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Bariatric surgery is recognized as a highly effective therapy for obesity since it accomplishes sustained weight loss, reduction of obesity-related comorbidities and mortality, and improvement of quality of life. Overall, bariatric surgery is associated with a 42% reduction of the cardiovascular risk and 30% reduction of all-cause mortality. This review focuses on some nutritional consequences that can occur in bariatric patients that could potentially hinder the clinical benefits of this therapeutic option. All bariatric procedures, to variable degrees, alter the anatomy and physiology of the gastrointestinal tract; this alteration makes these patients more susceptible to developing nutritional complications, namely, deficiencies of macro- and micro-nutrients, which could lead to disabling diseases such as anemia, osteoporosis, protein malnutrition. Of note is the evidence that most obese patients present a number of nutritional deficits already prior to surgery, the most important being vitamin D and iron deficiencies. This finding prompts the need for a complete nutritional assessment and, eventually, an adequate correction of pre-existing deficits before surgery. Another critical issue that follows bariatric surgery is post-operative weight regain, which is commonly associated with the relapse of obesity-related co-morbidities. Nu-tritional complications associated with bariatric surgery can be prevented by life-long nutritional monitoring with the administration of multi-vitamins and mineral supplements according to the patient’s needs.
Published by Baishideng Publishing Group Inc
World Journal of
World J Diabetes 2017 November 15; 8(11): 464-483
ISSN 1948-9358 (online)
Contents Monthly Volume 8 Number 11 November 15, 2017
November 15, 2017
Volume 8
Issue 11
| I
464 Bariatric surgery and long-term nutritional issues
Lupoli R, Lembo E, Saldalamacchia G, Avola CK, Angrisani L, Capaldo B
Retrospective Study
475 Reproductive disturbances among Saudi adolescent girls and young women with type 1 diabetes mellitus
Braham R, Robert AA, Musallam MA, Alanazi A, Swedan NB, Al Dawish MA
Contents World Journal of Diabetes
Volume 8 Number 11 November 15, 2017
Responsible Assistant Editor: Xiang Li Responsible Science Editor: Fang-Fang Ji
Responsible Electronic Editor: Li-Min Zhao Proong Editorial Ofce Director: Xiu-Xia Song
Proong Editor-in-Chief: Lian-Sheng Ma
World Journal of Diabetes
ISSN 1948-9358 (online)
June 15, 2010
Lu Qi, MD, PhD, Assistant Professor, Department of
Nutrition, Harvard School of Public Health, Boston, MA
02115, United States
Jingbo Zhao, PhD, Associate Professor, Aalborg
Hospital Science and Innovation Centre, Aalborg
Hospital, Aarhus University Hospital, Aalborg 9000,
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World Journal of Diabetes
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United States
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I-Ⅵ Editorial Board
Roberta Lupoli, Erminia Lembo, Gennaro Saldalamacchia, Claudia Kesia Avola, Luigi Angrisani, Brunella
464 November 15, 2017
Volume 8
Issue 11
Bariatric surgery and long-term nutritional issues
Roberta Lupoli, Erminia Lembo, Gennaro Saldalamacchia,
Claudia Kesia Avola, Brunella Capaldo, Department of Clinical
Medicine and Surgery, Federico University, 80131 Naples,
Luigi Angrisani, Department of Public Health, Federico
University, 80131 Naples, Italy
ORCID number: Roberta Lupoli (0000-0002-1701-7197);
Erminia Lembo (0000-0001-6711-887X); Gennaro Saldalamacchia
(0000-0002-2105-2462); Claudia Kesia Avola (Claudia Kesia
Avola); Luigi Angrisani (0000-0002-7695-5538); Brunella Capaldo
Author contributions: Capaldo B and Angrisani L devised the
study concept and design; Lupoli R, Lembo E, Saldalamacchia
G and Avola CK searched the literature; Capaldo B, Lupoli R,
Lembo E and Avola CK drafted the article; all authors revised the
article for important intellectual content; Capaldo B gave final
approval for the article.
Conict-of-interest statement: The authors declare that there
were no conicts of interest.
Open-Access: This article is an open-access article which was
selected by an in-house editor and fully peer-reviewed by external
reviewers. It is distributed in accordance with the Creative
Commons Attribution Non Commercial (CC BY-NC 4.0) license,
which permits others to distribute, remix, adapt, build upon this
work non-commercially, and license their derivative works on
different terms, provided the original work is properly cited and
the use is non-commercial. See:
Manuscript Source: Invited Manuscript
Correspondence to: Brunella Capaldo, MD, Department
of Clinical Medicine and Surgery, Federico II University, Via
Pansini 5, 80131 Naples, Italy.
Telephone: +39-81-7462302
Fax: +39-81-7462311
Received: June 9, 2017
Peer-review started: June 13, 2017
First decision: July 11, 2017
Revised: August 11, 2017
Accepted: September 4, 2017
Article in press: September 5, 2017
Published online: November 15, 2017
Bariatric surgery is recognized as a highly effective
therapy for obesity since it accomplishes sustained
weight loss, reduction of obesity-related comorbidities
and mortality, and improvement of quality of life.
Overall, bariatric surgery is associated with a 42%
reduction of the cardiovascular risk and 30% reduction
of all-cause mortality. This review focuses on some
nutritional consequences that can occur in bariatric
patients that could potentially hinder the clinical benets
of this therapeutic option. All bariatric procedures, to
variable degrees, alter the anatomy and physiology of
the gastrointestinal tract; this alteration makes these
patients more susceptible to developing nutritional
complications, namely, deficiencies of macro- and
micro-nutrients, which could lead to disabling diseases
such as anemia, osteoporosis, protein malnutrition.
Of note is the evidence that most obese patients
present a number of nutritional deficits already prior
to surgery, the most important being vitamin D and
iron deficiencies. This finding prompts the need for
a complete nutritional assessment and, eventually,
an adequate correction of pre-existing deficits before
surgery. Another critical issue that follows bariatric surgery
is post-operative weight regain, which is commonly
associated with the relapse of obesity-related co-
morbidities. Nu- tritional complications as soc iat ed
with bariatric surgery can be prevented by life-long
nutritional monitoring with the administration of multi-
vitamins and mineral supplements according to the
patient’s needs.
Key words: Bariatric surgery; Nutrient deciency; Roux-
en-Y gastric bypass; Sleeve gastrectomy; Pre-operative
Submit a Manuscript:
DOI: 10.4239/wjd.v8.i11.464
World J Diabetes 2017 November 15; 8(11): 464-474
ISSN 1948-9358 (online)
465 November 15, 2017
Volume 8
Issue 11
Lupoli R
et al
. Bariatric surgery and nutrition
decit; Weight regain
© The Author(s) 2017. Published by Baishideng Publishing
Group Inc. All rights reserved.
Core tip: Bariatric surgery is increasingly and successfully
applied for the treatment of morbid obesity. In spite of
multiple clinical benets,
, durable weight loss and
improvement/reversal of many comorbidities, a number
of nutritional complications can develop especially in
the long term, which could cause serious detriment to
patients’ health. We examine some important clinical
conditions that are caused by the deficit of vitamins
and micronutrients, such as anemia, osteoporosis, and
malnutrition. We also discuss the importance of careful
pre-operative assessments and the correction of pre-
existing nutritional deciencies, and present the current
recommendations for an appropriate biochemical and
nutritional monitoring in the long term.
Lupoli R, Lembo E, Saldalamacchia G, Avola CK, Angrisani L,
Capaldo B. Bariatric surgery and long-term nutritional issues.
World J Diabetes 2017; 8(11): 464-474 Available from: URL: DOI:
Obesity has become an important public health priority
because it increases the risk of comorbid conditions,
including diabetes, cardiovascular disease and several
types of cancers. In addition, it affects life quality and
expectancy[1]. The impact of obesity on life expectancy
has been well documented. Worldwide, over 2.5 million
deaths annually can be attributed to obesity. Of
particular concern is the growing economic burden that
the care of obesity and its complications imposes on
society and the health care system[2].
