From the Guidelines
To evaluate possible lactose intolerance, a hydrogen breath test is the most appropriate diagnostic method, as it is relatively easy to perform and has similar sensitivity and specificity to the mucosal lactase assay 1. When evaluating lactose intolerance, it is essential to consider the various diagnostic methods available. The lactose hydrogen breath test is the most widely used method and is probably superior to lactose tolerance tests. This test involves ingestion of 25–50 g lactose dissolved in 200–500 ml water after an overnight fast, and end expiratory breath samples are taken at 15–30 minute intervals for three hours. A rise of hydrogen concentration from basal levels by more than 20 parts per million is compatible with a positive diagnosis 1. Some key points to consider when evaluating lactose intolerance include:
- The lactose hydrogen breath test has a false negative rate of up to 25%, so a negative result does not exclude the diagnosis 1
- A trial of a lactose-free diet should be considered if the diagnosis is still suspected, even with a negative breath test result
- Lactase enzyme supplements can help manage symptoms by providing the enzyme needed to digest lactose
- Most adults worldwide have some degree of lactose intolerance, and severity varies widely, with many people able to tolerate small amounts of dairy without problems
- Yogurt and aged cheeses contain less lactose and may be better tolerated by individuals with lactose intolerance.
From the Research
Evaluation of Possible Lactose Intolerance
- Lactose intolerance is a common condition worldwide, affecting between 57% and 65% of the population 2.
- It is caused by a reduction or loss of the activity of the intestinal enzyme lactase-phlorizin hydrolase, leading to undigested lactose in the small intestine and subsequent fermentation by bacterial flora 2, 3.
- Symptoms of lactose intolerance include abdominal pain, diarrhea, flatulence, and bloating, with considerable variability in severity 3, 4.
Diagnostic Methods
- The hydrogen breath test (HBT) is a non-invasive and widely used method for diagnosing lactose intolerance, with high sensitivity and specificity 2, 3, 5.
- Other diagnostic methods include genetic testing, quick lactase test, and lactose tolerance test, which are often used as integration tests with HBT 2.
- Methane measurements may also be of additional value in diagnosing lactose intolerance, particularly in patients who are negative for hydrogen but positive for methane 5.
Management and Treatment
- Management of lactose intolerance consists of dietary restriction and/or drug therapy, including the use of exogenous enzymes, probiotics, and prebiotics 3, 4.
- Lactase supplements have been shown to reduce clinical symptoms and hydrogen breath excretion in patients with lactose intolerance 4.
- A lactose-poor diet can also lead to significant symptom improvement in patients with lactose intolerance 5.