Vitamin D status and parathyroid hormone relationship in adolescents and its association with bone health parameters: analysis of the Northern Ireland Young Heart's Project.

UNLABELLED: In girls, a plateau in parathyroid hormone (PTH) was observed at a 25-hydroxyvitamin D (25(OH)D) concentration of approximately 60 nmol/l. In boys, there was no plateau in PTH concentrations as 25(OH)D concentration increased. A 25(OH)D threshold of 60 nmol/l appears to have implications for bone health outcomes in both girls and boys. INTRODUCTION: Our objective was to investigate if there is a threshold 25(OH)D concentration where a plateau in PTH concentration is evident and to examine the impact of this relationship on bone mineral density (BMD) and bone turnover in a representative sample of adolescents. METHODS: We conducted a cross-sectional analysis among 1,015 Northern Irish adolescents aged 12 and 15 years. Serum 25(OH)D, PTH, osteocalcin, type 1 collagen cross-linked C-telopeptide (CTx), and BMD of the nondominant forearm and heel were measured. Nonlinear regression analysis was used to model the association between 25(OH)D and PTH. RESULTS: In girls, a plateau in PTH was observed at a 25(OH)D concentration of approximately 60 nmol/l (PTH = 47.146 + 370.314 x exp((-0.092 x 25(OH)D))) while no plateau in PTH was observed in boys (PTH = 42.144 + 56.366 x exp((-0.022 x 25(OH)D))). Subjects with 25(OH)D levels <60 nmol/l had significantly higher osteocalcin concentrations (P < 0.05) compared with those who had >or=60 nmol/l, while no significant (P > 0.05) differences were noted for CTx concentrations. In girls only, nondominant forearm BMD but not heel BMD was significantly higher (P = 0.046) in those with 25(OH)D concentrations >or= 60 nmol/l. CONCLUSIONS: Serum 25(OH)D levels above 60 nmol/l in Northern Irish adolescent girls prevent an increase in serum PTH levels and maintaining 25(OH)D >60 nmol/l in both girls and boys may lead to improved bone health outcomes.

Familial multiple coagulation factor deficiencies - chance associations and distinct clinical disorders.

The familial multiple coagulation factor deficiencies (FMCFDs) are a group of rare haemostatic disorders of genetic origin in which there is reduced plasma activity of more than one coagulation factor. FMCFDs may arise from co-incidental inheritance of separate coagulation factor deficiencies or from a single genetic or cytogenetic defect. All the FMCFDs present significant challenges in diagnosis and management yet there is little systematic evidence with which to guide clinical practice. This review summarizes the historical literature that describes the FMCFDs and introduces a refined classification of these disorders. The clinical and laboratory characteristics of the most common FMCFDs are considered in detail.

Habitual fish consumption does not prevent a decrease in LCPUFA status in pregnant women (the Seychelles Child Development Nutrition Study).

Information on the status of long-chain polyunsaturated fatty acids (LCPUFAs) in pregnancy and breast milk in very high fish-eating populations is limited. The aim of this study was to examine dietary intake and changes in fatty acid status in a population of pregnant women in the Republic of Seychelles. Serum docosahexaenoic acid (DHA) decreased significantly between 28-week gestation and delivery (n=196). DHA status did not correlate significantly with length of gestation and was not associated with self-reported fish intake, which was high at 527 g/week. In breast milk, the ratio of DHA to arachidonic acid (AA) was consistent with those observed in other high fish-eating populations. Overall the data suggest that high exposure to LCPUFAs from habitual fish consumption does not prevent the documented decrease in LCPUFA status in pregnancy that occurs as a result of foetal accretion in the third trimester of pregnancy.

Influence of habitual diet on antioxidant status: a study in a population of vegetarians and omnivores.

