Contribution of Bariatric Surgery to the Comprehension of Morbid Obesity

Convinced that morbid obesity was not due to food excess but rather to a metabolic disorder, we searched in the literature for data in favor of a metabolic disorder. We have found evidence in support of the thesis that the cause of morbid obesity is the inability to burn excessive caloric intake normally. It would involve the difficulty to increase heat with the amount of calories taken, which would be faulty and force fat deposition. This mechanism called dietinduced thermogenesis (DIT) allows the dispersion by heat of excessive calories to obtain energy balance. Results from bariatric surgery and particularly biliopancreatic diversion (BPD) give further support to this thesis. BPD would improve heat production to a meal (DIT) by one of these mechanisms: increased insulin sensitivity, change in intestinal hormone secretion, or chronic lipid malabsorption. Available results show that surgery, to be efficient, must change the physiology and not solely decrease food intake.     

Dietary flaxseed meal reduces proteinuria and ameliorates nephropathy in an animal model of type II diabetes mellitus

BACKGROUND: Evidence is emerging that varying the type or source of dietary protein intake can have beneficial effects on chronic renal disease. Consumption of soybean and soy-based food products, as the source of plant protein, can retard the development and progression of chronic renal disease. We studied the obese spontaneously hypertensive/NIH-corpulent (SHR/N-cp) rat, a model of obesity and type II diabetes mellitus that consistently develops nephropathy resembling diabetic nephropathy. We specifically sought to determine whether changing the source of protein intake from animal protein, casein, to plant protein in the form of either soy protein concentrate or flaxseed protein in the diet has a different impact on renal function and nephropathy in this model. METHODS: Male obese SHR/N-cp rats were randomly assigned to one of three diets containing either 20% casein, 20% soy protein concentrate, or 20% flaxseed meal. Except for the protein source, all three diets were identical and contained similar amounts of protein, fat, carbohydrates, minerals, and vitamins. All animals were maintained on these diets for 6 months. At the end of the study, blood sampling and 24-hour urine collections were performed for renal functional measurements, and the kidneys were harvested and examined for histologic evaluation. RESULTS: All three groups had similar amounts of food intake and body weight gain and exhibited fasting hyperglycemia and hyperinsulinemia. Plasma glucose levels did not differ among the three groups, but plasma insulin concentration was significantly lower in rats fed flaxseed meal than those fed either casein or soy protein concentrate. Mean plasma creatinine, creatinine clearance, and urinary urea excretion also did not differ significantly between the three groups. By contrast, urinary protein excretion was significantly lower (P < 0.01) in rats fed flaxseed than in rats fed either casein or soy protein concentrate. Morphologic analysis of renal structural lesions showed that the percentage of abnormal glomeruli with mesangial expansion and the tubulointerstitial score (an index of severity of tubulointerstitial damage) were significantly reduced in rats fed flaxmeal compared to those fed casein or soy protein concentrate. CONCLUSION: We conclude that dietary protein substitution with flaxseed meal reduces proteinuria and glomerular and tubulointerstitial lesions in obese SHR/N-cp rats and that flaxseed meal is more effective than soy protein in reducing proteinuria and renal histologic abnormalities in this model. The reduction in proteinuria and renal injury was independent of the amount of protein intake and glycemic control. Which dietary component(s) present in flaxseed meal is (are) responsible for the renal protective effect remains to be determined.     

Nutrient intake and dietary supplementation in body-builders

The micronutrient intake of a group of 76 body-builders was studied. Sixty-three per cent of the subjects supplemented their diets with vitamin and mineral pills. The highest pill consumption was 87 pills per day. Fifty-nine per cent of the subjects used high-protein powders. The benefits of these powders is open to question, since the diet already supplied a high 2.2 g protein per kilogram of body weight. Thirty-nine per cent of the subjects used vitamin/mineral pills as well as protein powders. Because of the use of dietary supplements, the food in the diet supplied only a small fraction of the total intake of most of the micronutrients. The food supplied adequate amounts of nutrients according to the US Recommended Dietary Allowances, and the use of dietary supplements can therefore not be justified.     

