Abstract
The breakdown and absorption of nutrients, a key function of the digestive system, is impaired in carbohydrate maldigestion and bacterial overgrowth of the small intestine. The resulting continuous irritation of the intestinal mucosa may have a systemic impact and lead to chronic conditions and increased susceptibility to parasitic infections. Precise diagnosis is therefore of great importance. Traditional methods are invasive, require large challenge doses or, as in elimination diets, do not provide definitive diagnosis. Measurement of hydrogen and methane levels in alveolar samples collected following a carbohydrate challenge is simple, non-invasive and provides good sensitivity and specificity. Breath tests can further definitively demonstrate lactose maldigestion, differentiate other carbohydrate intolerances and allow determination of severity of carbohydrate intolerance. Percentages of false-negatives and false-positives are low compared to traditional methods when instructions are followed properly. Technical advances in collection and analysis have greatly simplified breath tests. Advantages of breath testing for practitioners and patients make this a promising technique for future applications.