What are the nutritional consequences of bariatric surgery?
In the face of the global challenges of obesity and the relative failures of diets, more and more people are resorting to obesity surgery, also called bariatric surgery. 102,000 procedures were performed in Europe in 2014, nearly 47,000 in France including 13,879 gastric bypass, 27,761 sleeve and 4,533 gastric ring poses. Being operated on for reasons of obesity is not as trivial as this craze suggests. Long-term physical and anatomical consequences, changes in body perception, social upheavals and changes in the surroundings are all factors that profoundly change the life of the person being operated on. Food is not confined to a simple sum of calories whose reduction in theory promotes thinning. It also brings, beyond its social and emotional character, many micronutrients essential to the proper functioning of the body and the maintenance of an optimal state of health, which may be short-term in the long term. Thus, wanting to “pass on billiards” to erase unnecessary pounds is not an act with consequences as simple and promising as such surgery might suggest. The organization also sets up regulation systems that hinder the effectiveness of long-term weight loss. to want to “go over the billiards” to erase the extra pounds is not an act with consequences as simple and promising as such surgery might suggest. The organization also sets up regulation systems that hinder the effectiveness of long-term weight loss. to want to “go over the billiards” to erase the extra pounds is not an act with consequences as simple and promising as such surgery might suggest. The organization also sets up regulation systems that hinder the effectiveness of long-term weight loss.(see chart) , let’s not forget that cells demonstrate an unparalleled ability to adapt to their environment, including weight loss. Literally “weight loss” is indeed a loss, which the body will seek to compensate by many hormonal and neurobiological mechanisms.
Faced with this growing trend in the number of patients operated on, patient awareness and the training of health professionals are therefore essential. They were the subject of official recommendations by the Haute Autorité de Santé in 2009. A patient association in this field is particularly active and serves as a benchmark at the international level for the remarkable quality of its work, under the aegis of its president Anne-Sophie Joly. This is the National Collective of Obesity Associations (CNAO) I have the honor to be the nutritionist-referent and for which I spoke at the National Assembly in 2010 on this main theme that are the nutritional consequences of bariatric surgery. Although major, these consequences depend in fact on the type of surgery (gastric band, sleeve gastrectomy, gastric bypass, biliopancreatic diversion with duodenal switch) and are still only partially known, for lack of prospective studies and because of methodological limitations. retrospective studies available.
What are the nutritional consequences of bariatric surgery?
Restrictive and / or malabsorptive interventions lead to deficits or even nutritional deficiencies. The main causes of these deficiencies are a lack of digestive assimilation and a deficit of food intake by reducing ingestats, destructuring of the diet and possible intolerance to certain foods (fibers, proteins). Certain operations are also at the origin of a difficulty of tolerance of carbohydrate foods assimilated too quickly, called dumping syndrome. The main nutritional deficiencies resulting from bariatric surgery concern proteins and certain functional amino acids, iron, zinc, vitamin D, vitamin B12 and polyunsaturated fatty acids of the omega 3 family. However, other nutritional factors can be altered, in particular the balance of the intestinal flora which is now recognized as possible involvement in the prevalence of obesity. In addition, mechanisms of hunger and satiety inducing food intake are regulated in the body by various hormones and peptides gastro-intestinal act mainly by feedback mechanisms at the level of the hypothalamus, headquarters of regulatory centers of the appetite. Dysregulation of these systems may affect the feeding behavior causing a change in weight. Following a bariatric surgery, patients often describe a decrease in their appetite potentially related to the surgery they undergo. the mechanisms of hunger and satiety inducing food intake are regulated in the body by various hormones and gastrointestinal peptides that act mainly by feedback mechanisms at the level of the hypothalamus, seat of centers of appetite regulators. Dysregulation of these systems may affect the feeding behavior causing a change in weight. Following a bariatric surgery, patients often describe a decrease in their appetite potentially related to the surgery they undergo. the mechanisms of hunger and satiety inducing food intake are regulated in the body by various hormones and gastrointestinal peptides that act mainly by feedback mechanisms at the level of the hypothalamus, seat of centers of appetite regulators. Dysregulation of these systems may affect the feeding behavior causing a change in weight. Following a bariatric surgery, patients often describe a decrease in their appetite potentially related to the surgery they undergo. Dysregulation of these systems may affect the feeding behavior causing a change in weight. Following a bariatric surgery, patients often describe a decrease in their appetite potentially related to the surgery they undergo. Dysregulation of these systems may affect the feeding behavior causing a change in weight. Following a bariatric surgery, patients often describe a decrease in their appetite potentially related to the surgery they undergo.
