The August Nutrition Society Paper of the Month is from the British Journal of Nutrition and is entitled ‘Effect of oat intake on glycaemic control and insulin sensitivity: a meta-analysis of randomised controlled trials’.

Diabetes mellitus (DM) is one of the most serious chronic diseases, the incidence rate is consistently increasing all over the world however it used to be most common (especially type 2) in developed countries. The greatest increase in prevalence is, however, expected to occur in Asia and Africa. Perhaps a “Western-style” diet is the most important factor of the DM incidence increase in developing countries. There is no obvious cure for DM and the main management is keeping blood glucose levels as close to normal as possible, without causing hypoglycemia. A number of efficacy trials provided strong evidence for lifestyle change programmes in preventing type 2 diabetes among individuals with impaired glucose tolerance. Exploring a healthy diet and lifestyle to get the blood glucose levels controlled is critical for the prevention of type 2 diabetes.

Oat was recognized as a healthy food in the mid 1980s helping prevent heart disease and then it became more popular for human nutrition. Recent studies in food and nutrition have revealed the importance of its various components, such as dietary fiber especially, β-glucan, minerals and other nutrients. Oats and oat-enriched products have been proven to control blood glucose and are helpful in the treatment of diabetes. However, the results from clinical trials in humans investigating the effect of oat intake on glycemic control and insulin sensitivity are inconsistent. Therefore, we conducted a meta-analysis of randomized controlled trials (RCTs) to quantitatively assess whether oat intake has beneficial effect on glycemic control and insulin sensitivity and aim to make some suggestions for diabetes diet based upon what we found.

What have we done?

We conducted a literature search in PubMed, ScienceDirect Online and the Cochrane Library (up to October 2013) for RCTs that assessed the effect of oat intake on glucose control and insulin sensitivity. A random-effects model was used when overall pooled studies showed significant heterogeneity. Otherwise, a fixed-effects model was adopted. Quality assessment was conducted according to the modified Jadad scale.The sensitivity analyses and dose-effect calculations were also done to strengthen this work.

What did we find?

A total of 569 articles were initially identified after duplicates removed and 15 eligible articles were selected for analysis. The total numbers of participants were 673 in all studies. There was a slight decrease in fasting glucose concentrations, glycated hemoglobin and HOMA-IR in subjects after oat intake, but the difference was not significant. Subgroup analysis suggest that additional long-term and high-quality RCTs conducted in human subjects with parallel design are needed to further investigate the effect of oat intake on fasting glucose, which may provide evidence for the therapeutic potential of oats in diabetic patients or preventing glucose dysregulation in those with risk factors for DM.

 This paper is freely available for one month via the following link: journals.cambridge.org/ns/aug14

Nutrition Society Paper of the Month

Each month a paper is selected by one of the Editors of the five Nutrition Society Publications (British Journal of Nutrition, Public Health Nutrition, Nutrition Research Reviews, Proceedings of the Nutrition Society and Journal of Nutritional Science). This paper is freely available for one month.