The increasing prevalence of obesity and comorbid
conditions worldwide prompts for effective strategies
for both treatment and prevention[1]. The treatment of
obesity includes lifestyle changes (dietary restrictions
and increased physical activity), the use of medications,
and in some cases, surgery. Lifestyle changes can cause
a 2%-6% weight loss; however, after 1-5 years, almost
90% of the patients have returned to their original
weight or might even gain some weight. Drug treatment
in general leads to a 5%-15% weight loss and should
be considered only as an adjunct to lifestyle changes.
Unfortunately, with respect to lifestyle intervention,
medical treatment rarely yields satisfactory results in
the long term[1,3].
Bariatric surgery has proven to achieve greater
weight loss than non-surgical management and, most
importantly, has proven to maintain it in the long
term[4]. Thus, in patients with morbid obesity, i.e., a
body mass index of 40 or 35 kg/m2 with co-
morbidities, bariatric surgery is presently considered
to be the only effective therapy for obesity. Extensive
data demonstrate that surgery can improve or
even reverse many comorbidities, such as type 2
diabetes, hypertension, obstructive sleep apnea and
steatohepatitis[5-7]. With regard to type 2 diabetes,
observational and randomized controlled trials with a
follow-up duration of up to 5 years have established the
superiority of bariatric surgery over medical therapy at
achieving remission of the disease and improvement
of the overall cardiovascular risk profile[8-10]. One of
the longest weight-loss studies - the Swedish Obese
Subjects - evaluated the long-term effects of different
bariatric procedures and demonstrated significant
reductions in cardiovascular and cancer-related mortality
as well as significant improvement in the quality of
In spite of multiple clinical benefits, a number of
surgical and gastrointestinal complications can occur
following bariatric procedures, although the diffusion
of the laparoscopic approach and the expansion of
centers of excellence have greatly reduced the rate of
post-operative mortality and adverse events[14]. The
mean mortality rate is 0.3% for all procedures, which
is comparable to those for hip replacement (0.3%) or
laparoscopic cholecystectomy (0.3%-0.6%). Indeed,
even lower mortality rates (0.04-0.13) are achieved
in high-volume obesity centers[14]. Among the possible
complications, nutritional deficiencies deserve careful
consideration. They can develop as a consequence of
reduced intake and/or malabsorption of nutrients and
are more commonly seen after malabsorptive or mixed
procedures in comparison to the restrictive procedures.
Other causal factors include pre-operative deciencies,
post-surgery food intolerance, changes in taste and
eating patterns and non-adherence to dietary and
supplement recommendations. Nutritional deficiencies
can present with a wide range of clinical manifestations,
depending on the specific nutrients/micronutrients
that are involved, the severity, and the duration of the
deficiency states. Because they could cause serious
detriment to patientseveryday lives and, in some
instances, could result in life-threatening complications,
a nutritional screening both before and after surgery is
strongly recommended.
This review focuses on the main nutritional issues
related to bariatric procedures by examining some
important clinical conditions that are caused by the
decit of vitamins and micronutrients, such as anemia,
osteoporosis, neurologic disorders, and malnutrition.
We will also discuss the importance of careful pre-
operative assessments and the correction of pre-
existing nutritional deficiencies, which are quite
common in obese patients. Last, recommendations for
the prevention and treatment of nutritional deciencies
after bariatric surgery are presented.
Surgical procedures are generally classified into
restrictive procedures, in which the stomach’s capacity
466 November 15, 2017
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Issue 11
is greatly reduced, malabsorptive procedures, in which
malabsorption is the primary driver of the weight loss,
or a combination of restrictive and malabsorptive
elements (Figure 1). However, over the past few years,
it has become clear that weight loss is not only due
to reduced food intake and/or absorption induced by
modification of gastrointestinal anatomy but also a
consequence of changes in neural and gut hormonal
signals that regulate hunger and satiety, gut microbiota,
intestinal nutrient sensing, food preferences, and
possibly energy expenditure[15]. These so-called weight-
independent mechanisms contribute to a variable extent
to weight loss and metabolic improvement, depending
on the type of surgical technique.
Laparoscopic adjustable gastric banding (AGB)
An adjustable silicone band is placed around the upper
stomach, a few centimeters below the cardia, creating
a 15 to 30 mL gastric pouch. The diameter of the outlet
can be changed by injection of or removal of saline
through a portal placed in the subcutaneous tissue that
is connected to the band.
Roux-en-Y gastric bypass (RYGB)
A small, vertically oriented gastric pouch is created,
which remains attached to the esophagus at one end
and, at the other end, is connected to a small section
of the small intestine, thus bypassing the remaining
stomach and the initial loop of the small intestine.
Sleeve gastrectomy (SG)
The operation involves division of the stomach vertically,
which reduces its size by 75%. The pyloric valve at
the bottom of the stomach is preserved such that the
stomach function and digestion remain unaltered. The
procedure is not reversible and might be a rst stage
procedure to a RYGB or duodenal switch.
Biliopancreatic diversion (BPD)
The operation consists of a distal horizontal gastrectomy
that leaves a 200-250 mL of upper stomach. This
remnant stomach is anastomosed to the distal 250
cm of small intestine (alimentary limb). The excluded
small intestine (carrying bile and pancreatic secretion),
called the biliopancreatic limb, is connected to the small
bowel 50 cm proximal to the ileocecal valve. The 50-cm
common limb is the only segment where digestive
secretions and nutrients mix, which causes a marked
malabsorption, especially for fat and protein.
A recent survey by the International Federation
for the Surgery of Obesity showed that RYGB and SG
account for the large majority of bariatric procedures
(45% and 37%, respectively). The use of ABG has
drastically fallen during the last decade and currently
accounts for 10% of all procedures. BPD and its
duodenal switch (BPD/DS)variant, which are truly
malabsorptive procedures, are rarely used (< 2%) to
date given the high risk of nutritional complications[16].
According to a recent report from the American Society
of Hematology, people who have undergone bariatric
procedures show the highest risk for anemia, with
33%-49% of operated patients presenting anemia
within 2 years after surgery[17]. As expected, the
average prevalence of anemia is lower following LSG
(17%) and reaches 45%-50% after RYGB and BPD. It
should be noted that, as underlined for other nutrient
deciencies, up to 10%-12% of obese patients already
have anemia before surgery[18]; thus, baseline screening
for anemia is recommended in all patients who are
scheduled for bariatric procedures.
Patients with mild anemia are most likely asymptomatic;
however, when the anemia worsens, the patients could
present with symptoms, such as fatigue, pallor, and
dyspnea on exertion. Of note, the presence of anemia
increases by twofold the risk of hospitalizations as well
as the length of the in-hospital stay[19].
Post-bariatric anemia is in most cases due to iron
deficiency, along with vitamin B12 deficiency as a
secondary cause. Iron deficiency, expressed by low
serum ferritin, occurs in more than 30% of patients
after 5 years from surgery, with a similar rate after
RYGB and SG, as recently reported by Alexandrou
et al[20]. Iron-deficiency can be attributed to several
causes. Reduced iron absorption due to hypocloridria
and the bypassing of the duodenum and proximal
jejunum (which are the main sites of iron absorption)
are the primary mechanisms that lead to iron deciency.
Post-operative reduction in food intake and changes
in food preferences, such as intolerance for meat and
dairy products, are important contributory factors.
Measurement of serum ferritin is the best diagnostic
test for detecting iron deficiency since it is a more
specific and earlier indicator of iron body capacity
and becomes abnormal prior to a decrease in serum
iron con-centration. For this reason, ferritin and
hemoglobin should be periodically monitored in bariatric
patients. Current guidelines[21] recommend oral iron
supplementation in all operated patients for preventive
purposes. However, for the correction of iron deciency
(when iron deciency sets in), oral supplementation is
not sufficient, and intravenous iron administration is
Vitamin B12 deciency is a major cause of anemia in
patients who undergo BPD and RYGB, with a prevalence
of 19%-35% after 5 years[ 22]. Purely restrictive
procedures are usually not associated with vitamin
B12 deciency. Vitamin B12 deciency can result from
inadequate secretion of intrinsic factor, limited gastric
acidity and, above all, the bypassing of the duodenum,
which is the main site of vitamin B12 absorption. Since
the human body has substantial reserves of vitamin
B12, clinical manifestations of a decit can appear after
Lupoli R
et al
. Bariatric surgery and nutrition
467 November 15, 2017
Volume 8
Issue 11
a certain time from surgery, when the body stores are
depleted to as little as 5%-10%. In addition to anemia,
a lack of vitamin B12 can lead to neurological and
psychiatric symptoms, including paresthesia, numbness,
disturbance of coordination, memory disturbance and,
in some instances, dementia. Oral or intramuscular
supplementation of vitamin B12 is recommended after
malabsorptive procedures, while there is no evidence of
benets after restrictive surgery.
