Nutritional control of immunity: Balancing the metabolic requirements with an appropriate immune function.

The immune system is a highly integrated network of cells sensitive to a number of environmental factors. Interestingly, recent years have seen a dramatic increase in our understanding of how diet makes a crucial contribution to human health, affecting the immune system, secretion of adipocytokines and metabolic pathways. Recent experimental evidence indicates that diet and its components are able to profoundly influence immune responses, thus affecting the development of inflammatory and autoimmune diseases. This review aims to discuss some of the main topics concerning the impact of nutrients and their relative composition on immune cell development and function that may be particularly important for regulating the balance between inflammatory and tolerogenic processes. We also highlight the effects of diet on commensal bacteria and how changes in the composition of the microbiota alter intestinal and systemic immune homeostasis. Finally, we summarize the effects of dietary compounds on epigenetic mechanisms involved in the regulation of several immune related genes.

Energy-restricted, n-3 polyunsaturated fatty acids-rich diet improves the clinical response to immuno-modulating drugs in obese patients with plaque-type psoriasis: a randomized control clinical trial.

BACKGROUND & AIMS: Low-grade systemic inflammation associated with obesity may worsen the clinical course of psoriasis. This study aimed to assess the effectiveness of an energy-restricted diet, enriched in n-3 polyunsaturated fatty acids (PUFAs) and poor in n-6 PUFAs, on metabolic markers and clinical outcome of obese patients with psoriasis. METHODS: Forty-four obese patients with mild-to-severe plaque-type psoriasis treated with immuno-suppressive drugs were randomized to assume for six months either their usual diet or an energy-restricted diet (20 kcal/kg/ideal body weight/day) enriched of n-3 PUFAs (average 2.6 g/d). All patients continued their immuno-modulating therapy throughout the study. RESULTS: At 3 and 6 months, a significant clinical improvement was observed in patients assuming the low-calorie high n-3 PUFAs diet respect to controls. Specifically Psoriasis Area Score Index (7.7 ± 3.7, 5.3 ± 4.3 and 2.6 ± 3.0, respectively; p < 0.05), itch scores (15.4 ± 13.5, 12.3 ± 12.1 and 1.8 ± 5.9, respectively; p < 0.05) and Dermatological Life Quality Index (19.5 ± 1.9, 11.4 ± 3.5 and 5.1 ± 1.6; respectively, p < 0.05) all decreased respect to baseline. In these subjects but not in controls, a significant decrease in body weight (93.8 ± 10.1, 85.8 ± 11.4 and 83.1 ± 12.1 kg, respectively; p < 0.05), waist circumference (112.7 ± 7.2, 106.1 ± 10.3 and 101.9 ± 10.4 cm; p < 0.05), serum triglycerides (141.8 ± 51.1, 100.5 ± 26.6 and 90.2 ± 34.5 mg/dL; respectively, p < 0.05), serum total cholesterol (198.3 ± 31.7, 171.4 ± 29.0 and 176.5 ± 20.5 mg/dL; respectively, p < 0.05) and n-6/n-3 ratio intake also occurred (5.1 ± 0.9, 2.0 ± 0.9 and 2.3 ± 1.1; respectively, p < 0.05). CONCLUSIONS: In obese psoriatic patients, an energy-restricted diet designed to increase n-3 and reduce n-6 PUFAs, ameliorated the metabolic profile and, by increasing the response to immuno-modulating therapy, improved the clinical outcomes of the disease (ClinicalTrials.gov identifier: NCT01876875).

Evidence on the prevalence and geographic distribution of major cardiovascular risk factors in Italy.

OBJECTIVE: To assess the prevalence and geographic distribution of major cardiovascular risk factors in a large community-wide sample of the Italian population. DESIGN: A cross-sectional survey. Standardized methods were used to collect and measure cardiovascular risk factors. Data were adjusted for survey weightings. Qualitative and quantitative variables were compared with parametric and non-parametric tests, as appropriate. SETTING: Towns (n 193) across different Italian regions. SUBJECTS: Unselected adults (n 24 213; 12 626 men; 11 587 women) aged 18-98 years (mean age 56·9 (sd 15·3) years), who volunteered to participate in a community-wide screening programme over a 2 d period in 2007. RESULTS: Overall, the prevalence of major cardiovascular risk factors was: obesity, 22·7 % (women 18·9 %, men 26·1 %); overweight, 44·7 % (women 31·6 %, men 56·7 %); hypertension, 59·6 % (women 48·3 %, men 70·0 %); dyslipidaemia, 59·1 % (women 57·7 %, men 60·3 %); diabetes, 15·3 % (women 11·2 %, men 19·0 %) and smoking, 19·8 % (women 14·0 %, men 25·2 %). We found a high prevalence of unhealthy eating habits; fruit and vegetable consumption was below the recommended range in 60 % of the study population. Ninety per cent of the study population had more than one cardiovascular risk factor and 84 % had between two and five cardiovascular risk factors. There were differences among Italian macro-areas mainly for obesity, hypertension, dyslipidaemia and diabetes. CONCLUSIONS: The study provides alarming evidence on current prevalence data for major cardiovascular risk factors in a large sample of the Italian population. Particularly, obesity and hypertension represent a relevant public health problem. There is a pressing need for effective preventive health measures which must also take into account the differences among Italian macro-areas.

