Evaluation of Short-term Nutritional Regimens Following Bariatric Surgery

From the National Anemia Action Council, September 15, 2009:

Evaluation of Short-term Nutritional Regimens Following Bariatric Surgery

NAAC Review Published: September 15, 2009

The two types of bariatric procedures most often performed in Europe are adjustable gastric banding (AGB) and gastric bypass (GBP). The use of bariatric surgery has demonstrated long-term effectiveness on weight loss and comorbidities, including three recent studies, which used restrictive and malabsorption procedures, with findings of decreased mortality several years following the bariatric procedures. Gastric bypass, an irreversible restrictive and mildly malabsorptive procedure, is more efficient than AGB, a purely restrictive and reversible procedure, on weight loss and comorbidities. However, GBP potentially induces more nutritional deficits, compared to adjustable gastric binding. Adverse effects of bariatric surgery are not uncommon, but less is known about nutritional complications of bariatric surgery. In the present study, the authors prospectively compared the prevalence of nutritional deficiencies after AGB and GBP procedures.

A one-year prospective study of nutritional parameters was undertaken between 2004 and 2006 with 70 consecutive severe obese patients, of which 21 had undergone AGB and 49 had undergone GBP. Patients who had returned between nine and 15 months after the laparoscopic bariatric surgery were systematically reevaluated one year after surgery. Dietary advice was systematically given to patients before surgery, during hospitalization, and during followup, and included the administration of multivitamin supplements when necessary.

At one year following the procedures, digestive symptoms were more polymorphic in the GBP patients. At one year after surgery, all patients, except for two of the GBP group were taking multivitamin supplements versus none in the AGB group. The most frequent deficiencies before and after bariatric procedures were iron (assessed by transferrin saturation), vitamin B1, and C deficiencies. There were lower concentrations of B12 one year after surgery in the GBP group as compared to presurgery. Anemia was present at one year following the procedures in two AGB patients and five GBP patients. Three of the anemic patients had vitamin B12 deficiency, five patients had iron deficiency, and no patients had folate deficiency.

The authors concluded that the results demonstrated that severe nutritional deficiencies could be prevented on a short-term basis. Although systematic prescription of multivitamins may be unnecessary after AGB, oral vitamins B1 and C or iron should be prescribed when necessary. There was a high prevalence of iron, thiamine, and vitamin C deficiencies before surgery that affected nearly 50% of the obese population. Bariatric surgery did not worsen these deficiencies, except for a slight decrease of vitamin B1 after AGB.

Coupaye M, Puchaux K, Bogard C, Msika S, Jouet P, Clerici C, Larger E, Ledoux S. Nutritional consequences of adjustable gastric banding and gastric bypass: a 1-year prospective study. Obes Surg. 2009 Jan;19(1):56-65.

NAAC Expert Commentary:
Bariatric or weight loss surgery has become one of the most frequently performed surgical procedures in recent years. Contributors to the growth of bariatric surgery include the large number of morbidly obese patients, the success of the procedure where other methods of weight loss have failed, and the development of laparoscopic techniques. The standard today remains a Roux-en-Y bypass (GBP) that involves stapling of the stomach to create a small gastric pouch followed by bypass of the remaining stomach and duodenum by anastomosis of a segment of small bowel. A more recent approach involves banding the stomach to create the pouch and avoidance of any surgical bypass (ABP). The band is adjustable and removable, making this procedure reversible, whereas GBP is permanent.

Adverse effects of either procedure are common and range from death – a rare occurrence – to wound infection, hernia, and nutritional abnormalities. The latter includes deficiencies in iron, calcium, vitamins, as well as protein malabsorption, which leads to anemia, osteopenia, and neurological complications. Anemia is the most prevalent of all these adverse effects.

Coupaye and colleagues recently reported the results of their one-year prospective study of 110 consecutive patients who underwent either GBP or ABP. All patients had been instructed to take daily oral multivitamin supplements. Their primary goal was to differentiate one procedure from the other in terms of incidence of nutritional consequences. They evaluated all patients one year after surgery with a host of parameters including clinical findings and standard laboratory values. These included assessment of creatinine, vitamin, mineral, and iron levels. All patients lost weight with better results in the GBP group. The most frequent deficiencies were iron, vitamin B1, and vitamin C. Seven of the 70 patients (10%) who were studied were anemic. Five patients had iron deficiency and three had vitamin B12 deficiency. The incidence of anemia was not increased from the preoperative period.

The authors correctly pointed out that assessment of transferrin saturation rather than ferritin concentration is the most accurate way to determine iron deficiency. Ferritin is an acute-phase reactant protein that fluctuates in response to several factors including inflammation and insulin response. Transferrin saturation value, typically 20-50% in non-anemic patients, reports the percentage of iron bound to the transport protein, transferrin. Because transferrin has a relatively short half-life compared, for instance, to albumin, it is often used in overall nutritional assessments of protein turnover. Like ferritin, transferrin is influenced by insulin kinetics and inflammation, which leads to decreased levels.

What can we learn from the study by Coupaye et al? The incidence of pre-operative and postoperative anemia was the same, probably because of the authors’ postoperative multivitamin treatment regimen. The primary cause of anemia was iron deficiency, which has been reported by several other authors. Of most importance, we observe that anemia remains a chronic problem.

Several other reports of anemia after bariatric surgery^1-10 have reached similar conclusions, with several key points emerging: (1) Anemia is common with reported incidence ranging from 17-67%; (2) Anemia is chronic, worsens over time, and is recurrent after treatment; (3) Most post-bypass anemia is caused by iron deficiency, but other deficiencies including vitamin B12 and micronutrients can occur. The latter are particularly difficult to appreciate because of the long interval from bypass to depletion of reserves. Physicians should look for other causes by rounding up the usual suspects such as menstrual and gastrointestinal bleeding. (4) Anemia appears to be more prevalent after GBP than ABP, but ABP is still in its infancy. (5) Multi-vitamin and vitamin C oral treatment helps prevent the development of iron deficiency anemia. However, some people are resistant to oral treatment and will require parenteral iron. The bottom line is that bariatric surgery patients need life-long follow-up for diagnosis and treatment of anemia.

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