Dietary carbohydrates: a review of international recommendations and the methods used to derive them.

BACKGROUND/OBJECTIVES: Renewed dietary recommendations for carbohydrates have recently been published by various international health authorities. The present work (1) reviews the methods and processes (systematic approach/review, inclusion of public consultation) used to identify, select and grade the evidence underpinning the recommendations, particularly for total carbohydrate (CHO), fibre and sugar consumption, and (2) examines the extent to which variation in the methods and processes applied relates to any differences in the final recommendations. SUBJECTS/METHODS: A search of WHO, US, Canada, Australia and European sources identified 19 documents from 13 authorities with the desired detailed information. Processes and methods applied to derive recommendations were compiled and compared. RESULTS: (1) A relatively high total CHO and fibre intake and limited intake of (added or free) sugars are generally recommended. (2) Even where recommendations are similar, the specific justifications for quantitative/qualitative recommendations differ across authorities. (3) Differences in recommendations mainly arise from differences in the underlying definitions of CHO exposure and classifications, the degree to which specific CHO-providing foods and food components were considered, and the choice and number of health outcomes selected. (4) Differences in the selection of source material, time frames or data aggregation and grading methods appeared to have minor influence. CONCLUSIONS: Despite general consistency, apparent differences among the recommendations of different authorities would likely be minimized by: (1) More explicit quantitative justifications for numerical recommendations and communication of uncertainty, and (2) greater international harmonization, particularly in the underlying definitions of exposures and range of relevant nutrition-related outcomes.

Nutrition education in European medical schools: results of an international survey.

Consumers and patients are unsure of whom to trust for nutritional advice. Although medical doctors are seen as experts in nutrition and their advice is regularly followed, data are lacking on the amount of nutrition education in European medical school curricula. In line with US research, we distributed a survey on required and/or optional nutrition contact hours to medical education directors of all accredited medical schools (N=217) in Western European Union countries (N=14). In total, respondents from 32 medical schools (14.7%) from 10 countries indicated that nutrition education, in some form, was required in 68.8% of schools where, on average, 23.68 h of required nutrition education was provided. The results from this small-scale survey are comparable to a 2010 US study; conversely, European educators were satisfied with the amount of nutrition education. We substantiate the increasing concern over the inadequate amounts of nutrition education provided to medical students in Europe.

Impact of postprandial glycaemia on health and prevention of disease.

Postprandial glucose, together with related hyperinsulinemia and lipidaemia, has been implicated in the development of chronic metabolic diseases like obesity, type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). In this review, available evidence is discussed on postprandial glucose in relation to body weight control, the development of oxidative stress, T2DM, and CVD and in maintaining optimal exercise and cognitive performance. There is mechanistic evidence linking postprandial glycaemia or glycaemic variability to the development of these conditions or in the impairment in cognitive and exercise performance. Nevertheless, postprandial glycaemia is interrelated with many other (risk) factors as well as to fasting glucose. In many studies, meal-related glycaemic response is not sufficiently characterized, or the methodology with respect to the description of food or meal composition, or the duration of the measurement of postprandial glycaemia is limited. It is evident that more randomized controlled dietary intervention trials using effective low vs. high glucose response diets are necessary in order to draw more definite conclusions on the role of postprandial glycaemia in relation to health and disease. Also of importance is the evaluation of the potential role of the time course of postprandial glycaemia.

Cholesterol-lowering properties of different pectin types in mildly hyper-cholesterolemic men and women.

