An Almond-Based Low Carbohydrate Diet Improves Depression and Glycometabolism in Patients with Type 2 Diabetes through Modulating Gut Microbiota and GLP-1: A Randomized Controlled Trial

Nutrients. 2020 Oct 3;12(10):3036. doi: 10.3390/nu12103036.


Background: Alow carbohydrate diet (LCD) is more beneficial for the glycometabolism in type 2 diabetes (T2DM) and may be effective in reducing depression. Almond, which is a common nut, has been shown to effectively improve hyperglycemia and depression symptoms. This study aimed to determine the effect of an almond-based LCD (a-LCD) on depression and glycometabolism, as well as gut microbiota and fasting glucagon-like peptide 1 (GLP-1) in patients with T2DM.

Methods: This was a randomized controlled trial which compared an a-LCD with a low-fat diet (LFD). Forty-five participants with T2DM at a diabetes club and the Endocrine Division of the First and Second Affiliated Hospital of Soochow University between December 2018 to December 2019 completed each dietary intervention for 3 months, including 22 in the a-LCD group and 23 in the LFD group. The indicators for depression and biochemical indicators including glycosylated hemoglobin (HbA1c), gut microbiota, and GLP-1 concentration were assessed at the baseline and third month and compared between the two groups.

Results: A-LCD significantly improved depression and HbA1c (p <0.01). Meanwhile, a-LCD significantly increased the short chain fatty acid (SCFAs)-producing bacteria Roseburia, Ruminococcus and Eubacterium. The GLP-1 concentration in the a-LCD group was higher than that in the LFD group (p <0.05).

Conclusions: A-LCD could exert a beneficial effect on depression and glycometabolism in patients with T2DM. We speculate that the role of a-LCD in improving depression in patients with T2DM may be associated with it stimulating the growth of SCFAs-producing bacteria, increasing SCFAs production and GPR43 activation, and further maintaining GLP-1 secretion. In future studies, the SCFAs and GPR43 activation should be further examined.

Keywords: GLP-1; HbA1c; almond; carbohydrate; depression; diet; microbiota; short-chain fatty acids; type 2 diabetes.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Blood Glucose / metabolism
  • Depression / diet therapy*
  • Depression / etiology
  • Diabetes Mellitus, Type 2 / blood
  • Diabetes Mellitus, Type 2 / diet therapy*
  • Diabetes Mellitus, Type 2 / psychology
  • Diet, Carbohydrate-Restricted / methods*
  • Fasting / blood
  • Feces / microbiology
  • Female
  • Gastrointestinal Microbiome / physiology*
  • Glucagon-Like Peptide 1 / blood
  • Glycated Hemoglobin / metabolism
  • Glycemic Control / methods*
  • Humans
  • Male
  • Prospective Studies
  • Prunus dulcis*
  • Treatment Outcome


  • Blood Glucose
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human
  • Glucagon-Like Peptide 1