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Biomedical subjects

J Salas-Salvadó

Publications and source records attributed to J Salas-Salvadó.

At least 19 recordsLinked to original sources
PubMed2006

Subcutaneous adipose tissue cytokine production is not responsible for the restoration of systemic inflammation markers during weight loss.

CONTEXT: It has been suggested that weight loss can improve systemic inflammation associated with obesity by decreasing the adipose production of pro-inflammatory cytokines. This suggestion, however, remains controversial. OBJECTIVE: To analyse the effect of weight loss on peripheral inflammatory markers and subcutaneous adipocytokine production. DESIGN: Patients were studied at baseline, at the end of the weight loss period, and after 2 weeks of weight stabilisation. SUBJECTS: Nineteen morbid obese non-diabetic patients and 20 lean control subjects. INTERVENTION: During the weight loss period patients followed a 6-week low-calorie diet. MEASUREMENTS: Plasma levels of inflammatory markers, maximal in vitro whole-blood cytokine production, subcutaneous adipose tissue expression and content of several cytokines. RESULTS: Obese subjects had higher circulating levels of C reactive protein (CRP), serum amyloid A (SAA), interleukin IL-6, IL-1 and soluble tumor necrosis factor receptors (sTNFR). Weight loss was associated with a significant decrease in CRP, SAA, leucocytes and plasma IL-6. Maximal in vitro cytokine production of IL-1 and sTNFR1 increased during this period. Weight loss did not induce significant changes in the adipose concentrations of IL-6, IL-1 or sTNF-receptors. However, adipose expression of IL-6, IL-1, TNFalpha, membrane cofactor protein-1 and adiponectin increased at the end of the weight loss period. During weight maintenance, circulating inflammatory parameters increased and in some cases returned to baseline. CONCLUSIONS: A low-calorie diet is associated with an improvement in the systemic inflammatory status. This seems to be due to energy restriction rather than to adipose mass loss, since inflammatory levels return to baseline soon after weight stabilisation. Furthermore, a negative energy balance and fat mobilisation are associated with increased subcutaneous cytokine adipose expression.

Adult↗
PubMed2006

C-reactive protein, adiposity and cardiovascular risk factors in a Mediterranean population.

BACKGROUND: Understanding the distribution of high-sensitivity C-reactive protein (CRP) and its relations with classic cardiovascular risk factors in specific populations is important for further diagnostic use. METHODS: We studied 1,157 adult subjects (652 women and 505 men) participating in the Health Study of Catalonia. CRP concentrations were measured with a high-sensitivity turbidimetric assay. RESULTS: Median levels of CRP were 1.57 mg/l and 25% of both men and women had CRP values >3 mg/l. No differences were observed between men and women even after adjustment for age and body mass index (BMI). After patients with CRP values above the 97.5th percentile (n = 31) had been excluded, CRP concentrations increased significantly with increasing levels of cardiovascular risk factors in both men and women. Men and women with metabolic syndrome showed significantly higher levels of CRP than their counterparts, even after adjustment for BMI and age. In a multiple regression analysis, BMI, triglycerides and fasting glucose were independent predictors of CRP in women and together explained 42% of its variance. In men, CRP was independently and positively associated to waist circumference, smoking, diastolic blood pressure, uric acid and triglycerides, and negatively associated to HDL-cholesterol. Altogether these variables explained 51% of its variability. CONCLUSIONS: The present study describes, for the first time, CRP concentrations in a sample that is representative of a Spanish Mediterranean community. CRP distribution and correlates are very similar to those reported previously in spite of the different lifestyle and nutritional habits, and the lower rates of cardiovascular diseases in our population.

Adipose Tissue↗
PubMed2006

Conjugated linoleic acid intake in humans: a systematic review focusing on its effect on body composition, glucose, and lipid metabolism.

