Are you Feeling your Oats Today?
The number of people with diabetes mellitus has doubled over the past 3 decades. WHO estimates 150 million people worldwide have diabetes and the number will double by 2025. There is increasing interest in finding nutritional components which may help control healthy blood glucose levels. Oats are considered unique among cereal grains, partially because they contain β-glucan, a high-molecular weight polysaccharide exhibiting high viscosity at relatively low concentrations. Because of its viscous nature, β-glucan, slows starch digestion and helps slow the absorption of glucose from the gut.
Bao and colleagues searched the scientific literature for randomized controlled trials (RCTs) studying the effect of oat intake on glycemic control and insulin sensitivity. They reviewed 569 articles and selected 15 articles meeting their criteria with 673 subjects published before October, 2013. The β-glucan content ranged from 3 to 10 mg/d (median of 5 mg/d). Five studies enrolled healthy people and 10 enrolled individuals with metabolic diseases (type 2 diabetes, overweight, hypercholesterolemia, hypertension). They report oat intake significantly lowered fasting insulin concentrations and glycemic responses (area under the curve).There was a reduction in fasting glucose and glycosylated hemoglobin concentrations in people consuming oats but they were not statistically significant differences.
Oats have health benefits beyond blood glucose control. The US FDA approved a health claim for reducing plasma cholesterol and risk of heart disease in 1997 as did the UK Joint Health Claims Initiative in 2004. Application of the claim requires a product to contain 0.75 g of β-glucan per serving. In 2010, EFSA approved a health claim: Oat beta-glucan has been shown to lower/reduce blood cholesterol. Blood cholesterol may reduce the risk of (coronary) heart disease.
Have you had any oats today?
Bao L, Cai X, Xu M, Li Y. Effect of oat intake on glycaemic control and insulin sensitivity: a meta-analysis of randomized controlled trials. 2014 Br J Nutr doi: 10.1017/S0007114514000889
Othman RA, Moghadasian MH, Jones PJ. Cholesterol-lowering effects of oat β-glucan. 2011 Nutr Rev doi: 10.1111/j.1753-4887.2011.00401.x
Scientific opinion on the substantiation of a health claim relating to oat beta-glucan and lowering blood cholesterol and reduced risk of (coronary) heart disease. 2010 EFSA J doi: 10.2903/j.efsa.2010.1885