|Year : 2020 | Volume
| Issue : 3 | Page : 110-117
Alopecia and zinc deficiency in postbariatric surgery patients
Omar Al-Komi1, Anas Hasson Alnajjar1, Mohamed Abdelghafour Khalifa1, Abdullah Murhaf Al-Khani1, Osman Habib Basheir2
1 Department of Clinical Sciences, Research Unit, College of Medicine, Sulaiman Alrajhi University, Albukayriyah, Al-Qassim, Saudi Arabia
2 Department of Surgery, College of Medicine, Sulaiman Alrajhi University, Albukayriyah, Al-Qassim, Saudi Arabia
|Date of Submission||13-Feb-2021|
|Date of Acceptance||22-Jun-2021|
|Date of Web Publication||19-Jul-2021|
Dr. Mohamed Abdelghafour Khalifa
Research Unit, College of Medicine, Sulaiman Al Rajhi University, P.O. Box 777, Bukairyah, Al-Qassim 51941
Source of Support: None, Conflict of Interest: None
Background: Bariatric surgeries form an integral part of morbid obesity management. In addition, alopecia is steadily being reported as a postoperative event. Alopecia is related to the nutritional deficiency occurring due to bariatric surgery, postoperative rapid weight loss, and major surgery-related stress. This review aims to evaluate rates of zinc deficiency as a postoperative complication of bariatric surgery and its association with alopecia.
Methodology: A PubMed literature search conducted between February 6, 2020 and April 3, 2020, from which 32 studies were identified that reported zinc status and hair loss following bariatric surgery.
Results: Most of the articles, 14 (48.28%) articles, 7 (24.14%) articles, reported prospective cohort and retrospective cohort studies, respectively. Moreover, 16 (55.17%) publications were about Roux-en-Y gastric bypass (RYGB) surgery, while sleeve gastrectomy was conducted in 9 (31.03%) studies. Rates of zinc deficiency were reported in 93.10% of the studies. Five studies (17.24%) included the rates of alopecia and most of them revealed female predominance. Decreased food intake was considered as a common cause of zinc deficiency after gastrectomy; on the other hand, decreased zinc absorption was a factor in RYGB patients.
Conclusion: Bariatric surgery is an effective measure in managing morbid obesity and its complications. However, it could be associated by zinc deficiency and consequent alopecia, particularly in females. A meta-analysis is needed to assess this correlation more thoroughly and to determine the potential value of regularly giving micronutrient supplements to prevent such a complication.
Keywords: Alopecia, gastrectomy, zinc
|How to cite this article:|
Al-Komi O, Alnajjar AH, Khalifa MA, Al-Khani AM, Basheir OH. Alopecia and zinc deficiency in postbariatric surgery patients. Saudi Surg J 2020;8:110-7
|How to cite this URL:|
Al-Komi O, Alnajjar AH, Khalifa MA, Al-Khani AM, Basheir OH. Alopecia and zinc deficiency in postbariatric surgery patients. Saudi Surg J [serial online] 2020 [cited 2021 Dec 1];8:110-7. Available from: https://www.saudisurgj.org/text.asp?2020/8/3/110/321727
| Introduction|| |
Obesity is an emerging global public health issue since decades, nearly tripling since 1970s. Recently, the World Health Organization (WHO) reported that nearly two-fifths of adults (18-years and over) were overweight and another fifth were obese. Moreover, obesity is a major risk factor for many cardiometabolic diseases including diabetes mellitus, hypertension, ischemic heart disease, and cerebrovascular injury. An advancement in obesity management is bariatric surgery, currently an integral part of morbid obesity management, which can be categorized into restrictive and malabsorptive types. Indications for bariatric surgery include patients with a body mass index (BMI) of ≥40 kg/m2 or at a BMI ≥35 kg/m2 with comorbidities.
