What is the primary cause of lactose intolerance in individuals with a deficiency of the enzyme lactase?

A Genetic mutation ✓
B Inflammation of the small intestine
C Imbalanced gut microbiome
D Insufficient dietary intake of lactose

Explanation

Lactose intolerance is primarily caused by a deficiency of the enzyme lactase, which is often due to a genetic mutation that affects the production or function of the enzyme.

Source

National Institute of Diabetes and Digestive and Kidney Diseases
Metabolic and Nutritional Disorders Nutrition and Metabolism Carbohydrate Metabolism Medium MEDICAL Confidence: high