Peptide YY(3-36) inhibits morning, but not evening, food intake and decreases body weight in rhesus macaques

Peptide YY(3-36) [PYY(3-36)] is a hormone that is released after meal ingestion that is currently being investigated for the treatment of obesity; however, there are conflicting reports of the effects of PYY(3-36) on energy balance in rodent models. To shed light on this controversy, we studied the effect of PYY(3-36) on food intake and body weight in a nonhuman primate. Intravenous PYY(3-36) infusions before a morning meal transiently suppressed the rate of food intake but did not suppress the evening meal or 24-h intake. Twice-daily or continuous intravenous PYY(3-36) infusions to supraphysiological levels (levels that exceeded normal physiological levels) again suppressed the rate of feeding for the morning but not the evening meal. Twice-daily intravenous PYY(3-36) infusions for 2 weeks significantly decreased body weight in all test animals (average weight loss 1.9%) without changing insulin response to glucose infusion. These results show that endogenous PYY(3-36) may alter morning but not evening meal intake, and supraphysiological doses are required for effective suppression of food intake.     

Caloric supplements for patients on low-protein diets?

Protein-calorie malnutrition (PCMN) in patients suffering from chronic renal failure treated with a low-protein diet (LDP) is generally considered to be the major adverse effect of such a diet. One cause of PCMN might be that these protein-restricted diets do not supply enough energy, although all of them are supposed to provide at least 35 kcal/kg body weight (BW). In order to test this hypothesis, we analyzed the hypothetical protein and energy intake of a patient on different LPDs. The food intake of such a patient was simulated by analyzing the average composition of 28 complete daily menus. The daily menus simulating 9 dietary schedules (0.3 g protein/kg BW; n = 6; 0.6 g protein/kg BW; n = 3) were taken from 5 different German cookery books. Our analysis revealed that only 2 schedules supplied enough energy. All others were deficient in energy by about 500 kcal/day. The deficiency occurred to the same extent in schedules for diets providing 0.3 and 0.6 g of protein/day. Therefore we conclude that PCMN in patients on LPDs is often due to an insufficient energy supply. The use of less protein-restricted diets does not necessarily prevent PCMN, as also these diets may be low in calories. Thus the use of caloric supplements, e.g. wine or polysaccharides, and correct dietary counseling by a skilled dietitian are recommended.     

Effects of preoperative exposure to a high-fat versus a low-fat diet on ingestive behavior after gastric bypass surgery in rats

Background

The consumption of high fat and sugar diets is decreased after gastric bypass surgery (GB). The mechanisms remain unclear, with tests of motivated behavior toward fat and sugar producing conflicting results in a rat model. These discrepancies may be due to differences in presurgical maintenance diets. The authors used their GB rat model to determine whether the fat content of preoperative maintenance diets affects weight loss, calorie intake, and macronutrient selection after surgery.

Methods

Male Wistar rats were either low-fat diet fed (LFDF) with normal chow or high-fat diet fed (HFDF) before randomization to GB or sham surgery. In food preference test 1, the animals were offered the choice of a vegetable drink (V8) or a high-calorie liquid (Ensure), and in food preference test 2, they could choose normal chow or a solid high-fat diet.

Results

The GB groups did not differ significantly in terms of body weight loss or caloric intake. In food preference test 1, both groups responded similarly by reducing their preference for Ensure and increasing their preference for V8. In food preference test 2, the HFDF-GB rats reduced their preference for a solid high-fat diet gradually compared with the immediate reduction observed in the LFDF-GB rats.

Conclusion

The consumption of presurgical maintenance diets with different fat contents did not affect postoperative weight loss outcomes. Both the LFDF-GB and HFDF-GB rats exhibited behaviors consistent with the possible expression of a conditioned taste aversion to a high-fat stimulus. These results suggest that for some physiologic parameters, low-fat-induced obesity models can be used for the study of changes after GB and have relevance to many obese humans who consume high-calorie but low-fat diets.     

