Fibre has beneficial effects on postprandial glycaemia. In particular, soluble fibre may be particularly beneficial because of its ability to form viscous solutions when exposed to the aqueous environment of the gut. Increased viscosity provides a physical barrier to the digestion of carbohydrate, and this may explain the ability of soluble fibre to benefit individuals with blood sugar disorders such as diabetes and glucose intolerance. Xanthan gum is a fibre produced by the bacteria Xanthomonas campestris, which is used as an thickening additive by the food industry due to its viscosity enhancing effects. Like guar gum, xanthan gum also increases the viscosity of the chyme in the gut when taken orally, and this may produce beneficial glycaemic effects in humans. Xanthan gum may therefore be beneficial as a treatment to diabetes, a disease characterised by poor blood sugar control. Studies have previously shown that xanthan gum can inhibit postprandial lipogenesis following a high carbohydrate meal.
Researchers have assessed the effects of xanthan gum in the control of blood sugar disorders. For example in one study1 researchers fed xanthan gum containing muffins to diabetic and nondiabetic subjects over a 12 week period, on top of their normal ad libitum diets. The muffins were administered in such as way as to provide a consistent 12 grams of xanthan gum per day. The diabetic subjects all had type 2 diabetes with moderately elevated plasma levels of glucose, but were not taking insulin to control their blood sugar. Following 12 weeks of treatment, the muffins had had a beneficial effect on the fasting blood glucose levels in the diabetic subjects. In addition, postload glucose levels were lowered in response to an oral glucose tolerance test. Plasma levels of total cholesterol were also reduced in the diabetic subjects. In addition, there was a trend towards lowered levels of gastric inhibitory peptide (glucose-dependent insulinotropic peptide; GIP), plasma very low density lipoprotein (VLDL) and gastrin.
This study suggests that xanthan gum may have beneficial effects on metabolic regulation in those with a disorder of blood sugar control. This is inline with previous and more recent data suggesting that soluble fibre is beneficial to the health because it regulates carbohydrate digestion. Many studies investigating the effects of fibre on postprandial glycaemic have had to use high intakes of fibre that may be unpalatable. However, the 12 grams in this study was well tolerated and no problems were reported in consuming the fibre in the muffins. Considering the muffins each contained 17.6 grams of carbohydrate, the vast majority of which was sugar, and that they also added 840 kcal to the diet of each subject it is surprising that they had such a beneficial effect. The most striking effect of the 12 grams of xanthan gum was the ability to lower the fasting blood glucose in just 3 weeks, and then produce greater falls over the next three weeks. In this regard xanthan gum may be one of the more beneficial fibres that have been investigated.
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