A randomised controlled trial of dietary improvement for adults with major depression (the ‘SMILES’ trial)

Summary & key facts

Researchers ran a 12-week study to see if improving diet could help adults with moderate to severe depression. People who got seven one-on-one sessions with a clinical dietitian and who followed a healthier, Mediterranean-style eating plan improved more than people who got friendly social visits. About one third of the diet group reached remission of their depressive symptoms, compared with about one in twelve in the control group. The study was small and short, and most participants were also receiving therapy or medication, so the results are promising but not definitive.

Key facts:

• The study lasted 12 weeks and compared a dietary program led by a clinical dietitian to a control program of social support with the same number and length of visits.
• Sixty-seven adults with moderate to severe depression and poor baseline diets started the trial.
• About 55 of the 67 people were already using some form of therapy, including psychotherapy, medication, or both.
• People in the diet group had a much larger drop in depression scores than those in the social support group over 12 weeks.
• Remission of depression, defined by the researchers as a low score on the depression scale, happened in about 32% of the diet group and about 8% of the control group.
• The researchers calculated that for every four people who received the dietary program, one additional person reached remission compared with the social support group.
• The authors ran extra analyses to check whether missing data or people dropping out changed the result and found the main benefit was still present.
• Limitations include the small number of participants, the short 12-week follow-up, and the fact that the study tested diet as an add-on to other treatments for many participants.

Abstract

Australia and New Zealand Clinical Trials Register (ANZCTR): ACTRN12612000251820 . Registered on 29 February 2012.

Topics

Diet and metabolism studies Eating Disorders and Behaviors Nutritional Studies and Diet

Categories

Health Sciences Medicine Physiology

Tags

Clinical trial Depression (economics) Economics Internal medicine Macroeconomics Medicine Physical therapy Randomized controlled trial

Conditions & symptoms

Depression Lack of energy or motivation Poor sleep Sadness or low mood