The effects of fat loss after bariatric surgery on inflammation, serum hepcidin, and iron absorption: a prospective 6-mo iron stable isotope study

Iron: The silent culprit in your adipose tissue

Iron plays a vital role in essential biological processes and requires precise regulation within the body. Dysregulation of iron homeostasis, characterized by increased serum ferritin levels and excessive accumulation of iron in the liver, adipose tissue, and skeletal muscle, is associated with obesity and insulin resistance. Notably, iron excess in adipose tissue promotes adipose tissue dysfunction. As optimal adipose tissue function is crucial for maintaining a healthy phenotype in obesity, a comprehensive understanding of iron homeostasis in adipose tissue is imperative for designing new therapeutic approaches to improve and prevent adipose tissue dysfunction. Here, we conducted a review of relevant studies, focusing on and providing valuable insights into the intricate interplay between iron and adipose tissue. It sheds light on the impact of iron on adipogenesis and the physiology of both white and brown adipose tissue. Furthermore, we highlight the critical role of key modulators, such as cytosolic aconitase, mitochondria, and macrophages, in maintaining iron homeostasis within adipose tissue.

Iron, glucose and fat metabolism and obesity: an intertwined relationship

A bidirectional relationship exists between adipose tissue metabolism and iron regulation. Total body fat, fat distribution and exercise influence iron status and components of the iron-regulatory pathway, including hepcidin and erythroferrone. Conversely, whole body and tissue iron stores associate with fat mass and distribution and glucose and lipid metabolism in adipose tissue, liver, and muscle. Manipulation of the iron-regulatory proteins erythroferrone and erythropoietin affects glucose and lipid metabolism. Several lines of evidence suggest that iron accumulation and metabolism may play a role in the development of metabolic diseases including obesity, type 2 diabetes, hyperlipidaemia and non-alcoholic fatty liver disease. In this review we summarise the current understanding of the relationship between iron homoeostasis and metabolic disease.

Prevalence and Risk Factors of Anemia in Patients After Bariatric Surgery in Qassim Region, King Fahad Specialist Hospital

Introduction There is a high prevalence of obesity among the Saudi population. Anemia due to iron deficiency or an inflammatory state is often associated with obesity. Multiple nutritional deficiencies are associated with bariatric surgeries, with anemia being one of the commonest causes. Aim This study aimed to evaluate the prevalence of anemia after bariatric surgery among patients in the Qassim Region, Saudi Arabia. Patients and methods This retrospective cohort study was conducted at King Fahad Specialist Hospital Al-Qassim (Buraydah), Saudi Arabia. We reviewed data from patients' records who underwent bariatric surgeries from January 2018 to January 2021. By using a structured data collection form, we collected data such as demographic variables, surgery perioperative-related data, postoperative complications and interventions, type of transfusion required after surgery, postoperative medications and/or supplements and duration, and blood count indices. Results Of the 520 patients who underwent bariatric surgery, 61% were females, and 31.7% were aged between 26 to 35 years old. The most prominent type of bariatric surgery was sleeve gastrectomy (97.1%). The prevalence of anemia among patients who underwent bariatric surgery was 28.1%. Independent risk factors for anemia were female gender, microcytic red blood cells, and low normal hematocrit and hemoglobin (Hgb) levels. It is interesting to know that sleeve gastrectomy and elevated BMI levels are considered to be the protective factors for developing anemia postoperatively. Conclusion There was a high prevalence of anemia among bariatric patients postoperatively. Female gender with decreasing hematocrit and hemoglobin levels after the surgery might be more at the receiving end for developing anemia than the other patients. Further longitudinal studies are needed to establish the prevalence and risk factors for developing anemia among bariatric surgery patients.

Trends in the Intraindividual Double Burden of Overweight/Obesity and Anemia among Adult Women Living in 33 Low- and Middle-Income Countries: A Secondary Analysis of Demographic and Health Surveys from 2000-2019

BACKGROUND

Changes in overweight/obesity and anemia among women have been investigated in multiple studies, but the rate at which their coexistence at the individual level has evolved remains unknown.

OBJECTIVES

We aimed to 1) document trends in the magnitude and inequalities of the co-occurrence of overweight/obesity and anemia; and 2) compare these with overall trends in overweight/obesity, anemia, and the co-occurrence of anemia with normal weight or underweight.

METHODS

For this cross-sectional series study, we used 96 Demographic and Health Surveys from 33 countries with available anthropometric and anemia data among nonpregnant adult women (20-49 y old; n = 1,648,308). The primary outcome was defined as the coexistence of overweight or obesity (BMI ≥25kg/m2) and anemia (hemoglobin concentrations <12.0 g/dL) within the same individual. We computed overall and regional trends through multilevel linear regression models and by sociodemographic characteristics (i.e., wealth, education, and residence). Estimates at the country level were calculated through ordinary least square regression models.