Studies performed on different species show that the consumption of conjugated linoleic acid (CLA) leads to a loss of fat and total body weight, reduces the plasma concentrations of total and LDL cholesterol, and has an antiinflammatory effect. This article reviews the clinical trials on human beings that evaluate how mixtures of CLA isomers administered as supplements or CLA-enriched products can affect total body weight, body composition, plasma lipid profile, glycemia, insulinemia, insulin sensitivity, lipid oxidation, and inflammation. After analyzing the few studies published to date in reduced samples of healthy humans or patients with overweight, obesity, metabolic syndrome, or diabetes, we deduce that there is not enough evidence to show that conjugated linoleic acid has an effect on weight and body composition in humans. However, some of these studies have observed that the administration of various CLA isomers has adverse effects on lipid profile (it decreases HDL cholesterol concentration and increases Lp(a) circulating levels), glucose metabolism (glycemia, insulinemia or insulin sensitivity), lipid oxidation, inflammation, or endothelial function. Therefore, long-term randomized clinical trials, controlled with placebo, need to be made in large samples of patients to evaluate the efficacy and safety of CLA isomers before its indiscriminate use in human beings can be recommended.

Adiposity↗
PubMed2004

[Nutrient content and health effects of nuts].

Nuts are foods with a high energy density, due in part to its small water content. They also present a low saturated fat content (<7%) but a high unsaturated fat contribution (40-60%). They represent one of the richest sources of dietary fiber, which is basically of the insoluble type. The effects of nut intake on health have been widely studied. Several prospective epidemiological studies performed on large cohorts have consistently shown that regular consumption of small amounts of nuts is negatively related to the risk of cardiovascular disease and to the risk of cardiovascular or all-cause mortality. From these studies can be concluded that regular consumption of small amounts of nuts leads to a 30-50% reduction in the risk of cardiovascular disease. Additionally, intervention studies have shown a positive effect of nut intake on lipid profile with significant reductions in total and LDL cholesterol levels and small or null effects on the HDL fraction. More recently, some studies have focused on the effect of nuts on body weight. At present, no evidences support a detrimental effect of nut consumption on body weight. On the contrary some weight loss studies suggest a beneficial effect of nut intake on body weight regulation.

Body Mass Index↗
PubMed2003

Potential uses and benefits of phytosterols in diet: present situation and future directions.

Over the past decade, the possibility of using phytosterols as ingredients in functional foods has led to numerous research studies in relation to their ability to reduce blood cholesterol. Many different types of carriers have been tested, with good results. The main conclusion is that the effective doses were between 1.5 and 3g/day, leading to reductions between 8% and 15% in LDL-cholesterol. The principal mechanism of action is based on interference with the solubilisation of the cholesterol in the intestinal micelles and, thus, absorption is reduced. Work has also been done on the optimal pattern of administration, and it has been found that ingesting phytosterols in a single dose per day or between meals are equally effective methods. The only side effect is that they can interfere with the absorption of carotenoids, but this can be compensated for in the diet or by adding these compounds in appropriate carriers. It has also been reported that phytosterols have anticancer properties and act as immune system modulators. There are several possible future lines of research: alternative sources with a high phytosterol content must be found, industrial processes must be implemented which minimise their loss, phytosterols must be included in food composition tables, the potential of the different types of phytosterols must be discerned, the genetic bases of their action must be elucidated, synergic effects with other compounds must be studied, side effects must be minimised, and the effects of long-term treatment must be defined precisely.

Anticholesteremic Agents↗
PubMed2003

Nut consumption, body weight and insulin resistance.

The beneficial effects of nuts on cardiovascular health are well known. However, since nuts provide a high caloric and fat content, some concern exists regarding a potential detrimental effect on body weight and insulin resistance. The current data available did not support such a negative effect of nut consumption on the short term or when nuts are included on diets that meet energy needs. Furthermore, there is some intriguing evidence that nuts can help to regulate body weight and protect against type II diabetes. This, however, still has to be proved and more research is needed to address the specific effects of nuts on satiety, energy balance, body weight and insulin resistance.

Body Weight↗
PubMed2002

TNFalpha expression of subcutaneous adipose tissue in obese and morbid obese females: relationship to adipocyte LPL activity and leptin synthesis.

