A large body of research has accumulated to show that soluble fibre is beneficial to the health. In particular, because of its water absorbing and bulking action, soluble fibre can slow gastric transit time and decrease the absorption rate of glucose from the gut. This has beneficial properties in terms of lowering the blood glucose and blood insulin levels. Reports in the literature suggest that the more soluble the fibre, the greater its glucose and insulin lowering effect becomes. In this regard guar gum, a water soluble galactomannan fibre from Cyanopsis tetragonolobus (Indian cluster bean) is particularly effective. However, oat gum comprises of (1-3),(1-4)-β-D-glucan (β-glucan), a highly viscous polysaccharide that shows properties that may be beneficial in controlling insulin and glucose blood levels. Because oat fibre is more readily available, it may be a cheaper alternative to guar gum.
For example, researchers1 have investigated the blood insulin and blood glucose response to the consumption of 50g of glucose alone or in combination with 14.5g of oat gum (comprising of roughly 80% β-glucan) or 14.5g of guar gum in nine healthy subjects. The results showed that rises in plasma glucose and insulin levels were significantly greater following the glucose only meal, compared to the gum meals at both 20 and 60min. However, there was no significance difference between the guar gum or oat gum meals in terms of insulin and blood sugar responses. By 3h, the insulin and glucose levels had effectively returned to baseline in all groups. Eight of the subjects found the oat gum more palatable. The area under the curved for glucose decreased by 57.2% and 61.7% in the oat and guar gum meals, respectively, with similar results for insulin.
These results suggest that oat gum containing mainly β-glucan, which is more widely available and more palatable than guar gum containing galactomannan, is as effective at lowering blood insulin and blood glucose levels and may therefore be of higher commercial value or practical use in this regard. These results support research investigating the effect of pectin, a soluble fibre in many commonly eaten fruits such as apples. These types of soluble fibre therefore show promise as effective treatments in those individuals with hyperglycaemia and may allow more effective control of blood glucose in those with insulin insensitivity, such as occurs in metabolic syndrome. Because oats are readily available and cheap, they could be added to other foods in order to provide higher intakes of fibre and to decrease postprandial blood glucose levels. In addition, soluble fibres have been shown to successfully lower cholesterol levels in both healthy and hyperlipidaemic individuals.
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