Restrictive bariatric procedures aim to decrease the stomach size, to induce early satiety, and to reduce the amounts of nutrients available for absorption; these include vertical band gastroplasty, laparoscopic sleeve gastrectomy (LSG), and adjustable gastric banding. Alternatively, malabsorptive procedures decrease nutrients absorption through bypassing the stomach and reducing the available absorptive surface area for direct contact with the ingested nutrients; these surgeries include Roux-en-Y gastric bypass (RYGB) and biliopancreatic diversion. Significant postoperative improvement is expected, for example, body weight could be reduced up to 40% with sustained results for long periods.
Nonetheless, metabolic and nutritional complications of such procedures are not uncommon. Depending on the type of surgery, these complications are thought to be secondary to changes in the neural and hormonal gut signaling pathways which regulate hunger/satiety cycle, gut microbiota, food predilection, energy disbursement, decreased food intake, and/or alterations in the absorptive surface area of the stomach and small intestines. Nausea, vomiting, and diarrhea may also occur postoperatively. Consequently, this may trigger electrolytes and fluids imbalance that can persist up to 5 years after surgery. Dumping syndrome and depression can also affect patients postoperatively. However, one of the most esthetically disturbing side effects of bariatric surgery is hair loss. Reports of alopecia in postbariatric patients are increasing, especially in the female gender. For instance, Jaime Ruiz-Tovar described in his study that 41% of his sample of obese females had indeed reported hair loss in the postoperative course after SG. The typical pattern of hair loss following bariatric surgery is a diffuse loss known as telogen effluvium, which could result from both nutritional and nonnutritional causes such as micronutrient deficiencies, particularly zinc deficiency, rapid weight loss and other stressors (for example, major surgery). In the absence of a nutritional deficiency, hair loss seldom persists for more than 6 months. Therefore, we wanted to assess the need for a meta-analysis by conducting a scoping-review.
In this scoping review, we aimed to identify whether zinc deficiency is present in postoperative patients and its association with postoperative alopecia. This review could serve as a general map of this issue. Accordingly, we formulated the following questions: Is zinc deficiency one of the complications after bariatric surgery, and how is it related to alopecia?
| Methodology|| |
This paper was designed using the Preferred Reporting Items for Systematic Reviews and Meta-analysis Protocols for Scoping Reviews.
Eligibility criteria information sources
In this scoping review, the studies needed to report quantitative or qualitative changes of zinc level status following bariatric surgery (SG, Biliopancreatic Diversion, RYGB, duodenal switch, and Gastric banding), for which the indication for surgery was morbid obesity. Peer-reviewed articles must be written or translated to English and published on PubMed before January 2020. We excluded papers of case reports or case series. Moreover, exclusion covers ones, in which zinc deficiency or zinc status among participants was not reported, or another pathology interfered with zinc level changes or indication of gastrectomy.
To screen and identify potentially relevant literature, a search on PubMed database was conducted and papers dated up to January 2020 were checked. The searching methodology was initially drafted by two authors, OA and AH, then it was refined through a group discussion with the rest of the authors. No other databases or supplementary materials were checked.
The following mesh terms were used for our PubMed search, “Bariatric Surgery” AND “Zinc,” “Gastrectomy” AND “Alopecia,” “Gastrectomy” AND “Zinc,” and “Bariatric Surgery” AND “Alopecia”. Other studies having the following keywords, “Hair loss” AND “SG,” and “Micronutrients Deficiencies” AND “SG” AND “Zinc” AND “Iron” were also added.
Since our aim was to evaluate zinc deficiency as a postoperative complication of bariatric surgery and its association with alopecia, it was reasonable to add the following mesh terms “Micronutrients Deficiencies,” “Alopecia,” and “Zinc” to our PubMed search. Unlike other types of bariatric surgeries, gastrectomy was not included as a subcategory under the mesh term “Bariatric Surgery” in the PubMed search engine. Consequently, we had to add a separate mesh term for “gastrectomy.”
