Soluble soybean fiber: a 3-month dietary toxicity study in rats

• Published in: Food and chemical toxicology 2003-08, Vol.41 (8), p.1111-1121
• Main Authors: Takahashi, T, Nakamura, A, Kato, M, Maeda, H, Mandella, R.C, Broadmeadow, A, Ruckman, S.A
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological - drug effects; Administration, Oral; adverse effects; Animals; Biological and medical sciences; Blood Chemical Analysis; blood chemistry; Body Weight - drug effects; chemical structure; Cholesterol - blood; Diet; dietary fiber; Dietary Fiber - administration & dosage; Dietary Fiber - toxicity; Dietary fibre; Dose-Response Relationship, Drug; Eating - drug effects; feed intake; Female; Food toxicology; Glycine max; Hematologic Tests; Male; Medical sciences; No-Observed-Adverse-Effect Level; nutrient intake; Organ Size - drug effects; Rat; Rats; Rats, Sprague-Dawley; soluble fiber; Soluble fibre; soybean products; Spleen - drug effects; Spleen - pathology; Toxicity; toxicity testing; Toxicology
• ISSN: 0278-6915; 1873-6351
• DOI: 10.1016/S0278-6915(03)00065-6

Soluble soybean fiber (SSF) is a food ingredient intended for human consumption. SSF was administered in the diet to Sprague–Dawley CD® rats at concentrations up to 40,000 ppm for three months. Unformed stool was detected during the early and middle part of the treatment period and was considered an exaggeration of a normal physiological response to the fibre content in the diets, to which the animals appeared to adapt. This finding has been reported with other water-soluble fibres and was not considered an adverse effect. Decreased weight gain and food intake during the first half of the treatment period are possible sequelae of increased intestinal throughput. Adaptation was indicated by subsequently improved weight gain and food consumption. Decreased serum cholesterol occurred in males receiving 30,000 or 40,000 ppm and this has been reported before in rats fed soluble fibre. Haemoconcentration (indicated by increased erythrocyte count, haematocrit and haemoglobin concentration) and decreased spleen weight are likely related to minor fluid imbalances during exposure to high concentrations of dietary fibre and occurred at all SSF concentrations. The spleen was microscopically normal. In conclusion, the no-observed-adverse-effect level (NOAEL) for SSF in this study was 40,000 ppm (equivalent to 2.43 g/kg bodyweight/day for males and 2.91 g/kg bodyweight for females).