No difference in the 24-hour interstitial fluid glucose profile with modulations to the glycemic index of the diet.

OBJECTIVE: Reducing the glycemic index (GI) of the diet may decrease metabolic risk, primarily through reduction and stabilization of blood glucose. The objective of this research was to investigate whether incorporation of lower or higher GI foods into mixed meals had different effects on daylong glucose profiles, measured in interstitial fluid by a continuous glucose-monitoring system. METHODS: The study was a randomized, balanced, two-way crossover intervention of 2 x 1-wk periods of lower and higher GI diets. Participants were 12 overweight healthy adult women (mean body mass index +/- standard deviation 27.5+/-2.3 kg/m(2)). Changes in GI were achieved through substitution of key staple carbohydrate-rich foods. After a 4-d run-in on each dietary regimen, participants wore the continuous glucose-monitoring system over 2 d of identical controlled feeding in the laboratory, separated by 1 d of ad libitum consumption at home. RESULTS: On controlled days, diets differed in GI by 15 U and provided equal energy, macronutrients, and fiber. On ad libitum days, diet diaries revealed a difference in GI of 14+/-1 U (mean +/- standard error), with no detectable difference in energy, macronutrient, or fiber intake. No differences were observed in glucose profiles between higher and lower GI interventions in the controlled or ad libitum setting. There was significant agreement in area under the glucose curve on repeated controlled feeding days (intraclass correlation 0.75). CONCLUSION: This study indicates that a difference in dietary GI of 14-15 U is insufficient to alter daylong glycemia as measured in interstitial fluid by the continuous glucose-monitoring system.

Role of dietary intervention and nutritional follow-up in heart transplant recipients.

BACKGROUND: Obesity, dyslipidemia, hypertension, and diabetes mellitus are common features after heart transplantation and they lead to coronary artery disease and graft loss. AIM: To determine the effects of a dietary intervention on nutritional status and metabolic outcome of two groups enrolled during or after the first year from the transplant. METHODS: Forty two subjects (mean age 51.36+/-12.4 yr) were studied; 20 were enrolled during the first year by the transplant, 22 were enrolled after the first year from the transplant (7.9+/-3.86 and 56.86+/-38.6 months after surgery, respectively). According to diet compliance both groups were divided into two subgroups and they were prospectively followed for 4 years. Anthropometric measurements, biochemical nutritional markers, and dietary records were collected at baseline (T0) and after a 12-month follow-up period (T12) and a 48-month follow-up period (T48). Body composition was performed at T0 and T12. RESULTS: Diet compliance was associated with a decrease in total cholesterol, triglycerides and glucose plasma level and with a weight loss mainly due to a decrease in fat mass. CONCLUSION: Our study shows the efficacy of dietary intervention to obtain an early and late weight and metabolic control after heart transplant.

Body mass index and bioelectrical vector distribution in 8-year-old children.

OBJECTIVE: To describe bioelectrical impedance vector distribution in relation to BMI (body mass index; body weight/stature(2)) in a population of healthy children in order to detect possible changes in body composition status. DESIGN: Observational study involving 464 healthy 8-year-old children. The subjects were divided into three groups based on their BMI: 218 normal weight (NW) children with BMI<18.4 for male and BMI<18.3 for female; 135 overweight (OW) children with BMI 18.4 to <21.6 for male and with BMI 18.3 to <21.6 for female; 111 obese (OB) children with BMI>/=21.6. Skinfold thickness was measured at the triceps using a Holtain caliper. Bioelectrical impedance analysis (BIA) measurements were performed. Total body water (TBW), fat-mass (FM), fat-free mass (FFM), body cell mass (BCM) and extra-cellular water (ECW) were estimated using conventional BIA regression equations. The resistance-reactance graph (RXc graph) method was used for vector BIA using as reference population the set of 353 children with BMI 14.0-21.5kg/m(2). RESULTS: Mean vector displacement followed a definite pattern, with progressive vector shortening in groups with increasing BMI class, and along a fixed phase angle. This pattern indicates an increase in TBW due to an increase in soft tissue mass with an average, normal hydration. In NW children, vectors out of the right and upper half of the 75% tolerance ellipse indicating leanness, and vectors falling out of the right and lower half of the tolerance ellipse indicating undernutrition, show a significantly reduced value of BCM but no significant differences in FM or triceps skinfold thickness (TST), respectively, compared to vectors falling within the 75% tolerance ellipse. CONCLUSIONS: Although BMI is a reliable measure to grade overweight, it cannot differentiate whether weight change is due to variation of FM, FFM or water. In our study a different impedance vector pattern has been associated with normal weight to obesity, and we have established the trajectory followed by the impedance vector of standardized age, healthy children grouped by BMI. This BIVA may be useful for clinical purposes due to ability to detect changes in hydration or body composition in children.

