Effects of lactose-free and low-lactose dairy on symptoms of gastrointestinal health: A systematic review

Lactose intolerance can be the result of, or aggravated by, deficiency of β-galactosidase in the gastrointestinal tract, and is characterised by, e.g., diarrhoea, abdominal pain, bloating, flatulence, and nausea. This review examines the response to lactose-free milk and dairy products and health-related outcomes and consolidates a total of 23 studies on ≥90% hydrolysed dairy products (n = 10), lactose-free dairy products and whole dairy products (n = 10), lactose hydrolysed, lactose-free and whole dairy products (n = 2), and mildly hydrolysed and lactose-free milk (n = 1). Fourteen reported consumption of low-lactose or lactose-free milk, and four reported fewer symptoms of gastrointestinal distress compared with controls. Two studies reported greater symptoms with higher volume of milk consumed. Results were not consistent across studies. However, lactose-free or low-lactose dairy products form an important part of the diet for lactose intolerant individuals, providing important nutrients that reduce risk of deficiencies.