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Background: It is unknown whether diets with a high dietary total antioxidant capacity (TAC) can modify oxidative stress, low-grade inflammation, or liver dysfunction, all of which are risk factors for type 2 diabetes and cardiovascular disease. Objective: We studied the effect of high- and low-TAC (HT and LT, respectively) diets on markers of antioxidant status, systemic inflammation, and liver dysfunction. Design: In a crossover intervention, 33 healthy adults (19 men, 14 women) received the HT and LT diets for 2 wk each. Dietary habits were checked with a 3-d food record during both diet periods and the washout period. Results: Fruit and vegetable, macronutrient, dietary fiber, and alcohol intakes did not differ significantly between the 2 diets, whereas dietary TAC, [alpha]-tocopherol, and ascorbic acid were significantly (P < 0.001) higher during the HT diet. Plasma [alpha]-tocopherol rose during the HT and decreased during the LT diet (P < 0.02 for difference) without changes in markers of oxidative stress except plasma malondialdehyde, which decreased unexpectedly during the LT diet (P < 0.05). Plasma high-sensitivity C-reactive protein, alanine amino-transferase, gamma-glutamyltranspeptidase, and alkaline phosphatase concentrations decreased during the HT compared with the LT diet (mean [+ or -] SEM for pre-post changes: -0.72 [+ or -] 0.37 compared with 1.05 [+ or -] 0.60 mg/L, P < 0.01; -1.73 [+ or -] 1.02 compared with 2.33 [+ or -] 2.58 U/L, P < 0.01; -2.12 [+ or -] 1.45 compared with 5.15 [+ or -] 2.98 U/L, P < 0.05; and 1.36 [+ or -] 1.34 compared with 5.06 [+ or -] 2.00 U/L, P < 0.01, respectively). Conclusion: Selecting foods according to their TAC markedly affects antioxidant intake and modulates hepatic contribution to systemic inflammation without affecting traditional markers of antioxidant status.

Background: Many laboratories offer glycemic index (GI) services. Objective: We assessed the performance of the method used to measure GI. Design: The GI of cheese-puffs and fruit-leather (centrally provided) was measured in 28 laboratories (n = 311 subjects) by using the FAO/WHO method. The laboratories reported the results of their calculations and sent the raw data for recalculation centrally. Results: Values for the incremental area under the curve (AUC) reported by 54% of the laboratories differed from central calculations. Because of this and other differences in data analysis, 19% of reported food GI values differed by >5 units from those calculated centrally. GI values in individual subjects were unrelated to age, sex, ethnicity, body mass index, or AUC but were negatively related to within-individual variation (P = 0.033) expressed as the CV of the AUC for repeated reference food tests (refCV). The between-laboratory GI values (mean [+ or -] SD) for cheese-puffs and fruit-leather were 74.3 [+ or -] 10.5 and 33.2 [+ or -] 7.2, respectively. The mean laboratory GI was related to refCV (P = 0.003) and the type of restrictions on alcohol consumption before the test (P = 0.006, [r.sup.2] = 0.509 for model). The within-laboratory SD of GI was related to refCV (P < 0.001), the glucose analysis method (P = 0.010), whether glucose measures were duplicated (P = 0.008), and restrictions on dinner the night before (P = 0.013, [r.sup.2] = 0.810 for model). Conclusions: The between-laboratory SD of the GI values is [approximately equal to] 9. Standardized data analysis and low within-subject variation (refCV < 30%) are required for accuracy. The results suggest that common misconceptions exist about which factors do and do not need to be controlled to improve precision. Controlled studies and cost-benefit analyses are needed to optimize GI methodology. The trial was registered at clinicaltrials.gov as NCT00260858. KEY WORDS Clinical trial, humans, dietary carbohydrate, glycemic index, glucose, methodology