BACKGROUND: Antioxidant status can be used as a biomarker to assess chronic disease risk and diet can modulate antioxidant defence. OBJECTIVE: To examine effects of vegetarian diet and variations in the habitual intakes of foods and nutrients on blood antioxidants. SUBJECTS AND SETTING: Thirty-one vegetarians (including six vegans) and 58 omnivores, non-smokers, in Northern Ireland. DESIGN: A diet history method was used to assess habitual diet. Antioxidant vitamins, carotenoids, uric acid, zinc- and ferric-reducing ability of plasma (FRAP) were measured in fasting plasma and activities of glutathione peroxidase (GPX), superoxide dismutase (SOD) and glutathione S-transferase (GST) and level of reduced glutathione (GSH) were measured in erythrocytes. RESULTS: Vegetarians had approximately 15% higher levels of plasma carotenoids compared with omnivores, including lutein (P< or =0.05), alpha-cryptoxanthin P< or =0.05), lycopene (NS), alpha-carotene (NS) and beta-carotene (NS). The levels/activities of all other antioxidants measured were similar between vegetarians and omnivores. Total intake of fruits, vegetables and fruit juices was positively associated with plasma levels of several carotenoids and vitamin C. Intake of vegetables was positively associated with plasma lutein, alpha-cryptoxanthin, alpha-carotene and beta-carotene, whereas intake of fruits was positively associated with plasma beta-cryptoxanthin. Intake of tea and wine was positively associated with FRAP value, whereas intake of herbal tea associated positively with plasma vitamin C. Intakes of meat and fish were positively associated with plasma uric acid and FRAP value. CONCLUSIONS: The overall antioxidant status was similar between vegetarians and omnivores. Good correlations were found between intakes of carotenoids and their respective status in blood.

Effect of vitamin D supplementation on vitamin D status and bone turnover markers in young adults.

OBJECTIVE: To assess the vitamin D status of healthy young people living in Northern Ireland and the effect of vitamin D supplementation on vitamin D status and bone turnover. DESIGN: Double-blinded randomised controlled intervention study. SETTING: University of Ulster, Coleraine, Northern Ireland. SUBJECTS: In total, 30 apparently healthy students (15 male and 15 female subjects), aged 18-27 years, were recruited from the university, with 27 completing the intervention. INTERVENTIONS: Subjects were randomly assigned, to receive either 15 microg (600 IU) vitamin D(3) and 1,500 mg calcium/day (vitamin D group), or 1,500 mg calcium/day (control group) for 8 weeks between January and March. Vitamin D status, bone turnover markers, serum calcium and parathyroid hormone concentrations were measured at baseline and post intervention. RESULTS: At baseline, vitamin D status was low in both the vitamin D group (47.9 (s.d. 16.0)) and the control group (55.5 (s.d. 18.6) nmol/l 25(OH)D). Post intervention vitamin D status was significantly higher in the vitamin D-treated group (86.5 (s.d. 24.5)) compared to the control group (48.3 (s.d. 16.8) nmol/l) (P<0.0001). There was no significant effect of supplementation on bone turnover markers or PTH concentrations. CONCLUSIONS: This study suggests that young adults in Northern Ireland do not consume an adequate daily dietary intake of vitamin D to maintain plasma vitamin D concentrations in the wintertime. A daily supplement of 15 microg vitamin D(3) significantly increased vitamin D status in these individuals to levels of sufficiency. Achievement of an optimum vitamin D status among young adults may have future positive health implications.

Investigation of the medium-term effects of Olibratrade mark fat emulsion on food intake in non-obese subjects.

OBJECTIVE: To investigate the effect of Olibra fat emulsion on medium-term food intake and appetite in non-obese subjects. DESIGN: Double-blind, placebo-controlled, within-subject crossover. SETTING: University of Ulster, Coleraine. SUBJECTS: A total of 28 subjects (14 male, 14 female). INTERVENTIONS: Subjects were randomly assigned to receive either a 200 g portion of test (5 g of Olibra fat) or control (5 g milk fat) yoghurt for breakfast for 2 x 3 week 'study' phases, separated by a 3-week 'wash-out' phase. On days 1, 8 and 22 of the study phases, food intake 4 h post-consumption of the yoghurt was assessed by pre- and post-covert weighing at an ad libitum buffet-style test lunch. Throughout each of these study days, appetite was assessed using visual analogue scales (VAS) at regular intervals. For the remainder of the study days, and the following 24 h ('post-study days'), subjects reported their food intake using weighed dietary records. RESULTS: Consumption of the Olibra emulsion had no significant effect on mean energy, macronutrient or amounts of food consumed at the lunch 4 h post-consumption. Self-reported food intakes indicated that there was no significant effect of the emulsion on energy intakes for the remainder of each study day and post-study days. There was considerable individual variation in food intakes following consumption of the Olibra emulsion, with 46, 59 and 57% of subjects reducing their energy intakes at lunch on days 1, 8 and 22. There was no consistent effect of the emulsion on appetite ratings. CONCLUSIONS: In contrast to earlier studies, there was no evidence of a short- or medium-term effect of the Olibra emulsion on food intake or appetite. This could be owing to numerous confounding factors influencing eating behaviour and/or the different study design used in the present study.

