Defi ciency conditions in bariatric surgery

Deficiency conditions in bariatric surgery


The Ukrainian Journal of Clinical Surgery
Bariatric surgery has proven to be effective in the treatment of morbid obesity [1,2], but it is not without a certain risk of complications in the short and long-term follow-up periods.
Nutritional and micronutrient deficiencies are considered an important complication.Nutritional deficiencies can have a wide range of clinical manifestations, depending on the specific nutrient/micronutrient deficiency involved in vital processes, its severity and duration (see table).In addition, these deficiencies may decompensate over time, leading to serious consequences, such as anaemia (iron, folic acid, vitamin B12 deficiency), peripheral neuropathy (folic acid, vitamins B6, B12, copper deficiency), Wernicke's encephalopathy (vitamin B1 deficiency) and metabolic bone diseases (vitamin D, calcium deficiency).
Thus, patients after bariatric surgery need constant follow-up to identify these complications, their effective treatment and prevention.

Deficiency states in morbid obesity
In patients with morbid obesity, deficiency states are very common [3 -5], as they usually consume unhealthy, high-cal-orie, low-quality food with an unbalanced nutritional composition.
At least one deficiency condition was observed in 66% of patients who were candidates for bariatric surgery, despite a daily high-calorie diet of (2801 ± 970) kcal/day.Low levels of iron, ferritin, vitamin B12, and haemoglobin were found in 12.6, 8.7, 10.6, and 7.7% of patients, respectively, and folic acid deficiency was 26.8% before surgery [6].
Patients with morbid obesity are most often diagnosed with vitamin D deficiency -up to 78.8% [6,7].Low preoperative levels of haemoglobin, vitamin B12, and ferritin are usually independently associated with decreased levels of trace elements after surgery.In addition, deficiencies in vitamins D and B1 and albumin persist in the long term after surgery, so it is important to identify deficiency states before surgery [7].
Candidates for surgery for morbid obesity require laboratory tests that include measurement of micronutrient and vitamin levels at least once before surgery.The screening should include a panel of water-and fat-soluble vitamins and minerals, especially for patients who are planning combined or