Folic acid deficiency is a potential complication of
bariatric procedures that can contribute to anemia.
The prevalence of this decit after both restrictive and
malabsorptive procedures ranges from 9% to 39%[23,24].
It can manifest as macrocytic anemia, piastrinopenia,
leucopenia, or glossitis. It could cause growth retardation
and, in pregnant women, congenital defects (neural
tube). Since folate is absorbed throughout the small
intestine, the deficiency is primarily induced by a
shortage of dietary intake rather than malabsorption.
Furthermore, folate deficiency can be aggravated by
vitamin B12 deciency since the latter is necessary for
the conversion of inactive methyltetrahydrofolic acid to
the active tetrahydrofolic acid. Folate deciency can be
easily corrected by oral supplementation.
Abnormalities of bone metabolism
Bariatric surgery could impact bone metabolism
and induce significant changes, such as decreased
mechanical loading, calcium/vitamin D malabsorption
with secondary hyperparathyroidism, nutritional
deprivations, changes in fat mass and alterations in fat-
and gut-derived hormones[25-27].
In general, weight loss, achieved through dietary
restriction, drugs or bariatric surgery, is associated
with a significant reduction in bone mineral density
(BMD) and increased bone turnover[28]. In particular,
the bone loss reported after non-surgical weight loss is
much lower (1%-2%)[29] than that found after bariatric
procedures (8%-13%)[30,31] A recent meta-analysis of
studies that compare bariatric vs a non-operated control
group showed reduced BMD at the femoral neck but not
at the lumbar spine[30]. However, it is important to note
that the measurement error at the spine BMD is greater
than at other sites, which could likely account for this
discrepancy. In addition, there is high heterogeneity in
the studies analyzed with regard to different surgery
procedures, study design (most retrospective), and
patient characteristics (ethnicity, sex, menopausal/
postmenopausal stage, follow-up length), which could
account for the differences between the two sites.
Overall, the reductions in the BMD results are greater
after malabsorptive or mixed than after restrictive
procedures. Studies that compare RYGB and SG
have shown a greater bone loss after RYBG than SG,
especially at the hip and femoral neck[32]. Accordingly,
bone turnover expressed by circulating markers such
as CTX, PINP, TRAcP5b was significantly higher after
RYGB than after SG[33]. The difference in the BMD
between the two procedures could also be related to
the different hormonal patterns induced by the two
operations. Indeed, there is increasing evidence that
many fat- and gut-derived hormones could affect bone
health[25,33,34]. In particular, low levels of GIP, ghrelin,
amylin, and insulin and high levels of PYY exert negative
Adjustable gastric band
Port placed
under skin
Sleeve gastrectomy
Gastric sleeve
(new stomach)
portion of
Roux-en-Y gastric bypass
Digestive juice
portion of
Biliopancreatic diversion
removed Duodenal switch
Partially resected
Digestive loop
Digestive juice Common loop
Bilio-pancreatic loop
Figure 1 Commonly performed bariatric surgeries. Modied from
Lupoli R
et al
. Bariatric surgery and nutrition
468 November 15, 2017
Volume 8
Issue 11
effects on the bone mass. In contrast, low serotonin
and high GLP-1 levels appear to positively influence
the bone metabolism[25]. However, further studies are
needed to better dene the role of these hormones in
the regulation of bone metabolism.
Bariatric surgery is associated with an increased
risk of fractures[35,36]. In a population-based study, the
cumulative incidence of any new fracture at 15 years
was 58% in bariatric patients compared to 24% in non-
operated men and women of similar age. The relative
risk for any fracture was increased by 2.3-fold both at
the traditional osteoporotic (hip, spine, wrist) and at
non-osteoporotic sites[35].
Calcium and vitamin D deficiencies are the main
factors that are responsible for the accelerated bone
loss after bariatric surgery. The incidence of calcium
deciency after surgery is almost 10%[37] and is caused
by reduced calcium absorption that results from
bypassing the duodenum and proximal jejunum, which
are the main sites of absorption. In some cases, calcium
deciency could be exacerbated by low calcium intake
due to the intolerance/exclusion of milk products.
The prevalence of hypovitaminosis D after surgery
varies between 25% and 73%, depending on the
duration of the follow-up and its defining parameters
(25-OH-vitamin D < 20 or < 30 ng/mL). It is important
to note that hypovitaminosis D exists in a large
proportion of patients prior to surgery, with reports that
range from 25% to 80%. However, bariatric surgery
per se affects the vitamin D status[38]. Indeed, similar
to calcium deficiency, hypovitaminosis D could be a
consequence of fat malabsorption, due to the bypass
of the primary absorption sites of liposoluble vitamins
in the small intestine[39,40]. In fact, a duodenal surgical
bypass decreases cholecystokinin secretion, which
results in a reduction in pancreatic lipolytic enzyme
secretions and alteration in biliary salts, which in turn
leads to an alteration in fat digestion and steatorrhea[24].
In addition, after both malabsorptive and restrictive
procedures, reduced intake of dairy products, vomiting,
and non-adherence to supplement recommendations
could worsen the vitamin D status[39,40].
These are no clear recommendations for vitamin
D doses following bariatric surgery, since individual
patients could require larger or smaller doses according
to the degree of deficit. Current recommendations[21]
indicate that at least 5000 IU/d is required to maintain
adequate vitamin D levels after RYGB, while higher
doses (up to 50000 IU) are required after BPD. Recent
studies have suggested that the vitamin D level should
be maintained at over 25-30 ng/mL for the effective
prevention of osteoporosis and fracture risk. Daily
calcium supplementation (preferably as calcium citrate)
from 1200 to 2000 mg daily is recommended. It must
be considered that oral calcium could interfere with the
absorption of some essential minerals such as iron, zinc
and copper.
Deciencies of other vitamins and minerals
Low serum levels of fat-soluble vitamins (vitamin A, K
and E) have been found to occur after malabsorptive
procedures (BPD and long limb RYGB). However, the
available data are largely based on clinical reports
and, therefore, are insufficient to estimate the real
prevalence of these deficiencies. In two series of
studies, the incidence of vitamin A deficiency was
61%-69% at 2-4 year after BPD, with or without
duodenal switch[41,42]. In a third series, the incidence
was as low as 5% by 4 year[43]. Clinical manifestation
of vitamin A decits are night blindness, xerophthalmia
and dry hair.
Low levels of vitamin K have been reported in
50%-60%[42] of patients who underwent BPD or BPD/
DS, but no clinical symptoms such as easy bruising,
increased bleeding, or clotting alterations were reported.
With regard to the water-soluble vitamins, thiamine
(vitamin B1) deficiency can occur in up to 49% of
patients after surgery as a result of bypass of the
jejunum, where it is primarily absorbed, or in the
presence of impaired nutritional intake from persistent,
severe vomiting[44]. The early symptoms of thiamine
deficiency are nausea and constipation, followed by
neurological and psychiatric complications known
as Wernicke-Korsakoff syndrome. The prevalence of
vitamin C deficiency ranges from 10%-50%[45,46], but
it rarely results in manifest clinical signs (poor wound
healing, petechiae, bleeding gums).
