Teens have more nutritional deficiencies after gastric bypass vs sleeve gastrectomy

Last Updated: 2019-12-06

By Marilynn Larkin

NEW YORK (Reuters Health) - More than twice as many teens who underwent Roux-en-Y gastric bypass (RYGB) for weight loss had multiple nutritional deficiencies compared to those who underwent sleeve gastrectomy (SG), researchers say. Ongoing nutrition monitoring and supplementation is recommended, regardless of surgery type.

"The higher prevalence of micronutrient deficiencies - particularly iron and B12 - after RYGB versus SG is an important differentiating risk when discussing these procedures with adolescents/families, particularly because the primary benefit, mean observed weight loss, is not significantly different between the two surgeries up to five years postoperatively," Dr. Thomas Inge of Denver and Children's Hospital Colorado in Aurora said.

"Shared risk factors for micronutrient deficiencies after RYGB and SG include decreased volume and variety of food intake; reduction of both gastric acid (important for absorption of food-based iron) and gastric intrinsic factor (prevents B12 degradation); markedly reduced absorption of iron in isotope studies; and imperfect adherence to required vitamin/mineral supplementation," he told Reuters Health by email.

"Why RYGB is associated with a higher prevalence of iron and B12 deficiencies versus SG...requires more research," he added. "Possible mechanisms include anatomical ...and physiological differences, including procedure-specific changes in biochemical regulators of micronutrient transport and uptake."

The study cohort included 161 adolescents who underwent RYGB and 65 who had SG from 2007-2012. The mean age was 16.5 years and mean body mass index was 52.7 at surgery; 75% were female, and 72%, white.

Serum levels of ferritin; red blood cell folate; vitamins A, D, B1, B12; and parathyroid hormone were measured annually for five years.

As reported in Clinical Gastroenterology and Hepatology, the overall mean body mass index decreased 23% at five years, with no significant difference between procedures.

However, after RYGB, but not SG, serum concentrations of vitamin B12 decreased significantly, whereas serum levels of transferrin and parathyroid hormone increased.

Ferritin levels decreased significantly after both procedures. Hypo-ferritinemia was seen in 2.5% of patients before RYGB and 71% at five years after RYGB, and 11% before SG and 45% five years after VSG.

No significant changes after either procedure were found in serum levels of folate or vitamins A, B1, or D from baseline through five years.

The proportion of patients with at least two nutritional deficiencies increased significantly over five years after RYGB (from 12% to 59%), but not after SG (6% to 27%). Similarly, the prevalence of at least three nutritional deficiencies increased following RYGB (from 3% to 19%) but remained low after SG (rising from 2% to 2.3%).

Dr. Inge said, "For adolescents with a history of poor adherence to taking medications, regardless of the chosen metabolic and bariatric surgery (MBS) procedure, preoperative behavioral interventions (e.g., led by a clinical psychologist) can be implemented to reduce barriers and develop skills to improve medication/supplement intake."

"Current micronutrient screening, prevention, and treatment guidelines after MBS are driven by adult data," he added. "The needs of adolescents and young adults may differ and require additional study."

Dr. Marc Bessler, Director of the Center for Metabolic and Weight Loss Surgery at Columbia University Medical Center in New York City, commented in an email to Reuters Health, "In general I believe lifelong micronutrient supplementation and annual testing is appropriate after bariatric surgery."

"It makes sense that gastric bypass, which decreases acid exposure to ingested nutrients and bypasses the duodenum, would have more Iron and B12 issues," he said. "Sleeve would be less likely to have these issues given it does not bypass duodenum. "

"Sleeve is likely best option for most teens, given the lower risk of long-term complications such as ulcers, bowel obstruction and possibly calcium metabolism that can lead to osteopenia," he added. "Though B1 was not different (between the groups), there is a small subset of patients with food intolerance in the weeks after surgery who can develop a dangerous B1 deficiency that physicians should be aware of."

SOURCE: http://bit.ly/2DPRTR4 Clinical Gastroenterology and Hepatology, online November 6, 2019.