RESULTS

From 2000 to 2019, the co-occurrence of overweight/obesity and anemia increased modestly at an annual rate of 0.18 percentage points (95% CI: 0.08, 0.28 percentage points; P < 0.001), ranging from 0.73 percentage points in Jordan to -0.56 percentage points in Peru. This trend occurred in parallel with overall increases in overweight/obesity and reductions in anemia. The co-occurrence of anemia with normal weight or underweight was reducing in all countries, except Burundi, Sierra Leone, Jordan, Bolivia, and Timor-Leste. Stratified analyses yielded an upward trend in the co-occurrence of overweight/obesity and anemia across all subgroups but particularly in women from the 3 middle wealth groups, no education, and capital city or rural residents.

CONCLUSIONS

The rising trend in the intraindividual double burden suggests that efforts to reduce anemia among women living with overweight/obesity may need to be revisited to accelerate progress toward the 2025 global nutrition target of halving anemia.

Long-Term Outcomes of Iron Deficiency Before and After Bariatric Surgery: a Systematic Review and Meta-analysis

PURPOSE

This study reviews the prevalence of iron deficiency (ID) in bariatric surgery candidates and the long-term outcomes of the prevalence of ID after bariatric surgery.

MATERIALS AND METHODS

A systematic literature search and meta-analysis were performed in PubMed for articles published by August 31, 2022, including these search terms: bariatric surgery, metabolic surgery, weight loss surgery, obesity surgery, sleeve gastrectomy, gastric banding, gastric bypass, duodenal switch, duodenojejunal bypass, iron, iron deficiency, sideropenia, and hypoferritinemia. Fifty-seven studies examining a total of 26,328 patients with morbidly obese were included in this meta-analysis finally.

RESULTS

The results showed a prevalence of 17% of ID in bariatric surgery candidates and a prevalence of 14%, 17%, 26%, 34%, 23%, 38%, and 23% of ID at 1-, 2-, 3-, 4-, 5-, 8-, and 10-year follow-up after bariatric surgery, respectively. Additionally, the results showed a prevalence of 15%, 19%, 35%, 38%, 29%, 30%, and 23% of ID at 1-, 2-, 3-, 4-, 5-, 8-, and 10-year follow-up after Roux-en-Y gastric bypass, respectively; a prevalence of 12%, 12%, 15%, 31%, and 17% of ID at 1-, 2-, 3-, 4-, and 5-year follow-up after sleeve gastrectomy, respectively; and a prevalence of 19% of ID at 1-year follow-up after anastomosis gastric bypass.

CONCLUSION

As a result, preoperative evaluation and correction of ID may lead to better outcomes for bariatric surgery candidates. ID is also common in patients after bariatric procedures, especially RYGB. Long-term, even lifelong, medical and nutritional monitoring and tailored interventions are critical.

Prevalence of anemia and related nutrient deficiencies after sleeve gastrectomy: A systematic review and meta-analysis

This study aimed to investigate the prevalence of anemia and related nutrient deficiencies after sleeve gastrectomy (SG). Four online databases were searched for relevant articles. Thirty-one studies with 7639 patients were included in the meta-analysis. The pooled anemia prevalence was 7%, 6%, 9%, 10%, 12%, 25%, 20%, and 18% at baseline, 3 months, 6 months, 12 months, 24 months, 36 months, 48 months, and 60 months, respectively. Although the prevalence of vitamin B12 and folate deficiencies remained low postoperatively, the prevalence of ferritin deficiency steadily increased from 6% at baseline to 27% at 60 months. The prevalence of serum iron deficiency decreased from 13% at baseline to 6% at 24 months and increased to 20% at 60 months. Anemia and ferritin deficiency were strongly correlated (Pearson correlation coefficient = 0.774, p = 0.041). Subgroup analysis suggested that age ≤40 years, preoperative anemia, and insufficient iron supplementations were high-risk factors for postoperative anemia. SG is associated with an increased risk of anemia and decreased iron storage over long-term observation. Routine iron supplementations may reduce anemia after SG; however, the dosages recommended by current guidelines may be insufficient. More strict monitoring schedules and supplementation strategies should be established for the timely detection and management of postoperative anemia.

Changes in Nutritional Outcomes After Sleeve Gastrectomy: a Systematic Review and Meta-analysis

PURPOSE

The aim of this meta-analysis is to evaluate the changes in nutritional indicators in individuals with obesity before and after SG.

MATERIALS AND METHODS

A systematic retrieval of the available literature was performed using PubMed, Embase, Web of Science, and Chinese National Knowledge Infrastructure databases. The following indicators were evaluated: serum 25-hydroxyvitamin D [25(OH)D], calcium, phosphorus, iron, vitamin B12, folate, magnesium, and zinc from pre-operation to post-operation.