BACKGROUND/OBJECTIVES: Viscous fibers typically reduce total cholesterol (TC) by 3-7% in humans. The cholesterol-lowering properties of the viscous fiber pectin may depend on its physico-chemical properties (viscosity, molecular weight (MW) and degree of esterification (DE)), but these are not typically described in publications, nor required by European Food Safety Authority (EFSA) with respect to its generic pectin cholesterol-lowering claim. SUBJECTS/METHODS: Here, different sources and types of well-characterized pectin were evaluated in humans. Cross-over studies were completed in mildly hyper-cholesterolemic persons receiving either 15 g/day pectin or cellulose with food for 4 weeks. RESULTS: Relative low-density lipoprotein (LDL) cholesterol (LDL-C) lowering was as follows: citrus pectin DE-70=apple pectin DE-70 (7-10% reduction versus control)>apple pectin DE-35=citrus pectin DE-35>OPF (orange pulp fiber) DE-70 and low-MW pectin DE-70>citrus DE-0. In a subsequent 3-week trial with 6 g/day pectin, citrus DE-70 and high MW pectin DE-70 reduced LDL-C 6-7% versus control (without changes in TC). In both studies, high DE and high MW were important for cholesterol lowering. Source may also be important as citrus and apple DE-70 pectin were more effective than OPF DE-70 pectin. Pectin did not affect inflammatory markers high-sensitivity C-reactive protein (hsCRP) nor plasma homocysteine. CONCLUSIONS: Pectin source and type (DE and MW) affect cholesterol lowering. The EFSA pectin cholesterol-lowering claim should require a minimum level of characterization, including DE and MW.

Gastrointestinal targets of appetite regulation in humans.

The aim of this paper is to describe and discuss relevant aspects of the assessment of physiological functions - and related biomarkers - implicated in the regulation of appetite in humans. A short introduction provides the background and the present state of biomarker research as related to satiety and appetite. The main focus of the paper is on the gastrointestinal tract and its functions and biomarkers related to appetite for which sufficient data are available in human studies. The first section describes how gastric emptying, stomach distension and gut motility influence appetite; the second part describes how selected gastrointestinal peptides are involved in the control of satiety and appetite (ghrelin, cholecystokinin, glucagon-like peptide, peptide tyrosin-tyrosin) and can be used as potential biomarkers. For both sections, methodological aspects (adequacy, accuracy and limitation of the methods) are described. The last section focuses on new developments in techniques and methods for the assessment of physiological targets involved in appetite regulation (including brain imaging, interesting new experimental approaches, targets and markers). The conclusion estimates the relevance of selected biomarkers as representative markers of appetite regulation, in view of the current state of the art.

Gastrointestinal responses following acute and medium term intake of retrograded resistant maltodextrins, classified as type 3 resistant starch.

DESIGN: Study part 1 was executed as a randomized double-blind placebo-controlled crossover study and study part 2 as a longitudinal study. SUBJECTS: Forty-one healthy adult volunteers aged 18-24 years were recruited from the student population of the University of Salford. All subjects enrolled and completed study part 1 and 39 subjects enrolled and completed study part 2. INTERVENTIONS: In study part 1, individuals consumed, in random order 0, 20, 40, 60, 80, 100 or 120 g of a RRM containing starch product incorporated in pre-prepared foods on individual test days. Assuming a minimum content of 50% RRM in the starch product this delivered respectively 0, 10, 20, 30, 40, 50 or 60 g of RRM. All foods were prepared and coded by personnel not involved in carrying out the tests. Test days were separated by 7 day washout periods. In study part 2, consumption of RRM was increased from 3.6 g at day 1 in incremental doses up to each subject's MNED as determined in study 1, to be achieved at day 14. Subsequently, RRM intake was from day 15-21 in a way that the final intake at day 21 was at least 10 g above the individual MNED. In both parts of the study, subjects reported the prevalence and magnitude of GI symptoms. RESULTS: No significant change was observed in either defecation frequency and faecal consistency or the number of subjects experiencing any GI symptoms, following consumption of foods containing 0-60 g RRM. The individual MNED at which an increase in symptoms did not occur was determined as 60 g RRM for 71% of the subjects who participated in study part 1. Regression analysis showed that consumption of gradually increasing doses of RRM in food products over 21 days was associated with a significant increase in the mean symptom score for flatulence (P=1.5 x 10(-4)), total bowel movement frequency (P=0.023) and bowel movement frequency to pass watery faeces (P=0.0157). Increasing the ingested dose of RRM by 10 g above the predetermined MNED, however, did not provoke significant increases in GI symptoms. In both studies, the majority of symptom responses were classified by the subjects as 'little more than usual'. CONCLUSIONS: Consumption of up to 60 g RRM is tolerated well by most individuals with no evidence of any significant dose-dependent increase in the magnitude of symptoms or the occurrence of multiple GI symptoms. However, a mild laxative effect when consuming >60 g RRM is suggested. Although there was no change in GI responses following consumption of increasing doses of RRM over 21 days, generally a dose of 10 g RRM above the MNED level was tolerated well during medium term intake.