Calorie Intake and Meal Patterns up to 4 Years after Roux-en-Y Gastric Bypass Surgery

Background: Roux-en-Y gastric bypass (RYGBP) is the most popular surgical treatment for morbid obesity in the U.S.A., producing significant and durable weight loss with improvement in co-morbidities. Although a greater number of patients are undergoing surgical treatment for obesity, little data are available regarding their food intake after surgery. This study was undertaken to evaluate the caloric amount, nutrient composition and meal patterns of patients 18 months to 4 years after RYGBP. Ethnic differences in food intake were also investigated. Methods: Questionnaires were mailed to 360 patients who had undergone RYGBP at least 18 months prior to the onset of the study. Results: Data were available from 69 patients, 52% Caucasian, 25% African-American, 23% Hispanic. 30 months after surgery, the average daily calorie intake was 1733 ± 630 kcal (n=68, range 624-3486 kcal), with 44% of calories from carbohydrates, 22% from protein and 33% from fat. Sugar-sweetened beverages represented 7% of total caloric intake. Patients consumed 3 meals and 3 snacks per day on average. Food intake from dinner and an evening snack represented 40% of the daily caloric intake. Snacks accounted for 37% of the daily intake. Percent excess weight loss (%EWL) was 58 ± 17% and was not different among ethnic groups. However, Hispanics reported consuming fewer snacks and fewer calories. %EWL correlated with the total daily caloric intake (r= .446, P <0.001). Follow-up attendance was 54% at 1 year after surgery but fell to 10% at 3 years. Only 77% of patients were taking vitamin supplements. Conclusion: RYGBP resulted in significant weight loss. Caloric intake was quite variable. Long-term follow-up remained low, putting patients at risk for metabolic and vitamin deficiencies. The relationship between caloric intake and long-term weight changes remains to be studied.     

Vitamin paradox in obesity: Deficiency or excess?

Since synthetic vitamins were used to fortify food and as supplements in the late 1930 s, vitamin intake has significantly increased. This has been accompanied by an increased prevalence of obesity, a condition associated with diabetes, hypertension, cardiovascular disease, asthma and cancer. Paradoxically, obesity is often associated with low levels of fasting serum vitamins, such as folate and vitamin D. Recent studies on folic acid fortification have revealed another paradoxical phenomenon: obesity exhibits low fasting serum but high erythrocyte folate concentrations, with high levels of serum folate oxidation products. High erythrocyte folate status is known to reflect long-term excess folic acid intake, while increased folate oxidation products suggest an increased folate degradation because obesity shows an increased activity of cytochrome P450 2E1, a monooxygenase enzyme that can use folic acid as a substrate. There is also evidence that obesity increases niacin degradation, manifested by increased activity/expression of niacin-degrading enzymes and high levels of niacin metabolites. Moreover, obesity most commonly occurs in those with a low excretory reserve capacity(e.g., due to low birth weight/preterm birth) and/or a low sweat gland activity(black race and physical inactivity). These lines of evidence raise the possibility that low fasting serum vitamin status in obesity may be a compensatory response to chronic excess vitamin intake, rather than vitamin deficiency, and that obesity could be one of the manifestations of chronic vitamin poisoning. In this article, we discuss vitamin paradox in obesity from the perspective of vitamin homeostasis.     

Current complementary and alternative therapies for multiple sclerosis

Opinion statement The use of complementary and alternative medicine (CAM) appears to be high in the general population and in patients with multiple sclerosis (MS). There are no diets or dietary supplements that are definitely effective in altering the disease course in MS. However, diets and dietary supplements that increase the intake of polyunsaturated fatty acids may produce mildly beneficial effects. Because these approaches are not definitely effective, they may be of limited interest to physicians and other conventional health providers. In contrast, for patients with MS, these interventions may be of considerable interest, because they may be mildly effective and are inexpensive and relatively safe. Vitamin D, ginkgo biloba, cannabinoids, and Padma 28 produce immunomodulatory actions and therapeutic effects in experimental autoimmune encephalomyelitis. However, for these compounds, there are not enough clinical trial data or safety information to support their use as disease-modifying therapies. The role of antioxidant compounds in MS is unclear. There is no evidence that vitamin B12 supplementation or gluten-free diets are effective MS therapies. Conventional health providers can play an important role in the care of MS patients by being open to discuss CAM therapies and by providing objective MS-relevant CAM information.     