Selection of sources of evidence
We found 101 published articles in our search on the PubMed database. Before the beginning, data extractors set the data extraction method and the screening process. Later, this was evaluated and edited by the expert authors. The screening process was held by the data extractors, who worked together to increase the consistency of the reviewing process. Then, we evaluated titles, abstracts, and then full texts to choose the eligible papers.
Data Items and charting process
All reviewers set the variables and items to extract during the charting process. We chose these items to determine the strength of the published papers in the hierarchy of evidence. This facilitates the extraction of qualitative and quantitative data. Both data extractors used Microsoft Excel software during the screening process to identify the eligible paper with their inclusion and exclusion purposes. Then, the data extractors picked up the relevant data from the methodology and result.
Pertinent data on eligibility criteria (indication for surgery was morbid obesity), methodology (length of follow up and type of bariatric surgery), results (zinc/iron cutoff point, pre- and postoperative rates of zinc/iron deficiency, average zinc/iron levels, and alopecia rates variation between males and females), and significance level (P value and/or confidence interval) was checked, extracted, and tabulated. However, some data (e.g. iron levels, average of preoperative zinc/iron deficiency, and alopecia rates) were scarcely reported by few articles. An extra table was added to include those articles which reported only qualitative/descriptive data on zinc levels and alopecia following bariatric surgery. The final version of our charting table form is added within this paper.
| Results|| |
The original search was conducted between (February 6–April 3, 2020), this yielded (n = 128) results. Duplicates were removed to end up with 101 records. All the records were screened, titles, abstracts, and then full texts, to identify whether they met the inclusion criteria and eventually, if they have potentially relevant literature. Thirty-two articles were included as they met the eligibility criteria. Then, n = 3 and n = 29 studies were included for the qualitative and quantitative synthesis of the results, respectively [Figure 1].
|Figure 1: Flow chart of citations. From Moher D, The PRISMA Group (2009)|
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The data regarding year of publication, sample size, study type, type of surgery, follow-up period, rates of zinc deficiency/mean concentration of zinc, and rates of alopecia are demonstrated in [Table 1], [Table 2], [Table 3], [Table 4]. The same set of data is reported for 13 articles studying zinc and/or alopecia status before and after SG in [Table 1]. A second table was added for tabulating relevant data to 17 articles discussing zinc and/or alopecia status before and after RYGB surgery [Table 2]. Zinc status before and after other types of bariatric surgeries are reported in [Table 3]. Qualitative measures extrapolated from three articles are shown in [Table 4]. The number of studies available per intervention varied from one to eighteen.
|Table 4: Qualitative measures of zinc deficiency after bariatric surgeries|
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Sleeve gastrectomy and zinc deficiency
Nine articles identified zinc status before and after SG, three were about laparoscopic SG (LSG), and a single article was about modified LSG (MLSG), [Table 1]. Four papers were of prospective cohort design, five were retrospective cohort studies, others were a comparative study, a cross-sectional study, a meta-analysis, and randomized controlled trial. The length of follow-up was (3–36) months.,,,,,,,,
Six studies showed rates of zinc deficiency (5%–45.1%) in patients after SG.,,,,, In these studies, the rate was incrementing during follow-up, except in one study where it decreased from (25.6%) 12 months postoperatively to (6.6%), 24 months post-operatively. In contrast, the rate of zinc deficiency significantly increased after SG in only two studies.,
Postoperative alopecia was identified in four studies.,,, One study reported a significant association with zinc deficiency. Furthermore, it was significantly identified as a postsurgical complication, with female predominance.,
Zinc deficiency was identified preoperatively in two studies. The rate was increasing after LSG., On the other hand, zinc deficiency was not detected after LSG in another article. In a randomized controlled trial, 14% of patients had zinc deficiency over 36 months after MLSG and all of them developed alopecia.
A meta-analysis found a decreased serum zinc after bariatric surgery with effect size (−0.77) CI 95% ([ − 1.20]–[−0.35]).