Role of dietary intervention on metabolic abnormalities and nutritional status after renal transplantation.

BACKGROUND: In these last years, several traditional risk factors for cardiovascular disease, like obesity, dyslipidaemia, hypertension and post-transplant diabetes mellitus have been also identified as important non-immunological risk factors leading to the development of chronic allograft nephropathy, the first cause of graft loss in transplanted patients. The aim of the present study was to determine the effects of a 12-month dietary regimen on the nutritional status and metabolic outcome of renal transplant recipients in the first post-transplant year. METHODS: Forty-six cadaver-donor renal transplant recipients (mean age 40.8 +/- 10.1-years), enrolled during the first post-transplant year (4.8 +/- 3.3 months) and followed prospectively for a 12 month period. Biochemical and nutritional markers, anthropometric measurements, body composition (by conventional bioelectrical impedance analysis) and dietary records (using a detailed food-frequency questionnaire) at baseline and after 12 months. RESULTS: Compliance to the diet was related to sex (male better than female) and was associated with weight loss primarily due to a decrease in fat mass, with decrease in total cholesterol and glucose plasma levels and with a concomitant rise in serum albumin. CONCLUSION: After renal transplantation, health benefits of proper metabolic balance that include reduced body fat, weight loss, lower cholesterol and triglycerides levels and an improvement, fasting glucose levels can be obtained when dietary intervention occurred.

Bioelectrical impedance analysis and age-related differences of body composition in the elderly.

BACKGROUND AND AIM: Significant changes in body composition that have important health related effects may occur in the elderly. In this study, we evaluated the bioelectrical characteristics in a large group of apparently healthy Caucasian men in the age range 50-80 years, as a function of age and body mass index. METHODS: We studied 315 men with ages ranging from 50 to 80 years. They were divided into three groups according to body mass index (kg/m(2)): 18.5-24.9 normoweight (NW); 25.0-29.9 overweight (OW); > or =30 obese (OB), and they were classified in nine age subgroups: 50-59 (young-old, YO); 60-69 (old, O); 70-80 (oldest, OS). Fat-free mass, fat mass and body cell mass were investigated using conventional bioelectrical impedance analysis. Body composition was also assessed by bioelectrical impedance vector analysis and the RXc graph method. RESULTS: Body cell mass decreased significantly with age particularly in subgroups of the OW and OB groups (p<0.05). Mean vector displacement followed a definite pattern, with downward migration of the ellipses in the OW and OB groups, after 70 years of age. CONCLUSIONS: Ageing was associated with a pattern of vector bioelectrical impedance analysis indicating decreased soft tissue mass (fat-free mass and body cell mass), particularly in OW and OB-OS healthy men. We suggest 70 years of age as a cut-off for significant quantitative and qualitative (tissue electrical properties) body composition modifications. This bioelectrical impedance vector analysis pattern associated with ageing and across the different body mass index categories, may be useful for clinical purposes and can be used in geriatric routine to accurately assess the body composition modifications occurring in the elderly.

Body composition and cardiovascular risk factors in pretransplant hemodialysis patients.

BACKGROUND: Obesity, hyperlipemia and cardiovascular complications contribute to a significant proportion of morbidity and mortality of renal transplant patients and have negative effects on renal survival. Aim of the present study was to evaluate the main abnormalities in body composition and the prevalence of some cardiovascular risk factors in a population of hemodialyzed (HD) patients awaiting renal transplantation. METHODS: We studied 151 HD patients, all included in a waiting list for renal transplantation, 97 males and 54 females, with mean age 47.4+/-12 years. Patients were divided into three groups according to their body mass index (BMI) (kg/m2): 18.5 to 24.9 (normoweight, NW); 25.0 to 29.9 (overweight, OW); > or =30 (obese, OB). The body composition measurements were obtained the day after the mid-week HD session using bioelectrical impedance analysis (BIA). RESULTS: We found that 47 patients were NW (31%), while 56 were OW (37%), and 48 were OB (32%). BIA-measured body cell mass was (BCM) significantly increased in the OW as compared with the NW group (P<0.001), but, of note, no significant difference was found in OB group in comparison with the OW. Total cholesterol and triglycerides plasma levels were significantly elevated in OW and OB patients with respect to NW (P<0.05) and an increased prevalence of diabetes was seen in OB patients (NW: 6%, OW: 5%, OB: 12%). CONCLUSIONS: These data show that a large proportion of patients awaiting renal transplant are overweight or obese and a consistent part of them have other cardiovascular risk factors associated. Furthermore, obese HD patients have a BCM lower than predicted on the basis of BMI and show an altered metabolic profile. A better understanding of the characteristics of patients included in the renal transplant waiting list is crucial in order to design prospective studies that aim to define the proper risk profile for the selection of patients.