INTRODUCTION: Tumor necrosis factor (TNFalpha) has been invoked as an adipostat. Accordingly, the adipose tissue expression of TNFalpha has been shown to be proportional to the degree of adiposity. The regulatory role of TNFalpha in obesity may be controlled by several mechanisms. These include the inhibitory effect on LPL activity, the mediation on glucose homeostasis or the effect on leptin. To assess the role of TNFalpha in obesity we measured adipocyte TNFalpha expression in 96 females with a wide range of adiposity and with or without type 2 diabetes. We analysed the relationship between TNFalpha expression, adipocyte LPL activity, insulin resistance and leptin in this population. RESULTS: The TNFalpha and leptin expression of the adipose tissue in obese and morbid obese patients were significantly higher than in controls. Obese and morbid obese patients had slightly higher levels of LPL activity, but these differences were not significant. We observed a significant relationship between adipose TNFalpha expression and body mass index (r=0.35, P<0.001). TNFalpha expression was negatively related to LPL activity (r=-0.28, P<0.05) and positively related to leptin expression (r=0.35, P<0.001). CONCLUSION: Our results indicate that obese women, even those with morbid obesity, over-express TNFalpha in subcutaneous adipose tissue in proportion to the magnitude of the fat depot and independently of the presence of type 2 diabetes. The TNFalpha system may be a homeostatic mechanism that prevents further fat deposition by regulating LPL activity and leptin production.

Adipocytes↗
PubMed2001

The metabolic puzzle during the evolution of HIV infection.

Abnormalities in energy, protein, lipid and glucose metabolism have been described in HIV patients since the beginning of the epidemic. With the new antiretroviral agents, nutritional status and survival have improved dramatically. However, since these therapies were introduced, there have been more descriptions of metabolic abnormalities, some of which were similar to and others of which were in conflict with those reported in previous years. This paper reviews the complexity of the metabolic abnormalities in HIV infections before and after the introduction of highly active antiretroviral therapy, and discusses such etiopathogenic mechanisms as secondary infections, antiretroviral drugs and persistent immune activation, which may be involved in these derangements.

Anti-HIV Agents↗
PubMed2001

Leptin concentrations do not correlate with fat mass nor with metabolic risk factors in morbidly obese females.

AIMS: To investigate the determinants of leptinemia in a cohort of morbid obese females compared to those of normal weight and mild-to-moderate obesity, and the relationships between leptin and metabolic derangements associated with obesity. METHODS: Recruited females were: moderately obese [n=44; body mass index (BMI) 25-40 kg/m2], morbidly obese (n=34; BMI > or = 40 kg/m2) and normal weight volunteers (n=12; BMI 19-25 kg/m2). Fat mass assessed by bioelectrical impedance and fat distribution by waist-to-hip ratio (WHR) were determined in all subjects. Biochemical determinations included plasma leptin, lipoprotein profile, fasting insulin and cortisol. RESULTS: Plasma leptin values were significantly increased in morbid obese patients (54.95 +/- 1.8 ng/ml) compared to those moderately obese (30.2 +/- 1.7 ng/ml; p<0.001) and to controls (9.77 +/- 1.4 ng/ml; p<0.001). Fat and age-adjusted leptin values were not different between groups. When subjects with a BMI <40 kg/m2 were considered, plasma leptin was significantly and positively related to anthropometric variables (BMI, percentage body fat and WHR), total cholesterol, LDL-cholesterol, plasma triglycerides, AST, ALT and uric acid; and negatively with HDL-cholesterol. In contrast, when morbidly obese patients were analyzed separately, no relationships were observed between leptin concentrations and BMI, percentage of adiposity or biochemical variables. For obese patients no significant differences were observed in the adjusted leptin values with respect to the presence of diabetes, dyslipidemia or hypertension. CONCLUSIONS: In morbidly obese women, the plasma leptin concentrations, although increased, do not reflect the amount of adipose stores, and as such, factors other than simply adiposity need to be invoked to explain the variation in leptin values.

Adipose Tissue↗
PubMed2000

Wernicke's syndrome after bariatric surgery.

Two young females with severe morbid obesity presented with Wernicke's syndrome after Roux-en-Y gastro-jejunum bypass had been performed. The first patient had recurrent vomiting and dyplopia two months post-surgery. Physical examination indicated bilateral ophthalmoparesia with conserved convergence and ataxia. The second patient had frequent vomiting episodes over the previous three months together with lower limb hypotonia, myoclonia and generalised tonicoclonic seizures on two occasions within one year of surgery. In both cases routine blood test, ion levels (sodium, potassium, calcium, phosphates), electroencephalogram and CT scan were normal. Thiamine therapy was instigated on the basis of clinical intuition and the first patient achieved complete remission within 24 hours while the second improved gradually in that two years later only mild lower limb hypotonia and a slight cognitive deficit remains. Erythrocyte transketolase activity determinations were abnormal on two separate occasions for this second patient. Vitamin B1 determinations were not available for the first patient. In conclusion, the restriction in energy intake and the persistent vomiting together with malabsorption induced by the surgical intervention could explain the vitamin deficiency causing Wernicke's encephalopathy. This indicates a need for close monitoring and systematic vitamin supplementation in those patients who undergo bariatric surgery.

