Food for Thought: How Food & Nutrition Affects Mental Health

We often hear advice on eating for physical health, but less about how diet impacts mental wellbeing. Emerging research highlights how food affects systems that regulate mood, stress, cognition, and emotional balance. This blog covers how food and nutrition influences mental health and the practical changes you can make to eat for your mental wellbeing.

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How food affects mental wellbeing

Nutrient-rich foods support neurotransmitter production, reduce chronic inflammation and feed the good bacteria found in the gut, supporting a healthy gut microbiome – all of which influence positive mental health. Nutrient-rich foods also support brain development and function, as well as the systems that regulate brain and mental health; during pregnancy, they event support the development of the brain in the growing foetus.

Diets high in ultra-processed foods (UPFs), foods high in saturated fats and those high in artificial sweeteners and emulsifiers, on the other hand, are linked to poor gut health, increased chronic low-grade inflammation and disrupted mood regulation.

Evidence-based strategies to support your mental wellbeing include:

Eating 30+ plant foods per week to improve and sustain your gut microbiome
Increasing omega-3 fatty acids, particularly EPA, for mood enhancement and DHA for brain structure
Including fermented foods to support a healthy-gut microbiome
Reducing pro-inflammatory foods, such as those that are highly processed, sugar-sweetened beverages and refined carbohydrates

How food positively impacts mental health

1. The gut–brain connection

The gut–brain connection plays a pivotal role in mental health. This two-way communication system involves a complex network of microorganisms, biochemicals and nerves that link the gut and brain. Remarkably, the gut produces over 90% of the body’s serotonin, a neurotransmitter involved in regulating mood, appetite and sleep.

A healthy gut:

Supports the production of serotonin, dopamine and GABA – key brain chemicals that work together to regulate mood, motivation and stress
Helps regulate the immune system and stress responses
Maintains the gut lining and protects against chronic low-grade inflammation

Diets high in UPFs can damage the gut barrier, leading to increased intestinal permeability (sometimes called “leaky gut”). This allows inflammatory substances to enter the bloodstream – raising the risk of chronic inflammation and poor mental health outcomes.

2. Omega-3 fatty acids

Omega-3s are essential for brain function and emotional regulation. The most important for mental health are the long-chain omega-3s, EPA and DHA. They help build brain cells, regulate neurotransmitters, and reduce chronic low-grade inflammation. Oily fish such as salmon, mackerel and sardines are excellent sources of EPA and DHA.

Most plant-based sources only contain ALA – a shorter-chain omega-3 found in foods such as flax seeds, chia seeds and walnuts. The body can convert ALA into EPA and DHA, but only in small amounts – often less than 10%. So, ALA alone may not provide enough to achieve the full benefits. To get the full brain-health benefits, it needs to be consumed in large, regular amounts, or combined with a supplement.

For those seeking a plant-based alternative, algal oil – derived from certain species of microalgae – is a direct and sustainable source of the long-chain omega-3 fatty acids EPA and DHA. Unlike fish oil, algal oil is plant-based friendly and free from marine contaminants, making it an important option for vegetarians, vegans, and anyone looking to reduce seafood consumption while supporting brain health and emotional wellbeing.

3. Key vitamins and minerals for mental wellbeing

Micronutrients play a key role in the systems that support mood, focus and emotional regulation. Getting enough of the right nutrients helps your brain and body function at their best. For example:

B vitamins (B6, B9, B12) are essential for serotonin and dopamine production – mood-regulating hormones
Magnesium and zinc help calm the nervous system, support GABA activity (which helps you feel relaxed), and reduce chronic inflammation
Tryptophan and tyrosine are amino acids used to make neurotransmitters—especially when supported by cofactors like B vitamins and iron.
Iron and vitamin D are important for energy, thinking clearly and immune balance

Deficiencies in these nutrients are linked to higher rates of depression, anxiety and emotional instability. Nutrient-dense whole foods are the best way to meet these needs. If you follow a more restrictive diet, like vegetarian or vegan, you might want to consider a supplement, especially for nutrients like vitamin B12.

How food negatively impacts mental health

1. Ultra-processed foods (UPFs)

Ultra-processed foods are industrially made products that contain ingredients not typically found in a home kitchen – emulsifiers, artificial sweeteners, preservatives, refined sugars, industrial oils and endocrine-disrupting chemicals. Think crisps, biscuits, sweetened cereals, fast food, soft drinks and reconstituted meat products.

These ingredients can have a range of effects on the body and brain. Diets high in ultra-processed foods have been linked to:

Reduced gut health and less diverse gut bacteria
Higher levels of inflammation and oxidative stress
Disrupted brain signalling and hormone balance

UPFs are often high in calories but low in fibre and important micronutrients that support gut and brain health. They also tend to contain high amounts of refined seed oils and omega-6 fatty acids. While omega-6 fats aren’t harmful on their own, eating too much of them – especially without enough omega-3s – can promote inflammation.

Ideally, we need to eat omega-6 and omega-3 fats in a balanced ratio of about 1:1 – but in Western diets, it’s often 20:1. Emerging research suggests that the imbalance of omega-3s and omega-6s fatty acids is associated with chronic inflammation, which plays a role in depression.

