on our diets, thus our mental wellbeing.

This week, we got the lowdown from Marta Decarli – Balance’s expert nutritional lifestyle coach – on how mood-boosting and brain-healthy foods can rehaul your approach to your diet.

How does food affect our brain?

Marta Decarli: Our brain is a hungry organ. Despite only weighing around 2% of our body weight, it uses up about 20% of our daily energy intake. This energy comes from the foods we eat, especially carbohydrates, which are broken down into glucose, the brain’s preferred fuel.

But it’s not just about calories. Nutrients from food influence brain structure, neurotransmitters (chemical messengers like serotonin and dopamine), inflammation levels, and even the health of our gut, which directly connects to our brain via the gut-brain axis.

When we nourish ourselves well, we support better focus, memory, mood and even sleep. When we don’t, it’s harder to think clearly, stay motivated, and feel emotionally balanced.

What are the best foods for brain function?

MD: The best foods for brain health are ones that fuel it steadily, reduce inflammation, and provide key nutrients that support brain cell repair and communication. Some great options include:

Oily fish (like salmon, sardines, mackerel) – rich in omega-3 fatty acids, which help build brain cell membranes and reduce mental decline.
Berries – packed with antioxidants that reduce oxidative stress and support memory.
Nuts and seeds – particularly walnuts, flaxseeds, and chia, which provide healthy fats and vitamin E.
Leafy greens – like spinach and kale, which are high in folate and vitamin K, are associated with slower cognitive decline.
Whole grains – provide steady glucose for brain fuel and contain B vitamins that support nerve health.
Eggs – rich in choline, a key nutrient for memory and brain development.
Dark chocolate (in moderation) – contains flavonoids and can boost mood and focus.

How does restricting sugar, which is a current diet trend, affect our brain?

MD: Reducing excess added sugar is generally a good idea for both physical and mental health. While the brain needs some glucose to function, spikes from high-sugar foods can lead to crashes in energy and mood, poor concentration, and even increased anxiety.

However, cutting all carbohydrates or going extremely low-sugar can backfire, especially if not done mindfully. Many people report feeling irritable, foggy-headed, or low when they dramatically reduce carbs without ensuring they're still getting slow-release energy from whole grains, legumes, fruits, and vegetables.

Balance is key. The goal is to avoid the highs and lows of sugar, not to remove all sources of brain fuel.

Do you think nutrition has a direct correlation with our mental health? If so, why?

MD: Absolutely – and this isn’t just opinion. The emerging field of nutritional psychiatry shows a clear link between diet and mental health conditions like depression and anxiety.

A diet high in ultra-processed foods, sugar, and trans fats can increase inflammation and disrupt the gut microbiome, both of which are linked to poorer mood. On the flip side, Mediterranean-style diets rich in whole foods, healthy fats, and fibre are associated with better emotional wellbeing and lower rates of depression.

Your brain makes neurotransmitters from the nutrients you give it. So what you eat quite literally shapes your mood, clarity, and resilience.

We hear a lot about superfoods at the moment. What are these specifically, and how can they help our cognitive function?

MD: "Superfood" is more of a marketing term than a scientific one – but it usually refers to foods that are exceptionally rich in nutrients.

Some superfoods that can support brain health include:

Turmeric – contains curcumin, which crosses the blood-brain barrier and may support memory and reduce inflammation.
Blueberries – rich in anthocyanins, shown to improve memory and delay brain ageing.
Green tea – contains both caffeine and L-theanine for focus and calm.
Seaweed – a good source of iodine, important for thyroid (and therefore brain) health.

Rather than obsessing over specific superfoods, it’s better to focus on a wide variety of colourful, whole foods that consistently support your brain’s needs.

Vitamins and mineral-infused products are big on the market at the moment. What vitamins should we be looking out for – in our food or otherwise – to help our brains?

MD: Your brain thrives on a range of vitamins and minerals. The most important include:

B Vitamins (especially B6, B12, and folate) – support energy metabolism and neurotransmitter function.
Vitamin D – low levels are linked to low mood and cognitive issues.
Omega-3 fatty acids – particularly EPA and DHA, found in oily fish.
Magnesium – involved in over 300 processes in the body and supports stress regulation.
Zinc and iron – important for brain development and concentration.

If you eat a varied diet, you can get many of these from food. But if you’re vegan, vegetarian, or have dietary restrictions, a supplement may help. Always check with a qualified practitioner before starting anything new.

How have you or your clients found food to help your mental health/ cognitive function?

MD: Many of my clients notice that when they start eating more whole foods and less ultra-processed snacks, they feel more stable, more motivated, and less foggy. Just small changes – like switching a sugary breakfast for something protein-rich and slow-releasing – can make a big difference.

Personally, I’ve found that when I prioritise hydration, eat enough healthy fats, and include greens daily, I’m more focused and less reactive emotionally. It’s not about perfection, but about consistency.

What are the first steps we can take to rehaul our diet and head to a more brain-healthy plan?

MD: Start small and build momentum. Here are a few steps to get going:

Eat colourfully – aim for a variety of vegetables and fruits every day.
Choose whole over ultra-processed – swap white bread for wholegrain, crisps for nuts or seeds.
Include protein in every meal – helps balance blood sugar and improve mental clarity.
Stay hydrated – even mild dehydration can affect focus and mood.
Mind your gut – include fibre-rich foods and fermented items like yoghurt or kefir.
Limit added sugars and caffeine spikes, especially if you struggle with energy dips or anxiety.