Gastric Sleeve, also known as laparoscopic Sleeve Gastrectomy, has become very popular in recent years. Since it is considered to be a restrictive therapy only, it was initially thought the procedure would not cause nutritional deficiencies. However, an increasing number of studies describe nutritional deficiencies in patients who have undergone the procedure1,2,3.
The causative factors for these deficiencies are thought to be the following2,3:
- Faster passage of food along the digestive tract as a result of accelerated gastric emptying may be leading to a decrease in absorption of nutrients in general.
- Resection of the fundus leads to decreased production of hydrochloric acid (HCl) by the parietal cells in the stomach. This sparsity of HCl has a negative effect on iron absorption, as the HCl has a role in the break up of iron before it is absorbed.
- Decrease in secretion of Intrinsic Factor (IF). As IF is essential to the absorption of vitamin B12, this is likely to cause vitamin B12 deficiency and may cause anaemia.
- Decreased food intake and possibly poor food choices of the patient.
- Vomiting and food intolerance caused by the procedure.
Indeed, studies on the short term effects of Gastric Sleeve have confirmed deficiencies. Capoccia et al. showed in a study in 138 patients following Laparoscopic Gastric Sleeve (LGS) that a significant proportion of patients developed vitamin B12 and folate deficiency4. Even though Capoccia did not see any iron deficiency in this patient group, Aarts et al. did report an iron deficiency in 43% of the 60 patients who had undergone the same procedure. Anaemia was seen in 26% of patients. In addition, Aarts recorded significantly low B12, folate, and Vitamin D levels in this group5.
In 2017, new research has been published that describes the long-term effects of Gastric Sleeve after 4-5 years1-3:
Pellitero et al. followed 176 patients for a longer period of time after Gastric Sleeve surgery, collecting 5 year follow-up data for 51 patients. Ben-Porat et al. reported the results of their study in 192 patients, following 27 of them up for 4 years, and Gillon et al. collected 5 year data for a total of 116 patients (336 patients at baseline). The results and conclusions of all these studies are very similar: in the long term, compliance of multivitamin use decreases, and nutrient deficiencies are present in a substantial proportion of patients. Continued monitoring with appropriate supplementation advice is recommended. Below you will find some further details with regard to the outcomes of the studies.
It is clear that compliance in taking multivitamins decreases quite dramatically over the years. Pellitero et al. saw self-reported compliance decrease from 85% in the first year to 50.9% in the fifth year1. Similar percentages were seen in the other studies, where compliance went from 92.6% in the first year to 37% at 4 years3 and from 75% to 54% at 5 years2. Even lower were the compliance figures for supplements taken in addition to multivitamins, such as patients taking extra vitamin D: at 5 years Pellitero et al. reported compliance of 25%1, whereas Ben-Porat et al. saw only 11.1% of patients compliant at 4 years3. Compliance with extra vitamin B12 supplementation was only 20-30% at 5 years in the study led by Gillon et al2.
Vitamin D is an important nutrient that assists with normal bone metabolism. Obesity itself is associated with a high prevalence of vitamin D deficiency3, due to a kidnapping effect of the adipose tissue on the circulating vitamin D1. Ben-Porat et al. reported very high prevalence of vitamin D deficiency pre-operatively of 96.2%, continuing at the high percentage of 89% and 86% at 1 and 5 years respectively3. Gillon et al. reported lower deficiency percentages in their study, noting only 6.7% of patients had vitamin D deficiency at 5 years2. In this particular study, it was not clear whether patients were using additional supplements, which makes it harder to draw a conclusion on this. Finally, Pellitero et al. found that, despite adequate supplementation, 73% of the patients were vitamin D deficient at baseline. In this study, for patients with a vitamin D level below 30 ng/mL, a supplementation with high-dose 16,000 IU calcifediol preparation was administered every 2 weeks. Despite this extra supplementation, the deficiency persisted in 35% of patients over the course of 5 years. In addition, PTH levels increased in 29.7% of patients, indicating disturbances in the calcium metabolism1. Based on these data, Pellitero et al. recommend an increase of the dosing of vitamin D even beyond the extra doses given in the study1.