What is the point of nutritional supplementation?
The rate of onset and level of deficiencies vary significantly depending on the type of intervention, preoperative nutritional status, literature and associated protocols. In summary, the earliest deficiencies are iron and zinc, vitamin B12 at 1 year and vitamin D permanently. No recommendation has been made for specific intakes of micronutrients in the form of supplementation, although the use of micronutrient supplementation mentioned above is regular at supra-physiological doses in the pre- and post-operative phases. At the postoperative stage, the use of dietary supplements is carried out within a regulatory framework defining maximum daily doses in micronutrients that are sometimes insufficient with regard to malabsorption and justifying the use of specific supplements, particularly in iron, vit. B12 and lives. D. The choice of food supplements may then appear anecdotal for the nutrients concerned: for many criteria may affect the quality of products, including the bioavailability of the minerals used. Moreover, the use of an appropriate supplementation can make it possible to satisfy the needs in the nutrients not concerned by the systematic supplementation, or whose prevalence of the deficiencies is poorly or not studied at the biological level. The nutritional monitoring of the operated patient is a major stake, all the more so in view of the increasing evolution of the number of interventions and the difficulty of controlling the quality of food intake in the long term. The caloric approach of the food ration is also sometimes the sole criterion for determining the nutritional balance by the autonomous patient, whereas the malabsorption associated with the restriction can induce deficient deficits situations and the appearance of secondary functional disorders. . This is why the identification and analysis of these functional disorders, independently of biological balances, represent a complementary approach to food pedagogy. The global approach to the micronutritional management of operated patients,
- BMI ≥ 40 kg / m2 or BMI ≥ 35 kg / m2 associated with at least one comorbidity that can be improved after surgery
- In second intention after failure of a medical, nutritional, dietetic and psychotherapeutic treatment well conducted during 6-12 months
- Patients who understood and accepted the need for long-term medical and surgical follow-up
- Acceptable operating risk
- Cognitive, mental, or severe eating disorders
- Addiction (alcohol, drugs)
- No prior medical care identified
- Life-threatening diseases in the short and medium term
Evolution of weight in patients followed after bariatric intervention – Sjöström L, Lindroos A, Peltonen M et al. Lifestyle, diabetes, cardiovascular and risk factors 10 years after bariatric surgery. N Engl J Med 2003; 351: 2683-93
- Coronary heart disease: 56%
- Diabetes: 92%
- Cancer: 60%
But … 58% suicide rate among operated patients (11.1 vs 6.4 per 10,000)
Study (2) out of 4,334 surgical patients: 8 of 2,117 operated patients developed diabetes, compared to 177 of 2,167 members of the control group.
Statistical analysis shows that the use of these operations at least halves the risk of developing type II diabetes.
(1) Ted D. Adams et al. Long-Term Mortality after Gastric Bypass Surgery, N Engl J Med 200
(2) Incidence of type 2 diabetes after bariatric surgery: population-based matched cohort study. H. Booth et al. The Lancet Diabetes & Endocrinology, 201
For those who want to go further
Such surgery is not without risks, particularly in terms of nutrition. Although still underestimated, the nutritional consequences depend in fact on the type of surgery: restrictive (gastric band, sleeve gastrectomy), mixed ( gastric bypass ) or malabsorptive (biliopancreatic diversion with duodenal switch). Taking into account these consequences and their identification is therefore essential in the context of the follow-up of operated patients, especially and especially in the long term. The question arises of the interest and the modalities of a possible nutritional supplementation according to the types of interventions practiced and the nutritional status of the patients in pre and post-operative phases. According to the recommendations of the HAS (High Authority of Health) of 2009, the supplementation must be systematic in case of malabsorptive surgery, in particular in vitamins D and B12, Iron and Calcium, and discussed after restrictive surgery according to the biological and clinical assessment. According to the recommendations of the SMOB (Swiss Society for the Study of Morbid Obesity and Metabolic Disorders)Vitamin and mineral supplementation should be routine after all types of bariatric surgery for the next 24 months. In the United States, various medical and surgical societies involved in the management of obese subjects have issued joint recommendations. These authors recommend that the preoperative assessment include at least a martial assessment (serum iron, ferritin), a dosage of vitamins B12 and D (1,2) .
