July 8, 2010

Gut Check: Do Chicory Inulin Products Cause GI Distress?

The June 2010 issue of the Journal of the American Dietetic Association features an article entitled "Gastrointestinal Tolerance of Chicory Inulin Products." In it, researchers from the University of  Minnesota (and Cargill, Inc.) set out to determine at what dose does added inulin fibers in food cause unwanted gastrointestinal disturbances.

Inulin is a soluble dietary fiber found naturally in plant foods like onions, leeks, garlic, asparagus, bananas, artichokes and chicory root. It is increasingly being added to what are normally low-fiber foods in order to boost their fiber content; in these cases, chicory root extract is becoming the inulin additive of choice. 

In the study, twenty-six healthy men and women aged 18-60 who usually age less than 15 g fiber per day were given a combination of either placebo, 5 g oligofructose (short chain fiber), 10 g oligofructose, 5 g inulin (longer-chain fiber) or 10 g inulin in a meal. They each took "fiber challenges" over a 10 week period with a 1-week washout period. Tolerance was reported by frequency of one of seven GI domains: gas/bloating, nausea, flatulence, GI cramping, diarrhea, constipation and GI rumbling. 

The study found that oligofructose and inulin in "practical doses" were generally well-tolerated. Ten-gram oligofructose caused the most symptoms, but the study pointed out that if spread out over the day, even high doses of fiber can be well-tolerated.

The bottom line application was: "Excellent sources of fiber" (5 g/serving) was well-tolerated for both short and long chain inulin. Furthermore, the chain length of inulin product affects tolerance. Inulin is fermented slowly and steadily so it is likely more well-tolerated than shorter chain oligofructose which is fermented rapidly. 

It is important to note that one of the authors on the paper is a senior manager of regulatory and scientific affairs at Cargill, Inc. Cargill's extensive product list does include inulin additives like Oliggo-Fiber Inulin, the health benefits of which are most likely overstated on the Oliggo-Fiber product page.