It's good to talk: children's views on food and nutrition.

OBJECTIVE: To gain an insight into children's views about food and nutrition. DESIGN: Data were collected in focus group discussions; two focus group sessions were undertaken with each school group. SETTING: A total of 11 postprimary schools in Northern Ireland and England. SUBJECTS: In all, 106 children aged 11-12-y-old (n = 52 boys, n = 54 girls). RESULTS: Focus group transcripts were analysed using qualitative research methodology. Major barriers to healthy eating were taste, appearance of food, filling power, time/effort, cost, choice/availability, risk, rebellion, and body image/weight concerns. The main difference between sexes was in terms of motivating factors for eating well; girls tended to focus primarily on their appearance whereas boys appeared to be more influenced by sport. There was some mention of balance and variety within the focus group discussions, however, in practice, the children had a tendency to categorise foods as either 'good' or 'bad', 'healthy' or 'unhealthy'. CONCLUSIONS: This study has revealed a number of barriers to, and motivations for, healthy eating, which should be taken into account when planning nutrition intervention strategies aimed at children moving into adolescence. While it may be possible to immediately attempt to address some of the barriers identified in this study, for example, in nutrition education initiatives, other barriers (such as the lack of available, attractive and affordable healthy foods in the school canteen) will prove more difficult to tackle without changes at the policy level. Overall, it appears that health promotion specialists have a major challenge ahead in order to encourage this age group to view healthy eating as an attractive and achievable behaviour. SPONSORSHIP: Food Standards Agency, London, UK.

Carbonated soft drink consumption and bone mineral density in adolescence: the Northern Ireland Young Hearts project.

UNLABELLED: In an observational study of 1335 boys and girls aged 12 and 15 years, higher intakes of carbonated soft drinks (CSDs) were significantly associated with lower bone mineral density at the heel, but only in girls. Owing to the upward trend in CSD intake in adolescence, this finding may be of concern. INTRODUCTION: High consumption of carbonated soft drinks (CSD) during adolescence may reduce bone mineral accrual and increase fracture risk. The aim of this study was to examine the relationship between CSD consumption and bone mineral density (BMD) in a representative sample of adolescents. MATERIALS AND METHODS: This was a cross-sectional observational study in 36 postprimary schools in Northern Ireland. Participants included 591 boys and 744 girls either 12 or 15 years old. BMD was measured by DXA, and usual beverage consumption was assessed by the diet history method. Adjusted regression modeling was used to investigate the influence of CSD on BMD. RESULTS: A significant inverse relationship between total CSD intake and BMD was observed in girls at the dominant heel (beta, -0.099; 95% CI, -0.173 to -0.025). Non-cola consumption was inversely associated with dominant heel BMD in girls (beta, -0.121; 95% CI, -0.194 to -0.048), and diet drinks were also inversely associated with heel BMD in girls (beta, -0.087; 95% CI, -0.158 to -0.016). However, no consistent relationships were observed between CSD intake and BMD in boys. Cola consumption and nondiet drinks were not significantly related to BMD in either sex. CONCLUSION: CSD consumption seems to be inversely related to BMD at the dominant heel in girls. It is possible that the apparent association results from the displacement of more nutritious beverages from the diet. Although the inverse association observed between CSD consumption and BMD is modest and confined to girls, this finding may have important public health implications given the widespread use and current upward trend in CSD consumption in Western populations.

Relationship between physical activity and bone mineral status in young adults: the Northern Ireland Young Hearts Project.