Gastrointestinal tolerance of erythritol and xylitol ingested in a liquid.

OBJECTIVES: To determine and compare the gastrointestinal (GI) responses of young adults following consumption of 45 g sucrose, 20, 35 and 50 g xylitol or erythritol given as a single oral, bolus dose in a liquid. DESIGN: The study was a randomized, double-blind, placebo-controlled study. SUBJECTS: Seventy healthy adult volunteers aged 18-24 years were recruited from the student population of the University of Salford. Sixty-four subjects completed the study. INTERVENTIONS: Subjects consumed at home without supervision and in random order, either 45 g sucrose or 20, 35 and 50 g erythritol or xylitol in water on individual test days, while maintaining their normal diet. Test days were separated by 7-day washout periods. Subjects reported the prevalence and magnitude of flatulence, borborygmi, bloating, colic, bowel movements and the passage of faeces of an abnormally watery consistency. RESULTS: Compared with 45 g sucrose, consumption of a single oral, bolus dose of 50 g xylitol in water significantly increased the number of subjects reporting nausea (P<0.01), bloating (P<0.05), borborygmi (P<0.005), colic (P<0.05), watery faeces (P<0.05) and total bowel movement frequency (P<0.01). Also 35 g of xylitol increased significantly bowel movement frequency to pass watery faeces (P<0.05). In contrast, 50 g erythritol only significantly increased the number of subjects reporting nausea (P<0.01) and borborygmi (P<0.05). Lower doses of 20 and 35 g erythritol did not provoke a significant increase in GI symptoms. At all levels of intake, xylitol produced significantly more watery faeces than erythritol: resp. 50 g xylitol vs 35 g erythritol (P<0.001), 50 g xylitol vs 20 g erythritol (P<0.001) and 35 g xylitol vs 20 g erythritol (P<0.05). CONCLUSIONS: When consumed in water, 35 and 50 g xylitol was associated with significant intestinal symptom scores and watery faeces, compared to the sucrose control, whereas at all levels studied erythritol scored significantly less symptoms. Consumption of 20 and 35 g erythritol by healthy volunteers, in a liquid, is tolerated well, without any symptoms. At the highest level of erythritol intake (50 g), only a significant increase in borborygmi and nausea was observed, whereas xylitol intake at this level induced a significant increase in watery faeces.

Infection assessment of totally implanted long-term venous access devices.

AIM: Comparison of catheter tip versus port content culture techniques to assess infection in totally implanted vascular access devices (TIVAD). MATERIALS AND METHODS: Comparison of pocket swab, catheter-tip and port content cultures after removing the silicon puncture septum in a prospectively collected consecutive series of 102 TIVAD removed for clinical suspicion of infection, between May 2000 and March 2003. RESULTS: 102 totally implanted port-catheters in 98 patients, age ranging from 1 to 90 years (median 53 years), were removed 7 to 2616 days after insertion (median 210 days). Infection of the pocket surrounding the port was found in 21 cases, all proven by a positive culture of the pocket swab. Out of the remaining 81 cases without pocket infection, 32 had only a positive catheter tip culture, whereas 56 had a positive port content culture (p = 0.0002). Always the same microorganism was isolated in the 32 patients with positive catheter tip and port content cultures. The main organisms identified within TIVAD were Coagulase Negative Staphylococcus (CNS) (41 cases) and Candida sp (15 cases). Eight out of the 21 pocket infections were caused by Staphylococcus aureus. CONCLUSION: In the presence of local signs of infection, taking cultures of the pocket surrounding the port is sufficient for diagnostic purposes. When infection is localized within the device only, port content cultures taken after removal of the silicon septum are more often positive than cultures of the catheter tip, and constitute therefore a more reliable tool for the assessment of TIVAD infection.

