Fat food for a bad mood. Could we treat and prevent depression in Type 2 diabetes by means of omega-3 polyunsaturated fatty acids? A review of the evidence

Diabet Med. 2005 Nov;22(11):1465-75. doi: 10.1111/j.1464-5491.2005.01661.x.


Aims: Evidence strongly suggests that depression is a common complication of Type 2 diabetes mellitus. However, there is considerable room to improve the effectiveness of pharmacological antidepressant agents, as in only 50-60% of the depressed subjects with diabetes does pharmacotherapy lead to remission of depression. The aim of the present paper was to review whether polyunsaturated fatty acids (PUFA) of the omega-3 family could be used for the prevention and treatment of depression in Type 2 diabetes.

Methods: MEDLINE database and published reference lists were used to identify studies that examined the associations between omega-3 PUFA and depression. To examine potential side-effects, such as on glycaemic control, studies regarding the use of omega-3 supplements in Type 2 diabetes were also reviewed.

Results: Epidemiological and clinical studies suggest that a high intake of omega-3 PUFA protects against the development of depression. There is also some evidence that a low intake of omega-3 is associated with an increased risk of Type 2 diabetes, but the results are less conclusive. Results from randomized controlled trials in non-diabetic subjects with major depression show that eicosapentaenoic acid is an effective adjunct treatment of depression in diabetes, while docosahexanoic acid is not. Moreover, consumption of omega-3 PUFA reduces the risk of cardiovascular disease and may therefore indirectly decrease depression in Type 2 diabetes, via the reduction of cardiovascular complications.

Conclusions: Supplementation with omega-3 PUFA, in particular eicosapentaenoic acid, may be a safe and helpful tool to reduce the incidence of depression and to treat depression in Type 2 diabetes. Further studies are now justified to test these hypotheses in patients with Type 2 diabetes.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Adult
  • Depressive Disorder / prevention & control*
  • Diabetes Mellitus, Type 2 / diet therapy
  • Diabetes Mellitus, Type 2 / psychology*
  • Fatty Acids, Omega-3 / therapeutic use*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Randomized Controlled Trials as Topic


  • Fatty Acids, Omega-3