Although most of the literature focuses on calcium
and iron, deficiencies of other essential minerals such
as magnesium, zinc, copper, and selenium have been
reported in bariatric patients[47]. Essential minerals act
as enzymatic cofactors in several biochemical pathways,
and therefore, their deficiency could cause variable
clinical manifestations that involve neurological, cardiac
and gastrointestinal systems. Mineral deficiencies are
more common after BPD and RYGB; however, the real
prevalence of these disturbances cannot be precisely
estimated since most deciencies can be present already
before surgery (see the next paragraph). In addition,
for some minerals such as copper and magnesium, the
circulating concentrations might not reflect their total
body stores, thus leading to underestimation of the real
Protein malnutrition
Protein malnutrition remains the most severe macronutrient
complication associated with malabsorptive surgical
procedures. It has been reported in 7%-21% of
patients who underwent BPD and is a consequence
of poor protein digestion and absorption secondary
to altered biliary and pancreatic function[48]. Protein
malnutrition can also occur after RYGB, where the Roux
limb exceeds 150 cm, with an incidence of 13% at
the 2-year follow-up. SG and AGB can lead to protein
malnutrition in patients who present maladaptive eating
behaviors after surgery, those who avoid protein food
sources and those who have protracted vomiting. The
clinical signs of protein malnutrition include edema,
hearing loss and low serum albumin level (< 3.5 g/dL).
Protein malnutrition associated with malabsorptive
Lupoli R
et al
. Bariatric surgery and nutrition
469 November 15, 2017
Volume 8
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procedures causes an annual hospitalization rate of
1% per year and leads to significant morbidity and
poor outcomes[49,50]. Monitoring the serum albumin
concentration is useful for the evaluation of the protein
nutritional state, although the serum protein level often
remains in the normal range until late. Measurement of
lean body mass by means of dual X–ray absorptiometry
or body bioimpedence assessment can be helpful for
the evaluation of body composition, although their
accuracy appears to be limited in bariatric patients.
According to consensus guidelines[21], the prevention
of protein malnutrition requires an average daily
protein intake of 60-120 g (1.1 g/kg of ideal body
weight), which should be increased by 30% following
BPD. Furthermore, great emphasis is posed on regular
training and aerobic exercise as being essential to
preserving lean mass and especially muscle mass.
Patients with severe protein malnutrition should be
managed with modular protein supplements that are
rich in branch-chain amino acids and, eventually, enteral
Post-operative weight regain
The regain of the weight lost is one of the main concerns
of bariatric patients over the long term. The incidence of
this phenomenon is quite variable according to the type
of procedure performed, the length of follow-up and,
above all, the criteria to dene weight regain. Among
different denitions, the most widely accepted method
refers to a regain of 25%-30% of the maximum weight
lost, corresponding to the weight before surgery, with
the subtraction of minimum weight or “nadir” after
surgery[51-53]. A recent review has shown that the rates
of weight regain for SG range from 5.7% at 2 years
to 75.6% at 6 years[54]. For RYGB, the percentage of
failure to maintain weight loss varies from 7% to 50%
of the subjects and tends to be higher in superobese
patients[55]. AGB is associated with the largest weight
regain (35%-40% of the weight lost), as evidenced in
several clinical studies[11,51].
The failure to maintain long-term weight loss
has important consequences on the patients’ health,
including the relapse of obesity-related co-morbidities[56].
Furthermore, it has substantial economic repercussions
for the recurrent costs associated with the management
of on-going obesity. Therefore, there have been many
efforts to understand the biological and psychologic/
behavioral bases that underlie this important
One of the major factors responsible for weight
regain is the reduction in energy expenditure (EE),
which is generally paralleled by the simultaneous loss of
lean body mass[57]. Recently, Tam et al.[57] showed that
EE is signicantly reduced 1 year after RYGB (-124 ±
42 kcal/die) as well as after SG (-155 ± 118 kcal/die)
compared to the baseline. These ndings extend what
was already known with diet-induced weight loss and
give support to the view that the reduction in EE is a
homeostatic mechanism that counteracts a reduction
in the caloric intake, which is aimed at preventing
excessive weight loss; however, in some conditions, it
could favor weight regain.
Another factor that contributes to weight regain
is the changes in entero-hormone and appetite
regulation[56]. As widely demonstrated, BS is associated
with a recovery of the postprandial response of GLP-1,
which increases by 3- to 6-fold compared to pre-surgery
levels[58]. Interestingly, it has been shown[52] that in
patients operated by RYGB, the post-meal response
of GLP1 was significantly greater in individuals who
maintained weight loss compared to individuals who
failed, which suggests that this hormone plays a role in
the maintenance of a favorable weight outcome. With
regard to ghrelin, the results are quite controversial,
with some but not all[59] studies showing greater and
more sustained suppression of ghrelin levels in bariatric
patients who maintained appropriate weight loss
compared to those who regained weight[60,61].
Moreover, mental health disorders, such as depression,
alcohol and drug use, and food urges are predictive
factors of weight regain[62,63]. Although binge eating
is more frequent among obese patients who make
recourse to BS (10%-50%), there is no doubt that its
persistence after surgery is associated with a minor
weight loss and an early weight regain[64].
Beyond all of the above-mentioned factors, the
success of bariatric surgery is strongly influenced
by the patients’ motivation to adhere to a healthier
lifestyle, including controlled energy intake and physical
activity[65]. In the Swedish Obese Subjects study[66],
the reported mean energy intake was 2900 kcal/die
before surgery, 1500 kcal/die 6 mo after surgery and
approximately 2000 kcal/die 4-10 years after surgery,
which demonstrates a progressive increase in calorie
intake over the years. These data emphasize dietary
counselling and the practice of physical exercise as
fundamental measures to prevent weight recidivism.
It is a common belief that nutritional deficiencies are
rare in Western countries due to the availability of low
cost and unlimited variety of food supply. However,
obese subjects often adopt an unhealthy diet that is
rich in high-calorie food with an unbalanced nutritional
composition[67,68]. The concomitant presence of high
calorie intake and nutrient deficiencies could impact
the effectiveness of calorie utilization, which could
determine a vicious cycle that leads to further weight
gain, depression, eating disorders, metabolic syndrome,
fatigue and more[67]. In support of these concepts, a
growing number of studies in the literature attest to
the frequent occurrence of nutrient and/or vitamin/
mineral deciencies in morbidly obese individuals prior
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. Bariatric surgery and nutrition
470 November 15, 2017
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to bariatric surgery, before weight loss and possible
surgical-related malabsorption set in.
With regard to the vitamin status, most evidence
refers to a 25(OH)vitamin D decit. Vitamin D insufciency
(< 30 ng/dL) has been reported in approximately 90%
of different study populations, and ranges from 65%[69]
to 100%[70], while vitamin D deciency (< 20 ng/dL) is
observed in approximately 60% of the patients, ranging
from 22%[71] to 83%[72]. The prevalence of severe
deficit (< 10 ng/dL) could reach 25%[73]. The degree
of deciency is predicted by the degree of obesity and
race, with African Americans being at higher risk[74].
Obese individuals are more likely to be deficient
in vitamin D because of the higher volumetric dilution
and sequestration of this fat-soluble hormone in
the adipose tissue[75]. As the fat mass increases, an
individual will require greater amounts of vitamin D (via
photoproduction from sun exposure, dietary intake,
and/or supplementation). Moreover, although there is no
difference in the vitamin D3 production between obese
and lean individuals, obese patients show an impaired
release of vitamin D3 from the skin[76]. Genetic variation
in the function of the vitamin D binding protein and
vitamin D receptor could also influence the 25(OH)D
levels, with some studies suggesting a higher frequency
of the poorer functioning forms in obesity[77,78].
The prevalence of vitamin B12 deciency in patients
scheduled for BS is reported in approximately 18% of
patients. Similarly, low levels of vitamin B1 (thiamine)
are reported in up to 20% of bariatric candidates. Few
studies have assessed the vitamin C status in bariatric
candidates, with a prevalence that ranges from 15%[69]
to 33%[79]. With regard to vitamins A and E, their
deciencies are less frequent[69,73]. In particular, vitamin
A has been found to be inversely associated with BMI,
age and number of comorbidities[73]. This nding most
likely occurs because low vitamin A levels are related to
increased oxidative stress, insulin resistance, impaired
glucose metabolism, cancers, and age-related macular
degeneration[80], all of which are commonly associated
with morbid obesity.
