28-Day oral toxicity study in rats with high purity barley beta-glucan (Glucagel (TM))

Beta-glucans are glucose polymers present in cereal grains, particularly barley and oat. Consumption of these grains or concentrated beta-glucan preparations has been shown to lower blood cholesterol. The present study was conducted to assess the safety of a high purity (>75%) barley beta-glucan (Glucagel (TM)). The product was fed to Wistar rats (5/sex/group) at dietary levels of 0% (control), 1%, 5% and 10% for 28 days. Clinical and neurobehavioural observations, growth, feed and water consumption, ophthalmoscopy, haematology, clinical chemistry, urinalysis, organ weights, necropsy and histopathological examination revealed no adverse effects of Glucagel (TM). High-dose males exhibited lower plasma cholesterol and phospholipids levels and a higher plasma urea level. These slight changes were considered of no toxicological significance. Full and empty caecum weights were increased in mid- and high-dose males. This caecal enlargement was a physiological response to the consumption of a high amount of indigestible carbohydrate and considered of no toxicological concern. In conclusion, feeding Glucagel (TM) at dietary levels up to 10% for 28 days was tolerated without any signs of toxicity. This dietary level was equivalent to 7.7 g Glucagel (TM) (5.8 g beta-glucan)/kg body weight/day in male rats and 7.8 g Glucagel (TM) (5.9 g betaglucan)/kg body weight/day in female rats. (C) 2009 Elsevier Ltd. All rights reserved.