Table 1.

Clinically meaningful effects of representative fiber supplements

	No water‐holding capacity			Water‐holding capacity
	Insoluble	Soluble low/no viscosity		Viscous, gel‐forming			Viscous, nongelling
Fiber	Wheat bran	Wheat dextrin	Inulin	Partially hydrolyzed guar gum	β‐glucan	Psyllium	Methylcellulose
Common brand name	All‐Bran®	Benefiber®	Fiber‐Choice®	Generic	Quaker Oats®	Metamucil®	Mirafiber®, Citrucel®
Source	Wheat	Heat/acid‐treated wheat starch	Chicory root	Guar beans	Oats, barley	Seed husk, blonde psyllium	Chemically treated wood pulp
Degree of fermentation	Poorly fermented	Readily fermented	Readily fermented	Readily fermented	Readily fermented	Nonfermented	Nonfermented
Cholesterol lowering				+/−b	+	+
Improved glycemic control				+/−b	+	+
Constipation	+a					+	+/−c
Diarrhea						+
IBS						+

^aIf particle size is sufficiently large/coarse to stimulate the mucosa.

^bRaw guar gum is a viscous/gel‐forming fiber, but PHGG is hydrolyzed to reduce viscosity (eliminate gelling) for improved palatability. A reduction in viscosity (loss of gel formation) correlates with a reduction in/loss of efficacy.

^cMethylcellulose has an OTC indication for relief of constipation, but there are no well‐controlled clinical studies in constipated patients to support efficacy versus placebo. The American College of Gastroenterology determined that methylcellulose had insufficient clinical data to recommend it for treatment of chronic constipation (Brandt et al., 2005).