Background: Insulin resistance (IR) and liver steatosis (LS) are interlinked metabolic derangements whose prevalence is rapidly increasing, but the effect of dietary carbohydrate quality on LS is unknown. Objective: The objective was to describe the relation of IR and LS to total carbohydrate, total dietary fiber, and the glycemic index (GI) and glycemic load of the diet. Design: The study was a cross-sectional evaluation of 247 apparently healthy subjects who had no evidence of viral, toxic, or autoimmune hepatitis and who were unselected for alcohol intake. The homeostasis model assessment index was used as a surrogate measure of IR, and a liver echography was used as a proxy for LS grading. Dietary data were collected by using 3-d food records. Total carbohydrate intake, total dietary fiber, GI, and glycemic load were calculated by using a semiquantitative food-frequency questionnaire concerning the dietary sources of carbohydrates. Results: The prevalence of high-grade LS (HG-LS) increased significantly across quartiles of dietary GI (P for trend < 0.034): HG-LS in the 4th quartile (high GI) was twice that in the first 3 quartiles (low to medium GIs), whereas no relation was observed with total carbohydrates, total dietary fiber, or glycemic load. In insulin-sensitive subjects (first 3 quartiles of homeostasis model assessment index of IR), the prevalence of HG-LS did not differ significantly between GI groups, but, in insulin-resistant subjects (4th quartile of homeostasis model assessment index of IR), it was twice as high in those with high GI as in those with low to medium GIs (P = 0.005). Conclusions: High-GI dietary habits are associated with HG-LS, particularly in insulin-resistant subjects. Dietary advice on the quality of carbohydrate sources therefore may be a complementary tool for preventing or treating LS of metabolic origin. Am J Clin Nutr 2006;84:136-42. KEY WORDS Diet, glycemic index, insulin resistance, liver steatosis, metabolic syndrome

Dietary polyphenolic compounds are poorly absorbed in the small intestine. The absorbed fraction follows the common metabolic pathway of drugs, undergoing phase II enzymatic detoxification with the conjugation of glucuronic acid, sulfate, and methyl groups. However, the unabsorbed fraction can reach the colon, becoming available for the wide array of enzymes produced by the local commensal microbiota. Gut bacteria can hydrolyze glycosides, glucuronides, sulfates, amides, esters, and lactones and are able to break down the polyphenolic skeleton and perform reactions of reduction, decarboxylation, demethylation, and dehydroxylation. These complex modifications generate several low–molecular-weight metabolites that can be efficiently absorbed in situ, subsequently undergoing further phase II metabolism, locally andor at the liver level, before entering the systemic blood circulation and finally being excreted in urine in substantial quantities that exceed the excretion of phenolic metabolites formed in the upper gastrointestinal tract. This brief work focuses on the phenolic composition and colonic microbial transformation of 2 of the most polyphenol-rich dietary sources, namely, green tea and coffee, and a new interesting and innovative ingredient, hazelnut skin, recently evaluated as one of the richest edible sources of polyphenolic compounds.

Abstract: Large interest has recently risen in the development of “functional” foods, products that may provide a health benefit beyond the traditional nutrients. Foods rich in antioxidants and, simultaneously, characterized by a low glycemic index (GI), can reduce, through a double mechanism, the risk of increased postprandial oxidative stress, which is one of the constituent of the onset of several chronic diseases. Nutritionally enhanced tortillas were therefore developed by incorporating ingredients with well-documented nutritional functionality (carrots, soy, and wholemeal kamut) in a standard wheat tortillas formulation, in an attempt to create low GI and antioxidant-rich products while preserving sensory acceptability and physico-chemical properties. Five tortilla prototypes were developed and characterized for sensory acceptability, textural attributes, color, total antioxidant capacity, and in vivo GI. The simultaneous combination of carrot juice, soy, and wholemeal kamut resulted in a very interesting product that was not only the most acceptable by the consumers (although slightly harder than the standard control) but also showed the lowest GI and was relatively high in total antioxidant capacity.

As a broad range of professionals in clinical and nonclinical settings requires some expertise in human nutrition, the university system must offer academic courses tailored to these different specific needs. In the Italian university system there is still uncertainty with regard to the learning objectives regarding human nutrition. In the ministerial decrees defining the criteria for establishing university courses, the indications about education in human nutrition are rather inconsistent, sometimes detailed, but often just mentioned or even only implied. Education in human nutrition requires both an appropriate duration (number of university credits included in the degree format for different disciplines) and course units that are designed in order to achieve specific expertise. The university system should appropriately design and distinguish the nutritional competencies of the different types of graduates. Physiology and biochemistry are the academic disciplines mostly involved in teaching fundamentals of human nutrition, while the discipline sciences of applied nutrition and dietetics more strictly focuses on applied nutrition and clinical nutrition. Other academic disciplines that may contribute to education in human nutrition, depending on the type of degree, are internal medicine (and its subspecialties), hygiene, endocrinology, food technologies, food chemistry, commodity science, and so forth.