Roux-en-Y-gastric bypass surgery and zinc deficiency
Seventeen papers addressed zinc status after RYGB surgery and laparoscopic RYGB surgery over a period of follow-up ranging from 2 to 60 months [Table 2]. Nine used prospective cohort design,,,,,,,,, and three were of retrospective cohort design.,, The last six papers were of cross-sectional, RCT, comparative, longitudinal paired, retrospective, descriptive, and observational study and retrospective review designs.,,,,,
The rate of postoperative zinc deficiency was reported as 15.4%–84.1%.,,,,,,,,,, Postoperative zinc deficiency rates were significantly different from preoperative zinc deficiency rates in three papers.,, In a longitudinal paired study, postoperative serum level zinc was significantly decreased in 89% of patients as compared to preoperative levels. The average level of serum zinc was decreased postoperatively as compared to the preoperative zinc level in four papers,,,, and this difference was significant in Billeter et al. study.
In Ledoux, a prospective cohort, 35% of patients significantly developed alopecia with female predominance.
Zinc status before and after other bariatric surgeries
In a prospective cohort study, the average zinc level significantly decreased from 740 ± 230 ng/ml to 500 ± 130 ng/ml after laparoscopic adjustable gastric banding with a P = 0.001. In Costa MM study, all patients who had zinc deficiency after gastric bypass surgery. Furthermore, in a prospective cohort and another retrospective cohort study, most patients had zinc deficiency after biliopancreatic diversion and duodenal switch over period of 60 and 12 months, respectively,, [Table 3].
Burge et al., in a prospective cohort study in 1995, observed no changes in zinc concentrations 1.5–3 months after RYGB. However, zinc intake was lower than the recommended dietary intake postoperatively after Modified Long Vertical Gastroplasty in Cooper et al.'s prospective cohort study. Moreover, correction of micronutrient deficiencies before SG could enhance micronutrient status postoperatively.
| Discussion|| |
Our review addresses an important issue of zinc deficiency and its association with postoperative alopecia. To answer this question, papers dated up to January 2020 were checked using the aforementioned methodology, see part 2. Subsequently, 33 primary studies addressing the rates of zinc deficiency and/or alopecia in postbariatric surgery patients were included after excluding duplicate articles and those which did not met our eligibility criteria [Figure 1]. Specific data regarding year of publication, sample size, study type, type of surgery, follow-up period, rates of zinc deficiency/mean concentration of zinc, and rates of alopecia were tabulated [Table 1], [Table 2], [Table 3], [Table 4].
Our review showed that zinc has an essential biophysiological role in hair growth [Figure 2]. Furthermore, studies had reported an association of zinc deficiency with postoperative alopecia development., Either the rate of zinc deficiency or the mean concentration of zinc following SG including LSG and modified SG, and gastric bypass surgeries were reported by (n = 29) studies, and it had ranged from 0%–45.1% to 15.4%–85.1%, respectively [Table 1] and [Table 2]. Our findings indicate a paucity of research focusing specifically on the epidemiological and etiological aspects of alopecia following bariatric surgeries. Rate of postoperative alopecia was investigated by (n = 5) studies, which overall reported female predominance.,,,, One study reported alopecia in patients undergoing RYGB (35%) and SG (61%). Pirolla et al., Katsogridaki, G, and Ruiz-Tovar, J had demonstrated that alopecia rates following SG were 14%, 56%, and 41%, respectively.
|Figure 2: Sleeve gastrectomy and Roux-Y-Gastric bypass and their association with zinc deficiency and consequent alopecia. Decreased food intake is considered as the most common cause of zinc deficiency after gastrectomy, on the other hand, decreased zinc absorption was the most common factor in Roux-en-Y gastric bypass patients,,,,,,,,,|
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Both Katsogridaki et al. and Ruiz-Tovar et al. have reported that a significant association between hair loss and zinc perioperative levels. In addition, Pirolla et al., Ruiz-Tovar et al., and Katsogridaki et al. have shown that giving zinc supplements postoperatively was associated with a cessation of hair loss. It is worthy to note that both Katsogridaki et al. and Ruiz-Tovar et al. have declared that, alongside zinc status, other factors such as preoperative micronutrients deficiency, postoperative levels of iron, and Vitamin B12 may have a contributive role in the development of alopecia.
