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Vitamin Deficiency after Laparoscopic Roux-en-Y GB
Abstract & Commentary
By Helen Sohn, MD, Assistant Professor of Surgery, Department of Surgery, USC. Dr. Sohn reports no financial relationship relevant to this field of study.
Synopsis: Vitamin deficiencies after laparoscopic Roux-en-Y gastric bypass are more common and involve more vitamins, even those that are water soluble, than previously appreciated.
Source: Clements RH, et al. Incidence of vitamin deficiency after laparoscopic Roux-en-Y gastric bypass in a university hospital setting. Am Surg. 2006;72:1196-1202.
Vitamin deficiency after gastric bypass surgery is a known complication. The purpose of this study was to measure the incidence of vitamin deficiency after laparoscopic Roux-en-Y gastric bypass in a university hospital setting. All patients who underwent laparoscopic Roux-en-Y gastric bypass from January 2002 to December 2004, and completed a 1- and 2-year follow-up after surgery, were selected. Of the total 498 patients, 318 (65%) had vitamin results at the one-year follow up. Of the 366 eligible for the 2-year follow up, 141 (39%) had vitamin results. Patients were further grouped based on gender, race, and Roux limb length, and the incidence of vitamin deficiencies were also studied.
The incidence of vitamin A (retinol) deficiency was 11%, vitamin C was 34.6%, vitamin D25OH was 7%, vitamin B1 was 18.3%, vitamin B2 was 13.6%, vitamin B6 was 17.6%, and vitamin B12 was 3.6% 12 months after surgery. There was no statistical difference in the incidence of vitamin deficiencies between one and 2 years. In univariate and multivariate logistic regression of one- and 2-year follow up, black patients (vitamins A, D, and B1 for 1 year and B1 and B6 for 2 years) and women (vitamin C at 1 year) were more likely to have vitamin deficiencies. Vitamin deficiencies after laparoscopic Roux-en-Y gastric bypass are more common and involve more vitamins, even those that are water soluble, than previously appreciated. Black patients tend to have more deficiencies than other groups. The bariatric surgeon should be committed to the long-term follow-up and care of these patients. Further prospective and randomized studies are necessary to provide appropriate guidelines for supplementation. (Am Surg. 2006;72:1196-1202.)
The fact that vitamin deficiencies are common after a surgical procedure that restricts the intake and absorption of nutrients, is not alarming. That is the reason why all these patients are placed on chewable vitamins postoperatively and given vitamin B12 injections. What this study shows is that the deficiency is underestimated and that close follow up and supplementation is important in hopes of preventing clinical manifestation of the deficiency. It is debatable whether additional supplementation is indeed necessary in patients with subclinical deficiencies when there is no control group to compare to.
Clements and colleagues comment on the fact that there is no control group. They admit that the vitamin levels were not checked preoperatively due to practicalities. I assume that means they were not checked due to lack of reimbursement. And we assume that their vitamin levels were normal because they did not display any symptoms. That is a big assumption, considering that their unbalanced and unhealthy dietary habits and intakes, along with other factors, are what got them to a point of needing gastric bypass surgery. Yet even without symptoms, the levels were checked and followed closely after the surgery. Another way to get control data would have been to check vitamin levels on a group of patients with similar body mass index. And how about if we put normal people on the same dietary restrictions as those after gastric bypass surgery? What would be the prevalence of vitamin deficiency in a group of patients who have limited dietary habits for one reason or another? What about non-obese people that undergo a gastric resection or a small bowel resection, restricting either the intake or the absorption of nutrients but not for the purpose of weight loss? Would these people have similar vitamin deficiencies if we measured their levels? And should we put all asymptomatic people on supplementation, or do we just need better balanced diet?
It becomes evident that we don't have vitamin levels on these other groups of people because we don't check the levels routinely unless they manifest symptoms of vitamin deficiency. So what do these subclinical vitamin deficiencies in one group of patients mean to us? Should we focus on supplementation while placing restrictions (not only the amount) on their diet? We should instead focus on taking steps toward establishing healthier and more balanced dietary habits, especially after procedures that reduce the intake and/or the absorption of nutrients. (This commenter does not profess to practice nor even know how to achieve such healthy habits.)