Adult↗
PubMed2000

Plasma acyl-estrone levels are altered in obese women.

A group of obese women (BMI>27 kg/m2; N=73) was studied together with lean controls (BMI <27 kg/m2; N=25). Three groups were defined by the compliance with: BMI lower than 27 kg/m2, glycaemia lower than 5.5 mM and insulinaemia lower than 0.2 nM (controls, group 1, N=19). The subjects with BMI>27 kg/m2, glucose >5.5 mM and insulin >0.2 nM constituted group 3 (N=41), and those with BMI>27 with glycaemia and/or insulinaemia lower than the limits set constituted group 2 (N=32). The women in group 3 had higher fat content, BMI and fat-free mass than those in group 2 and the controls. There were no changes in most plasma parameters, such as free estrone and beta-estradiol. Leptin levels were higher in groups 2 and 3 than in controls. In controls, leptin and acyl-estrone levels were well correlated with BMI and fat content; this correlation was not found in groups 2 and 3 for acyl-estrone, although it was found for leptin. Acyl-estrone levels were lower than expected in most obese women when compared to those of controls, suggesting an altered availability or function of this hormone. In obese women, acyl-estrone levels -and probably function- are lower than expected, contrasting with maintained leptin-BMI correlations. The role of insulin in the control of body weight, perhaps through acyl estrone-mediated effects, should be re-evaluated.

Acylation↗
PubMed1999

Tumour necrosis factor, a key role in obesity?

Tumour necrosis factor-alpha (TNF) is a pleiotropic cytokine involved in many metabolic responses in both normal and pathophysiological states. In spite of the fact that this cytokine (also known as "cachectin") has been related to many of the metabolic abnormalities associated with cachexia, recent studies suggest that TNF may also have a central role in obesity modulating energy expenditure, fat deposition and insulin resistance. This review deals with the role of TNF in the control of fat mass and obesity.

Adipose Tissue↗
PubMed1998

Effect of malabsorption on nutritional status and resting energy expenditure in HIV-infected patients.

OBJECTIVE: To assess the influence of malabsorption on nutritional status and energy expenditure in patients at different stages of HIV infection. DESIGN AND METHODS: Fifty HIV patients were classified into three groups: Group 1, HIV asymptomatic patients (n=17); Group 2, AIDS without opportunistic infection (n=16); Group 3, AIDS patients with active infection (n=17). Clinically-healthy subjects (n=19) were used as controls. Parameters measured were: anthropometry, body composition by tetrapolar bioelectrical impedance; resting energy expenditure (REE) by open-circuit indirect calorimetry; malabsoption by D-xylose absorption and triolein breath tests. RESULTS: Malabsorption (defined as abnormality of xylose and/or fat absorption test) was found in 34 (68%) of patients: 9 (53%) Group 1; 11 (69%) Group 2; 14 (82%) Group 3. Twenty-seven (54%) had sugar malabsorption and 21 (42%) fat malabsorption. A significant relationship was observed between malabsorption and weight loss. REE measured was significantly lower in malabsorptive patients than in non-malabsorptive patients and controls (6006.3+/-846.5 versus 6443.4 + 985.5 versus 6802.1+/-862.7 kJ/day, respectively; P < 0.05). The REE adjusted for fat-free mass was lower in malabsorptive than in non-malabsorptive patients and slightly higher than in controls, although the differences were not statistically significant. CONCLUSIONS: The results suggest that malabsorption is a frequent feature in HIV infection and is related to the HIV-related weight loss. Hypermetabolism is not a constant phenomenon in HIV infection since, in the presence of malabsorption, our patients show an appropriate metabolic response with a compensatory decrease in REE.

Adult↗
PubMed1998

During intense exercise, obese women rely more than lean women on aerobic energy.