Various studies were reporting zinc levels using different cutoff point values and measurement units; therefore, our estimation of the actual prevalence and significance of zinc deficiency following bariatric surgery could be potentially influenced by such variations. Moreover, disparity in the length of follow-up period between the different studies could affect this estimation. In addition, one study remarked that the patient's mean intake of zinc was only 39% of the Australian recommended dietary intake 2 months following vertical gastroplasty. In addition, he noted that zinc levels remained below half the reference daily intake at 5 months postoperatively. Furthermore, Schiavo et al. suggested that the correction of micronutrient deficiencies before SG could be useful in preventing early micronutrient deficiencies following SG. Thence, and based on the preceding rationales, we suggest that a meta-analysis is probably needed to thoroughly assess the correlation between zinc deficiency following bariatric surgeries and consequent alopecia and to estimate the potential value of regularly giving micronutrient supplements before and/or after surgery to prevent such a complication.
To the best of our knowledge, there is only a single meta-analysis that had been done previously by Freeland-Grave et al., in which she discussed the topic of trace element deficiencies following bariatric surgery. However, rates of alopecia were neither studied nor reported.
We acknowledge certain limitations of this review. Only one data base was used for data collection, a potential publication bias issue. In addition, data charting was done independently between the data collectors and no criss-cross was done to eliminate potential interobserver variability. Finally, no critical appraisal of the included papers was done.
| Conclusion|| |
Bariatric surgery is an effective measure in the management of morbid obesity. Further evidence suggests that it could be potentially associated with zinc deficiency and subsequently, alopecia – with female predominance. A more detailed analysis of the literature should assess the relationship between zinc deficiency and alopecia following bariatric surgeries. We have found some methodological variations between studies/papers investigating zinc deficiency following bariatric surgery. Because of these variations, we recommend conducting a meta-analysis to weigh the effect size of these factors and to check if there is a potential value for regularly giving micronutrient supplements before and/or after surgery to prevent alopecia. Thereafter, we could determine the potential value of micronutrient supplements perioperatively for patients at risk.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Manzoni AP, Weber MB. Skin changes after bariatric surgery. An Bras Dermatol 2015;90:157-66.
Freeland-Graves JH, Lee JJ, Mousa TY, Elizondo JJ. Patients at risk for trace element deficiencies: Bariatric surgery. J Trace Elem Med Biol 2014;28:495-503.
Miras AD, le Roux CW. Mechanisms underlying weight loss after bariatric surgery. Nat Rev Gastroenterol Hepatol 2013;10:575-84.
Ruiz-Tovar J, Oller I, Llavero C, Zubiaga L, Diez M, Arroyo A, et al.
Hair loss in females after sleeve gastrectomy: Predictive value of serum zinc and iron levels. Am Surg 2014;80:466-71.
Rushton DH. Nutritional factors and hair loss. Clin Exp Dermatol 2002;27:396-404.
Moher D, Liberati A, Tetzlaff J, Altman DG, Group P. Preferred reporting items for systematic reviews and meta-analyses: The PRISMA statement. PLoS Med 2009;6:e1000097.
Katsogridaki G, Tzovaras G, Sioka E, Perivoliotis K, Zachari E, Magouliotis D, et al.
Hair loss after laparoscopic sleeve gastrectomy. Obes Surg 2018;28:3929-34.
Goldenshluger M, Goldenshluger A, Keinan-Boker L, Cohen MJ, Ben-Porat T, Gerasi H, et al.
Postoperative outcomes, weight loss predictors, and late gastrointestinal symptoms following laparoscopic sleeve gastrectomy. J Gastrointest Surg 2017;21:2009-15.
Ledoux S, Flamant M, Calabrese D, Bogard C, Sami O, Coupaye M. What are the micronutrient deficiencies responsible for the most common nutritional symptoms after bariatric surgery? Obes Surg 2020;30:1891-7.
