These foods will boost your mood - how to eat for better mental health

Words By Dr Marissa Kelaher, Graphics by Dr Taisia Cech

Have you ever noticed that what you eat seems to affect your mood?

That some foods make you feel brighter, and more positive, while others make you sluggish and down?

Well, it turns out this isn’t just your imagination - its backed by science too!

Nutritional psychiatry, or the study of how food affects mental health and wellbeing, is a growing area of medical research.

Its confirming what many traditional cultures have intuitively known for years - that what we eat can have a huge impact on our mental health and brain function. And fortunately awareness and research around how diet can help mental health is starting to grow, at a time when we need it most.

While we don't tend to associate mood and mental health with our physical health, in reality they are intricately intertwined.

We are sadly seeing this in the real world - with rates of mental illness skyrocketing, and with these mirroring rates of chronic diseases such as type 2 diabetes, cardiovascular disease, obesity and dementia.

The rates of suicide have increased by 30% over the last 20 years, and over a billion people are currently living with mental illness worldwide.

This means a holistic approach to mental and physical health has never been more important - looking at the whole person, and what we do on a day to day basis.

We know mental health is complex, and is affected by many factors such as genetics, past experiences, trauma, environment, and other health issues. But we also know lifestyle factors play a huge role in mental and physical wellbeing, and central to these is our diet.

And best of all, eating a ‘mood healthy ‘ diet is great for overall health too - so there’s plenty of reasons to try it!

Can Changing Our Diet Really Help Mental Wellbeing?

The short answer is YES!!

The foods we eat are thought to impact mental health in three main ways:

1. they provide nutrients that are needed to produce essential brain chemical (neurotransmitters) - and lack of these nutrients can affect levels of neurotransmitters, impacting on mental wellbeing.

2. they can increase or reduce inflammation and overall health of our brain tissues, as well as impacting our metabolic health, which in turn impacts mental well-being and brain health.

3. they affect our gut health by promoting the growth of 'good' or 'bad' bacteria. Did you know 95% of serotonin (happy hormone) is made in your gut, and the vagus nerve directly connects the gut and brain sending signals back and forth constantly - meaning you literally are what you eat! Your gut bacteria also produce GABA, a neurotransmitter that helps with anxiety, sleep, and mood. To learn more about eating for gut health please see our blog post on this, or to learn more about how gut health works, see our blog post here.

One of the most famous clinical trials on diet and mental health was the SMILES trial), conducted by The Food and Mood Institute in Australia.

This aimed to see if changing diet could directly improve the mood of people with depression, and was a gamechanger, as it was one of the first to specifically change people's diet, and track what happened with their mood.

The trial placed half the trial participants on a 'mood boosting' diet, while the other half received social and emotional support..

And the results were astounding!

They found that a massive 30% of people with severe depression improved after 12 weeks of dietary changes, compared to only 8% of people who just received emotional support.

This is equivalent to the effects of many commonly used antidepressants!!

Interestingly, peoples grocery bills in the diet group also dropped - they actually saved money by eating better, as the foods used in the trial were simple cheap whole foods such as veges, legumes, and whole grains.

This trial used a diet called the MODIMED diet, which is a modified version of the Mediterranean diet.

The MODIMED diet isn't anything fancy though - it's a simple whole food diet high in vegetables (5 servings/day), fruits (3 servings), whole grains (5-8 servings/day), olive oil (60ml/day), nuts (1 serving/day) and dairy (2-3 servings/day, ideally fermented).

Legumes, fish, red meat and eggs were all eaten several days per week with this eating pattern, and ultra-processed foods /foods with added sugar were avoided or eaten very rarely.

The MODIMED diet was designed based around existing knowledge of which foods and nutrients are known to promote brain and mood health. And these are almost all whole plant foods 🌿

Another RCT (randomised controlled trial) that came out in 2022 (the AMMEND trial) followed on from the SMILES trial, and looked specifically at whether diet changes could help depression in young men.

In New Zealand, as in many other countries, young males are one of the highest risk groups for depression and suicide, so this trial is especially relevant to our culture.

The AMMEND trial ran over 12 weeks, and participants either changed their diet to a Mediterranean style diet similar to the SMILES trial (under guidance of a nutritionist) , or were given social and emotional support.