RESULTS

A total of 38 studies met inclusion criteria. A significant increase was observed in serum 25(OH)D (SMD = 0.70, 95%CI 0.38 to 1.02, P < 0.001), phosphorus (SMD = 0.40, 95%CI 0.14 to 0.67, P = 0.003), iron (SMD = 0.50, 95%CI 0.38 to 0.62, P < 0.001), and folate (SMD = 0.37, 95%CI 0.09 to 0.65, P = 0.01) after SG. Nevertheless, the increasing trend of serum phosphorus (P = 0.143) and folate (P = 0.774) disappeared in the unprescribed subgroup. A significant decrease in serum zinc (SMD =  - 0.41, 95%CI - 0.81 to - 0.01, P = 0.044) was found after SG. No significant changes in serum calcium (SMD = 0.08, 95%CI - 0.09 to 0.25, P = 0.372), vitamin B12 (SMD = 0.10, 95%CI - 0.13 to 0.33, P = 0.398), and magnesium (SMD = 0.24, 95%CI - 0.10 to 0.58, P = 0.169) were observed. However, a significant decrease in serum calcium (P = 0.042) and vitamin B12 (P = 0.037) was found in the unprescribed subgroup.

CONCLUSIONS

Serum 25(OH)D, phosphorus, iron, and folate levels improved after a careful monitoring and due to a rigorous supplementation. The optimal dose of calcium, magnesium, and zinc supplementation has yet to be established; therefore, a broader supplementation of trace elements and minerals has to be suggested.

Association between obesity and iron deficiency (Review)

Obesity is a risk factor for several comorbidities and complications, including iron deficiency anemia. Iron deficiency anemia is a serious global public health problem, with a worldwide prevalence. The high prevalence of obesity in combination with iron deficiency incidence observed in different age and sex categories suggests an association between obesity and iron status. Obesity may disrupt iron homeostasis, resulting in iron deficiency anemia. The association between obesity and iron deficiency may be due to increased hepcidin levels mediated by chronic inflammation. Hepcidin is a small peptide hormone that functions as a negative regulator of intestinal iron absorption. Significant body weight loss in overweight and obese individuals decreases chronic inflammation and serum hepcidin levels, resulting in improved iron status due to increased iron absorption. However, further randomized controlled trials are required to confirm this effect.

The effects of reducing chronic inflammation in overweight women on serum hepcidin and iron absorption with and without supplemental ascorbic acid

Although hepcidin synthesis is stimulated by inflammation and inhibited by Fe deficiency, the strength of their opposing effects on serum hepcidin (SHep) in humans remains unclear. It was recently shown that an inflammatory stimulus in anaemic women did not increase SHep or decrease Fe absorption. The enhancing effect of ascorbic acid on Fe absorption may not be effective during inflammation because of increased SHep. Our study aim was to test whether reducing inflammation in Fe-depleted overweight (OW) women with low-grade inflammation would lower SHep and improve Fe absorption with and without ascorbic acid, compared with normal-weight (NW) women without inflammation. Before and after 14 d of anti-inflammatory treatment (3 × 600 mg ibuprofen daily) in OW and NW women (n 36; 19-46 years of age), we measured SHep and fractional Fe absorption (FIA) (erythrocyte Fe incorporation) from 57Fe- and 58Fe-labelled test meals with and without ascorbic acid. There were significant group effects on IL-6, C-reactive protein, serum ferritin and SHep (for all, P < 0·05). There was a significant treatment effect on SHep (P < 0·05): in OW women, treatment decreased IL-6 by approximately 30 % and SHep by approximately 45 %. However, there were no significant treatment or group effects on FIA. Body Fe stores (BIS) were a significant positive predictor of SHep before and after treatment (P < 0·001), but IL-6 was not. Reducing chronic inflammation in OW women halved SHep but did not affect Fe absorption with or without ascorbic acid, and the main predictor of Fe absorption was BIS.

Inorganic Iron Supplementation Rescues Hematological Insufficiency Even Under Intense Exercise Training in a Mouse Model of Iron Deficiency with Anemia

Iron deficiency anemia (IDA) due to malnutrition and/or blood loss is a common condition, especially in women of reproductive age. Intense exercise can induce anemia via an inflammatory response, but whether intense exercise affects the efficacy of iron supplementation to treat IDA is unclear. Here, we show in a mouse model of IDA that acute intense swimming increased IL-6 levels in the blood, but did not affect the maximum elevation of plasma iron following oral administration of 0.5 mg/kg Bw iron. However, compared with the control group without intense exercise, acute intense swimming was associated with a significant decrease in plasma iron 2 and 4 h after iron loading that could be attributed to rapid iron absorption in peripheral tissues. In the chronic experiment, IDA mice administered 0.36, 1.06, or 3.2 mg/kg Bw iron per day that were subjected to 11 intense swimming sessions over 3 weeks showed significantly decreased recovery levels for hemoglobin and red blood cell count during the early phase of the experimental period. At the end of the experimental period, significant, dose-dependent effects of iron, but not the main effect of intense exercise, were seen for recovery of hemoglobin and red blood cell counts, consistent with the acute exercise study. These results suggested that intense exercise in the presence of IDA does not inhibit iron absorption from the gastrointestinal tract and that iron supplementation can enhance the recovery process even after intense exercise.