Among the minerals, iron deficiency is the most
common and ranges from 20% to 47%[81]. Iron and
ferritin deciency and iron-deciency anemia are more
frequent in younger patients (< 25 years) than in older
patients and in women than in men, although this
nding is not conrmed in all studies[82]. Iron deciency
in obese patients is likely related to the negative impact
that chronic inammation exerts on iron homeostasis.
In particular, there is evidence that cytokines (TNFα and
Assessments Pre-operative 1 mo 3 mo 6 mo 12 mo 18 mo 24 mo Annually
Calcium AGB, SG,
Magnesium AGB, SG,
Phosphorus AGB, SG,
Zinc AGB, SG,
Iron AGB, SG,
Transferrin AGB, SG,
Ferritin AGB, SG,
Vitamin A AGB, SG,
Vitamin E AGB, SG,
Vitamin D AGB, SG,
Vitamin B1 AGB, SG,
Vitamin B6 AGB, SG,
AGB3, SG3,
Vitamin B12 AGB, SG,
Parathormone AGB, SG,
Table 1 Schedule of biochemical and nutritional assessments for the different bariatric procedures
1Useful, including all contents in the space; 2Recommended, including all contents in the space; 3Every 2-5 years. AGB: Laparoscopic adjustable gastric
banding; SG: Sleeve gastrectomy; RYGB: Roux-en-Y gastric bypass; BPD: Biliopancreatic diversion.
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. Bariatric surgery and nutrition
471 November 15, 2017
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IF) can induce the apoptosis of erythroid progenitor
cells and increase hepcidin levels, which leads in turn,
to reduced intestinal iron absorption and reduced
The prevalence of zinc deficiency prior to bariatric
surgery amounts to 10.2%[84-86]. Interestingly, some
studies have shown an inverse association of zinc
levels, with C-reactive protein highlighting the adverse
influence of systemic low-grade inflammation on the
zinc status[84].
Overall, the high prevalence of pre-surgery nutritional
deficiencies in bariatric candidates supports the need
for a careful pre-operative evaluation of the nutritional
status, to assess and adequately correct the pre-
existing decits.
Nutritional deficiencies represent a relevant long-
term clinical problem in patients who underwent
bariatric surgery as a result of modifications to the
gastrointestinal anatomy and physiology, which could
impact macro- and micro-nutrient absorption. Therefore,
the best practices guidelines[21] highly recommend
regular metabolic and nutritional monitoring after
bariatric surgery, which frequency varies according to
the type of procedure. In light of the high prevalence of
nutrient deciencies even prior to surgery, the current
Guidelines also underscore the need for a complete
pre-surgery nutritional assessment in all candidates
for bariatric surgery. The schedule of the biochemical
and nutritional monitoring for the different procedures
is reported in Table 1. Although there are few studies
with long-term nutritional follow-up, there is general
agreement that nutritional assessments should be
performed throughout life; furthermore, multivitamin
and calcium supplementation with added vitamin D
is recommended for all weight-loss surgery patients.
In conclusion, nutritional surveillance is an essential
component of the management of bariatric patients
for the following reasons: (1) increases the patients
adherence to healthy dietary habits and appropriate
supplementation regimens; (2) prevents the risk of
weight regain; (3) facilitates the detection of possible
nutritional deficiencies that could develop despite
medical therapy; and (4) contributes to maintaining a
good quality of life.
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Volume 8
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Preoperative nutritional status of patients undergoing Roux-en-Y
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86 Papamargaritis D, Aasheim ET, Sampson B, le Roux CW.
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Trace Elem Med Biol 2015; 31: 167-172 [PMID: 25271186 DOI:
P- Reviewer: Klimontov V, Panchu P, Saisho Y S- Editor: Ji FF
L- Editor: A E- Editor: Zhao LM
Lupoli R
et al
. Bariatric surgery and nutrition
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... Six patients were observed with iron deficiency anemia necessitating iron supplements (19%) and 5 with B12 or vitamin D deficiencies (16%). This rate of nutrient deficiency resembles other reports in adults undergoing LSG and is favorable compared to adults and adolescences undergoing RYGB [6,29,30]. The rate of symptomatic cholelithiasis necessitating cholecystectomy during 10-year follow-up in our cohort was 22%, higher than previously reported for a 5-year follow-up period following RYGB (11% in the AMOS study), but this could be attributed to the longer follow-up time [7]. ...
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Purpose Metabolic and bariatric surgery (MBS) has emerged as the most effective treatment for adolescents with severe obesity. Despite the steady increase in frequency of MBS in adolescents, most reports focus on short-term (1–2 years) follow-up. Objective To report on long-term weight loss and status of obesity-related comorbidities of adolescents who underwent laparoscopic sleeve gastrectomy (LSG). Methods A retrospective analysis of prospectively collected data of patients younger than 18 years who underwent LSG between January 2008 and July 2014 was performed. Results During the study period, 46 patients (mean age 16.19 ± 1.07 years) underwent LSG, 31 of them (67.39%) completed long-term follow-up and were included in the study. Mean follow-up time was 10.84 ± 2.35 years. There were 18 females (58%). Mean body-mass index (BMI) was 44.94 ± 4.33 kg/m² and 30.11 ± 710, before, and 10-year following surgery, respectively, a reduction of 33.24% (P < 0.001). Long-term TWL% was 32.31 ± 12.02. Twenty-one patients (67.74%) achieved a BMI < 30 kg/m². Following weight reduction, resolution of hypertension was noted in 8 patients (88.9%, P < 0.001). Frequent long-term side effects of surgery were gastrointestinal reflux disease (GERD) and alopecia in 22.58% and 48.39%, respectively. Symptomatic cholelithiasis necessitated cholecystectomy in 22.58% of the patients. Using a 1–10 scale, the overall patient satisfaction in the long term was 8.97. Conclusion Our data suggests that LSG is a durable intervention for weight reduction in adolescents. Graphical Abstract
... When hyposideremia was identified in obese adolescents by Wenzel et al. (1962). Clinically, obesity treatment surgery reduces the risk of obesity-related complications, but increases the risk of nutritional complications because it artificially alters the physiological state and anatomy of the gastrointestinal tract (Lupoli et al. 2017). In a study (Coimbra et al. 2018) of 20 individuals who underwent laparoscopic adjustable gastric banding (LAGB) for 13 months, Coimbra et al. observed a significant reduction in body weight and BMI, accompanied by decreased levels of hepcidin, ferritin and inflammatory factors such as IL-6, from which they inferred that decreased levels of IL-6 may be responsible for reduced hepcidin. ...
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Obesity is one of the major public health problems threatening the world, as well as a potential risk factor for chronic metabolic diseases. There is growing evidence that iron metabolism is altered in obese people, however, the highly refined regulation of iron metabolism in obesity and obesity-related complications is still being investigated. Iron accumulation can affect the body’s sensitivity to insulin, Type 2 diabetes, liver disease and cardiovascular disease. This review summarized the changes and potential mechanisms of iron metabolism in several chronic diseases related to obesity, providing new clues for future research.
... The known mechanisms by which bariatric surgery succeeds in achieving its therapeutic effects are: altered diet (significantly energy restricted with increased protein intake), changes in the anatomy and physiology of the gastrointestinal tract (GIT) induced by the type of procedure performed (thus, with specific changes in food digestion and absorption) and lack of adequate nutritional supplementation [65]. ...
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Surgery of the gastrointestinal tract can result in deep changes among the gut commensals in terms of abundance, function and health consequences. Elective colorectal surgery can occur for neoplastic or inflammatory bowel disease; in these settings, microbiota imbalance is described as a preoperative condition, and it is linked to post-operative complications, as well. The study of bariatric patients led to several insights into the role of gut microbiota in obesity and after major surgical injuries. Preoperative dysbiosis and post-surgical microbiota reassessment are still poorly understood, and they could become a key part of preventing post-surgical complications. In the current review, we outline the most recent literature regarding agents and molecular pathways involved in pre- and post-operative dysbiosis in patients undergoing gastrointestinal surgery. Defining the standard method for microbiota assessment in these patients could set up the future approach and clinical practice.
