A randomized crossover study to assess the effect of an oat-rich diet on glycaemic control, plasma lipids and postprandial glycaemia, inflammation and oxidative stress in Type 2 diabetes

• Published in: Diabetic medicine Vol. 30; no. 11; pp. 1314 - 1323
• Main Authors: McGeoch, S. C., Johnstone, A. M., Lobley, G. E., Adamson, J., Hickson, K., Holtrop, G., Fyfe, C., Clark, L. F., Pearson, D. W. M., Abraham, P., Megson, I. L., MacRury, S. M.
• Format: Journal Article
• Language: English
• Published: Oxford Blackwell Publishing Ltd 01-11-2013; Blackwell; Wiley Subscription Services, Inc
• Subjects: Adult; Aged; Avena; Biological and medical sciences; Blood Glucose - metabolism; Cross-Over Studies; Diabetes; Diabetes Mellitus, Type 2 - blood; Diabetes Mellitus, Type 2 - diet therapy; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Energy Intake; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Fasting - blood; Feeding. Feeding behavior; Female; Fundamental and applied biological sciences. Psychology; Humans; Hyperglycemia - etiology; Inflammation - metabolism; Lipids - blood; Male; Medical sciences; Middle Aged; Oxidative Stress - physiology; Postprandial Period; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Vertebrates: endocrinology; United Kingdom > UK; Endocrinopathy; Type 2 diabetes; Obesity; Oxidative stress; Nutrition; Postprandial; Nutrition disorder; Lipids; Metabolic diseases; Inflammation; Crossover study; Feeding; Blood plasma; Randomization; Diet; Surveillance; Endocrinology; Nutritional status; Glycemia
• ISSN: 0742-3071; 1464-5491
• DOI: 10.1111/dme.12228

Aims
In the UK, lifestyle intervention is first‐line management in Type 2 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.
Methods
In a randomized crossover design, 27 volunteers with Type 2 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 16 weeks. 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, interleukin 6, interleukin 18, 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.
Results
There were no diet‐related effects on glycaemic control or glycaemic or insulinaemic responses to the test meal. Total cholesterol (5.1 ± 1.0 vs. 4.9 ± 0.8 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.
Conclusion
The oat‐enriched diet had a modest impact on lipid lowering, but did not impact on oxidative stress or inflammation in these volunteers with Type 2 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 Type 2 diabetes in terms of reducing systemic levels of inflammation and oxidative stress and therefore cardiovascular risk.