A series of untrained, healthy, obese women (body mass index 32.5 +/- 0.9 kg.m-2) were subjected to a protocol of intense exercise on a cycloergometer and compared with lean controls (body mass index 20. 9 +/- 0.5 kg.m-2). Physiological parameters, blood lactate, bicarbonate, plasma metabolites, oxygen consumption and CO2 production were measured. Impedance-derived extracellular water and plasma changes in lactate and bicarbonate were used to determine changes in bicarbonate pools and lactate-displaced CO2. From these and respiratory gases, the respiratory quotient was calculated and thence overall fuel consumption. Anaerobic energy during exercise accounted for about 1.8% of all energy consumed in the lean but only 0.7% in the obese. Obese women fatigued at lower workloads and energy expenditure levels than did the lean, and their lactate buildup was similar when compared on the basis of fat-free mass. The data support the postulation of fatigue being triggered by a combination of factors: stretched cardiovascular work would be the main factor for obese women, in part limiting lactate production. For lean women, the triggering factor for fatigue could be the loss of buffering capacity; but it is the combination of stretching cardiovascular capacity, exhaustion of glycogen and available glucose and increase in lactate/loss of bicarbonate buffer that determines the onset of fatigue.

Adult↗
PubMed1997

A study of the prognostic respiratory markers of sustained weight loss in obese subjects after 28 days on VLCD.

OBJECTIVE: To investigate parameters of energy metabolism during a 28 d VLCD to identify possible prognostic markers of weight change observed, subsequently, when the subjects were on a six-month hypocaloric diet. DESIGN: Longitudinal, clinical intervention study of a 2 MJ diet daily for 28 d and six month follow-up under a conventional, hypocaloric diet. SUBJECTS: Seven pre-menopausal women and one male all morbidly obese but otherwise healthy (age: 16-47 y, BMI 38.9-50.5 kg/m2). MEASUREMENTS: Body weight, resting energy expenditure (REE), resting respiratory quotient (RQ) and the 5 h thermic effect of food (TEF) were assessed by indirect calorimetry at the beginning and at the end of a 28 d VLCD treatment. Body composition was measured on day 1 by hydrodensitometry and tetrapolar bioelectrical impedance (TBIA), on day 28 by TBIA and nitrogen balance (NB) and by TBIA on follow-up. RESULTS: The individual weight loss during VLCD (mean 9.9 +/- 2.4 kg) was significant (P < 0.01) and correlated significantly with energy deficit (r = 0.83, P = 0.01). REE/FFM decreased 6.2% (FFMTBIA) and 8.9% (FFMNB), respectively. TEF28 was unchanged from TEF1 while fasting RQ declined during the intervention period but was back to baseline already within one month of follow-up even though the mean weight loss at six months had increased to 14.0 +/- 5.6 kg. There was a significant (P < 0.05) positive correlation between RQ28 and body-weight changes after one, three and six months of follow-up. The RQ28 explained 60-72% of the inter-individual variation in weight change. CONCLUSION: The resting RQ measurement is recommended as a simple and inexpensive assessment at the end of a strict weight-loss regimen in order to identify those individuals who may need greater assistance in maintaining a weight-loss when placed on a subsequent, free-living hypocaloric diet.

Adolescent↗
PubMed1997

The respiratory quotient as a prognostic factor in weight-loss rebound.

OBJECTIVE: To investigate the possible metabolic factors predisposing to weight gain subsequent to the cessation of a rapid-weight-loss diet. DESIGN: Prospective, longitudinal, intervention study of a 2 MJ diet daily for 28 d in a metabolic ward followed by a 12-month outpatient follow-up under a conventional, hypocaloric diet. SUBJECTS: Thirty-five females and one male, all with morbid obesity defined by a body mass index > or = 35 kg/m2. MEASUREMENTS: VO2 and VCO2 measured by 30 min indirect calorimetry to calculate resting energy expenditure and resting respiratory quotient at the beginning and end of very-low-calorie diet; body composition assessed by hydrostatic weighing on day 1; weight recorded on days 1 and 28 and at follow-up of 3, 6 and 12 months. RESULTS: From among all the variables considered, the resting respiratory quotient measured on day 28, even adjusted for weight loss during hospitalisation, was the only one that correlated significantly with the weight changes recorded during follow-up. CONCLUSION: Subjects who showed a respiratory quotient on day 28 in the lower range (< 0.72) were more able to maintain the weight-loss achieved with the very-low-calorie diet while those in the higher range (> 0.75) were less able to do so over the follow-up period. Thus, an appropriately measured respiratory quotient could prove useful in clinical practice as a prognostic marker of the long-term effectiveness of low- and very-low-calorie diets used to induce rapid weight loss.

Adult↗