The nutritional consequences of the reduction of caloric intake and, depending on the case, of malabsorption secondary to the intervention, are only partially known, in the absence of prospective studies and because of the methodological limitations of retrospective studies available. Moreover, the interpretation of these studies is often limited by their relatively short duration (2 years maximum), by the lack of precise information on the nature of the supplements consumed by the patients and by the absence of reference to the nutritional status. preoperatively.
Deficits and preoperative nutritional deficiencies
Beyond the consequences of the intervention on the nutritional status of patients, preoperative nutritional deficits exist according to a variable prevalence depending on the micronutrients considered. The etiologies appear above all of hygienic-dietary order, especially for lack of intake of fresh fruits and vegetables. Body composition can also influence nutritional status, especially vitamin C and D. Thus, independently of the risks associated with bariatric surgery and obesity, the literature shows an increase in the risk of depression (3) , stroke (4) and colorectal cancer (5) in case of vitamin B6 deficiency, mortality (6)and myocardial infarction in case of vitamin C deficiency (7) , insulin resistance and diabetes in case of vitamin D deficiency (8,9) .
Prevalence of preoperative deficits
Deficits and nutritional deficiencies postoperatively (10-13)
Restrictive and / or malabsorptive interventions lead to deficits or even nutritional deficiencies of varying frequency and intensity.
The main origins are:
- A deficit of food intake by decreasing ingesta, destructuring of the diet and possible intolerance to certain foods (fibers, proteins),
- A lack of assimilation by less secretion of gastric acid and loss of the mechanical functions of the stomach, decrease of the intrinsic factor,
- An asynergy between the arrival of the alimentary bolus and biliopancreatic secretions,
- Duodenojejunal malabsorption.
Protein absorption is in the duodenum and the small intestine. Several origins can explain protein deficiencies: reduction of intake (disgust for meat, insufficient chewing, intolerance), decrease in secretion of pancreatic enzymes and pepsinogen, decrease in surface area and absorption time (malabsorptive interventions). Given the difficulties of evaluation, the frequency of deficit is poorly evaluated but could reach up to 11.3% of obese subjects in the preoperative phase. Considering albuminemia, at 2 years protein deficiencies would affect 5.9 to 13% of patients according to the studies (4). The loss of lean mass is proportionately more severe in the obese subject than in the subject having a normal BMI and protein catabolism is increased in case of aggression, recommendations intake of 1.5 to 2 g / kg per day ( adjusted weight) therefore seem justified (14) .
Iron deficiency is most common after gastric bypass and biliopancreatic diversion and persists after many years. The origins are essentially a deficiency of intake covering only 80% of the recommended intakes at 12 and 24 months (16) , a decrease in the secretion of gastric acid and the duodenal absorption surface. Iron deficiency is revealed by macrocytic anemia contributing to asthenia. In the preoperative phase and according to the diagnostic criteria used, the frequency of deficiencies varies from 14 to 16% (serum iron determination) (17) , 16 to 26% (assay of ferritinemia, frequently high because of the association with a chronic inflammatory syndrome) or 47 to 51% (saturation assay) (19). The frequency of deficiency in the post-operative phase varies according to the delay following the intervention, thus highlighting the difficulties of compliance and quality of long-term supplementation: 6 to 33% of patients at 6 months (18 months). , 19) , 39 to 52% at 3 years, 35 to 74% at 4 years and 25 to 100% at 5 years (18,20)
Calcium and Vitamin D (21)
Calcium deficiencies are related to a deficiency of intake favored by a lactose intolerance, and the decrease of the absorption surface (duodenum and proximal jejunum). Lipid malabsorption reduces the absorption of vitamin D in the small intestine (jejunum and ileum). Deficiency of vitamin D and calcium can cause secondary hyperparathyroidism and decreased bone mass. In particular, it has been shown that intestinal short circuits were involved in 71% of osteomalacia cases (22) . The frequency of deficiencies after gastric bypass ranges from 50 to 63% in the short and long term (1 to 7 years) (18,23). The recommendations (2000 mg of calcium and 400 IU of vitamin D per day) do not seem satisfactory and the use of a supplementation in the preoperative phase is recommended (1000 to 3000 IU / day) despite the lack of consensus.