Micronutrient status in bariatric surgery patients receiving postoperative supplementation per guidelines: Insights from a systematic review and meta-analysis of longitudinal studies

The micronutrient status and optimal monitoring schedule after bariatric surgery have not been sufficiently assessed. This systematic review and meta-analysis investigated the longitudinal changes in micronutrient status after bariatric surgery. PubMed, EMBASE, and Cochrane Library were searched for articles that measured preoperative and postoperative serum micronutrient levels in patients undergoing Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG). Among guideline-adherent studies, the longitudinal changes in micronutrient status were investigated using weighted mean difference (WMD) using a random-effects model. Among the 82 included studies, the guideline adherence rates for micronutrient supplementation after bariatric surgery did not exceed 20%. In patients supplemented per guidelines, vitamin A significantly decreased after RYGB by -7.54 (95% confidence interval [CI], -10.16 to -4.92) μg/dl at 12-23 months, vitamin E decreased after RYGB by -2.35 (95% CI, -3.65 to -1.05) μg/dl at ≥24 months, and ferritin by -54.93 (95% CI, -77.19 to -32.67] μg/L at ≥24 months after SG, compared with baseline, with moderate level of evidence. Significant decreases in micronutrient levels at certain follow-up intervals in studies with supplementation per guidelines need to be considered to establish a post-bariatric micronutrient monitoring schedule for timely detection and management of micronutrient deficiencies.

The Immunophenotyping Changes of Peripheral CD4+ T Lymphocytes and Inflammatory Markers of Class III Obesity Subjects After Laparoscopic Gastric Sleeve Surgery - A Follow-Up Study

Purpose

Obesity is a chronic disorder characterized by a low-grade inflammatory state and immune cell irregularities. The study aimed to follow up on the changes in the peripheral CD4+ T lymphocytes and the pro-inflammatory cytokines; IL-6, TNF-alpha, MCP-1, and IL-10 at baseline and 12 weeks post-surgical intervention by the laparoscopic gastric sleeve (LGS) in morbidly obese patients (class III obesity subjects).

Materials and Methods

A prospective longitudinal research included 24 class III obesity subjects with a BMI > 40 kg/m². The subjects were enrolled from the Metabolic/Surgical Department at Hamad Medical Corporation (HMC)-Qatar. Fasting blood samples were collected at admission to LGS for weight loss and after 12 weeks of LGS. The immunophenotype of CD4+ T-cell populations; naïve (CD45RA⁺and CD27⁺), central memory T cells (CD45RO⁺ and CD27⁺), and effector memory (CD45RO⁺and CD27^-) and T-regulatory cell (CD4+CD25+ FoxP3+) were identified using flow cytometry. Plasma pro-inflammatory cytokines and adipokines were evaluated. A control group of lean subjects was used to compare changes of T-regulatory and inflammatory biomarkers with postoperative changes in obese patients.

Results

The means (SD) of age and BMI of class III obesity subjects was 32.32 (8.36) years and 49.02 (6.28) kg/m^2, respectively. LGS caused a significant reduction in BMI by 32%, p<0.0001. LGS intervention significantly decreased CD4+ T-lymphocytes and effector memory (TEM) cells but increased T-regulatory (Treg), naïve, and central memory (TCM) cells, with all p values < 0.05. The increase of Treg cells postoperative is significantly lower compared to lean subjects, p < 0.05. A significant reduction of plasma IL-6, TNF-α, and MCP-1, but IL-10 significantly increased after LGS, with all p<0.05. Adiponectin/leptin ratio improved after LGS by 2.9 folds, p<0.0001.

Conclusion

Weight loss by LGS accomplished a substantial rise of Treg and decreased EM T-lymphocytes with a shift from pro-inflammatory to the anti-inflammatory pattern.

Iron Deficiency in Obesity and after Bariatric Surgery

Iron deficiency (ID) is particularly frequent in obese patients due to increased circulating levels of acute-phase reactant hepcidin and adiposity-associated inflammation. Inflammation in obese subjects is closely related to ID. It induces reduced iron absorption correlated to the inhibition of duodenal ferroportin expression, parallel to the increased concentrations of hepcidin. Obese subjects often get decreased inflammatory response after bariatric surgery, accompanied by decreased serum hepcidin and therefore improved iron absorption. Bariatric surgery can induce the mitigation or resolution of obesity-associated complications, such as hypertension, insulin resistance, diabetes mellitus, and hyperlipidemia, adjusting many parameters in the metabolism. However, gastric bypass surgery and sleeve gastrectomy can induce malabsorption and may accentuate ID. The present review explores the burden and characteristics of ID and anemia in obese patients after bariatric surgery, accounting for gastric bypass technique (Roux-en-Y gastric bypass-RYGB) and sleeve gastrectomy (SG). After bariatric surgery, obese subjects' iron status should be monitored, and they should be motivated to use adequate and recommended iron supplementation.

Iron Fortification and Supplementation: Fighting Anemia of Chronic Diseases or Fueling Obesity?

