Narrative review of the link between intake of carbohydrates and mental health: Focus on anxiety and insomnia in adults

The burden of anxiety disorders, insomnia and their comorbidity has been well documented. This narrative review aims to synthesize current knowledge and discuss the results of studies from the field of nutritional epidemiology and nutritional psychiatry on the link between carbohydrate intakes and mental health. The review includes studies on anxiety or insomnia with ≥ 1000 adult participants from non-clinical populations. Most of the existing studies on anxiety and insomnia in relation to carbohydrate intake were cross-sectional, suggesting overall positive associations. Variables reflecting carbohydrate intakes positively associated with anxiety or insomnia were percentage of energy from carbohydrates, total and complex carbohydrates, starches, added sugars, refined grains, sweetened beverages, confectionary, pasta, glycemic index and glycemic load. In order to infer causality regarding the effect of carbohydrate intake on these two mental disorders, future prospective observational and interventional studies would be needed.