Sallé A, Demarsy D, Poirier AL, Lelièvre B, Topart P, Guilloteau G, et al.
Zinc deficiency: A frequent and underestimated complication after bariatric surgery. Obes Surg 2010;20:1660-70.
Alvarez V, Cuevas A, Olivos C, Berry M, Farías MM. Micronutrient deficiencies one year after sleeve gastrectomy. Nutr Hosp 2014;29:73-9.
Ferraz ÁA, Carvalho MR, Siqueira LT, Santa-Cruz F, Campos JM. Micronutrient deficiencies following bariatric surgery: A comparative analysis between sleeve gastrectomy and Roux-en-Y gastric bypass. Rev Col Bras Cir 2018;45:e2016.
Ruiz-Tovar J, Oller I, Tomas A, Llavero C, Arroyo A, Calero A, et al.
Mid-term effects of sleeve gastrectomy on calcium metabolism parameters, vitamin D and parathormone (PTH) in morbid obese women. Obes Surg 2012;22:797-801.
Belfiore A, Cataldi M, Minichini L, Aiello ML, Trio R, Rossetti G, et al.
Short-term changes in body composition and response to micronutrient supplementation after laparoscopic sleeve gastrectomy. Obes Surg 2015;25:2344-51.
Pirolla EH, Jureidini R, Barbosa ML, Ishikawa LC, Camargo PR. A modified laparoscopic sleeve gastrectomy for the treatment of diabetes mellitus type 2 and metabolic syndrome in obesity. Am J Surg 2012;203:785-92.
Eltweri AM, Bowrey DJ, Sutton CD, Graham L, Williams RN. An audit to determine if vitamin b12 supplementation is necessary after sleeve gastrectomy. Springerplus 2013;2:218.
Gehrer S, Kern B, Peters T, Christoffel-Courtin C, Peterli R. Fewer nutrient deficiencies after laparoscopic sleeve gastrectomy (LSG) than after laparoscopic Roux-Y-gastric bypass (LRYGB) – A prospective study. Obes Surg 2010;20:447-53.
de Torres Rossi RG, Dos Santos MT, de Souza FI, de Cássia de Aquino R, Sarni RO. Nutrient intake of women 3 years after Roux-en-Y Gastric bypass surgery. Obes Surg 2012;22:1548-53.
Madan AK, Orth WS, Tichansky DS, Ternovits CA. Vitamin and trace mineral levels after laparoscopic gastric bypass. Obes Surg 2006;16:603-6.
Chagas C, Saunders C, Pereira S, Silva J, Saboya C, Ramalho A. Vitamin A status and its relationship with serum zinc concentrations among pregnant women who have previously undergone Roux-en-Y gastric bypass. Int J Gynaecol Obstet 2016;133:94-7.
Ruz M, Carrasco F, Rojas P, Codoceo J, Inostroza J, Basfi-fer K, et al.
Zinc absorption and zinc status are reduced after Roux-en-Y gastric bypass: A randomized study using 2 supplements. Am J Clin Nutr 2011;94:1004-11.
Cominetti C, Garrido AB Jr., Cozzolino SM. Zinc nutritional status of morbidly obese patients before and after Roux-en-Y gastric bypass: A preliminary report. Obes Surg 2006;16:448-53.
Billeter AT, Probst P, Fischer L, Senft J, Kenngott HG, Schulte T, et al.
Risk of malnutrition, trace metal, and vitamin deficiency post roux-en-Y gastric bypass – A Prospective study of 20 patients with BMI<35 kg/m2
. Obes Surg 2015;25:2125-34.
Rojas P, Carrasco F, Codoceo J, Inostroza J, Basfi-fer K, Papapietro K, et al.
Trace element status and inflammation parameters after 6 months of Roux-en-Y gastric bypass. Obes Surg 2011;21:561-8.
