Evaluation of the effect of four fibers on laxation, gastrointestinal tolerance and serum markers in healthy humans.

Average dietary fiber intake in the United States is roughly half of the recommended amount. As new dietary fiber products are introduced to increase fiber intake, it is critical to evaluate the physiological effects of such fibers. This study examined the effect of 4 fibers derived from maize or tapioca on fecal chemistry, gastrointestinal (GI) symptoms and serum markers of chronic disease. Twenty healthy subjects completed the single-blind crossover study in which 12 g/day of fiber (pullulan, Promitor Resistant Starch, soluble fiber dextrin or Promitor Soluble Corn Fiber) or placebo (maltodextrin) were consumed for 14 days followed by a 21-day washout. GI symptom surveys were completed (days 3 and 14), stools were collected (days 11-14), diet was recorded (days 12-14) and fasting blood samples were obtained (day 15). The 4 test fibers were well tolerated, with mild to moderate GI symptoms. Total short-chain fatty acid (SCFA) concentrations did not differ among the treatments. Fecal pH and individual SCFAs were affected by some treatments. Stool weight and serum markers of chronic disease did not change with these treatments. Increasing fiber intake by 12 g/day was well tolerated and may have a positive impact on colon health due to fermentation.