Low-carbohydrate diets: nutritional and physiological aspects.

Recently, diets low in carbohydrate content have become a matter of international attention because of the WHO recommendations to reduce the overall consumption of sugars and rapidly digestible starches. One of the common metabolic changes assumed to take place when a person follows a low-carbohydrate diet is ketosis. Low-carbohydrate intakes result in a reduction of the circulating insulin level, which promotes high level of circulating fatty acids, used for oxidation and production of ketone bodies. It is assumed that when carbohydrate availability is reduced in short term to a significant amount, the body will be stimulated to maximize fat oxidation for energy needs. The currently available scientific literature shows that low-carbohydrate diets acutely induce a number of favourable effects, such as a rapid weight loss, decrease of fasting glucose and insulin levels, reduction of circulating triglyceride levels and improvement of blood pressure. On the other hand some less desirable immediate effects such as enhanced lean body mass loss, increased urinary calcium loss, increased plasma homocysteine levels, increased low-density lipoprotein-cholesterol have been reported. The long-term effect of the combination of these changes is at present not known. The role of prolonged elevated fat consumption along with low-carbohydrate diets should be addressed. However, these undesirable effects may be counteracted with consumption of a low-carbohydrate, high-protein, low-fat diet, because this type of diet has been shown to induce favourable effects on feelings of satiety and hunger, help preserve lean body mass, effectively reduce fat mass and beneficially impact on insulin sensitivity and on blood lipid status while supplying sufficient calcium for bone mass maintenance. The latter findings support the need to do more research on this type of hypocaloric low-carbohydrate diet.

The effect of two sports drinks and water on GI complaints and performance during an 18-km run.

Gastrointestinal (GI) complaints are frequently experienced during running. Sports drinks to prevent dehydration and hypoglycemia during exercise are generally used. The aim was to investigate the effect of 3 different drinks on GI complaints and performance during competitive running in a controlled field study. Ninety-eight well-trained subjects (90 M, 8 F, age 41 +/- 8 y) performed a competitive 18-km run three times within 8 days. The study was a controlled, standardized field experiment following a randomized, crossover design. Three different drinks were compared: water, a sports drink (CES), and a sports drink with added 150 mg/l caffeine (CAF). The incidence of GI complaints and the effect of the drinks on performance was studied. Each subject consumed 4 times 150 ml as follows: at the start, after 4.5 km, 9 km, and 13.5 km. Fluid intake was controlled. Incidence and intensity of GI complaints during the run were determined using a 10 points scale questionnaire. There were no significant differences in performance between the 3 drinks. Run time (18 km, mean +/- SD): WAT 1 : 18 : 03 +/- 08 : 30, CES 1 : 18 : 23 +/- 08 : 47, CAF 1 : 18 : 03 +/- 08 : 42. The use of carbohydrate-containing sports drinks led to higher incidences of all types of GI complaints compared to water. Significant differences (p < 0.05) were reached for flatulence; incidence: WAT 17.9 %, CES 28.6 %, CAF 30.6 %, and reflux; incidence: WAT 55.7 %, CES 78.6 %, CAF 72.5 %. There were no significant differences in intensity of the GI complaints. Addition of caffeine to CES had no effect on GI complaints, compared to CES alone. We conclude that sports drinks used during an 18-km run in cool environmental conditions do not support the performance better than mineral water. The use of sports drinks during an 18-km run leads to a higher incidence of both upper and lower GI complaints compared to water. Addition of caffeine to the sports drink has no effect on either running performance or GI complaints.