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The Ukrainian Journal of Clinical Surgery malabsorptive interventions.Re-measurement of laboratory parameters before surgery should be individualised for each patient [8,9], as deficiency states identified before surgery require appropriate treatment to avoid further decompensation after surgery.So far, no threshold levels have been established for, for example, vitamin D, with the latest optimal values ranging from 21 to 30 ng/ml [8].
Deficiency of water-soluble vitamins after bariatric surgery Vitamin B1 (thiamine) is absorbed in the proximal small intestine, so its deficiency can often be observed after combined or malabsorptive surgery [9].The human body's own thiamine stores are low [8].These characteristics may explain why thiamine deficiency occurs after a short period of persistent vomiting following surgical complications such as slippage syndrome after gastric banding [10], gastric tube torsion after sleeve gastrectomy [8], or anastomotic stenosis after gastric bypass surgery [11].Vitamin B1 deficiency has also been reported after biliopancreatic bypass and its modifications [12].
The manifestations of thiamine deficiency include peripheral neuropathy, Wernicke's encephalopathy, Korsakoff syndrome, and cardiomyopathy [13,14].These clinical conditions can be severe and life-threatening if not recognised in time and treated immediately.Borderline deficiency can cause less severe symptoms that can be missed.Therefore, oral or parenteral thiamine should be initiated in any patient with persistent vomiting that interferes with adequate nutrition, even before positive laboratory results are available.Patients with symptoms of thiamine deficiency should be switched to oral supplementation only after 1 to 2 weeks of parenteral administration until symptoms resolve [13,14].
Refeeding syndrome is a life-threatening condition that occurs as a result of water and electrolyte imbalances, in particular hypophosphatemia, which causes a serious complication such as cardiac arrhythmia [10,15].Empirical thiamine supplementation is also indicated after bariatric surgery for high-risk patients.The risk group includes women, African Americans, patients who do not take concomitant therapy, patients with heart failure, persistent or recurrent vomiting, patients on parenteral nutrition for a long time, and alcohol drinkers [13].
Wernicke's encephalopathy is an acute neuropsychiatric syndrome that develops in the setting of acute thiamine deficiency, characterised by ataxia, ophthalmoparesis, nystagmus and confusion.It most often occurs in the first weeks or months after bariatric surgery [13].It can occur after both combined and gastrorestrictive surgeries.It should be noted that patients after combined operations are more likely to develop this pathological condition [16].The onset of encephalopathy symptoms is always preceded by nutritional deficiency as a consequence of persistent prolonged vomiting, although non-compliance with the recommendations of adjunctive therapy and excessive alcohol consumption are also risk factors [16].
Computed tomography of the brain, especially magnetic resonance imaging, can be used to confirm the diagnosis.Radiological signs include hyperintensity in the thalamus, mam-millary bodies, and third and fourth ventricles [13].The recommended treatment is 500 mg of parenteral thiamine three times a day until the symptoms of encephalopathy resolve [13].Recovery usually occurs within 3 to 6 months after starting therapy if symptoms are recognised early [16].
Patients who received a suboptimal dose of thiamine or had more than one acute symptom were more likely to progress later to a permanent neurological condition, Korsakoff syndrome [17].This is a neuropsychiatric disorder characterised by severe amnesia, confabulations, and leading to lifelong disability.
Vitamins B12 (cobalamin) and B9 (folic acid) Vitamin B12 deficiency after bariatric surgery can be the result of insufficient secretion of intrinsic factor Castle, hypoacidity, and, most importantly, exclusion from the duodenum as the main site of its absorption [6,18].
The cobalamin depot in the liver is usually sufficient, so its deficiency is rare in the first year after surgery, but this deficiency tends to increase in the long term.Vitamin B12 deficiency was observed with a frequency of 14.3% after sleeve resection and 16% after gastric bypass surgery [19].In addition to anaemia, vitamin B12 deficiency can cause neurological and psychiatric symptoms [7].
Regular screening of vitamin B12 levels is necessary during the first year after bariatric surgery.This is especially important for patients taking medications that exacerbate vitamin B12 deficiency, such as metformin, proton pump inhibitors, and anticonvulsants [13].
In patients with a history of anaemia and vitamin B12 deficiency, it is important to remember about metabolic deficiency of this vitamin, so it is important to determine the level of the latter in combination with the level of methylmalonic acid and homocysteine [13].It should also be remembered that intramuscular or intranasal administration of vitamin B12 has a higher bioavailability than oral supplementation, as only 1% of oral vitamin B12 is passively absorbed without intrinsic factor Kasl [13].
Complex folate is absorbed in the duodenum and proximal colon, so its deficiency is primarily caused by a decrease in dietary intake and to a lesser extent by absorption disorders, especially after combined operations.In addition, folic acid deficiency can be exacerbated by vitamin B12 deficiency, as the latter is required for the conversion of inactive methyltetrahydrofolic acid to active tetrahydrofolic acid [6].
The incidence of folic acid deficiency after bariatric surgery ranges from 3.6 to 4.2%.Folic acid deficiency in women who have undergone bariatric surgery during pregnancy can cause neurological abnormalities in the fetus, such as growth retardation and birth defects, so sufficient folic acid is especially important in women of reproductive age [18].