The significant worldwide increase in obesity has become a major health problem. Excess adiposity has been extensively linked to inflammation. Recently, studies have shown that dietary intake and microbiota dysbiosis can affect the health of the gut and lead to low-grade systemic inflammation, worsening the state of obesity and further exacerbating inflammation. The latter is shown to decrease iron status and potentially increase the risk of anemia by inhibiting iron absorption. Hence, anemia of obesity is independent of iron intake and does not properly respond to increased iron ingestion. Therefore, countries with a high rate of obesity should assess the health impact of fortification and supplementation with iron due to their potential drawbacks. This review tries to elucidate the relation between inflammation and iron status to better understand the etiology of anemia of obesity and chronic diseases and wisely design any dietary or medical interventions for the management of anemia and/or obesity.

Iron-Enriched Nutritional Supplements for the 2030 Pharmacy Shelves

Iron deficiency (ID) affects people of all ages in many countries. Due to intestinal blood loss and reduced iron absorption, ID is a threat to IBD patients, women, and children the most. Current therapies can efficiently recover normal serum transferrin saturation and hemoglobin concentration but may cause several side effects, including intestinal inflammation. ID patients may benefit from innovative nutritional supplements that may satisfy iron needs without side effects. There is a growing interest in new iron-rich superfoods, like algae and mushrooms, which combine antioxidant and anti-inflammatory properties with iron richness.

Inflammatory Markers and Hepcidin are Elevated but Serum Iron is Lower in Obese Women of Reproductive Age

Limited evidence suggests that serum iron and hepcidin concentrations are dysregulated in obesity and inflammation. The objective of the present study was to compare C-reactive protein, interleukin-6, circulating levels of hepcidin, serum lipids, and iron status in obese vs. normal-weight women of childbearing age. Healthy women aged 18–30 years were recruited for the study (n = 47: 25 obese and 22 normal weight). Fasting blood samples were obtained to measure serum lipids (total cholesterol, HDL, LDL cholesterol, triglycerides, non-HDL cholesterol), complete blood count, serum iron, total iron-binding capacity, transferrin saturation, serum ferritin, hepcidin, C-reactive protein, and interleukin-6. Obese women had significantly higher mean serum C-reactive protein (p < 0.001), interleukin-6 (p < 0.001), hepcidin (p = 0.024), triglycerides (p < 0.001) and total cholesterol/HDL ratio (p < 0.001) but lower HDL (p = 0.001) and serum iron/hepcidin ratio (p = 0.011) compared with normal-weight women. BMI correlated positively with inflammatory markers, triglycerides, LDL and total cholesterol/HDL ratio, and negatively with HDL and serum iron/hepcidin ratio. Serum iron correlated negatively with ferritin in the obese group (p = 0.030) but positively in normal weight women (p = 0.002). BMI and ferritin were the only predictors of serum iron/hepcidin ratio accounting for 23% of the variation among subjects. Studies are needed to examine anti-inflammatory dietary approaches that can improve iron biomarkers in obese women.

Evaluation of Micronutrient Status Post Laparoscopic Sleeve Gastrectomy: an Australian Perspective

BACKGROUND

Laparoscopic sleeve gastrectomy (LSG) is a type of bariatric technique that has comparable outcomes to Roux-en-Y gastric bypass, the current gold standard. However, it can be associated with nutritional deficiencies postoperatively. The aim of this study was to evaluate micronutrient status post LSG.

METHODS

This is a retrospective study of 565 patients who underwent an LSG from January 2015 to September 2018. Patients lost to follow-up at 3, 6 and 12 months were 6.3%, 18.6% and 32.4%, respectively. Follow-up of the patients included regular dietetic input and micronutrient supplementation. Data that was collected included both anthropometry and nutritional markers.

RESULTS

The mean preoperative weight and body mass index (BMI) were 118.13 ± 25.36 kg and 42.40 ± 7.66 kg/m², respectively. Statistically, significant reductions in anthropometric parameters including weight, BMI (30.50 kg/m²), total weight loss (28.03%), excess weight loss (72.03%) and BMI loss (12.32 kg/m²) were observed at all timepoints up to 12 months follow-up. At 12 months, there were significant increases in 25-OH vitamin D with the incidence of deficiency decreasing from 45.7 to 15.0% compared to baseline. The incidence of hyperparathyroidism also decreased from 32.2 to 18.9% compared to baseline, and incidence of folate deficiency increased from 7.7 to 19.2%. Other nutritional parameters including calcium, iron, ferritin, vitamin B12, holotranscobalamin (active B12) and haemoglobin did not significantly change.

CONCLUSIONS

Modest effects on micronutrient status were observed in the 12-month postoperative period. Of clinically significant, de novo folate deficiencies increased, and vitamin D deficiency and hyperparathyroidism decreased. Thus, optimizing postoperative micronutrient status is imperative following LSG.