In the UK, UPFs make up over half of the average diet, and up to 65% in some groups, especially children. Not all processed foods are harmful, but as a rule of thumb, if you wouldn’t recognise the ingredients on the label from your kitchen cupboard, it’s probably ultra-processed.

You don’t need to cut them out completely. Try making small swaps, like homemade pizza instead of ordering one the local takeaway, to support your mood and overall wellbeing

What to eat for better mental wellbeing

1. 30+ plant foods a week

Eating a wide variety of plant foods each week can be a powerful way to support both your physical and mental wellbeing. Aiming for 30 or more different types helps feed a diverse and healthy gut microbiome, which plays a key role in brain function and emotional balance.

Different plant foods offer different types of fibre and phytonutrients – natural compounds found in fruits, vegetables, wholegrains, legumes, herbs, and spices. Phytonutrients have antioxidant, anti-inflammatory, and brain-protective properties. Some, like flavonoids and polyphenols, may help reduce oxidative stress in the brain and support things like memory, focus, and mood regulation.

Try including:

Fruits and vegetables – especially leafy greens (rich in folate), berries (high in antioxidants), and cruciferous veg like broccoli
Wholegrains – oats, brown rice and quinoa provide steady energy and support serotonin production
Legumes, nuts and seeds – high in fibre, protein and micronutrients that help regulate mood

Even herbs and spices count towards your weekly total! The key is variety and starting off small – try and add 2 or 3 new plant-based foods into your meals each week.

2. Fermented foods

Fermented foods may offer some mental health benefits through their impact on the gut–brain connection. These foods contain live microorganisms (also known as probiotics), either naturally present or added during fermentation, that can positively influence gut health and help serotonin production.

Together, these benefits may help:

Increase the diversity of beneficial gut microbes
Support immune function and lower inflammation
Improve digestion and nutrient absorption
Strengthen the gut lining, which helps maintain good gut-brain communication

Try:

Live yoghurt or kefir, and sourdough bread
Marmite (a great plant-based source of vitamin B12, folate and magnesium!)
Kimchi, sauerkraut and kombucha
Miso and tempeh (fermented soy-based products)
Fermented legumes and pulses can also help feed a more diverse microbiome, supporting gut health, mood, and reducing inflammation over time.

3. Increase omega-3 intake

Because omega-3s play such an important role in brain structure, mood regulation, and reducing inflammation, getting enough of them can really help support your mental wellbeing. At the same time, cutting back on heavily processed fats, like those found in ultra-processed foods, can reduce inflammation and make room for healthier fats in your diet.

You can find omega-3s in:

Oily fish like salmon, sardines and mackerel
Algae oil supplements – a plant-based, vegan-friendly source of EPA and DHA
Some plant-based foods like flaxseeds, chia seeds, walnuts, and hemp seeds (which contain ALA, a shorter-chain omega-3)

If you don’t eat fish, combining ALA-rich foods with a daily algae-based omega-3 supplement is a great way to support your mental health.

Foods to limit for better mood and mental health

While no food needs to be off-limits entirely, some can affect mood, energy, and gut health – especially when eaten often or in large amounts.

1. Sugary foods

Too much added sugar can disrupt your gut’s healthy bacteria, which may increase inflammation and impact how you feel physically and emotionally.

Refined sugars cause a quick sugar rush – rapid spikes in blood sugar – that’s often followed by a crash, which can leave you feeling low in mood and energy
Over time, excess sugar can drive inflammation, which is linked to mental health issues if it persists over time

2. Fizzy and artificially sweetened drinks

What you drink can have just as much impact as what you eat.

Sugary drinks can increase inflammation and promote energy crashes
Diet drinks may disrupt the gut microbiome due to artificial sweeteners
Even fruit juices and smoothies, though nutritious in small amounts, can be high in sugar without fibre – stick to no more than one small glass per day

3. Ultra-processed foods

As mentioned above, these often contain components that are pro-inflammatory, can harm gut health and provide little nutritional value.

Common culprits include:

Fast food
Ready meals and packaged snacks
Flavoured crisps and fast food
Sweetened breakfast cereals

Too many omega-6 fats, especially without enough omega-3s, can increase inflammation. Cutting back on UPFs, even gradually, can make a real difference to your mood and gut health.

4. Caffeine and alcohol

Both caffeine and alcohol affect the brain and nervous system, so it’s worth being mindful of how much you consume.

Too much caffeine can worsen anxiety, raise stress hormones (like cortisol), and disrupt sleep
Alcohol affects serotonin levels and can act as a depressant – especially in larger amounts

Aim for balance: Try limiting caffeine later in the day and drinking alcohol in moderation.

Food for thought: everyday eating for long-term mental health

The way we eat affects the systems that shape how we feel: from the balance of chemicals in the brain to the health of our gut and the body’s response to stress and inflammation.

You don’t need an all-or-nothing approach. Improving your mental health through food doesn’t require perfection, even small changes can support your mental wellbeing over time.

References available on request

Where to get help

If you need further advice on supporting yourself or a young person with their mental health, take a look at the services below that can help.

Papyrus

Offers confidential advice and support for young people struggling with suicidal thoughts, as well as family and friends; and information about how to make a safety plan.

Its helpline service – HOPELINE247 – is available to anybody under the age of 35 experiencing suicidal thoughts, or anybody concerned that a young person could be thinking of suicide.

Opening times:24/7 every day of the year
0800 068 4141
Text: 88247