Glycaemic index methodology.

The glycaemic index (GI) concept was originally introduced to classify different sources of carbohydrate (CHO)-rich foods, usually having an energy content of >80 % from CHO, to their effect on post-meal glycaemia. It was assumed to apply to foods that primarily deliver available CHO, causing hyperglycaemia. Low-GI foods were classified as being digested and absorbed slowly and high-GI foods as being rapidly digested and absorbed, resulting in different glycaemic responses. Low-GI foods were found to induce benefits on certain risk factors for CVD and diabetes. Accordingly it has been proposed that GI classification of foods and drinks could be useful to help consumers make 'healthy food choices' within specific food groups. Classification of foods according to their impact on blood glucose responses requires a standardised way of measuring such responses. The present review discusses the most relevant methodological considerations and highlights specific recommendations regarding number of subjects, sex, subject status, inclusion and exclusion criteria, pre-test conditions, CHO test dose, blood sampling procedures, sampling times, test randomisation and calculation of glycaemic response area under the curve. All together, these technical recommendations will help to implement or reinforce measurement of GI in laboratories and help to ensure quality of results. Since there is current international interest in alternative ways of expressing glycaemic responses to foods, some of these methods are discussed.

Effects of short-chain fructo-oligosaccharides on glucose and lipid metabolism in mild hypercholesterolaemic individuals.

BACKGROUND: The intake of 10 g/day of short-chain-fructo-oligosaccharides (sc-FOS) has been shown to increase significantly bifidus counts and to produce high amounts of short-chain fatty acids (SCFA), presumed to influence glucose and lipid metabolism. AIM: To evaluate the effects of moderate intake of sc-FOS on glucose and lipid metabolism in individuals with mild hypercholesterolaemia. DESIGN: A randomized double-blind sequential cross-over study. SUBJECTS AND METHODS: Thirty subjects of both genders (20 M/10 F), mean age 45.5+/-9.9 years (M+/-SD), BMI 26.6+/-2.2 kg/m(2), with plasma cholesterol >5.17 and <7.76 mmol/l and plasma triglycerides <3.45 mmol/l, participated in the study. The study was performed after a wash-out period of 1 month and a run-in period of 1 month to stabilize patients on a standard diet (CHO 50%, fat 30%, protein 20%, fibre 20 g/day) plus placebo (maltodextrine plus aspartame 15 g/day). At the end of run-in, subjects were randomly assigned to receive sc-FOS (Actilight) (10.6g/day) or placebo (maltodextrine plus aspartame 15 g/day) with tea and/or coffee for a duration of 2 months and thereafter switched to the other treatment for additional 2 months. Plasma glucose, total and lipoprotein (VLDL, LDL, HDL) cholesterol and triglyceride concentrations were measured in the fasting state at the end of run-in and of each treatment period. At the end of the two treatment periods, patients consumed a standard test meal (protein 15%, carbohydrate 34%, fat 51%, kJ 3988) 1h after the administration of 5.3g of sc-FOS or placebo; plasma glucose, insulin, free fatty acid (FFA) and triglyceride responses to the test meal were evaluated. RESULTS: No significant difference in fasting parameters was detected between the two treatments. After sc-FOS and placebo plasma cholesterol levels were, respectively, 6.47+/-0.70 and 6.44+/-0.78 mmol/l (n.s.) and plasma triglycerides were 1.53+/-0.71 and 1.56+/-0.53 mmol/l (n.s.). No significant differences were observed in cholesterol and triglyceride content of VLDL, LDL and HDL and in plasma Apo A1 levels; conversely, fasting plasma Lp(a) concentrations were significantly increased after sc-FOS (37+/-38 vs. 33+/-35 mg/dl; P<0.005). Postprandial responses of glucose, FFA and triglycerides were not significantly different between sc-FOS and placebo, while postprandial insulin response (incremental area) was significantly reduced after sc-FOS compared to placebo (14,490+/-7416 vs. 17,760+/-7710 pmol/l x 300 min; P<0.02). CONCLUSIONS: A moderate intake of sc-FOS has no major effects on lipid metabolism, both in the fasting and in the postprandial period, in individuals with mild hypercholesterolaemia. A small but significant increase of Lp(a) concentrations was observed with sc-FOS consumption together with a reduction of the postprandial insulin response; however, the clinical relevance of these small effects is unclear.