Bariatric Surgery: Remission of Inflammation, Cardiometabolic Benefits, and Common Adverse Effects

Obesity is associated with increased mortality as a result of several comorbidities which occur in tandem with the obese state. Chronic inflammation is well documented in obesity, and evidence from numerous studies support the notion that the increased inflammation in individuals with obesity accentuates the comorbidities seen in this condition. The remission of comorbidities such as metabolic, cardiovascular, and neurological complications occurs following bariatric procedures. Bariatric surgery significantly reduces mortality and results in remarkable weight loss and reversal in several obesity-related comorbidities. There is indisputable evidence that the resolution of inflammation that occurs after bariatric surgery mitigates some of these comorbidities. With the increasing use of bariatric surgery for the treatment of severe obesity, it is pivotal to elucidate the underlying mechanisms responsible for the notable improvements seen after the procedure. This review summarizes underlying mechanisms responsible for the remission of obesity-related abnormalities and discusses the common adverse effects of bariatric surgery. Well-stratified, large-scale studies are still needed for a proper evaluation of these underlying mechanisms.

Clinical Practice Guidelines for the Perioperative Nutrition, Metabolic, and Nonsurgical Support of Patients Undergoing Bariatric Procedures - 2019 Update: Cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic and Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

OBJECTIVE

The development of these updated clinical practice guidelines (CPGs) was commissioned by the American Association of Clinical Endocrinologists (AACE), The Obesity Society (TOS), American Society for Metabolic and Bariatric Surgery (ASMBS), Obesity Medicine Association (OMA), and American Society of Anesthesiologists (ASA) Boards of Directors in adherence with the AACE 2017 protocol for standardized production of CPGs, algorithms, and checklists.

METHODS

Each recommendation was evaluated and updated based on new evidence from 2013 to the present and subjective factors provided by experts.

RESULTS

New or updated topics in this CPG include: contextualization in an adiposity-based chronic disease complications-centric model, nuance-based and algorithm/checklist-assisted clinical decision-making about procedure selection, novel bariatric procedures, enhanced recovery after bariatric surgery protocols, and logistical concerns (including cost factors) in the current health care arena. There are 85 numbered recommendations that have updated supporting evidence, of which 61 are revised and 12 are new. Noting that there can be multiple recommendation statements within a single numbered recommendation, there are 31 (13%) Grade A, 42 (17%) Grade B, 72 (29%) Grade C, and 101 (41%) Grade D recommendations. There are 858 citations, of which 81 (9.4%) are evidence level (EL) 1 (highest), 562 (65.5%) are EL 2, 72 (8.4%) are EL 3, and 143 (16.7%) are EL 4 (lowest).

CONCLUSIONS

Bariatric procedures remain a safe and effective intervention for higher-risk patients with obesity. Clinical decision-making should be evidence based within the context of a chronic disease. A team approach to perioperative care is mandatory, with special attention to nutritional and metabolic issues.

Iron deficiency anaemia revisited

Iron deficiency anaemia is a global health concern affecting children, women and the elderly, whilst also being a common comorbidity in multiple medical conditions. The aetiology is variable and attributed to several risk factors decreasing iron intake and absorption or increasing demand and loss, with multiple aetiologies often coexisting in an individual patient. Although presenting symptoms may be nonspecific, there is emerging evidence on the detrimental effects of iron deficiency anaemia on clinical outcomes across several medical conditions. Increased awareness about the consequences and prevalence of iron deficiency anaemia can aid early detection and management. Diagnosis can be easily made by measurement of haemoglobin and serum ferritin levels, whilst in chronic inflammatory conditions, diagnosis may be more challenging and necessitates consideration of higher serum ferritin thresholds and evaluation of transferrin saturation. Oral and intravenous formulations of iron supplementation are available, and several patient and disease-related factors need to be considered before management decisions are made. This review provides recent updates and guidance on the diagnosis and management of iron deficiency anaemia in multiple clinical settings.

Clinical practice guidelines for the perioperative nutrition, metabolic, and nonsurgical support of patients undergoing bariatric procedures - 2019 update: cosponsored by American Association of Clinical Endocrinologists/American College of Endocrinology, The Obesity Society, American Society for Metabolic & Bariatric Surgery, Obesity Medicine Association, and American Society of Anesthesiologists

OBJECTIVE

The development of these updated clinical practice guidelines (CPG) was commissioned by the American Association of Clinical Endocrinologists, The Obesity Society, the American Society of Metabolic and Bariatric Surgery, the Obesity Medicine Association, and the American Society of Anesthesiologists boards of directors in adherence to the American Association of Clinical Endocrinologists 2017 protocol for standardized production of CPG, algorithms, and checklists.

METHODS

Each recommendation was evaluated and updated based on new evidence from 2013 to the present and subjective factors provided by experts.

RESULTS

New or updated topics in this CPG include contextualization in an adiposity-based, chronic disease complications-centric model, nuance-based, and algorithm/checklist-assisted clinical decision-making about procedure selection, novel bariatric procedures, enhanced recovery after bariatric surgery protocols, and logistical concerns (including cost factors) in the current healthcare arena. There are 85 numbered recommendations that have updated supporting evidence, of which 61 are revised and 12 are new. Noting that there can be multiple recommendation statements within a single numbered recommendation, there are 31 (13%) Grade A, 42 (17%) Grade B, 72 (29%) Grade C, and 101 (41%) Grade D recommendations. There are 858 citations, of which 81 (9.4%) are evidence level (EL) 1 (highest), 562 (65.5%) are EL 2, 72 (8.4%) are EL 3, and 143 (16.7%) are EL 4 (lowest).

