The journal Nutritional Neuroscience, published a paper in April 2017, exploring the relationship between diet and depression.
The authors note that converging evidence from laboratory, population research, and clinical trials suggests that healthy dietary patterns, such as the traditional Mediterranean-style whole-food diet, and specific dietary factors, including omega-3 polyunsaturated fatty acids (PUFAs), vitamin B6 and folate, antioxidants, and zinc, may influence the risk for depression. Despite the consistency of published evidence on the relationship between dietary patterns and depressive disorders, arising from numerous observational studies carried out in recent years on large and heterogeneous populations (including diverse cultures and age groups), and the emerging evidence suggesting that dietary improvement may prevent depression, there are no dietary recommendations currently available regarding depression.
Major depressive disorder is a common, chronic condition that imposes a substantial burden of disability globally. As current treatments are estimated to address only one-third of the disease burden of depressive disorders, there is a need for new approaches to prevent depression or to delay its progression. While in its early stages, converging evidence from laboratory, population research, and clinical trials now suggests that dietary patterns and specific dietary factors may influence the risk for depression. However, largely as a result of the recency of the nutritional psychiatry field, there are currently no dietary recommendations for depression.
The aim of this paper is to provide a set of practical dietary recommendations for the prevention of depression, based on the best available current evidence, in order to inform public health and clinical recommendations.
Five key dietary recommendations for the prevention of depression emerged from current published evidence. These comprise: (1) follow ‘traditional’ dietary patterns, such as the Mediterranean, Norwegian, or Japanese diet; (2) increase consumption of fruits, vegetables, legumes, wholegrain cereals, nuts, and seeds; (3) include a high consumption of foods rich in omega-3 polyunsaturated fatty acids; (4) replace unhealthy foods with wholesome nutritious foods; (5) limit your intake of processed-foods, ‘fast’ foods, commercial bakery goods, and sweets.
Although there are a number of gaps in the scientific literature to date, existing evidence suggests that a combination of healthful dietary practices may reduce the risk of developing depression. It is imperative to remain mindful of any protective effects that are likely to come from the cumulative and synergic effect of nutrients that comprise the whole-diet, rather than from the effects of individual nutrients or single foods. As the body of evidence grows from controlled intervention studies on dietary patterns and depression, these recommendations should be modified accordingly.
The paper makes five key recommendations:
- Follow ‘traditional’ dietary patterns, such as the Mediterranean, Norwegian, or Japanese diet. The available evidence suggests that traditional dietary habits may be beneficial for positive mental health.
- Increase your consumption of fruits, vegetables, legumes, wholegrain cereals, nuts, and seeds. These foods should form the bulk of the diet as they are nutrient dense, high in fibre, and low in saturated and trans-fatty acids.
- Include a high consumption of foods rich in omega-3 PUFAs. Fish is one of the main sources of omega-3 PUFAs, and higher fish consumption is associated with reduced depression risk.
- Limit your intake of processed-foods, ‘fast’ foods, commercial bakery goods, and sweets. These foods are high in trans-fatty acids, saturated fat, refined carbohydrates, and added sugars, and are low in nutrients and fibre. Consumption of these foods has been associated with an increased risk or probability of depression in observational studies.
- Replace unhealthy foods with wholesome nutritious foods. Healthy dietary patterns (e.g. fruits, vegetables, wholegrain cereals, and fish) and unhealthy dietary patterns (e.g. sweets, soft-drinks, fried food, refined cereals, and processed meats) are independent predictors of lower and higher depressive symptoms, respectively.
As all NTs and functional medicine trained practitioners will recognise, these core recommendations make good clinical sense, but in themselves will not transform someone’s mental health alone. Further manipulation of the microbiome, may be another intervention, as well as suitable personal skill developments.
 Opie RS, Itsiopoulos C, Parletta N, Sanchez-Villegas A, Akbaraly TN, Ruusunen A, Jacka FN. Dietary recommendations for the prevention of depression. Nutr Neurosci. 2017 Apr;20(3):161-171. View Abstract