Inulin vs Polydextrose: which is worse?

What is Inulin?

Inulin is a naturally occurring prebiotic dietary fiber (fructan polysaccharide) found in chicory root, Jerusalem artichoke, garlic, onions, and bananas. Commercial inulin is extracted primarily from chicory root. It resists digestion in the small intestine and is fermented by beneficial gut bacteria in the colon, promoting growth of Bifidobacterium and Lactobacillus species.

What is Polydextrose?

Polydextrose is a synthetic polymer of glucose (with some sorbitol and citric acid) created under heat and vacuum conditions. It functions as a soluble dietary fiber, providing only 1 kcal/g. It is used to add bulk to reduced-calorie foods while also contributing fiber content. The FDA approved it as GRAS in 1981.

Documented risks

Inulin: Generally safe and beneficial. At doses above 15–20 g/day, inulin commonly causes bloating, gas, abdominal cramping, and diarrhea due to rapid fermentation in the colon. This is well documented in peer-reviewed research. It is contraindicated for people with fructan intolerance or irritable bowel syndrome following a low-FODMAP diet. At normal food fortification levels (3–8 g/serving), it is tolerated by most adults.

Polydextrose: At doses above ~90 g/day, polydextrose can cause flatulence, bloating, and loose stools. At normal food use levels it is well tolerated. EFSA confirmed its safety in 2012. It functions as a soluble prebiotic fiber, feeding beneficial gut bacteria. No genotoxicity, carcinogenicity, or reproductive toxicity has been identified.