The second week in May is Mental Health Awareness Week in the UK. Part of my job as a herbalist is to explain the role that certain dietary choices play in health. Not only physical health but also mental health issues such as autism and depression. This is especially true in my role as a GAPS practitioner. Yet there is little research on the effect that making dietary changes have on mental health.

Now at last, results of studies on this topic are becoming available. A recent review of studies on food choices shows their affect on children’s mental health. Another study explains the importance of food quality during pregnancy and the affect on the future emotional health of the child.

The recent SMILES study (Supporting the Modification of lifestyle in Lowered Emotional States) provides yet more scientific evidence. In this study researchers describe the effect of dietary change on people with depression. The SMILES diet follows the pattern of the so called Mediterranean diet. This is a pattern of eating with known health benefits.

Participants in the SMILES study ate foods ad libitum from twelve key food groups:

• whole-grains
• vegetables
• fruit
• legumes
• low-fat and unsweetened dairy foods
• raw and unsalted nuts
• fish
• lean red meats
• chicken
• eggs
• olive oil

Whilst reducing intake of foods from other categories:

• sweets
• refined cereals
• fried foods
• fast food
• processed meats
• sugary drinks

Participants also had seven personalised support sessions with a dietician. In addition, they were given recipes and meal plans to help them make the changes to their new diet. The results show that improvements in the diet significantly reduced symptoms of depression.

As the researchers explain, there are several ways that food choices can influence depression:

• influencing inflammation in the body
• reducing oxidative stress
• directly affecting brain function
• influencing the gut microbiota

Furthermore, researchers say some benefits of the diet may not be related to the actual food. Such as the necessary lifestyle changes. Cooking, shopping and regular meal patterns may all provide a therapeutic benefit.

The SMILES study was relatively small. So the researchers suggest this work should be repeated with a larger number of participants. However, the study does show significant improvements in clinical depression through diet. What’s more, improving the diet quality is likely to benefit concurrent physical disease.

The SMILES study diet has some major differences to those recommended in the GAPS diet. Even so, by removing the ‘junk’ it shows that improving the quality of food eaten can improve mental health.