Changes in Iron Absorption After Roux-en-Y Gastric Bypass
Marjolein A. P. Ligthart
Frits J. Berends
Ignace M. C. Janssen
Cees J. H. M. van Laarhoven
Edo O. Aarts
Hans de Boer
Published online: 11 January 2018
Springer Science+Business Media, LLC, part of Springer Nature 2018
Introduction Iron deficiency is one of the most common deficiencies that may occur after Roux-en-Y gastric bypass (RYGB).
Little is known about the optimal treatment of post-RYGB iron deficiency.
Aim The aim of this study is to evaluate the changes in iron absorption characteristics after RYGB for two oral iron formulations,
one presented in tablet form and one as in the form of a solution.
Method Iron absorption in 24 obese women was studied before and 1 month after RYGB. Twelve patients were tested with a
single dose of 600 mg ferrous fumarate in tablet form (195 mg of elementary iron, group 1), and 12 patients received a single dose
of 1390 mg ferrous gluconate as a solution (160 mg of elementary iron, group 2). Serum iron levels were measured before (T
and every hour after ingestion of the supplement (T
Results Before surgery, iron absorption was similar for the two supplements (P = 0.71). However, RYGB was associated with a
decrease in fumarate iron absorption (P < 0.001) but did not affect gluconate iron absorption (P = 0.13). Postoperative absorption
of fumarate iron was significantly lower than gluconate iron at T1 (P < 0.05), but the overall difference over 9 h did not reach
statistical significance (P =0.53).
Conclusion RYGB adversely affects the absorption of ferrous fumarate tablets but not that of solubilized ferrous gluconate. A
solubilized supplement is therefore preferred as the supplement of first choice after RYGB.
Keywords Morbid obesity
Roux-en-Y gastric bypass
Laparoscopic Roux-en-Y gastric bypass (RYGB) is the most
commonly performed bariatric procedure because it is highly
successful in establishing sustained weight loss [1–3].
However, RYGB is also associated with an increased risk of
malabsorption [3, 4]. Iron deficiency is one of the most com-
mon deficiencies post-RYGB. It occurs in up to 60% of pa-
tients, with a rise in prevalence proportional to the length of
follow-up and a higher prevalence in premenopausal women
than in men of similar age .
Previous studies have demonstrated that the absorption of
some oral iron supplements decreases post-RYGB. Ruz et al.
studied iron absorption before and 6, 12, and 18 months post-
RYGB with radioactive-labeled ferrous ascorbate and found a
decrease of 60% at 6 months after surgery, without any sig-
nificant improvement thereafter . Gesquiere et al. used fer-
rous sulfate in an oral iron challenge test for patients who had
become iron-deficient post-RYGB and found a suboptimal
rise in serum iron levels in 22 out of 23 patients . The
observed decrease in iron absorption after RYGB has been
attributed to the decline in gastric acid secretion (gastric acid
is necessary to reduce the poorly absorbable ferric iron to the
absorbable ferrous iron that is transported into the
enterocytes), the bypassing of the duodenum (the most effi-
cient intestinal iron absorption site due to the presence of
brush border ferrireductase, an enzyme that promotes the con-
version of ferric to ferrous iron).
* Wendy Schijns
Department of Surgery, Rijnstate Hospital, Postal number 1190,
6800, TA Arnhem, The Netherlands
Department of Surgery, Radboud UMC, Nijmegen, The Netherlands
Department of Internal Medicine, Rijnstate Hospital,
Arnhem, The Netherlands
Obesity Surgery (2018) 28:1738–1744