... Approximately 35 % of patients experience weight-regain from two years post-surgery, which is physiologically and psychologically detrimental to patient outcomes (Baig, Priya, Mahawar, & Shah, 2019;Karmali et al., 2013). In some patients, weight regain may occur due to continuation or reemergence of previous maladaptive eating behaviors (Lupoli et al., 2017;Pizato, Botelho, Gonçalves, Dutra, & de Carvalho, 2017). ...
Background Weight-regain is commonly experienced after bariatric surgery. This qualitative enquiry aimed to explore participants' self-reported enablers and barriers to prevent future weight-regain post-surgery. Methods Eligible adults were recruited at 12-months post-bariatric-surgery at Counties Manukau, Auckland. Participants were invited to attend data collection at their 18-month group nutrition-education session, and to participate in a focus group at 21-months post-surgery. Thematic analysis was used to evaluate patient experiences. Results Participants (n = 28) were mostly female (73.2 %), New Zealand European (41.5 %), and had gastric sleeve surgery (92.3 %). Five key themes emerged from the analysis: A Life Changing Health Journey - participants experienced a decrease in obesity-related comorbidities and a subsequent decrease in medications. Weight change and food intolerances impacted quality of life. Challenge of managing a New Healthy Lifestyle - financial stress, buying healthier foods and social events were new challenges, often centred on food. Changing Eating Behavior - all participants struggled managing eating behaviors. Mindset Changes - post-surgery most participants had a positive mindset, increased confidence, and feelings of happiness. However, many struggled with mindset around weight and food. A need for On-going Support - most felt under-supported and expressed a need for longer, specific follow-up care. Conclusion Post-surgery group education sessions provided participants with increased support from both health professionals and peers on the same journey, to overcome struggles such as binge eating or identifying new coping strategies. Findings provide important insights into the challenges patients with bariatric surgery face and key learnings to develop specific supports for future care practices.
... the catabolic phase disappears, and the weight stabilizes [7,8]. Therefore, this period can theoretically lead to fetal malnutrition and impaired growth, resulting in insufficient gestational weight and its specific stressful influence on the organs [3,6,9]. While several organizations have recommendations for the optimal timing of pregnancy after BS, it lacks any scientific evidence at present. ...
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PurposeThis study aimed to evaluate the impact of gestational weight gain (GWG) after laparoscopic sleeve gastrectomy (LSG) on maternal and perinatal outcomes according to the Institute of Medicine (IOM) recommendations.Materials and MethodsA retrospective, multicenter, observational study of pregnant women who had undergone LSG between 2012 and 2021 was conducted. According to the IOM criteria, GWG was grouped as insufficient, appropriate, and excessive.ResultsA total of 119 pregnancies were included in this study. GWG was appropriate in 28 (23.5%), insufficient in 32 (26.9%), and excessive in 59 (49.6%) of the cases. The time from operation to conception was significantly longer in the excessive group than in the insufficient (P = 0.000) and appropriate groups (P = 0.01). The mean GWG was significantly higher in the excessive group than in the appropriate (P = 0.000) and insufficient groups (P = 0.000). When the groups were evaluated according to the IOM recommendations, no statistically significant difference were found between the groups regarding birthweight, gestational age (GA), preterm birth, and whether their child was small or large for their gestational age. Furthermore, there were no differences in terms of anemia and ferritin deficiency level at early pregnancy and predelivery between the groups.Conclusion The GWG after LSG did not impact maternal and perinatal outcomes.Graphical abstract
... The bodymass index (BMI; weight in kg/height in m2), which has a high connection with body fat, is used in these surveys to measure obesity [2]. Obesity can be treated with lifestyle modifications (dietary restraints and increased physical activity), pharmaceutical usage, and in rare circumstances, surgery [3]. The most effective treatment in extreme obesity is bariatric surgery [4]. ...
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Introduction and importance Bariatric surgeries are introduced as novel procedures in the whole world. Among the most important side effects after these surgeries is malnutrition. One of the reasons for suffocation can be the patient's psychological problems (such as depression). Paying attention to these symptoms can be effective in managing post-surgical complications. Case presentation A 36-year-old female patient who was operated with SASJ BYPASS surgery method presented three weeks after the surgery with symptoms of weakness, lethargy, nausea, vomiting, and PO (Per OS) intolerance, which did not respond to outpatient treatment. Barium swallow imaging and abdominopelvic CT scan was done for the patient and findings were normal. During conservative treatment and total parenteral nutrition (TPN) the patient underwent psychiatric consultation and took psychiatry medications. Gradually after these consultation sessions the patient had a good PO tolerance, no edema and no weakness and was discharged in a good condition. She was advised to continue psychologic consultation sessions besides other post-surgical follow ups. Clinical discussion After complete assessment of malnutrion etiologies after bariatric surgeries it was advised to ensure that the patients demonstrate an understanding of the bariatric surgical procedure, necessity of changes in eating habits. Any existing psychological issues should be identified and treated the patient should be educated to make a commitment to multidisciplinary care after these surgeries. Conclusion With continued communication, support, and multidisciplinary monitoring, nutritional complications can be minimized among patients undergoing bariatric surgeries. Level of evidence: V.
... control despite aggressive calcium replacement [1]. Bariatric surgery has been associated with micronutrient deficiency, especially vitamin D deficiency [2] [3]. ...
Background Obesity is a chronic condition that affects millions globally; consequently, bariatric surgery is the key to this serious issue. Bariatric procedures are rapidly expanding in number and methods to address the recognized problems. So, it would make a sense for surgeons and patients if there is a more physiological bypass surgery technique in Morbid obesity. This study aims to evaluate the outcome proposed technique. Patients and methods The present study is a retrospective analysis on 256 participants subjected to the proposed bypass procedure from December 1999 to January 2017, the participants were followed up for an interval of 3years. Results The findings of the present study revealed a significant Excess Weight Loss (EWL). In addition, patients experienced decreased calcium, iron, vitamin B12, Hemoglobin, zinc, and Prothrombin Concentration. However, three to six months after surgery, they experienced a significant improvement until they reached normal levels without any supplement, with a three-year follow-up. Conclusion This proposed Bypass Operation aims to adequate digestions as well as selective absorption without inducing any vital deficit. Most of study's population showed no elements inadequacies, although few percentages emerged during the interval of maximal weight reduction, and it were transient and minimal. No minerals or vitamins were needed.
Introduction Morbid obesity is a known risk-factor for increased complications following total hip arthroplasty (THA). Thus, many orthopaedic surgeons recommend bariatric surgery (BS). However, there is no consensus on the type (commonly either a Roux-en-Y gastric bypass [RYGB] or sleeve gastrectomy [SG]) and timing of BS prior to THA. Therefore, the purpose of this study is to compare BS recipients prior to THA to assess differences in 90-day to 2-year medical/surgical complications as well as revisions for: (1) type of BS (RYGB and SG); and (2) timing of BS. Additionally, we aim to assess risk factors for postoperative prosthetic joint infections (PJIs), dislocations, and revisions. Methods We queried a national, all-payer database to identify patients undergoing primary THA from January 2010 to October 2020 ( n = 715,100). Patients were then divided into 6 cohorts: 2 cohorts without history of BS (body mass index [BMI] kg/m ² 20–35 [ n = 59,995]) and BMI > 40 [ n = 36,799]); 2 cohorts with previous RYGB ( n = 1278) or SG ( n = 1051); and 2 cohorts that underwent BS either 6–12 months ( n = 412) and >12 months ( n = 1655) prior to the THA. Bivariate chi-square analyses of medical and surgical outcomes at 90 days–2 years were conducted. Multivariate logistic regressions identified independent risk factors for PJIs, dislocations, and revisions. Results At 90 days–2 years, no differences in postoperative medical/surgical complications or revisions were seen among timing or type of BS. The BMI > 40 kg/m ² cohort had the highest complication profile among all other cohorts. Timing and type of BS has similar odds of PJIs, dislocations, and revisions. Conclusions Patients undergoing RYGB or SG 6–12 months and >1 year prior to THA showed similar complications profiles. These results suggest, bariatric patients do not need to wait 1 year before undergoing a THA.