Assessment of food intake in rural area school children

Children food intake is influenced by family nutritional habits and economic status. According to the results of our survey, only 54.8% of the children have taken their breakfast, although all of them recognize the importance of this meal. 9.6% of the children are not using fresh fruits and vegetables in their diets, even if these are the main sources of vitamin C. Regarding the milk consumption, most of the children use this food item once (35.5%) or twice (19.4%) a day and only 16.1% occasionally. Although most of the children (93.5%) know that excessive salt intake represents a risk factor for their health, 87.1% have preferences for salted and spiced foods. Under the influence of advertising, certain changes in the nutritional habits have been noticed; instead of traditional snacks, children are more attracted to fast-food type snacks.     

Nutrition,insulin resistance and dysfunctional adipose tissue determine the different components of metabolic syndrome

Obesity is an excessive accumulation of body fat that may be harmful to health. Today, obesity is a major public health problem, affecting in greater or lesser proportion all demographic groups. Obesity is estimated by body mass index(BMI) in a clinical setting, but BMI reports neither body composition nor the location of excess body fat. Deaths from cardiovascular diseases, cancer and diabetes accounted for approximately 65% of all deaths, and adiposity and mainly abdominal adiposity are associated with all these disorders. Adipose tissue could expand to inflexibility levels. Then, adiposity is associated with a state of low-grade chronic inflammation, with increased tumor necrosis factor-α and interleukin-6 release, which interfere with adipose cell differentiation, and the action pattern of adiponectin and leptin until the adipose tissue begins to be dysfunctional. In this state the subject presents insulin resistance and hyperinsulinemia, probably the first step of a dysfunctional metabolic system. Subsequent to central obesity, insulin resistance, hyperglycemia, hypertriglyceridemia, hypoalphalipoproteinemia, hypertension and fatty liver are grouped in the so-called metabolic syndrome(MetS). In subjects with MetS an energy balance is critical to maintain a healthy body weight, mainly limiting the intake of high energy density foods(fat). However, high-carbohydrate rich(CHO) diets increase postprandial peaks of insulin and glucose. Triglyceride-rich lipoproteins are also increased, which interferes with reverse cholesterol transport lowering highdensity lipoprotein cholesterol. In addition, CHO-rich diets could move fat from peripheral to central deposits and reduce adiponectin activity in peripheral adipose tissue. All these are improved with monounsaturated fatty acid-rich diets. Lastly, increased portions of ω-3 and ω-6 fatty acids also decrease triglyceride levels, and complement the healthy diet that is recommended in patients with MetS.     

Nutritional recommendations for individuals with diabetes mellitus.

The diabetic diet is fundamentally a healthy diet, high in complex carbohydrates, high in dietary fibre, low in fat. A nutritionally adequate, mixed diet is satisfactory for most people with diabetes and special foods or food supplements are not required. The dietary recommendations directed towards the diabetic population are essentially similar to those recommended by most authorities for the population as a whole. Education of diabetic patients and their families and also individualised diet and meal planning are essential components in the management of diabetes mellitus. Weight loss and subsequent maintenance of a desirable body weight should be achieved when necessary. The amount of carbohydrate should be liberalised, including a wide variety of fibre-rich complex carbohydrates. In some individuals modest amounts of sucrose taken at meal times are acceptable. Foods with lower glycaemic indices should be offered on trial to people with diabetes. Total fat intake, especially saturated fat, should be restricted. More research is needed before recommendations regarding eicosapentaenoic acid supplementation can be made. Protein intake should be restricted to the Recommended Daily Allowance except in groups at risk of negative nitrogen balance. A restriction in salt intake is advised. Alcoholic beverages and nutritive and non-nutritive sweeteners may be used, but in moderate amounts.     

Dietary habits and nutritional status of renal transplant patients.