Vitamin B12 deficiency was seen in all studies at baseline and the prevalence appeared to stay relatively stable over the course of the
4-5 years the patients were monitored. Prevalence was 13.6% and 15.4% at 1 and 4 years in the Ben-Porat et al. study3, while Gillon et al. described deficiency in 19%, 12.8% and 3.8% of patients at respectively 1, 2 and 5 years2. In the Pellitero et al. study, vitamin B12 deficiency decreased from 6.9% to 0% in 5 years1.
It is important to note that part of the patients was using additional vitamin B12 supplementation and that hepatic stores may be sufficient to maintain vitamin B12 levels months or even years within normal range after bariatric surgery. As vitamin B12 deficiency can cause serious disorders, such as peripheral neuropathy and myelopathy, Pellitero et al. recommend testing for vitamin B12 deficiency periodically in order to supplement if needed1.
Iron and ferritin
Iron deficiency and low ferritin levels can be expected based on the fact that the Gastric Sleeve procedure reduces the amount of hydrochloric acid (HCl) in the stomach, impairing the transformation of non-haem iron from meals to a more absorbable form2. This effect is confirmed by these long term studies: the percentage of patients experiencing ferritin levels below reference values increased significantly from 3.3% at baseline to 36.2% at 5 years in the Gillon et al. study2, even while patients were taking multivitamins. Pellitero et al. saw the percentage move from 21.3% at baseline to 10.8% and 17.3% at 1 and 2 years, while increasing again at 5 years to 24.5% percent of patients1 The percentage of patients with iron deficiency fluctuated between 44% at baseline to 28.6% at 4 years in Ben-Portat et al. study3.
Gastric Sleeve may be one of the least invasive bariatric procedures, but nutritional deficiencies are still seen both short term and long term in patients who have undergone the procedure. This is likely due to decreased food intake, but also on the negative effect of the procedure on HCl production and Intrinsic Factor release, leading to decreased absorption of iron and vitamin B12.
Recent publications on the subject of nutrient status after Gastric Sleeve at the long term show deficiencies despite the use of standard multivitamins. The authors recommend stimulation of multivitamin compliance1, lifelong medical surveillance and long term nutritional follow up and supplementation maintenance3. In addition, as Pellitero et al. describes, the study results indicate that the current multivitamin supplementation protocol is not efficient enough for the prevention of some nutritional deficits. Thus, it is necessary to improve supplementation protocols to tailor to the Gastric Sleeve patients needs, decrease the specific deficiencies and avoid future complications1.
1. Pellitero S, Marinez E, Puig R, Leis A, Zavala R, Granada MS, Pastor C, Moreno P, Tarasco J, Puig-Domingo M, Balibrea J. 2017. Evaluation of Vitamin and Trace Element Requirements after Sleeve Gastrectomy at Long Term. Obes.Surg vol 27; 1674-1682
2. Gillon S, Jeanes YM, Andersen JR, Vage V. 2017. Micronutrient status in morbidly obese patients prior to laparoscopic sleeve gastrectomy and micronutrient changes 5 years post- surgery. Obes. Surg. Vol 27; 606-612
3. Ben-Porat T, Elazary R, Goldenshluger A, Dagan SS, Mintz Y, Weiss R. 2017. Nutritional deficiencies four years after laparoscopic sleeve gastrectomy- are supplements required for a lifetime? Surgery for Obesity and Related Disorders (13) 1138-1144
4. Capoccia D, Coccia F, Paradiso F, Abbatini F, Casella G, Basso N, Leonetti F. 2012. Laparoscopic gastric sleeve and micronutrients supplementation: our experience. J Obes 2012:1-5 5. Aarts EO, Janssen IMC, Berends FJ. 2011. The gastric sleeve: losing weight as fast as micronutrients? Obes Surg. 21:207-11