Objectives Vitamin B12 deficiency is frequent after obesity surgery. The goal of this study was to establish the current practices in specialized obesity centers in terms of dosage, supplementation, and management of B12 deficiency after obesity surgery. Materials and methods In 2021, a survey has been sent to the 37 French specialized obesity centers to perform an assessment of the physician professional practices relating to B12 supplementation after obesity surgery. Results Forty-one responses were collected from 29 centers, representing a response rate of 78%. All physicians routinely monitored plasma B12 in the postoperative period. The first intent route of B12 supplementation after obesity surgery was mainly: oral, then intramuscular, then subcutaneous, with respectively 38 (93%), 9 (22%), and 3 responses (7%). The preferred prescription for prevention of B12 deficiency, used as long-term maintenance therapy, was 1 mg per week, orally (n = 21; 51%). The other schemes used for that purpose were rare and specific to a single center. In case of B12 deficiency, the two most used therapeutic schemes were 1 mg per day orally for 15 days (n = 8; 20%) and 1 mg intramuscular per week for 1 month (n = 4; 10%). Conclusion This assessment of the current physician professional practices revealed a diversity in the practices of B12 supplementation after obesity surgery, with a trend to favor the oral route. This is due to the lack of evidence and clear-cut recommendations. A comparative randomized study would help to identify the best route and posology for B12 supplementation after obesity surgery.
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Background: The reported prevalence of hypocalcemia after bariatric surgery ranges from 1% after Roux-en-Y gastric bypass (RYGB) to 25% after bilio-pancreatic diversion-duodenal switch (BPD-DS). Objective: We aimed to define the prevalence of post-operative hypocalcemia and identify clinical predisposing factors. Setting: The study was conducted in an Academic Medical Center, USA. Methods: Retrospective analysis of all patients undergoing bariatric surgery from May 2008 to December 2014 at Mayo Clinic Rochester, Minnesota was performed. Patients with revision surgeries were excluded. Hypocalcemia was defined as the lowest recorded serum calcium occurring at least 2 weeks post-operatively. Results: Nine hundred ninety-nine patients fulfilled the criteria above. After correction for serum albumin concentration, 36 patients had serum calcium ≤8.9 mg/dl. Mean serum calcium was 8.1 ± 0.6 mg/dl. The prevalence was 1.9% in the RYGB group, 9.3% in the sleeve gastrectomy (SG) group, and 10% in the BPD-DS group. In all three surgical types, patients with hypocalcemia had significantly lower serum albumin and serum 25 (OH) vitamin D concentrations when compared to their normocalcemic counterparts (P < 0.01). The presence of renal insufficiency and vitamin D deficiency was associated with the highest risk of developing hypocalcemia after surgery [OR 16.8 (6.45-47.7) and 7.1(2.9-17.3), respectively]. Pre-operative renal insufficiency increased the odds of developing hypocalcemia by 20-fold. Conclusions: In our series, hypocalcemia was identified in 3.6% of patients undergoing all bariatric surgery. Patients who are predisposed to developing post-operative hypocalcemia, such as those with pre-operative renal impairment, or post-operative vitamin D deficiency and renal insufficiency, may benefit from increased surveillance and prevention strategies.
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PurposeGhrelin is a gut hormone that induces hunger, gastric acid secretion, and gastrointestinal motility. A number of studies have previously demonstrated a possible correlation between a decrease in ghrelin level and weight loss after Roux-en-Y gastric bypass (RYGB). This study aimed to assess if there was a relationship between ghrelin level and weight regain after RYGB nadir weight had been achieved. Materials and Methods Sixty-three consecutive RYGB patients who were referred for an upper endoscopy were enrolled. Weight and responses to the 21-item Three-Factor Eating Questionnaire (TFEQ-R21) were collected. Ghrelin levels were measured. Upper endoscopy was performed to evaluate pouch length and stoma diameter. Multivariate linear regression was performed to assess an association between ghrelin level, TFEQ-R21 score, pouch length, stoma diameter, and percentage of weight regained. ResultsSubjects were 47 ± 10 years old and had a BMI of 38 ± 7.7 kg/m2. Out of 63 patients, 76 % had weight regain (gaining of ≥20 % of maximal weight lost after the RYGB) and 24 % did not. Average pouch length was 44 ± 13 mm, stoma diameter 20 ± 6.6 mm, and ghrelin levels 125 ± 99 ng/ml. Ghrelin level was not associated with weight regain (β = 0.17, p = 0.2). GJ stoma diameter was associated with weight regain (β = 0.39, p < 0.01) and the uncontrolled eating domain of the TFEQ-R21 (β = 0.45, p < 0.01). Conclusion Ghrelin levels do not appear to correlate with weight change after RYGB nadir weight has been achieved. A dilated GJ stoma diameter is a risk factor for weight regain and uncontrolled eating behavior after RYGB.
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Background Bariatric patients regularly present with insufficient vitamin D status before and after surgery, which requires substantial supplementation to treat. This review aims to assess the effect of sleeve gastrectomy on vitamin D status and the effectiveness of vitamin D supplementation. Methods This review was conducted in accordance with the Guidelines for Meta-Analyses and Systematic Reviews of Observational Studies. Results The current guidelines recommend initial vitamin D supplementation of at least 3000 IU/day post-operatively, with no need for follow-up testing after sleeve gastrectomy. Only one study has trialled a dose in line with the recommendations for this patient group. They found that it was effective in improving VitD status. Conclusions On-going monitoring of vitamin D status is necessary, as the recommended level is not often reached.
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Context: It is not known whether the magnitude of metabolic adaptation, a greater than expected drop in energy expenditure, depends on the type of bariatric surgery and is associated with cardiometabolic improvements. Objective: To compare changes in energy expenditure (metabolic chamber) and circulating cardiometabolic markers 8 weeks and 1 year after roux-en-y bypass (RYGB), sleeve gastrectomy (SG), laparoscopic adjustable gastric band (LAGB) or low-calorie diet (LCD). Design, setting, participants and intervention: This was a parallel arm, prospective observational study of 30 individuals (27 females, 46±2y, BMI=47.2±1.5kg/m(2)) either self-selecting bariatric surgery (RYGB=5, SG=9, LAGB=7) or an LCD (n=9) intervention (800kcal/day for 8 weeks followed by weight maintenance). Results: After 1 year, RYGB and SG had similar degrees of body weight loss (33-36%) whereas LAGB and LCD had 16% and 4% weight loss, respectively. After adjusting for changes in body composition, 24-hour energy expenditure was significantly decreased in all treatment groups at 8 weeks (-254 to -82kcal/day), a drop which only persisted in RYGB (-124±42kcal/day; p=0.002) and SG (-155±118kcal/day; p=0.02) groups at 1 year. The degree of metabolic adaptation (24-hour and sleeping energy expenditure) was not significantly different between the treatment groups at either time-point. Plasma HDL and total and high molecular weight adiponectin were increased and triglycerides and hsCRP levels reduced 1 year after RYGB or SG. Conclusions: Metabolic adaptation of ∼150kcal/day occurs after RYGB and SG surgery. Future studies are required to examine whether these effects remain beyond 1 year.
Background: Obesity is associated with vitamin D insufficiency and secondary hyperparathyroidism. Objective: This study assessed whether obesity alters the cutaneous production of vitamin D3 (cholecalciferol) or the intestinal absorption of vitamin D2 (ergocalciferol). Design: Healthy, white, obese [body mass index (BMI; in kg/m²) ≥ 30] and matched lean control subjects (BMI ≤ 25) received either whole-body ultraviolet radiation or a pharmacologic dose of vitamin D2 orally. Results: Obese subjects had significantly lower basal 25-hydroxyvitamin D concentrations and higher parathyroid hormone concentrations than did age-matched control subjects. Evaluation of blood vitamin D3 concentrations 24 h after whole-body irradiation showed that the incremental increase in vitamin D3 was 57% lower in obese than in nonobese subjects. The content of the vitamin D3 precursor 7-dehydrocholesterol in the skin of obese and nonobese subjects did not differ significantly between groups nor did its conversion to previtamin D3 after irradiation in vitro. The obese and nonobese subjects received an oral dose of 50000 IU (1.25 mg) vitamin D2. BMI was inversely correlated with serum vitamin D3 concentrations after irradiation (r = −0.55, P = 0.003) and with peak serum vitamin D2 concentrations after vitamin D2 intake (r = −0.56, P = 0.007). Conclusions: Obesity-associated vitamin D insufficiency is likely due to the decreased bioavailability of vitamin D3 from cutaneous and dietary sources because of its deposition in body fat compartments.
