AimsIn the UK, lifestyle intervention is first-line management in Type2 diabetes. It is unclear what type of diet is most efficacious for improving glycaemic control. This study investigated the effects of an oat-enriched diet on glycaemic control, postprandial glycaemia, inflammation and oxidative stress compared with standard dietary advice. MethodsIn a randomized crossover design, 27 volunteers with Type2 diabetes, managed on diet and lifestyle only, were observed for two consecutive 8-week periods following either the oat-enriched diet or re-enforced standard dietary advice. Volunteers attended at baseline (habitual intake) and 8 and 16weeks. Measurements included basic clinical measurements and fasted and postprandial (3-h) glucose and insulin in response to a healthy test meal. Markers of inflammation and oxidative stress, including high-sensitivity C-reactive protein, interleukin6, interleukin18, tumour necrosis factor-alpha, adiponectin, thiobarbituric acid reactive substances, oxygen radical antioxidant capacity, oxidized LDL and urinary isoprostanes, were also measured at fasting and in the postprandial period. ResultsThere were no diet-related effects on glycaemic control or glycaemic or insulinaemic responses to the test meal. Total cholesterol (5.11.0 vs. 4.90.8 mmol/l, P=0.019) concentrations declined following the oat-enriched diet compared with standard dietary advice. There was a postprandial decline in adiponectin concentration (P=0.009), but no effect of dietary intervention. None of the measures of oxidative stress or inflammation were altered by the oat-enriched diet compared with standard dietary advice. ConclusionThe oat-enriched diet had a modest impact on lipid lowering, but did not impact on oxidative stress or inflammation in these volunteers with Type2 diabetes. What's new? No differences were observed in measurements of glycaemic control following either chronic intervention with the oat-enriched diet or acutely following an oat-enriched meal. A small beneficial effect of oats on plasma lipid profiles was observed that may have implications for reducing cardiovascular risk profiles. Consumption of a relatively healthy test meal produced smaller inflammatory responses than reported using either artificially high fat or carbohydrate loads. Results reinforce the importance of adhering to healthy eating advice in Type2 diabetes in terms of reducing systemic levels of inflammation and oxidative stress and therefore cardiovascular risk.