Could your food choices be affecting your mood?

Transformational nutrition smiles study

Can what you eat really affect your mood? This is a really interesting area of research that is developing and the data we have to date is promising.  

Food is the body’s essential fuel. Alongside oxygen and water, without food, a human being cannot survive. As science has evolved, people are slowly waking up to the evidence that food choices can dramatically influence the quality of your life – your energy levels, your skin, your propensity to avoid illness and disease and one of the latest studies shows the effect of food choices on moods

The SMILES study 

Transformational Nutrition depression and dietA 2017 Randomised controlled trial, called the SMILES study, set out to investigate whether a dietary intervention could treat moderate to severe depression.  It was a 12 week, parallel group, single-blind study involving 67 participants. The intervention group received 7 nutritional consulting sessions alongside a Mediterranean diet whilst the control group received placebo, social support sessions of the same length and frequency.

The Montgomery–Åsberg Depression Rating Scale was used to assess the participants at 12 weeks and the results were impressive.  32% of those who received the dietary intervention were classified as no longer clinically depressed at the end of the trial compared with 8% in the placebo group.  This seems to suggest that diet alone can change levels of depression. It is important to note that the participants in this study were seriously depressed and continued to take medication throughout but it would appear that diet as an adjunct therapy did indeed benefit.  It also begs the question of whether diet alone could help to treat those with lower levels of depression so that medication isn’t required. This has not been researched to date but it is certainly something to consider – if you suffer from low moods, could the quality of you diet be the primary cause?  It is certainly something that I investigate with my clients if appropriate.

What was special about the diet?

Transformational Nutrition fibreTalking of diet then, let’s look a little closer at the composition of the diet implemented in the SMILES study. Firstly, it included 50g of fibre daily; compare this with the UK average of 15-20g. This was provided through the inclusion of plenty of plant based foods.  The participant’s guts were therefore loaded with dietary fibre which we know is good for our gut microbiota. When we digest fibre, we produce things like short chain fatty acids which provide us with energy and keep our colon healthy.  Our gut microbes communicate with our central nervous system, which is where the ‘gut: brain’ axis theory originates, so maintaining a healthy gut could play a key role in managing our mental state.

In addition to a huge increase in fibre, participants were asked to eat the following daily:

  • 1 serving of Nuts
  • 60 ml of Olive oil
  • 2-3 servings of dairy
  • 6 portions of vegetables
  • 3 portions of fruit
  • 5-8 servings of whole grains.

And the following weekly:

  • 1-4 portions of legumes
  • 3-4 servings of red meat
  • At least 2 portions of fish
  • 2-3 servings of poultry and up to 6 eggs.

They were, therefore, getting plenty of folate from the fruits, veggies and whole grains, vitamin B12 from dairy, eggs and red meat, omega 3 and selenium from the nuts and fish.  All of these important nutrients have been shown to help improve mood and symptoms of depression.

As you can see, it was a well-balanced diet that included plenty of carbohydrates, protein and healthy fats which would have met the energy requirements of the participants whilst providing them with all the necessary vitamins and minerals for a healthy functioning body.

I appreciate that vegetarians won’t like the presence of meat in the study. Non-meat eaters might want to replace meat with more fish, dairy, eggs or legumes depending on what their diet allows though I cannot promise anyone will enjoy the outcomes in the trial.

Can we put it all down to diet?

Transformational Nutrition family eating depressionIn addition to all this, participants were asked to exercise daily and enjoy meals with others.  Many studies show that people who exercise regularly benefit from a positive boost in mood and suffer less with depression.  Socialising over food may also have had an impact on; it promotes more mindful eating which has proven benefits for both our mental and physical health.  It prevents eating on the go in a stressed state which helps digestion and thus plays a part in promoting emotional well-being.


In summary, then, it would seem that we can, in fact, improve our mental health through our diet and lifestyle.  Such simple interventions could in turn help to manage and/or prevent the development of mental and physical disease.

So if you suffer from moods or depression, this study strongly suggests that you can positively affect this with your choice of food and remember that food does not have the negative side effects of some medication.