The Science Behind Food and Mood

We would argue that your nutrition should be one of the key considerations when it comes to supporting your mental health. But don’t just take it from us, let’s take a look at what the science says!

 Nutrition may have the potential to prevent and treat depression. The SMILES trial was the first randomised control trial which demonstrated that adopting a Mediterranean Diet can reduce symptoms of depression (1). Some ways in which a healthy diet may benefit mental health include:

• A high fibre intake can increase the production of short chain fatty acids, which helps to reduce inflammation in the body (2,3).
• A high fibre intake promotes beneficial bacteria and reduces the harmful bacteria in the gut that promote disease (2,3).
• Limiting ultra-processed foods and having foods rich in antioxidants (like polyphenols) can help to reduce oxidative stress which may cause neuronal damage (4).

 Which foods may help to prevent and treat depression?

 A greater intake of fruits, vegetables, nuts, seeds, legumes and fish has been associated with reduced depressive symptoms. Vegetables and fruits may help to reduce depressive symptoms due to their high levels of antioxidants, high fibre content, or their high micronutrient content which may alleviate deficiencies associated with some mental health disorders (3,4). Antioxidants help to reduce oxidative stress, which can contribute to neuronal damage, and reduce inflammation. Nuts have been shown to increase levels of brain-derived neurotropic factor, which has been found to be low in patients living with depression (4). Additionally, fish are an excellent source of omega-3 fatty acids which may be beneficial due to their anti-inflammatory properties which can increase levels of BDNF as well (4)!

 On the other hand, a poor diet can negatively influence brain health in several ways, whether directly or indirectly by disrupting the gut microbiota. Some factors that appear to influence risk of depression include:

• a pro-inflammatory diet that is high in added sugars and saturated/trans fatty acids (5).
• oxidative stress which may cause neuronal damage (5).
• lack of long chain omega 3 polyunsaturated fatty acids in the diet (5).
• folate deficiency (4).
• magnesium deficiency (4).
• low intake of Vitamin B12 (4).
• zinc deficiency (4).

A Western Diet is pro-inflammatory and often includes high amounts of saturated fats and added sugars while being low in the important nutrients mentioned above that can support brain health. In fact, research shows that there are higher rates of depression among those who have a diet high in saturated fat and added sugars (6).

 A Final Word

There are several proposed mechanisms that explain how the foods we eat can either negatively or positively influence the health of our brain. Including more nutrient-rich foods into your diet, such as those found in the Mediterranean Diet, and limiting ultra-processed foods typical in a Western Diet can help you to support your mood through food!

 References

•  Opie RS, O’Neil A, Jacka FN, Pizzinga J, Itsiopoulos C. A modified Mediterranean dietary intervention for adults with major depression: Dietary protocol and feasibility data from the SMILES trial. Nutr Neurosci 2018. https://doi.org/10.1080/1028415X.2017.1312841
• Dash S, Clarke G, Berk M, Jacka FN. The gut microbiome and diet in psychiatry: focus on depression. Current opinion in psychiatry. 2015;28(1):1-6.
• Miki T, Eguchi M, Kurotani K, Kochi T, Kuwahara K, Ito R, et al. Dietary fiber intake and depressive symptoms in Japanese employees: the Furukawa Nutrition and Health Study. Nutrition. 2016;32(5):584-9.
• Opie R, Itsiopoulos C, Parletta N, Sanchez-Villegas A, Akbaraly T, Ruusunen A, et al. Dietary recommendations for the prevention of depression. Nutritional neuroscience. 2017;20(3):161-71.
• Parletta N, Zarnowiecki D, Cho J, Wilson A, Bogomolova S, Villani A, et al. A Mediterranean-style dietary intervention supplemented with fish oil improves diet quality and mental health in people with depression: A randomized controlled trial (HELFIMED). Nutritional neuroscience. 2017:1-14.
• Vermeulen E, Stronks K, Snijder MB, Schene AH, Lok A, de Vries JH, et al. A combined high-sugar and high-saturated-fat dietary pattern is associated with more depressive symptoms in a multi-ethnic population: The helius (healthy life in an urban setting) study. Public health nutrition. 2017;20(13):2374-82.