A diverse fiber mixture reflecting a nutritionally balanced diet is well tolerated in healthy adults

Dietary fiber supports gastrointestinal health, yet most adults still fall short of recommended intake—leaving a persistent “fiber gap.”

A diverse mix of fibers, similar to those found in a balanced diet, may help close this gap—but tolerance matters, as more fiber can sometimes cause discomfort, such as bloating.

A new study in Current Developments in Nutrition examined whether a diverse fiber mixture designed to reflect a balanced diet is well tolerated in healthy adults.

Researchers tested a fiber mixture of arabinoxylan, β-glucan, pectin, and resistant starch, formulated to reflect the variety of fibers found in a balanced diet.

The study combined two complementary approaches: an in vitro fermentation model to assess short-chain fatty acid (SCFA) production and gas formation, and a clinical study in healthy adults aged 45–69 years. In the clinical study, participants consumed 6 g/day of the fiber mixture for four weeks in addition to their habitual diet, and gastrointestinal tolerance was assessed.

1. The fiber mixture was well tolerated 
   Throughout the four-week intervention, the fiber mixture was well tolerated. Gastrointestinal symptoms remained infrequent and within clinically acceptable limits, with most symptoms rated as causing no or only minor discomfort. Researchers observed a small, temporary increase in indigestion-related symptoms during the first week, which was consistent with an adaptation period following increased fiber intake.
   
   
2. Gut function remained stable 
   Gut function also remained stable throughout the study. No meaningful changes were observed in stool consistency or transit type, and although stool frequency increased temporarily during the first week, it stayed within normal ranges. Gastrointestinal-related quality of life remained unchanged over the course of the intervention.
   
   
3. Fiber supplementation helped close the “fiber gap” 
   Adding 6 g/day of the fiber mixture helped more participants reach the recommended daily fiber intake of 25 g, showing that moderate supplementation can be a practical way to complement habitual diets and help close the persistent “fiber gap.”
   
   
4. In vitro findings suggest a favorable fermentation profile 
   In vitro findings also pointed towards a favorable fermentation profile. The fiber mixture produced short-chain fatty acids (SCFAs), metabolites associated with gut health, and showed a higher SCFA-to-gas ratio than the individual fibers. This suggests the mixture may support efficient fermentation without excessive gas production.

Different dietary fibers have distinct chemical properties and fermentation capabilities. By combining fibers reflecting a balanced diet with complementary characteristics, fermentation processes may become more balanced, supporting SCFA production while moderating gas formation. This may also allow the gut microbiota to adapt more smoothly than it would with single-fiber intake. The study, therefore, suggests that fiber diversity, rather than fiber quantity alone, may be an important consideration in dietary strategies.

Closing the fiber gap is a major public health priority, but tolerance and consumer acceptance are essential for achieving sustained dietary change. These findings suggest that a diverse fiber approach may help support higher fiber intake, that moderate supplementation levels can be well tolerated in healthy adults, and that designing fiber solutions to reflect real dietary patterns may improve the overall user experience. 

Future research could explore how this fiber mixture performs in populations with lower baseline gut health, whether higher doses and longer-term intake remain similarly well tolerated, and how the mixture may affect microbiome composition, metabolic health, and satiety.

1. Dopheide L, Kozior M, Buco A, et al. 
   A diverse fiber mixture, reflective of a nutritionally balanced diet, is well tolerated by healthy adults. Current Developments in Nutrition. 2026.