Bariatric surgery is associated with bone loss but skeletal consequences may differ between Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG), the two most commonly performed bariatric procedures. Furthermore, severe weight loss is associated with high marrow adipose tissue (MAT); however, MAT is also increased in visceral adiposity. The purpose of our study was to determine the effects of RYGB and SG on BMD and MAT. We hypothesized that both bariatric procedures would lead to a decrease in BMD and MAT. We studied 21 adults with morbid obesity (mean BMI 44.1 ± 5.1 kg/m²) prior to and 12 months after RYGB (n = 11) and SG (n = 10). All subjects underwent DXA and QCT of the lumbar spine and hip to assess aBMD and vBMD. Visceral (VAT) and subcutaneous (SAT) adipose tissue was quantified at L1–2. MAT of the lumbar spine and femur was assessed by 1H–MR spectroscopy. Calcitropic hormones and bone turnover markers were determined. At 12 months after surgery, mean weight and abdominal fat loss was similar between the RYGB and SG groups. Mean serum calcium, 25(OH)-vitamin D, and PTH levels were unchanged after surgery and within the normal range in both groups. Bone turnover markers P1NP and CTX increased within both groups and P1NP increased to a greater extent in the RYGB group (p = 0.03). There were significant declines from baseline in spine aBMD and vBMD within the RYGB and SG groups, although the changes were not significantly different between groups (p = 0.3). Total hip and femoral neck aBMD by DXA decreased to a greater extent in the RYGB than the SG group (p < 0.04) although the change in femoral vBMD by QCT was not significantly different between groups (p > 0.2). MAT content of the lumbar spine and femoral diaphysis did not change from baseline in the RYGB group but increased after SG (p = 0.03). Within the SG group, 12-month change in weight and VAT were positively associated with 12-month change in MAT (p < 0.04), suggesting that subjects with less weight and VAT loss had higher MAT. In conclusion, RYGB and SG are associated with declines in lumbar spine BMD, however, the changes are not significantly different between the groups. RYGB may be associated with greater decline of aBMD at the total hip and femoral neck compared to SG. MAT content increased after SG and this was associated with lower weight and VAT loss.
Bariatric surgery results in rapid weight loss and beneficial metabolic effects, but may have negative effects on the skeleton. The objective of this prospective study was to evaluate changes in bone metabolism in response to bariatric surgery with two surgical techniques. 46 morbidly obese subjects (mean 44.9 years, BMI 42.1) with (n = 19) or without (n = 27) type 2 diabetes (T2DM) at baseline underwent either Roux-en-Y gastric bypass (RYGB, n = 21) or sleeve gastrectomy (SG, n = 25). Bone turnover markers (CTX, PINP, TRAcP5b, TotalOC and ucOC) were measured before and six months after surgery. Volumetric bone mineral density (vBMD) at lumbar spine and vertebral bone marrow (VBM) fat were measured in 21 subjects (7 RYGB and 14 SG) with three-dimensional quantitative computer tomography and ¹H MR spectroscopy, respectively. 25 non-obese subjects were recruited as controls (mean 45.8 years, BMI 23.0) and assessed at a single cross-sectional visit. Obese subjects had significantly lower bone turnover at baseline when compared to non-obese controls. Bone metabolic markers markedly increased post-operatively (p < 0.0001 for all). The activation of bone remodeling was significantly higher after RYGB than after SG and was particularly observed in patients, whose type 2 diabetes was in remission after weight loss. There was no change in volumetric BMD or marrow fat at lumbar spine six months after surgery in our sample. In conclusion, severe obesity decreases bone remodeling, which is activated after bariatric surgery. The increase in bone turnover after surgery is affected by the choice of surgical technique and by the post-surgery remission of T2DM.
Background: New evidence suggests that obesity is deleterious for bone health, and obesity treatments could potentially exacerbate this. Materials and methods: This narrative review, largely based on recent systematic reviews and meta-analyses, synthesizes the effects on bone of bariatric surgery, weight loss pharmaceuticals and dietary restriction. Results and conclusions: All three obesity treatments result in statistically significant reductions in hip bone mineral density (BMD) and increases in bone turnover relative to pre-treatment values, with the reductions in hip BMD being strongest for bariatric surgery, notably Roux-en Y gastric bypass (RYGB, 8%-11% of pre-surgical values) and weakest for dietary restriction (1%-1.5% of pre-treatment values). Weight loss pharmaceuticals (orlistat or the glucagon-like peptide-1 receptor agonist, liraglutide) induced no greater changes from pre-treatment values than control, despite greater weight loss. There is suggestive evidence that liraglutide may increase bone mineral content (BMC) - but not BMD - and reduce fracture risk, but more research is required to clarify this. All three obesity treatments have variable effects on spine BMD, probably due to greater measurement error at this site in obesity, suggesting that future research in this field could focus on hip rather than spine BMD. Various mechanisms have been proposed for BMD loss with obesity treatments, notably reduced nutritional intake/absorption and insufficient exercise, and these are potential avenues for protection against bone loss. However, a pressing outstanding question is whether this BMD reduction contributes to increased fracture risk, as has been observed after RYGB, and whether any such increase in fracture risk outweighs the risks of staying obese (unlikely).
This review focuses on the mechanisms underlying, and indications for, bariatric surgery in the reduction of cardiovascular disease (CVD), as well as other expected benefits of this intervention. The fundamental basis for bariatric surgery for the purpose of accomplishing weight loss is the determination that severe obesity is a disease associated with multiple adverse effects on health, which can be reversed or improved by successful weight loss in patients who have been unable to sustain weight loss by nonsurgical means. An explanation of possible indications for weight loss surgery as well as specific bariatric surgical procedures is presented, along with review of the safety literature of such procedures. Procedures that are less invasive or those that involve less gastrointestinal rearrangement accomplish considerably less weight loss but have substantially lower perioperative and longer-term risk. The ultimate benefit of weight reduction relates to the reduction of the comorbidities, quality of life, and all-cause mortality. With weight loss being the underlying justification for bariatric surgery in ameliorating CVD risk, current evidence-based research is discussed concerning body fat distribution, dyslipidemia, hypertension, diabetes mellitus, inflammation, obstructive sleep apnea, and others. The rationale for bariatric surgery reducing CVD events is discussed and juxtaposed with impacts on all-cause mortalities. Given the improvement of established obesity-related CVD risk factors after weight loss, it is reasonable to expect a reduction of CVD events and related mortality after weight loss in populations with obesity. The quality of the current evidence is reviewed, and future research opportunities and summaries are stated.
Since the 2007 Diabetes Surgery Summit in Rome, Italy, and the subsequent publishing of the world's first guidelines for the surgical treatment of type 2 diabetes (T2D), much new evidence regarding the efficacy and safety of metabolic surgery has emerged. Additional observational cohort studies support the superior effects of surgery over medical treatment with respect to glycemic control, weight loss, and even reduction in mortality and microvascular complications associated with T2D. Furthermore, new safety data suggest that the perioperative morbidity and mortality of metabolic surgery (5% and 0.3%, respectively) are now similar to that of common low-risk procedures, such as cholecystectomy and hysterectomy. The largest advance, however, has been the completion of 11 randomized controlled trials from around the globe that compare surgery with medical treatment of T2D. These studies with follow-up duration of 1-5 years involve nearly 800 patients without surgical mortality and with major complication rates of less than 5% and a reoperation rate of 8%. All but 1 of the 11 randomized controlled trials have shown the superiority of surgery over medical management at achieving remission or glycemic improvement. Surgery was also superior to medical treatment with respect to improving cardiovascular risk factors, such as weight loss and dyslipidemia, while reducing medication burden. This new efficacy and safety evidence should help guide physicians across the globe to the appropriate use of surgery as an effective treatment for patients suffering from T2D and obesity.