Your brain is incredibly sensitive to the food and drink you consume throughout the day. Just think about how alert you feel soon after drinking a cup of coffee!
Nutrition is important in taking care of the brain. It makes sense, therefore, that diet can have a powerful impact on our mental health. The link between diet and mental health was first brought into the spotlight by the SMILES trial in 2017. This study involved 67 adults with depression who consumed a poor diet. One group received a nutritional intervention to improve their diet, and the other received social support. Those in the dietary improvement group had a significantly greater reduction in depressive symptoms. In fact, 30% of participants in the dietary improvement group went into remission (i.e. were no longer considered depressed) at the end of 12 weeks, compared to just 8% in the social support group! Although, it is important to note that many were still on medication. While diet alone cannot be seen as a treatment for depression, these findings suggest that for people consuming a poor diet, improving nutritional intake alongside treatment might accelerate the rate of recovery.
This begs the question, could we also explore nutrition as a preventative strategy for the development of mental health conditions? Can we eat for a healthy brain?
What is the best diet for a healthy brain?
Dietary patterns that are rich in fruits, vegetables, legumes, wholegrains, fish, nuts and olive oil seem best to keep our brain healthy. This pattern is characteristic of the traditional Mediterranean diet.
Let’s explore in more detail why this dietary pattern contributes to good brain health.
Get your Omega-3!
The Mediterranean diet involves eating plenty of fish. Oily fish (e.g. salmon, sardines, mackerel etc.) is a rich source of Omega-3. Omega-3s are essential fats, meaning our bodies cannot make them, and we must get them from our diet. The two main types of Omega-3s in fish are EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid). Both are important in forming the structure of the brain cell. In fact, the human brain is nearly 60% fat, and DHA is the most abundant!
These fats ensure that brain cells can communicate effectively, promote the production of new brain cells in areas important for mood, and reduce inflammation. They also enhance the activity of the dopamine (reward) and serotonin (happy hormone) systems, both of which are downregulated in depression. A meta-analysis (high quality evidence) of over 1000 people found that Omega-3 supplementation was helpful in reducing depressive symptoms, compared to placebo.
So, avoiding Omega-3 deficiency can help support a healthy brain. It is recommended to eat at least 2 portions of fish a week, one being oily. For those who don’t consume oily fish, it’s worth considering an Omega-3 supplement. Pregnant women should check that their chosen supplement doesn’t contain vitamin A, as it can be harmful.
How can vegans and vegetarians get their Omega-3?
Plant sources of Omega-3 include nuts and seeds (e.g. walnuts, chia seeds and flaxseeds). These contain a type of Omega-3 called ALA (alpha-linoleic acid). However, ALA is not easily converted to DHA and EPA (the active forms) in our bodies. For this reason, if you are vegan or vegetarian you might consider an algae-oil supplement to reach your DHA and EPA requirements. Surprisingly, fish get their Omega-3 from the food they eat! Algae are the original manufacturers of Omega-3 through photosynthesis. It travels up the food chain as algae are eaten by zooplankton and krill, which in turn are eaten by fish. We can cleverly extract Omega-3 from algae so that it’s vegan and vegetarian friendly.
Eating a diversity of plant foods including fruits, vegetables, whole grains, legumes, nuts and seeds, positively impacts our gut microbiome (the trillions of microbes that live in our gut). New discoveries point to a link between gut health and mental health. This link is likely due to a two-way communication that occurs between the gut and the brain, referred to as the gut-brain axis. The more diverse your gut microbiome, the better. Plant foods contain lots of fibre and nutrients such as polyphenols (plant chemicals), both of which encourage your gut microbes to flourish. Extra virgin olive oil, a major part of the Mediterranean diet, is high in polyphenols and worth using as your primary cooking oil.
Another benefit of whole grains (e.g. brown rice, oats, quinoa, wholewheat pasta and wholegrain bread) is that they are packed with many of the B vitamins that support the healthy functioning of the nervous system, and are involved in the production of the neurotransmitters serotonin and dopamine that influence our mood.
Should we be concerned about the Western diet?
There are concerns that the Western Diet is detrimental to our mental health. This diet is typically high in refined carbohydrates (e.g. white pasta, rice and bread). During processing, the grains used to produce these carbohydrates are stripped of their fibrous outer layer, along with important B vitamins that are essential to brain health!
In the UK, we are vastly under consuming dietary fibre, with the average daily intake at 19g, compared to the recommended 30g. Did you know that only 30% of the UK population are eating their 5 a day?10]
Moreover, the majority of the UK population don’t consume enough oily fish, containing the brain-boosting, anti-inflammatory Omega-3s. This, combined with the overconsumption of alcohol, excess sugar and saturated fats, contributes to possible long-term systemic inflammation that is associated with depression.
The good news...
The good news is that improving your diet in line with current guidelines (rather than any extreme diets) can positively impact on brain health. While having a nutrient-dense diet does not make us immune to mental health difficulties, it is certainly worth considering how food choices shape our brains.
1.Jacka et al. (2017). A randomised controlled trial of dietary improvement for adults with major depression (the “SMILES” trial). https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-017-0791-y
2.Chang et al. (2009). Essential fatty acids and human brain. https://www.ncbi.nlm.nih.gov/pubmed/20329590
3.Liao et al. (2019). Efficacy of omega-3 PUFAs in depression: A meta-analysis. https://www.nature.com/articles/s41398-019-0515-5
4.BDA food fact sheet: Omega-3 https://www.bda.uk.com/foodfacts/omega3.pdf
5.Burdge (2004). Alpha-linolenic acid metabolism in men and women: nutritional and biological implications. https://insights.ovid.com/crossref?an=00075197-200403000-00006
6.Winwood (2014). Algal oil as a source of omega-3 fatty acids. https://www.sciencedirect.com/science/article/pii/B978085709428550014X
7.American Gut Project https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5954204/
8.Hidalgo et al. (2014). Effect of virgin and refined olive oil consumption on gut microbiota. Comparison to butter. https://www.sciencedirect.com/science/article/pii/S0963996914005079
9.Jacka et al. (2010). Association of Western and traditional diets with depression and anxiety in women. https://ajp.psychiatryonline.org/doi/full/10.1176/appi.ajp.2009.09060881?url_ver=Z39.88-2003&rfr_id=ori%3Arid%3Acrossref.org&rfr_dat=cr_pub%3Dpubmed&
10.National Diet and Nutrition Survey: Years 7 and 8. https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/699241/NDNS_results_years_7_and_8.pdf
11.SACN Advice on Fish Consumption. https://www.gov.uk/government/publications/sacn-advice-on-fish-consumption
12.Akbaraly et al. (2016). Dietary inflammatory index and recurrence of depressive symptoms. https://www.ncbi.nlm.nih.gov/pubmed/28070452
This post was written by Alice van der Schoot, a Registered Associate Nutritionist (ANutr, MSc) with a background in Neuroscience (BSc). She has a special interest in the impact of nutrition on the structure and function of the brain. You can find more information about Alice Nutrition on her website www.alicenutrition.com or through her Instagram channel @alicenutrition.
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