Clinical Edge

Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Fiber Supplementation and Metabolic Outcomes

Am J Clin Nutr; 2017 Dec; Thompson, et al

Isolated soluble fiber supplementation improves anthropometric and metabolic outcomes in overweight and obese adults, according to a recent study. The systematic review and meta-analysis included 12 randomized controlled trials with 609 participants from 2 to 17 weeks of duration. Outcomes related to weight management and glucose and insulin metabolism were evaluated. Researchers found:

  • Soluble fiber supplementation reduced body mass index (BMI) by 0.84, body weight by 2.52 kg, and body fat by 0.41%, compared with placebo.
  • Supplementation reduced fasting glucose by 0.17 mmol/L, and fasting insulin by 15.88 pmol/L, compared with placebo.


Thompson SV, Hannon BA, An R, Holscher HD. Effects of isolated soluble fiber supplementation on body weight, glycemia, and insulinemia in adults with overweight and obesity: a systematic review ad meta-analysis or randomized controlled trials. Am J Clin Nutr. 2017;106(6):1514-1528. doi:10.3945/​ajcn.117.163246.


Most Americans only get about 50% of the recommended daily fiber intake, with obese adults often getting even less.1 The most common dietary sources of fiber are cereals, fruits, and vegetables but most people don’t get enough fiber through these dietary sources, so consideration of additional fiber through supplementation may make sense. Soluble fiber intake leads to increased satiety, improved blood lipid concentrations, and improved glycemic response. Examples of soluble fiber include psyllium (Metamucil) which is a fermentable soluble fiber. Fermentable soluble fibers have advantageous metabolic benefits, though they often cause gas production and bloating. Non-fermentable soluble fibers like Methylcellulose (Citracel) typically do not cause gas production and bloating, though may not have as extensive metabolic benefits. The current study, showing clinically important reduction in weight (average 5 pounds) and improvement in glucose with soluble fiber supplementation, strongly suggests that recommendation of supplementation with soluble fiber might be a productive part of our advice to patients who are trying to lose weight. — Neil Skolnik, MD

  1. King DE, Mainous AG, Lambourne CA. Trends in dietary fiber intake in the United States, 1999-2008. J Acad Nutr Diet. 2012;112:642–8.