Lactose after Roux-en-Y gastric bypass for morbid obesity, is it a problem?

Area of Science:

• Gastroenterology
• Bariatric Surgery
• Nutritional Science

Background:

• Roux-en-Y gastric bypass (RYGB) surgery is associated with food intolerances and gastrointestinal (GI) complaints, particularly after dairy consumption.
• The prevalence of lactose malabsorption and intolerance, and associated GI symptoms, before and after RYGB requires further investigation.

Purpose of the Study:

• To determine the prevalence of lactose malabsorption and intolerance in patients before and after RYGB.
• To assess the frequency of gastrointestinal complaints related to daily dairy consumption in these patient groups.

Main Methods:

• Lactose breath tests (LBT) and lactose tolerance tests (LTT) were administered to 84 pre-operative and 84 post-operative RYGB patients.
• Gastrointestinal symptoms were recorded at baseline and post-testing, with malabsorption defined by positive LBT/LTT and intolerance by positive tests plus increased GI complaints.
• A questionnaire captured daily dairy consumption and subsequent GI complaints, comparing pre- and post-operative data.

Main Results:

• Lactose malabsorption increased significantly from 17.9% pre-operatively to 29.8% post-operatively (OR 2.46, p=0.03).
• No significant increase in proven lactose intolerance was observed (7.1% pre-op vs. 9.5% post-op, p=0.50).
• Gastrointestinal complaints after dairy consumption rose dramatically from 14.3% pre-op to 53.6% post-op (p<0.01).

Conclusions:

• RYGB surgery does not increase the incidence of proven lactose intolerance.
• A substantial increase in self-reported gastrointestinal complaints following dairy consumption occurs post-RYGB.
• The findings suggest that factors other than lactose, potentially including dairy fat content, contribute to post-RYGB gastrointestinal distress.