Vitamin K1 supplementation retards bone loss in postmenopausal women between 50 and 60 years of age.

Although several observational studies have demonstrated an association between vitamin K status and bone mineral density (BMD) in postmenopausal women, no placebo-controlled intervention trials of the effect of vitamin K1 supplementation on bone loss have been reported thus far. In the trial presented here we have investigated the potential complementary effect of vitamin K1 (1 mg/day) and a mineral + vitamin D supplement (8 microg/day) on postmenopausal bone loss. The design of our study was a randomized, double-blind, placebo-controlled intervention study; 181 healthy postmenopausal women between 50 and 60 years old were recruited, 155 of whom completed the study. During the 3-year treatment period, participants received a daily supplement containing either placebo, or calcium, magnesium, zinc, and vitamin D (MD group), or the same formulation with additional vitamin K1 (MDK group). The main outcome was the change in BMD of the femoral neck and lumbar spine after 3 years, as measured by DXA. The group receiving the supplement containing additional vitamin K1 showed reduced bone loss of the femoral neck: after 3 years the difference between the MDK and the placebo group was 1.7% (95% Cl: 0.35-3.44) and that between the MDK and MD group was 1.3% (95% Cl: 0.10-3.41). No significant differences were observed among the three groups with respect to change of BMD at the site of the lumbar spine. If co-administered with minerals and vitamin D, vitamin K1 may substantially contribute to reducing postmenopausal bone loss at the site of the femoral neck.

Delay in diagnosis of soft tissue sarcomas.

AIM: We reviewed 100 patients referred with soft tissue sarcoma between May 1999 to determine doctor- and patient-related delay. METHODS: Patient delay is defined as longer than one month from first symptoms till doctor's visit, doctor delay as longer than one month from first visit till definitive diagnosis. Sixty-eight patients had a multifactional delay. RESULTS: Forty-seven patients showed patient delay, with a median patient delay of 4 months, ranging from 2 to 240 months. The main reason for this delay is a painless mass that is mostly ignored. When pain is present, median patient delay is shorter.Twenty-seven patients experienced doctor delay, ranging from 2 to 79 months, with a median of 6 months. The most frequent reason was a misdiagnosis from the outset, on a clinical basis only, or due to a wrong diagnosis on ultrasound. Only two of these 27 patients had a biopsy, showing a benign tumour. High grade tumours are diagnosed earlier, 85% within 6 months. CONCLUSIONS: Delay in diagnosis of soft tissue sarcomas is still a problem requiring better patient and doctor education.

Nutritional aspects of short-chain fructooligosaccharides: natural occurrence, chemistry, physiology and health implications.

Short-chain fructooligosaccharides occur in a number of edible plants, such as chicory, onions, asparagus, wheat... They are a group of linear fructose oligomers with a degree of polymerisation ranging from n = 1 up to 5 (oligosaccharides). Short-chain fructooligosaccharides, to a large extent, escape digestion in the human upper intestine and reach the colon where they are totally fermented mostly to lactate, short chain fatty acids (acetate, propionate and butyrate), and gas, like dietary fibres. As a consequence of their fermentation, their caloric value is approximately 2 Kcal/g. A faecal bulking effect of fructooligosaccharides has been observed in humans. An important property of short-chain fructooligosaccharides is the stimulation of bifidobacterial growth specifically while suppressing the growth of potentially harmful species such as, for example, Clostridium perfringens in the colon. It is associated with a decrease in faecal pH, an increase in faecal or colonic organic acids, a decrease in the production of nitrogenous end products in urine and stools, a decrease in faecal bacterial enzymatic activities and a modification in faecal neutral sterols. The short-chain fructooligosaccharides enhance magnesium absorption in humans and have been shown, in animal models, to reduce colon tumour development by enhancing both colon butyrate concentrations and local immune system effectors.