CONCLUSIONS

Bariatric procedures remain a safe and effective intervention for higher-risk patients with obesity. Clinical decision-making should be evidence-based within the context of a chronic disease. A team approach to perioperative care is mandatory with special attention to nutritional and metabolic issues.

Greater blood volume and Hb mass in obese women quantified by the carbon monoxide-rebreathing method affects interpretation of iron biomarkers and iron requirements

BACKGROUND/OBJECTIVE

Iron deficiency (ID) is common in overweight and obese individuals (OW/OB) but the mechanism is uncertain. Greater blood volume (BV) in OW/OB may increase hemoglobin (Hb) mass and iron requirements, and confound iron biomarkers by hemodilution. Quantification of BV/PV changes in OW/OB is challenging and a formula to estimate BV/PV based on anthropometric indices would be valuable. In normal weight (NW) and OW/OB women, we aimed at: (1) measure BV and assess whether differences in BV affect concentrations and total circulating mass of Hb and iron biomarkers; (2) develop an algorithm describing BV in OW/OB.

SUBJECTS/METHODS

In a cross-sectional study, we measured BV in NW, OW, and OB non-anemic women (n = 62) by using the carbon monoxide-rebreathing method, body composition by dual energy X-ray absorptiometry, and iron and inflammatory status.

RESULTS

OW and OB women had 11 and 16% higher mean BV and PV compared to NW (P < 0.05), respectively. In OW/OB compared to NW, total circulating masses of IL-6, hepcidin, Hb, and sTfR were higher, while total mass of serum iron was lower (for all, P < 0.05). An equation including height, body mass and lean mass to estimate BV in all BMI groups (R2 = 0.76).

CONCLUSION

An equation based on anthropometric indices provides a good estimate of increased BV in OW/OB women. In OW/OB women, there is an increase in Hb mass that likely increases iron requirements for erythropoiesis and circulating TfR mass. At the same time, higher hepcidin concentrations may lower serum iron mass. Both these mechanisms may increase risk for ID in OW/OB women.

Metabolic surgery and iron homeostasis

Iron deficiency and anaemia after metabolic surgery, potentially modifiable nutritional complications, are becoming an increasing cause for concern as prevalence increases with time and there is limited evidence supporting the effectiveness of the current guidelines for prophylactic oral iron supplementation and treatment for deficiency. Abnormalities in iron nutrition predisposing to deficiency are common in severely obese patients, and the low-grade systemic inflammation, also common to these patients, reduces the effectiveness of oral iron supplementation. The surgical procedures result in alterations of foregut anatomy and physiology, which limit iron absorptive capacity and daily food intake. These alterations and the limited effects of oral iron supplementation explain the high prevalence of postoperative iron deficiency and anaemia. This review outlines current mechanisms concerning the pathogenesis of disordered iron nutrition in patients with severe obesity, current gaps in knowledge, and opportunities for quality improvement.

Adipose Tissue Expansion by Overfeeding Healthy Men Alters Iron Gene Expression

CONTEXT

Iron overload has been associated with greater adipose tissue (AT) depots. We retrospectively studied the potential interactions between iron and AT during an experimental overfeeding in participants without obesity.

METHODS

Twenty-six participants (mean body mass index ± SD, 24.7 ± 3.1 kg/m2) underwent a 56-day overfeeding (+760 kcal/d). Serum iron biomarkers (ELISA), subcutaneous AT (SAT) gene expression, and abdominal AT distribution assessed by MRI were analyzed at the beginning and the end of the intervention.

RESULTS

Before intervention: SAT mRNA expression of the iron transporter transferrin (Tf) was positively correlated with the expression of genes related to lipogenesis (lipin 1, ACSL1) and lipid storage (SCD). SAT expression of the ferritin light chain (FTL) gene, encoding ferritin (FT), an intracellular iron storage protein, was negatively correlated to SREBF1, a gene related to lipogenesis. Serum FT (mean, 92 ± 57 ng/mL) was negatively correlated with the expression of SAT genes linked to lipid storage (SCD, DGAT2) and to lipogenesis (SREBF1, ACSL1). After intervention: Overfeeding led to a 2.3 ± 1.3-kg weight gain. In parallel to increased expression of lipid storage-related genes (mitoNEET, SCD, DGAT2, SREBF1), SAT Tf, SLC40A1 (encoding ferroportin 1, a membrane iron export channel) and hephaestin mRNA levels increased, whereas SAT FTL mRNA decreased, suggesting increased AT iron requirement. Serum FT decreased to 67 ± 43 ng/mL. However, no significant associations between serum iron biomarkers and AT distribution or expansion were observed.