At the end of the trial, the group who changed their diet had significantly lower depression symptoms and scores, and better quality of life scores than the other group.

There was also a very high compliance rate in the diet group - meaning people were able to stick with their new way of eating.

As research shows that young men often have some of the lowest intake of vegetables and plant foods in New Zealand (think of the average meat pie, chips, takeaway and energy drink diet that's so common), this study was super exciting to see!

And one further trial (the HELFIMED trial), again compared depression scores in people who were put on a plant focused Mediterranean diet supplemented with omega 3, with people who attended social support groups, over a period of 6 months.

Yet again, the people in the diet group improved significantly compared to the control group - and the more their diets improved, the less depressed they became!!

Other large studies have found similar results - that people who eat a whole food, mostly plant based diet are consistently 30-50% less likely to suffer from anxiety and depression.

This diet also reduces the risk of neurodegenerative diseases such as Parkinsons disease and Alzheimers, and promotes better brain health. It's the eating pattern we teach and promote in our Reboot and Nutrition courses!

An exciting new study was also published recently (again by the Food and Mood institute), looking at the impact of increasing prebiotic fibre rich foods compared to probiotic supplements to improve anxiety, by altering the health of our gut microbiome (the Gut Feelings trial). This is one of the first trials that specifically examined this, although links between gut health and mental health have been gaining traction over the last few years.

This trial compared four groups over 8 weeks - a probiotic supplement and diet-as-usual (probiotic group); a high-prebiotic diet and placebo supplement (prebiotic diet group); a probiotic supplement and high-prebiotic diet (synbiotic group); and a placebo supplement and diet-as-usual (placebo group).

It found that the prebiotic diet group experienced significantly improved anxiety, stress, and sleep, whereas the other groups showed little change.

The prebiotic foods included 2 servings/day of wholegrain foods; 1 serving/day of legumes; 2 servings/day of specific fibre rich veges; 1 serving/day of prebiotic rich fruits; and 1 serving/day of nuts ie a plant focused, whole food Meditteranean style diet. You can find the food list here.

The impact of the Standard Western Diet on mental health

In contrast to the positive effects of the dietary patterns above, studies show that people who eat diets high in red/processed meat, refined grains, added sugar, high saturated fat and low in fresh fruit and vegetables (ie a standard Western diet) are significantly MORE likely to develop mental illness, as well as chronic physical health issues.

This is thought to be due to:

1) the effect of chronic inflammation and oxidative caused by a Western style diet (in particular a diet high in refined carbohydrates, saturated fat, and added sugar)

2) the negative effects of these foods on our gut microbiome (which in turn impacts our mental and physical health)

3) the lack of many essential micronutrients that are found mostly in whole plant foods as we mentioned at the start of this blog.

Sugary ultra-processed foods also affect our blood sugar (and not in a good way), and give us a huge dopamine hit - the feel good hormone that is linked with addiction - explaining part of why we crave them, even when they make us feel terrible and exhausted a few hours later.

The great news is, our tastebuds (and even our mouth bacteria) change within weeks of changing our diet - meaning its totally possible to ‘re-wire’ our tastes to enjoy fruit and veges instead of high sugar foods 😁

The Role of Micronutrients

In addition to overall diet, studies have shown that ensuring we get enough neuro-protective vitamins and minerals, such as B vitamins, omega 3 fatty acids, iron, magnesium, and zinc, can be highly beneficial to our brain and our mental health.

These nutrients are needed for neurotransmitter production (brain chemicals that send signals in our brain), as well as for energy production in our brain cells; so deficiencies can affect brain function - impacting on learning and memory, as well as increasing the risk of feeling irritable, stressed, and fatigued.

In particular, low levels of omega 3, folate, B12, and vitamin D are strongly linked to poorer mental health - so making sure we are getting enough of these can be hugely helpful to improve mental wellbeing.

A great paper from a nutritional psychiatrist in the US went further, and created an ‘antidepressant food scale’ - ranking different foods based on how rich they were in these brain essential nutrients.

Plant based foods consistently came out tops, in particular leafy greens, brassica, nuts/seeds, and fruit. Most animal based foods scored poorly, with the exception of seafood and organ meat (which still scored over ⅔ lower than green veges, but may be helpful to include in your diet if you wish to).