The absorption of Zinc is correlated with that of lipids, impaired as a result of malabsorptive surgeries. Deficiencies in animal protein intake are also a factor of deficit, including after restrictive surgery. Following gastric bypass, they affect 28% of patients at 3 months, 20 to 35% at 6 months and 30 to 42% at 12 and 24 months (24, 25) .
Magnesium deficiency can cause hypomagnesia in up to 34% of gastric bypass patients.
Group B vitamins
Deficits due to lack of food intake or malabsorption are frequent following interventions, particularly malabsorptive.
The vit. B1 is essential for energy metabolism: it is absorbed in the duodenum and in acidic medium. Deficiencies are more frequent in the case of malabsorptive surgeries (vomiting, reduction of intakes and absorption) and can be manifested by neurological disorders or even encephalopathy of Gayet-Wernicke. Vitamin B1 deficiencies after gastric bypass are estimated at 12% at 1 year (19 ) .
The vit. B8 circulates essentially in bound form before being released by biotinidase present in pancreatic juice and intestinal mucosa, the status of which may be disturbed by bariatric surgery. Deficiencies of biotin are manifested by an alteration of the general state, acidosis, mucocutaneous, neuropsychiatric and digestive signs. An optimal status is therefore particularly important, especially since household preparations cause food losses of 10 to 40%.
The vit. B9 (folate) is absorbed throughout the intestine: deficits are therefore mainly related to a lack of intake of fruits and vegetables. The consequences of a deficit in life. B9 are macrocytosis and anemia. The vit. B9 is particularly important in pregnancy because of the risk of neural tube closure abnormality in the fetus. It is also involved in the methylation of proteins and helps prevent the formation of homocysteine in combination with vitamins B6 and B12. The frequency of deficiencies varies according to the studies, from 0 to 63% at 1 year to 22% at 2 years, mainly depending on the use or not of a supplementation (18, 19) .
The vit. B12 is absorbed in the ileum: however, it must be separated from food proteins by acid hydrolysis and then bound to the intrinsic factor secreted by the gastric antral cells. The deficit lives. B12 increases in time. Deficiencies after gastric bypass appear from the first year when they concern 12 to 33% of patients and from 35 to 37% at 2 years (18,19). It is usual to recommend monthly supplementation by intramuscular injection of 1000 μg vitamin B12 in case of proven deficiency
Fat-soluble vitamins A, E, K
4 years after a biliopancreatic diversion, the prevalence of deficits lives. A, E and K vary between 5 and 69% despite taking a vitamin supplement in life. E. Vitamin A deficiencies are early: 35% at 6 months (18) then 17% of patients at 2 years (18, 19) . Daily intake of 5,000 IU could help avoid these deficiencies.
Polyunsaturated fatty acids
The status of polyunsaturated fatty acids (omega 3 and omega 6 GLA) is frequently deficient as a result of malabsorption and insufficient intakes. Polyunsaturated fatty acids are essential for the flexibility of cell membranes (formation of the double phospholipid layer) and are involved in particular as precursors of prostaglandins modulating inflammation and the immune system.
