Table 3.

Limitations of clinical and dietary intervention studies of fructose malabsorption and intolerance

• Optimal hydrogen breath test parameters are still under debate and reproducibility is limited.

• Fructose is usually provided in a liquid bolus dose in isolation from glucose, after fasting, in quantities not typical to foods, potentially resulting in over diagnosis.

• Most studies do not screen for or measure methane production, potentially resulting in under diagnosis.

• Testing methods vary widely in terms of test substance amount, breath testing protocol, and comparisons with other sugars.

• Poor correlation between a positive breath test and induction of symptoms limits causal attribution.

• Baseline fructose intake prior to dietary intervention is not typically assessed or reported.