The nutrients that are particularly important for mental health (and brain health) include:

🌱B12, which is found in eggs, dairy, and meat (or you can supplement if you're fully plant based), aim for blood levels >300pmol/L

🌱Folate, which comes from dark green leafy veges, brassica, legumes, peanuts, sunflower seeds, fruit, whole grains, liver, seafood, and eggs, aim for blood levels >20nmol/L

🌱Iron, which comes from beans, tofu, nuts, seeds, wheat germ, broccoli, dark leafy greens, eggs, and red meat, aim for blood levels 40-200 µg/L (women), or 40-300µg/L (men)

🌱Omega 3, which is found in oily fish or walnuts/flaxseed/chia seeds/hemp seeds (no standard blood tests available currently)

🌱Magnesium, which comes from nuts, whole grains, legumes, dark leafy greens, bananas and cocoa (we often need more of this when we're under stress), levels not reliable on blood tests

🌱Zinc, which is in legumes, nuts, seeds, oats, tofu, shellfish, and organ meat, aim for blood levels >12umol/L

🌱Vitamin D, which mostly comes from safe sun exposure (so supplements are often needed over winter in cooler climates), aim for blood levels 80-120 nmol/L

Levels of these nutrients (with the exception of omega 3 and magnesium) are easily checked on a blood test through standard labs via referral from your GP or health care provider (although costs usually apply for zinc and vit D tests, and may apply for B12 tests), and can be a simple way to ensure you’re optimising them!

How To Eat To Boost Your Mood With Food

🌿Focus on increasing intake of veges (especially dark green ones), brightly colored fruits, seeds, nuts, olive oil, legumes and whole grains. These are all ‘brain’ and ‘mood’ healthy foods, as well as being great for overall health.

🌿 Boost your fibre intake to create a healthy gut microbiome, by including plenty of whole grains, legumes, nuts and seeds.

🌿Add fermented foods to your diet, such as kimchi, miso, kefir, sauerkraut, and soy yoghurt to feed your gut microbiome, these also contain GABA and probiotics which may help reduce anxiety and improve sleep. See our blog post on what to eat for a better nights rest.

🌿Eat foods that contain the building blocks for serotonin (happy hormones) such as tofu, edamame beans, mushrooms, leafy greens, tomatoes, banana, and kiwifruit.

🌿Boost your intake of foods that help with GABA production (to reduce anxiety and improve sleep), such as fermented foods, leafy greens, brassica, kumara, and mushrooms.

🌿Cut back on refined grains, added sugar, red meat and processed foods, to reduce inflammation, improve your gut health, and stabilise your blood sugar levels.

🌿 Consider asking your GP to check levels of folate, B12, iron, zinc, and vitamin D (costs may apply), and potentially supplement omega 3 if you struggle to get enough in your diet.

If you want to learn more about how to eat a plant focused whole food diet that's great for your body, mind, and gut health, please check out our Reboot and Nutrition courses.

In addition to teaching you all about what healthy eating really looks like (and making it easy with 6 weeks of whole food plant based recipes!), we also take a deep dive into how it affects our mind, and how to eat for better mental and physical health!

Plus we explore gut health, how to reduce inflammation with diet, how to eat a balanced plant focused diet and how to meet all your nutrient needs from food - as well as practical tips, the science of fasting, mindful eating, and much more❤️

We run our Reboot course 3 times per year, whereas our Nutrition course is available year round.

If you’d like to optimise your wellbeing, we’d love you to join us!

Even small changes in your diet can help - so why not try it and see what difference you notice - there's nothing to lose and everything to gain!!

References:
https://pubmed.ncbi.nlm.nih.gov/19805699/
https://www.ncbi.nlm.nih.gov/pubmed/20485303
https://www.ncbi.nlm.nih.gov/pubmed/21715296
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636120/?report=reader
https://drewramseymd.com/depression-anxiety/heres-the-1-food-category-to-fight-depression
https://healthcentral.nz/food-for-thought-can-nutrients-nurture-better-mental-health/
https://journals.sagepub.com/doi/10.1177/0004867414565482

https://academic.oup.com/ajcn/advance-article-abstract/doi/10.1093/ajcn/nqac106/6571247

https://pubmed.ncbi.nlm.nih.gov/29215971/