Prevalence of postoperative vitamin deficiencies by type of intervention
Prevalence of postoperative mineral deficiencies by type of intervention
Consequences on the neuro-hormonal regulation of the appetite
The mechanisms of hunger and satiety that induce food intake are regulated in the body at the peripheral and central level; the peripheral system consists of various hormones and gastrointestinal peptides such as insulin, CRF, GLP-1, GIP, PYY, cholecystokinin, leptin, (anorectic) or ghrelin and adiponectin (orexigenes) which act mainly by positive or negative feedback mechanisms at the level of the hypothalamus. The latter is the seat of the appetite control centers, which integrate the central and peripheral messages by the use of different orexigenic neuropeptides (NPY, AgRP, MCH, orexins A and B, galanine) and neuropeptides and anorexigenic monoamines ( MSH, 5-HT and CART) (27). Dysregulation of these systems may affect the feeding behavior causing a change in weight. For example, ghrelin is further synthesized by the gastric fundus in response to weight loss: its plasma level increases. Similarly, the endocrine activity of the adipose tissue is modified with a decrease in leptin production and an increase in adiponectin secretion, in an attempt to restore the previous body weight (28).. Following a bariatric surgery, patients often describe a decrease in their appetite. Surgery involving resection of a portion of the gastric fundus, such as sleeve gastrectomy or gastric bypass, is accompanied by an alteration of the secretion of ghrelin with a lower elevation of its plasma level, despite the lost weight (29). , 30) . Increased secretions of PYY and GLP-1, neuro-hormonal mediators both produced by entero-endocrine L cells of the stomach after gastric bypass, could also play a role in the process of loss of appetite after such surgery (31)
Consequences on the intestinal flora
The roles of the intestinal flora are multiple and still unknown. On the weight aspect, some studies highlight differences in the composition of the microbiota in obese mice and thin mice (32, 33) , as well as in humans (30) . In case of obesity, the microbiota would seem to increase the carbohydrate and lipid absorption. However, the report firmicutes / bacteroidetes returns to normal following a gastric bypass weight loss, thus modifying the absorption capacity and energy storage of nutrients. It is currently unclear whether this return to normal is related to dietary modification or weight loss (34) .
Recommendations for nutritional supplementation
The rate of onset and level of deficiencies vary significantly depending on the type of intervention, preoperative nutritional status, literature and associated protocols. In summary, the earliest deficiencies are iron and zinc, vitamin B12 at 1 year and vitamin D permanently.
At the postoperative stage, no recommendation was made for specific intakes of micronutrients in the form of supplementation, even though the use of micronutrient supplementation mentioned above is regular at supra-physiological doses in the pre- and post-operative phases. In 2010, the French Society for Clinical Nutrition and Metabolism ( SFNEP ) and the French Society of Anesthesia and Resuscitation ( SFAR ) jointly published recommendations of good clinical practice on perioperative nutrition (35) . They highlight in particular the interest of a complete nutritional assessment in case of pre-operative weight loss, dosing vitamins B1, B9, B12, C, A, D and E.
At the post-operative stage, the use of food supplements is carried out within a regulatory framework defining maximum daily doses in micronutrients that are sometimes insufficient with regard to malabsorption and justifying the use of specific supplements (in iron, vit., B12 and vit. especially). The choice of food supplements may then appear anecdotal for the nutrients involved: for many criteria can affect the quality of products, including the bioavailability of the mineral salts used. Moreover, the use of appropriate supplementation may make it possible to satisfy the needs in nutrients not concerned by the supplementation, or for which the prevalence of deficiencies is poorly or not studied at the biological level: for example, meeting the needs of polyunsaturated fatty acids, functional amino acids or the balance of the intestinal microbiota. Nutritional monitoring of the patient is a major issue, especially in view of the increasing evolution of the number of interventions and the difficulty to control the quality of food intake of patients in the long term. The caloric approach of the food ration is also sometimes the sole criterion for determining the nutritional balance by the autonomous patient, whereas the malabsorption associated with the restriction can induce deficient deficits situations and the appearance of secondary functional disorders. . This is why the identification and analysis of these functional disorders, independently of biological balances, represent a complementary approach to food pedagogy. The global approach of the micronutritional management of the operated patients, associating a protocol of complementation adapted to personalized dietary advice and to the biological dosages, then finds a legitimate and necessary place within the framework of their long-term health(36-41) .
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