Lactose intolerance: a non-allergic disorder often managed by allergologists.

Area of Science:

• Genetics
• Gastroenterology
• Human Biology

Background:

• Lactose malabsorption stems from intestinal lactase deficiency, affecting most global populations.
• Primary lactose malabsorption is inherited; secondary forms arise from intestinal diseases.
• Malabsorbed lactose in the colon causes gastrointestinal symptoms, termed lactose intolerance.

Purpose of the Study:

• To explore the genetic basis of lactase persistence and non-persistence.
• To review diagnostic methods for lactose malabsorption and intolerance.
• To evaluate current and alternative management strategies for lactose intolerance.

Main Methods:

• Review of scientific literature on lactose malabsorption and intolerance.
• Analysis of genetic factors (SNPs) associated with lactase persistence.
• Examination of diagnostic techniques like hydrogen breath tests and genetic testing.

Main Results:

• Lactase non-persistence is ancestral; lactase persistence is linked to specific SNPs (C/T 13910, G/A 22018) and agricultural history.
• Diagnosis involves clinical assessment, dietary lactose elimination, hydrogen breath tests, and genetic tests.
• Current treatment often involves dairy exclusion, potentially causing nutritional deficits.

Conclusions:

• Lactase persistence is a Mendelian dominant trait influenced by population dairy history.
• Effective diagnosis relies on non-invasive tests.
• Alternative treatments like enzyme supplements, probiotics, and dietary adaptation strategies are being explored to mitigate nutritional disadvantages of dairy exclusion.