Safety of soy-derived phosphatidylserine in elderly people.

Phosphatidylserine (PS) is a phospholipid which has been claimed to enhance neuronal membrane function, and can be derived from several sources. Earlier studies used brain cortex derived PS, of which the human tolerability of 300mg daily in 130 patients has been shown. The human tolerability of PS derived from soybean has not been reported, although it is widely sold as a nutritional supplement which may improve cognitive function in the elderly. We report the results of a study of the safety of two dosages of soy-phosphatidylserine (S-PS) in elderly. Subjects were 120 elderly of both sexes who fulfilled the more stringent criteria for age-associated memory impairment; some also fulfilled the criteria for age-associated cognitive decline. Subjects were allocated at random to one of the three treatment groups: placebo, 300 or 600 mg S-PS daily. Standard biochemical and hematological safety parameters, blood pressure, heart rate and adverse events were assessed at baseline, after 6 and 12 weeks of treatment. No significant differences were found in any of the outcome variables between the treatment groups after Bonferonni-Holme correction. In conclusion, soy derived PS is a safe nutritional supplement for older persons if taken up to a dosage of 200 mg three times daily.

The effects of rehydration on cycling performance after exercise-induced dehydration.

The effects of 7.6% carbohydrate-electrolyte solution (CES) and placebos (P) on rehydration (R) after exercise-induced dehydration and on a subsequent time-trial (TT) of cycling performance were studied. Thirteen male subjects exercised in a thermally-controlled environment (28 degrees C, 63% RH) until 3% of their body weight was lost. After exercise, the subjects moved to a neutral environment (22 degrees C) and rested for 30 minutes prior to a 2-hour R period. During R, subjects were fed CES or P to a maximum volume of 120% of previous body mass loss at 0, 30, and 60 minutes, in bolus-doses of 50%, 40% and 30% respectively. After R, subjects performed a 1-hour TT with no further fluid intake. % R with CES was significantly higher than with P (70 +/- 3% vs 60 +/- 5%; p < 0.01). During the TT, blood glucose dropped in the CES group but not in the P group. It was found that, despite a more effective R with CES, the performance results did not differ between groups (65.1 +/- 2.2 minutes and 65.2 +/- 2.3 minutes for CES and P respectively). It is suggested that an insulin-mediated rebound effect on CHO metabolism during TT, in which no further CHO was supplied, nullified the benefits of rehydration.

The effect of guar gum addition to a semisolid meal on appetite related to blood glucose, in dieting men.

OBJECTIVE: To investigate whether addition of modified guar gum (GG) to a low-energy semisolid meal might be effective on appetite by modifying the response of blood glucose and other blood parameters. DESIGN: Three intervention periods of 2 weeks each, separated by washout periods of 4 weeks. Randomized and cross-over design. SUBJECTS: Fifteen overweight male subjects (mean+/-s.d.; age, 44+/-9 y; body mass index, 28.6+/-1.8 kg/m(2)). INTERVENTION: Subjects consumed a low-energy diet divided over three times a day, consisting of a semisolid meal with (SSM+) or without (SSM) addition of 2.5 g GG, or a solid meal (SM) with the same energy content (947 kJ) and macronutrient composition, plus a dinner of the subject's own choice. At the end of each intervention, time and number of meal initiations, dynamics of blood glucose and other blood parameters, and appetite ratings such as hunger and satiety were determined in a time-blinded situation. RESULTS: The changes in blood glucose from meal initiation to blood glucose peak and from peak to nadir were smaller with SSM+ and SM compared to SSM. Satiety before the third meal was higher with SSM+ and SM compared to SSM (P<0.01). Meal pattern, general appetite and total energy intake were similar for all treatments. CONCLUSIONS: We conclude that, similar to SM, SSM+ resulted in a more moderate change in blood glucose compared to SSM and positively affected satiety before the third meal, while general appetite, total energy intake and meal pattern did not differ.