BACKGROUND: Although dialysis nutritional problems are well described, nutritional problems after renal transplantation (RT) have received little attention. METHODS: Body composition as assessed by dual-energy x-ray absorptiometry in 115 stable patients 6.6 +/- 5.9 years after RT and repeated 2.9 years later, when a 3-day dietary history was obtained in 79 patients. RESULTS: Patients diet was generally sufficient, but was characterized by a high fat intake and deficiencies in folic acid, vitamin D, thiamine, iodine, selenium, and iron intake. Patients were often overweight, and at any given weight had a 4% to 5% higher proportion of body fat than normal. Loss of fat weight was related to high initial fat weight, long RT duration, and low plasma bicarbonate, but not steroid dose. CONCLUSION: Dietary advice concerning fat intake is indicated for RT patients, and nutritional supplements with folic acid and vitamin D are generally required. Their main nutritional problem is obesity. This is not adequately measured by body mass index, which should be supplemented by dual-energy x-ray absorptiometry. Attention should be paid to the prevention of acidosis.     

Assessing the evidence for weight loss strategies in people with and without type 2 diabetes

This review will examine topical issues in weight loss and weight maintenance in people with and without diabetes. A high protein, low glycemic index diet would appear to be best for 12-mo weight maintenance in people without type 2 diabetes. This dietary pattern is currently beingexplored in a large prevention of diabetes intervention. Intermittent energy restriction is useful but no better than daily energy restriction but there needs to be larger and longer term trials performed. There appears to be no evidence that intermittent fasting or intermittent severe energy restriction has a metabolic benefit beyond the weight loss produced and does not spare lean mass compared with daily energy restriction. Meal replacements are useful and can produce weight loss similar to or better than food restriction alone. Very low calorie diets can produce weight loss of 11-16 kg at 12 mo with persistent weight loss of 1-2 kg at 4-6 years with a very wide variation in long term results. Long term medication or meal replacement support can produce more sustained weight loss. In type 2 diabetes very low carbohydrate diets are strongly recommended by some groups but the long term evidence is very limited and no published trial is longer than 12 mo. Although obesity is strongly genetically based the microbiome may play a small role but human evidence is currently very limited.     

The nutritional status of black adults in rural districts of Natal and Kwazulu

A nutritional field survey was undertaken in 11 rural districts of Kwazulu. Standard anthropometric measurements (weight, height, triceps skinfold thickness, mid-arm circumference) were taken from 1 725 adults (616 males, 1 109 females), including 337 old-age pensioners, and a recall dietary intake questionnaire was completed by 297 male and 572 female Zulus. Mean body weights (+/- SD) were 95 +/- 10% of ideal for males and 118 +/- 15% for females. Consequently 39% of the male sample was undernourished (i.e. less than 80% ideal weight) and 17% of the female group obese (greater than 140% ideal weight). Undernutrition was significantly more common in old-age pensioners, with 73% of males and 23% of females being below 80% of the standard for body weight. Diet consisted mainly of refined maize meal (putu) 2-3 times per day. Meat and fresh milk were rarely taken, the average intake frequency for men being once a week and for women once a fortnight. Vegetable intake was seasonal, wild spinach and cabbage being consumed daily only during the summer rainfall months. Average fibre intake was therefore surprisingly low at approximately 10 g/d per individual. In conclusion, although poor socio-economic conditions are the root cause of most of the malnutrition problems observed, basic nutritional education can at least partially help by advising the population of the importance of a varied diet and the problems associated with obesity. More use of legumes, eggs, milk and fish products should significantly improve the diet. The reasons for the particularly high incidence of malnutrition among the elderly need further investigation.     