Pires LV, Martins LM, Geloneze B, Tambascia MA, Hadad do Monte SJ, do Nascimento Nogueira N, et al.
The effect of Roux-en-Y gastric bypass on zinc nutritional status. Obes Surg 2007;17:617-21.
Rosa FT, de Oliveira-Penaforte FR, de Arruda Leme I, Padovan GJ, Ceneviva R, Marchini JS. Altered plasma response to zinc and iron tolerance test after Roux-en-Y gastric bypass. Surg Obes Relat Dis 2011;7:309-14.
Costa MM, Belo S, Souteiro P, Neves JS, Magalhães D, Silva RB, et al.
Pregnancy after bariatric surgery: Maternal and fetal outcomes of 39 pregnancies and a literature review. J Obstet Gynaecol Res 2018;44:681-90.
Gobato RC, Seixas Chaves DF, Chaim EA. Micronutrient and physiologic parameters before and 6 months after RYGB. Surg Obes Relat Dis 2014;10:944-51.
Balsa JA, Botella-Carretero JI, Gómez-Martín JM, Peromingo R, Arrieta F, Santiuste C, et al.
Copper and zinc serum levels after derivative bariatric surgery: Differences between Roux-en-Y Gastric bypass and biliopancreatic diversion. Obes Surg 2011;21:744-50.
Hastuti AA, Costas-Rodríguez M, Anoshkina Y, Parnall T, Madura JA 2nd
, Vanhaecke F. High-precision isotopic analysis of serum and whole blood Cu, Fe and Zn to assess possible homeostasis alterations due to bariatric surgery. Anal Bioanal Chem 2020;412:727-38.
Böyük A, Banlı O, Gümüş M, Evliyaoğlu O, Demirelli S. Plasma levels of zinc, copper, and ceruloplasmin in patients after undergoing laparoscopic adjustable gastric banding. Biol Trace Elem Res 2011;143:1282-8.
Gjørup I, Gjørup T, Andersen B. Serum selenium and zinc concentrations in morbid obesity. Comparison of controls and patients with jejunoileal bypass. Scand J Gastroenterol 1988;23:1250-2.
Burge JC, Schaumburg JZ, Choban PS, DiSilvestro RA, Flancbaum L. Changes in patients' taste acuity after Roux-en-Y gastric bypass for clinically severe obesity. J Am Diet Assoc 1995;95:666-70.
Cooper PL, Brearley LK, Jamieson AC, Ball MJ. Nutritional consequences of modified vertical gastroplasty in obese subjects. Int J Obes Relat Metab Disord 1999;23:382-8.
Schiavo L, Pilone V, Rossetti G, Romano M, Pieretti G, Schneck AS, et al.
Correcting micronutrient deficiencies before sleeve gastrectomy may be useful in preventing early postoperative micronutrient deficiencies. Int J Vitam Nutr Res 2019;89:22-8.
Papamargaritis D, Aasheim ET, Sampson B, le Roux CW. Copper, selenium and zinc levels after bariatric surgery in patients recommended to take multivitamin-mineral supplementation. J Trace Elem Med Biol 2015;31:167-72.
Ogawa Y, Kinoshita M, Shimada S, Kawamura T. Zinc and skin disorders. Nutrients 2018;10:199.
Kil MS, Kim CW, Kim SS. Analysis of serum zinc and copper concentrations in hair loss. Ann Dermatol 2013;25:405-9.
Hoover E, Alhajj M, Flores JL. Physiology, hair. In: StatPearls. Treasure Island (FL): StatPearls; 2020.
Halawi A, Abiad F, Abbas O. Bariatric surgery and its effects on the skin and skin diseases. Obes Surg 2013;23:408-13.
DiBaise M, Tarleton SM. Hair, nails, and skin: Differentiating cutaneous manifestations of micronutrient deficiency. Nutr Clin Pract 2019;34:490-503.
Bistas KG, Tadi P. Biotin. In: StatPearls. Treasure Island (FL): StatPearls; 2020.
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4]