The effect of ad libitum ingestion of a caffeinated carbohydrate-electrolyte solution on urinary caffeine concentration after 4 hours of endurance exercise.

The purpose of the present study was to examine the effect of ad libitum ingestion of a carbohydrate-electrolyte solution (CES) with 150 mg x L (-1) caffeine (CAF) on urinary CAF concentration after 4 h of endurance exercise. Fifty-eight healthy and well-trained male subjects ingested ad libitum a 7 % CES with 150 mg x L (-1) CAF during 4 h cycling at 50 % of maximal work capacity. Total fluid consumption (mean +/- SE) was 2799 +/- 72 mL and CAF intake was 420 +/- 11 mg (5.7 +/- 0.2 mg x kg (-1) body weight). The post-exercise urinary CAF concentration (4.53 +/- 0.25 microg x mL (-1)) was below the doping level of the International Olympic Committee (12 microg x mL (-1)) in all subjects (range 1.20 - 10.84 microg x mL (-1)). A highly positive correlation was observed between CAF intake and post-exercise urinary CAF concentration (r = 0.68, p < 0.001). It is concluded that ad libitum ingestion of a CES with 150 mg x L (-1) CAF during 4 h cycling resulted in post-exercise urinary concentration below the doping level in all subjects.

Five-week intake of short-chain fructo-oligosaccharides increases intestinal absorption and status of magnesium in postmenopausal women.

Fermentable carbohydrates have been shown to be nondigestible by human enzymes in the small intestine but are fermented extensively in the large bowel to short-chain fatty acids (SCFAs), which can increase mineral absorption. It has been shown that feeding such carbohydrates including short-chain fructo-oligosaccharides (sc-FOSs) increases intestinal magnesium (Mg) absorption in animals, but their beneficial impact on Mg absorption in humans still remains to be established. Therefore, this work aimed to investigate the effect of moderate daily doses of sc-FOSs (10 g/day) on the intestinal absorption and status of Mg in postmenopausal women without hormone replacement therapy (HRT). Eleven healthy postmenopausal women aged 59 +/- 6 years (mean +/- SD) received for 5 weeks sc-FOS or sucrose (placebo) treatments according to a randomized, double-blind, crossover design separated by a washout period of at least 3 weeks. Subjects ingested 87.5 mg of stable isotope 25Mg together with a fecal marker. Subsequently, feces were collected for 5-7 days. An inductively coupled plasma mass spectrometer (ICP/MS) was used for 25Mg stable isotope measurements in feces, urine, and blood. Mg levels were assessed also at the beginning and at the end of each treatment in plasma, erythrocytes, and urine. These measurements allowed for the determination of net intestinal Mg absorption and Mg status. The results show that the addition of 10 g sc-FOS to the diet increased Mg absorption by 12.3%, from 30.2 +/- 5.0% (placebo treatment) to 33.9 +/- 7.2% (sc-FOS treatment; mean +/- SD; p < 0.02). This increase in intestinal Mg absorption was accompanied by an increase in plasma 25Mg level and led to a higher urinary 25Mg excretion. This is the first time that such an effect is shown in humans. The overall conclusion of this work is that the ingestion of moderate doses of sc-FOS did improve intestinal Mg absorption and status in postmenopausal women. Because of the important role of Mg in many cellular functions, such Mg absorption improvement may be particularly interesting when the dietary intake of Mg is limited.