Food for your Mood

While we’re often aware of the effects our mental state can have on our digestive system (ahem, cue anxiety poops or traveller's constipation), you may be less familiar of the effects your diet can have on your mental health! This connection is a two-way street, and the foods we eat can either have a negative or positive effect on our brain health. In fact, 90% of our serotonin (our happy hormone) is made in our gut. Serotonin in the gut plays a role in processes including digestion and may also send signals to the brain that affect the production of neurotransmitters there. 

Let’s look at some brain-healthy nutrients to include that may be beneficial in supporting your mental health.

• Tryptophan

Tryptophan is an amino acid found in protein-rich founds that gets converted into serotonin. Some of the best sources of tryptophan include eggs, turkey, chicken, milk, meat, legumes, and soy protein. Additionally, niacin is produced using tryptophan, and so if we don’t get enough, it can lower our levels of tryptophan. Aim to include sources of niacin such as mushrooms, wheat bran, tuna, chicken, peanuts and sunflower seeds.

• Vitamin B6

While all the B vitamins may be helpful in boosting your mood, B6 in particular is needed to convert tryptophan into serotonin, and including foods rich in B6 may help with serotonin production. Sources include eggplant, spinach, salmon, tuna, nuts and legumes.

• Magnesium

Magnesium is also important to produce serotonin, and deficiency may impair serotonin production. Some studies have shown magnesium supplementation has reduced stress levels and improved depression and anxiety [1]. Some great sources of magnesium include spinach, oat bran, broccoli, sesame seeds, Brazil nuts, almonds, and kidney beans.

• Zinc

There is evidence to suggest that zinc deficiency may be associated with an increased risk of depression, and zinc supplementation may reduce depressive symptoms [2]. Foods rich in zinc include oysters, seafood, meat, and fish. It can also be found in plant sources like whole grains and legumes, but it isn’t as easily absorbed.

• Selenium

Selenium acts as an antioxidant and may improve mental health through reducing inflammation. Studies have found that selenium supplementation in combination with probiotics has improved markers of mental health in women [3]. Selenium can be found in foods like Brazil nuts and seafood.

• Omega 3 fatty acids

There is research to suggest that omega-3s act as a prebiotic and help increase our good gut bacteria [4]. As our nervous system is largely made up from fats, including healthy fats in your diet is important for brain function! In fact, research suggests omega-3s can have a protective effect against a number of mental health issues including anxiety and depression [5]. Extra virgin olive oil, avocados, salmon, nuts and seeds are all great sources of omega-3s.

• Probiotics and fermented foods

Whilst it is early days in the research of probiotics, we are learning that some strains of probiotics can support good gut health. In addition to supporting good gut health, studies are starting to show that other probiotic strains may relieve stress and anxiety symptoms [6]. It’s thought to do so by increasing production of the neurotransmitter GABA in the gut, which has a calming effect and may help reduce anxiety. Watch this space as more research uncovers more beneficial strains.

•  Prebiotics

Our gut microbes love prebiotics, but research shows that our brains may love them too! Studies have shown that prebiotics have improved the symptoms of mental health conditions [7]. This may be through increasing the production of serotonin, reducing levels of our stress hormones, and helping maintain our brain’s barrier! Sources of prebiotics include asparagus, Jerusalem artichoke, onions, bananas, oats, and leeks.

Putting it all together

There are several key nutrients which may play a role in supporting brain function and improving mental health. While it can be helpful to understand key nutrients, following dietary patterns can be a useful way to incorporate all the above-mentioned nutrients, such as the Mediterranean diet! This has been shown in several studies, such as the SMILES trial that investigated the effects of adopting a modified Mediterranean diet among participants with depression. The study found that symptoms of depression significantly decreased upon adopting the diet [8]. Remember, the microbiome can begin to change within days of adjusting your diet, so it is never too late to start. Incorporating a Mediterranean-style diet rich in whole grains, vegetables, fruits, nuts, seeds, legumes, and extra virgin olive oil can help you incorporate the above brain-healthy nutrients and support your mental health.

References

[1] Noah L, Dye L, Bois De Fer B, Mazur A, Pickering G, Pouteau E. Effect of magnesium and vitamin B6 supplementation on mental health and quality of life in stressed healthy adults: Post-hoc analysis of a randomised controlled trial. Stress Health. 2021 Dec;37(5):1000-1009. doi: 10.1002/smi.3051. Epub 2021 May 6. PMID: 33864354; PMCID: PMC9292249.

[2] Wang J, Um P, Dickerman BA, Liu J. Zinc, Magnesium, Selenium and Depression: A Review of the Evidence, Potential Mechanisms and Implications. Nutrients. 2018 May 9;10(5):584. doi: 10.3390/nu10050584. PMID: 29747386; PMCID: PMC5986464.

[3] Jamilian M, Mansury S, Bahmani F, Heidar Z, Amirani E, Asemi Z. The effects of probiotic and selenium co-supplementation on parameters of mental health, hormonal profiles, and biomarkers of inflammation and oxidative stress in women with polycystic ovary syndrome. J Ovarian Res. 2018 Sep 14;11(1):80. doi: 10.1186/s13048-018-0457-1. PMID: 30217229; PMCID: PMC6137747.

[4] Rinninella E, Costantini L. Polyunsaturated Fatty Acids as Prebiotics: Innovation or Confirmation? Foods. 2022 Jan 6;11(2):146. doi: 10.3390/foods11020146. PMID: 35053879; PMCID: PMC8774454.

[5] DiNicolantonio JJ, O'Keefe JH. The Importance of Marine Omega-3s for Brain Development and the Prevention and Treatment of Behavior, Mood, and Other Brain Disorders. Nutrients. 2020 Aug 4;12(8):2333. doi: 10.3390/nu12082333. PMID: 32759851; PMCID: PMC7468918.

[6] Ma T, Jin H, Kwok LY, Sun Z, Liong MT, Zhang H. Probiotic consumption relieved human stress and anxiety symptoms possibly via modulating the neuroactive potential of the gut microbiota. Neurobiol Stress. 2021 Jan 12;14:100294. doi: 10.1016/j.ynstr.2021.100294. PMID: 33511258; PMCID: PMC7816019.

[7] Ansari F, Pourjafar H, Tabrizi A, Homayouni A. The Effects of Probiotics and Prebiotics on Mental Disorders: A Review on Depression, Anxiety, Alzheimer, and Autism Spectrum Disorders. Curr Pharm Biotechnol. 2020;21(7):555-565. doi: 10.2174/1389201021666200107113812. PMID: 31914909.

[8] Jacka FN, O'Neil A, Opie R, Itsiopoulos C, Cotton S, Mohebbi M, Castle D, Dash S, Mihalopoulos C, Chatterton ML, Brazionis L, Dean OM, Hodge AM, Berk M. A randomised controlled trial of dietary improvement for adults with major depression (the 'SMILES' trial). BMC Med. 2017 Jan 30;15(1):23. doi: 10.1186/s12916-017-0791-y. Erratum in: BMC Med. 2018 Dec 28;16(1):236. PMID: 28137247; PMCID: PMC5282719.