CONCLUSION

In healthy men, iron metabolism gene expression in SAT is associated with lipid storage and lipogenesis genes expression and is modulated during a 56-day overfeeding diet.

Iron deficiency after bariatric surgery: what is the real problem?

The growing prevalence of obesity explains the rising interest in bariatric surgery. Compared with non-surgical treatment options, bariatric surgery results in greater and sustained improvements in weight loss, obesity associated complications, all-cause mortality and quality of life. These encouraging metabolic and weight effects come with a downside, namely the risk of nutritional deficiencies. Particularly striking is the risk to develop iron deficiency. Postoperatively, the prevalence of iron deficiency varies between 18 and 53 % after Roux-en-Y gastric bypass and between 1 and 54 % after sleeve gastrectomy. Therefore, preventive strategies and effective treatment options for iron deficiency are crucial to successfully manage the iron status of patients after bariatric surgery. With this review, we discuss the risks and the contributing factors of developing iron deficiency after bariatric surgery. Furthermore, we highlight the discrepancy in the diagnosis of iron deficiency, iron deficiency anaemia and anaemia and highlight the evidence supporting the current nutritional recommendations in the field of bariatric research. In conclusion, we advocate for more nutrition-related research in patient populations in order to provide strong evidence-based guidelines after bariatric surgery.

Limitations of Serum Ferritin in Diagnosing Iron Deficiency in Inflammatory Conditions

Patients with inflammatory conditions such as inflammatory bowel disease (IBD), chronic heart failure (CHF), and chronic kidney disease (CKD) have high rates of iron deficiency with adverse clinical consequences. Under normal circumstances, serum ferritin levels are a sensitive marker for iron status but ferritin is an acute-phase reactant that becomes elevated in response to inflammation, complicating the diagnosis. Proinflammatory cytokines also trigger an increase in hepcidin, which restricts uptake of dietary iron and promotes sequestration of iron by ferritin within storage sites. Patients with inflammatory conditions may thus have restricted availability of iron for erythropoiesis and other cell functions due to increased hepcidin expression, despite normal or high levels of serum ferritin. The standard threshold for iron deficiency (<30 μg/L) therefore does not apply and transferrin saturation (TSAT), a marker of iron availability, should also be assessed. A serum ferritin threshold of <100 μg/L or TSAT < 20% can be considered diagnostic for iron deficiency in CHF, CKD, and IBD. If serum ferritin is 100-300 μg/L, TSAT < 20% is required to confirm iron deficiency. Routine surveillance of serum ferritin and TSAT in these at-risk groups is advisable so that iron deficiency can be detected and managed.

Physical exercise intervention at school improved hepcidin, inflammation, and iron metabolism in overweight and obese children and adolescents

BackgroundObesity is often associated with iron deficiency in children and adolescents. We aimed to study the effect of an 8-month physical exercise (PE) intervention on hepcidin and other markers of inflammation and on iron status in overweight/obese children and adolescents.MethodsSeventy-three overweight/obese children and adolescents participated in the 8-month-long longitudinal study. They were divided into two groups according to their participation in an after-school PE program: the PE group (n=44) and the control group (n=29). Hepcidin, interleukin (IL)-6, C-reactive protein (CRP), iron, ferritin, transferrin, and soluble transferrin receptor (sTfR) were evaluated.ResultsAt baseline, IL-6 correlated positively with hepcidin and negatively with iron and transferrin saturation, suggesting that increasing adiposity associates with increasing IL-6 and hepcidin synthesis, reducing iron availability. After 8 months, the PE group showed a decrease in BMI z-score (P=0.003), body fat mass (P=0.012), CRP (P=0.002), IL-6 (P=0.048), ferritin (P=0.013), hepcidin (P=0.040), and sTfR (P=0.010), and an increase in iron concentration (P=0.002). Moreover, the PE group, when compared with the control group, showed lower weight (P=0.026), BMI (P=0.040), waist circumference (P=0.010), and waist-to-height ratio (P=0.046).ConclusionWe showed that an 8-month-long intervention at school allowed a reduction in BMI z-score and an improvement in inflammation, reducing hepcidin levels and the disturbances in iron status.

New insights into iron deficiency and iron deficiency anemia

Recent advances in iron metabolism have stimulated new interest in iron deficiency (ID) and its anemia (IDA), common conditions worldwide. Absolute ID/IDA, i.e. the decrease of total body iron, is easily diagnosed based on decreased levels of serum ferritin and transferrin saturation. Relative lack of iron in specific organs/tissues, and IDA in the context of inflammatory disorders, are diagnosed based on arbitrary cut offs of ferritin and transferrin saturation and/or marker combination (as the soluble transferrin receptor/ferritin index) in an appropriate clinical context. Most ID patients are candidate to traditional treatment with oral iron salts, while high hepcidin levels block their absorption in inflammatory disorders. New iron preparations and new treatment modalities are available: high-dose intravenous iron compounds are becoming popular and indications to their use are increasing, although long-term side effects remain to be evaluated.