Deficiency of fat-soluble vitamins after bariatric surgery
Vitamin A. The absorption of this vitamin is reduced after bariatric surgery.Clinical manifestations of vitamin A deficiency include chicken blindness, xerophthalmia, and dry hair.The incidence of vitamin A deficiency is 11.1% one year after surgery.Vitamin A deficiency was detected in 70% of patients of UJCS.2023 July/August; 90(4) The Ukrainian Journal of Clinical Surgery reproductive age 4 years after Roux-en-Y gastric bypass or biliopancreatic shunting, which was explained by severe fat malabsorption and steatorrhoea [20].
Vitamin D. It is absorbed mainly in the jejunum and ileum.Thus, a high incidence of vitamin D deficiency is observed after procedures associated with impaired absorption, despite the usual use of supplements.
The most important consequence of vitamin D deficiency is bone demineralisation (see figure), so regular calcium and vitamin D supplementation is essential, especially after combined and malabsorptive surgery [14].Standard supplementation therapy is usually insufficient to maintain optimal vitamin D levels in malabsorptive patients, so significantly higher doses of oral forms or parenteral administration should be considered [21].
Vitamins E and K. Deficiency of these vitamins is quite rare.In a study involving 878 patients, vitamin K deficiency was observed with a frequency of 1.8% after Roux-en-Y gastric bypass and 7.4% after SADI surgery, and the frequency of vitamin E deficiency was 4.8 and 0.9%, respectively [22].The most common symptoms associated with vitamin E deficiency are neuropathy, myopathy, and anaemia [14].
Mineral deficiency after bariatric surgery Iron.The incidence of iron deficiency after restrictive surgery ranges from 14 to 18%, and after combined or malabsorptive surgery -from 15 to 51.3% [23,24].
Malabsorption of iron can develop due to the exclusion of the duodenum and proximal part of the jejunum, where the main absorption occurs.Reduced gastric acidity and rapid gastric emptying disrupt the conversion of trivalent iron into ferrous iron suitable for absorption.Reducing the intake of iron-rich foods is important.Iron absorption may be affected by interaction with other dietary supplements (e.g., calcium) [13,14].
Patients with polymenorrhagia are at higher risk of iron deficiency and anaemia [23].Other risk factors include procedures with impaired absorption, young age, preoperative anaemia, and low baseline ferritin levels [25].Measuring serum ferritin levels is the best diagnostic test for iron deficiency and the best indicator of iron status, as it decreases first before serum iron concentrations decrease.Prophylactic iron supplementation is recommended after all types of bariatric surgery [14].Severe iron deficiency anaemia usually requires intravenous iron supplementation or blood transfusion [25].
Calcium.It is absorbed mainly in the duodenum and proximal small intestine, which is facilitated by vitamin D in an acidic environment.Therefore, any bypass surgery, hypoacidic state reduces the level of vitamin D, which is often associated with reduced calcium absorption.The incidence of calcium deficiency after restrictive surgery is 3.9%, after combined surgery -4.3% [24,26].
Trace element deficiency after bariatric surgery Mineral deficiencies are more common after biliopancreatic and Roux-en-Y gastric bypass [27].
Most publications on deficiency states mainly describe calcium and iron deficiencies.Deficiencies of other essen-tial minerals, such as zinc, copper and selenium, are rarely reported in the literature [14].These essential minerals act as enzymatic cofactors in several biochemical pathways, and therefore their deficiency can cause a variety of clinical manifestations.
Zinc.This micronutrient is absorbed in the small intestine, so gastric bypass surgery can cause zinc malabsorption, but there are reports of zinc deficiency after gastric sleeve resection.
Copper.It is absorbed mainly in the stomach and proximal duodenum, and functions as a cofactor in many enzymatic reactions that are vital for the haematological, vascular, skeletal, antioxidant, and neurological systems [28].
For example, copper is a cofactor of superoxide dismutase (an antioxidant pathway), cytochrome c oxidase (involved in energy production) and amine oxidases (involved in the synthesis of neurotransmitters).
Copper deficiency can have severe clinical consequences.In addition, copper is also required for the transport of iron.Consequently, copper deficiency can also cause symptoms of iron deficiency, including anaemia.
Copper deficiency occurs with a frequency of 10-15% after gastric bypass surgery [28].It is sometimes difficult to recognise, as the symptoms of copper deficiency often resemble those of vitamin B12 deficiency.There are reports of peripheral neuropathy, myeloneuropathy with spastic ataxic gait after gastric bypass surgery [29] and pancytopenia with refractory anaemia due to copper deficiency [30].
Multiple non-consolidated rib fractures in a patient with morbid superobesity (body mass index 56 kg/m 2 ), vitamin D 25-OH 2 ng/ml and secondary hyperparathyroidism (parathyroid hormone 117 pg/ml) one year after trauma.

The Ukrainian Journal of Clinical Surgery
Selenium.Absorbed in the duodenum and proximal small intestine, it provides a part of multifunctional selenoproteins that are important for health [28].Selenium deficiency can lead to immune system dysfunction and infertility in men.Selenium deficiency is closely associated with myopathy, arrhythmia, and hypothyroidism.
In the literature, there are isolated reports of cardiomyopathy in the setting of selenium deficiency [31].Therefore, studies involving a large cohort of patients and longer-term follow-up are needed.There is also still no data on selenium deficiency depending on the type of surgery.The incidence of selenium deficiency after bariatric surgery ranges from 11 to 46% [32].
Determination of selenium levels before and after surgery should be recommended, in particular in cases of unexplained anaemia, fatigue, metabolic bone disease, chronic diarrhoea or cardiomyopathy, followed by the prescription of special supplements.
Patients undergoing bariatric surgery are always at increased risk of nutritional deficiencies, which can lead to serious complications if not recognised and treated immediately.
A multidisciplinary and individual approach with careful monitoring of trace elements and vitamins is mandatory for patients undergoing bariatric surgery.
Funding.No external sources of funding or support were sought.No fees or other compensation was paid.
Authors' contributions.All authors contributed equally to this paper.
Conflict of interest.The authors declare that they have no conflicts of interest.
Consent to publication.All authors have read and approved the final version of the manuscript and agreed to its publication.