Clinical question:
In patients with type 2 diabetes do soy supplements improve glycaemic control?
Studies have shown that soy intake is associated with a lower risk of type 2 diabetes. Does it also have benefits in treating people who already have the disease?
The evidence:
This is a systematic review of clinical trials. The search was limited to PubMed and The Cochrane Library.
The reviewers found eight trials that addressed the question. When they combined the data from these trials they found that intake of soy products was associated with a significant reduction in serum total cholesterol, triacylglycerol and low-density lipoprotein-cholesterol. There were no significant effects on fasting glucose, insulin and glycated haemoglobin.
Appraisal hints:
Users of this research are advised to consider:
- Whether the reviewers did enough to find all of the published research
- Was there a blind, independent assessment of the relevance and quality of each study?
- How data was extracted from each of the individual trials.
- Are the individual studies similar enough to warrant combining in a meta-analysis?
- Are the results consistent from one trial to another?
- There is a typographical error in the abstract of this paper.
Reference:
Yang B, Chen Y et al. Systematic review and meta-analysis of soy products consumption in patients with type 2 diabetes mellitus. Asia Pac J Clin Nutr. 2011;20(4):593-602.