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Many Teens Missing Micronutrients Years After Bariatric Surgery

The good news: Bariatric surgery can be a life-changer for severely obese teens. Not only do young people experience dramatic weight loss, but they also benefit from near-immediate improvement of diabetes plus longer-term reductions in heart health risks.

However, these benefits come with a caution: Recipients may develop nutrient deficiencies years after treatment that can carry their own health risks if not properly managed. Also, one of the two primary forms of bariatric surgery, gastric bypass, appears to cause more nutritional disruption than the other, vertical sleeve gastrectomy (VSG).

Findings from this study, led by experts at Cincinnati Children’s, were published online in the journal Clinical Gastroenterology and Hepatology.

“This study highlights the importance of annual nutritional screening,” says Stavra Xanthakos, MD, medical director of the Surgical Weight Loss Program for Teens at Cincinnati Children’s and first author of the study. “We also found that the risk of nutritional deficiency is lowest in patients with the highest intake of recommended vitamin and mineral supplements, so these risks can be minimized with appropriate supplementation and good adherence.”

Bariatric surgery has been offered to hundreds of thousands of adults since the 1990s and increasingly has been used to prevent severe obesity in teens.

Since 2007, experts at Cincinnati Children’s have been working with other top pediatric centers across the country to track outcomes from these surgical treatments through a large federally funded study called Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS).

In this study, Xanthakos; senior author Heidi Kalkwarf, PhD, RD; and their surgical colleagues, including Michael Helmrath, MD, at Cincinnati Children’s, and Thomas Inge, MD, PhD, at Children’s Hospital Colorado, focused on the nutritional impacts of the two most common forms of the surgery—Roux-en-Y gastric bypass (RYGB) and VSG. Their findings five years after treatment include the following:

• In both procedures, patients benefitted from weight loss of approximately 23%.
• After RYGB, levels of vitamin B12 declined significantly, but B12 levels didn’t drop after VSG.
• After RYGB, 71% of patients had low iron stores compared with 2.5% of patients prior to surgery.
• For those receiving VSG, 45% had low iron stores at five years, compared with 11% prior to surgery.
• More than twice as many RYGB participants than VSG recipients had multiple nutrient deficiencies at five years (59% vs 27%).
• No significant changes were found after either procedure for folate or vitamins A, B1, or D.

“Both B12 and iron deficiency can cause anemia, and B12 deficiency can also cause significant neurological dysfunction,” Kalkwarf says. “If caught early, dietary supplements can minimize these risks, which is why annual nutrition testing is so important. It’s also important to eat a well-balanced diet in addition to taking supplements and involve a registered dietitian in the pre- and postoperative care of these patients.”

Untreated, the most common symptoms of iron deficiency anemia in adults include fatigue, weakness, and exercise intolerance. In young children, iron deficiency also can lead to cognitive impairment, but it’s unknown whether developing iron deficiency in adolescence would have the same effect.

People with B12 deficiency can suffer from anemia but also can experience symptoms of depression, irritability, cognitive slowing, and forgetfulness. With severe deficiency, some can develop numbness or tingling in extremities, gait problems, and partial paralysis.

“In our bariatric surgery program at Cincinnati Children’s, all patients get annual micronutrient and nutritional assessments as recommended. It’s also important for them to continue annual nutritional screening after they transition to adult care later in life,” Xanthakos says.

“The positive message is that the risk of nutritional deficiency can be minimized with appropriate dietary supplementation, so these procedures should not be avoided solely due to nutritional concerns,” says Inge, Teen-LABS’ principal investigator. “These procedures are very helpful for severely obese adolescents, especially those struggling with diabetes, severe fatty liver disease, or sleep apnea.”

Longer-term follow-up is important to detect any other consequences from surgery, such as changes in bone health. “For pediatric surgeons, these findings suggest favoring the VSG procedure as the firstline approach in teens,” Inge says.

Meanwhile, newer endoscopic bariatric procedures approved for adults may eventually become available at younger ages. “We will need to study nutritional risks after these endoscopic procedures as well,” Xanthakos says.

— Source: Cincinnati Children’s Hospital Medical Center