Influence of Sleeve Gastrectomy on Several Experimental Models of Obesity: Metabolic and Hormonal Implications

Background Ghrelin is an important factor in the regulation of intake. Most ghrelin is synthesized in the gastric fundus, but this is not the only location. The aim of this experimental study was to analyze the effect of sleeve gastrectomy (removing fundus) on the volume of intake in four experimental models and determine how this relates to changes in weight, plasmatic levels of glycemia, ghrelin, GLP-1, and insulin. Methods Sleeve gastrectomy was performed on four experimental models: (1) non-obesity; (2) exogenous obesity caused by excessive calorie intake; (3) genetically determined obesity (Zucker rats); and (4) genetically determined obesity and type 2 diabetes mellitus (Zucker diabetic fatty; ZDF rats). Model 2 had a control group on which sleeve gastrectomy was not performed. Results In the non-obese group, there were few changes after intervention, but in model 2, sleeve gastrectomy led to normalization of weight and endocrine–metabolic parameters that were the same as those for non-obese rats. The exception was for GLP-1, which has an anorexigenic effect: GLP-1 remained higher. In Zucker rats, sleeve gastrectomy had a slight effect on all parameters. In ZDF rats, sleeve gastrectomy led to a reduction in intake and a stabilization of weight. Conclusions Sleeve gastrectomy is a very good option for exogenous obesity. Normalization of hormonal levels led us to find an extragastric ghrelin production.     

Effects of diet on chemically induced bowel cancer

One hundred and twenty-seven rats were fed one of four diets containing graded amounts of fibre or a diet with vitamin A supplements and were given, subcutaneously, dimethyl-hydrazine or saline. Stool weight correlated directly with fibre intake and the frequency of colonic tumours decreased as fibre intake increased. An artificial fibre-free diet was also associated with a reduction in the number of colonic tumours. Major changes were noted in the profile of bacteria from one dietary group to another but no correlation with the frequency of tumours was noted. A diet which provided vitamin A supplements sufficient to retard growth and raise serum and liver concentrations of the vitamin resulted in a modest reduction in the number of tumours.     

Pancreatic polypeptide is involved in the regulation of body weight in pima Indian male subjects

Pancreatic polypeptide (PP) is released from the pancreas in response to a meal. In humans, low-circulating PP levels have been observed in obesity, and administration of pharmacological doses of PP has been shown to decrease food intake. The aim of the present study was to investigate whether low circulating PP is associated with weight gain in Pima Indians. Plasma PP concentrations were measured after an overnight fast and 30 min after a standardized mixed meal in 33 nondiabetic male subjects who had a follow-up visit 4.9 +/- 2.5 years later. Cross-sectionally, fasting and postprandial PP levels were negatively associated with body size and adiposity. Prospectively, the change in PP response to the meal was negatively associated with the change in body weight (r = -0.53, P = 0.002). In contrast, a high fasting PP level was positively associated with change in body weight (r = 0.45, P = 0.009). In conclusion, our results provide evidence that, even within the physiological range, PP contributes to the regulation of energy balance in humans. However this contribution appears to be more complex than anticipated because of the opposite effect of fasting and postprandial PP on the risk of future weight gain.     

Preservation of renal reserve in chronic renal disease

Protein-induced increases in glomerular filtration rate (GFR), termed renal reserve, is said to be abrogated with the onset of renal disease. However, this notion is inconsistent with the results from animal studies which suggest that alterations in protein intake modulate the glomerular hemodynamics in experimental renal disease. Accordingly, 12 normal subjects and 15 patients with renal disease received a protein meal providing 1 g/kg body weight protein. The subjects were pretreated with either placebo or an angiotensin I converting enzyme inhibitor, enalapril. A significant (P less than 0.05) increase in inulin and para-aminohippurate (PAH) clearance was noted in normal subjects as well as in patients with renal disease. The increase in GFR over basal values in normal subjects (28 +/- 9%), patients with moderate renal failure (20 +/- 13%), and advanced renal failure (21 +/- 14%) was not different. Plasma renin activity was unchanged following protein meal in the placebo studies although it increased following enalapril administration. Enalapril pretreatment did not alter the glomerular vasodilation and hyperfiltration following protein meal. We conclude that protein meal induces glomerular hyperfiltration in renal disease and that this protein-induced hyperfiltration is not mediated by angiotensin II. Because glomerular hyperfiltration is implicated in the progression of renal disease, these data suggest that even in patients who have advanced renal failure, high-protein diets may exert a detrimental effect on the kidney.