Physical activity during the first three decades of life may increase peak bone mass and reduce future osteoporosis risk. The aim of this study was to determine the extent to which different components of physical activity may influence bone mineral status within a representative population sample of young men and women. Bone mineral density (BMD) and content (BMC) were determined at the lumbar spine and femoral neck in 242 men and 212 women, aged 20-25 years, by dual-energy X-ray absorptiometry. Physical activity was assessed by a self-report questionnaire designed to measure the frequency and duration of physical activity and its components (i.e., work, non-sports leisure, sports-related activities, and peak strain sports activities). Potential confounding factors such as height, weight, diet, and smoking habits were also assessed. In multivariate linear regression models, sports activity and peak strain sports activity undertaken by men were strongly associated with both lumbar spine BMD (beta = 0.35 [0.21, 0.49] and beta = 0.31 [0.17, 0.44], respectively) and BMC (beta = 0.33 [0.21, 0.45] and beta = 0.26 [0.14, 0.38], respectively) and femoral neck BMD (beta = 0.35 [0.21, 0.48] and beta = 0.27 [0.14, 0.40], respectively) and BMC (beta = 0.32 [0.19, 0.44] and beta = 0.29 [0.17, 0.41], respectively) (all p < 0.01), but work and non-sports leisure activities were not. In women, there were no associations between bone measurements and any component of physical activity. In models involving all subjects the gender/sports activity, but not the gender/peak strain, interaction term was statistically significant. Sports activity explained 10.4% of the observed variance in lumbar spine BMD in men, but <1% in women. These results demonstrate the importance of sports activities, especially those involving high peak strain, in determining peak bone status in young men. Failure to observe this association in women reflects their lower participation in such activities, but they may have the same capacity to benefit from these activities as men. Intervention studies are warranted to determine whether peak bone density in women can be improved by participating, during childhood and adolescence, in sports activities involving high peak strain.

Total homocysteine is not a determinant of arterial pulse wave velocity in young healthy adults.

AIMS: Hyperhomocysteinaemia has been associated with reduced pulse wave velocity (PWV) in patients with end-stage renal disease and in those with hypertension. The aim of this study was to examine the association between total homocysteine (tHcy) concentrations, the biochemical and genetic determinants of tHcy and PWV in healthy young adults. METHODS AND RESULTS: A total of 489 subjects aged 20-25 years participated. A fasting blood sample was taken and PWV measured using a non-invasive optical method. tHcy did not correlate with PWV, whether assessed at the aorto-iliac segment (P = 0.18), the aorto-radial segment (P = 0.39) or the aorto-dorsalis-pedis segment (P = 0.22). When tHcy was classified into normal (<15) and high (> or =15micromol/l), PWV did not differ between the two groups at any segment. PWV did not differ by MTHFR C677T or NOS3 G894T genotype, even when smoking and folate sub-groups were considered. Considering aortic PWV as a dependent variable, stepwise regression analysis showed that the only parameter entering the model for all segments was systolic blood pressure (aorto-iliac, P < 0.001; aorto-radial, P = 0.01; aorto-dorsalis-pedis, P = 0.001). Age, sex, COL1A1 genotype and triglycerides entered the model significantly for two of three segments. CONCLUSION: This study shows that arterial PWV is not associated with tHcy in a healthy young population.

Glutamine, exercise and immune function. Links and possible mechanisms.

Glutamine is the most abundant free amino acid in human muscle and plasma and is utilised at high rates by rapidly dividing cells, including leucocytes, to provide energy and optimal conditions for nucleotide biosynthesis. As such, it is considered to be essential for proper immune function. During various catabolic states including surgical trauma, infection, starvation and prolonged exercise, glutamine homeostasis is placed under stress. Falls in the plasma glutamine level (normal range 500 to 750 mumol/L after an overnight fast) have been reported following endurance events and prolonged exercise. These levels remain unchanged or temporarily elevated after short term, high intensity exercise. Plasma glutamine has also been reported to fall in patients with untreated diabetes mellitus, in diet-induced metabolic acidosis and in the recovery period following high intensity intermittent exercise. Common factors among all these stress states are rises in the plasma concentrations of cortisol and glucagon and an increased tissue requirement for glutamine for gluconeogenesis. It is suggested that increased gluconeogenesis and associated increases in hepatic, gut and renal glutamine uptake account for the depletion of plasma glutamine in catabolic stress states, including prolonged exercise. The short term effects of exercise on the plasma glutamine level may be cumulative, since heavy training has been shown to result in low plasma glutamine levels (< 500 mumol/L) requiring long periods of recovery. Furthermore, athletes experiencing discomfort from the overtraining syndrome exhibit lower resting levels of plasma glutamine than active healthy controls. Therefore, physical activity directly affects the availability of glutamine to the leucocytes and thus may influence immune function. The utility of plasma glutamine level as a marker of overtraining has recently been highlighted, but a consensus has not yet been reached concerning the best method of determining the level. Since injury, infection, nutritional status and acute exercise can all influence plasma glutamine level, these factors must be controlled and/or taken into consideration if plasma glutamine is to prove a useful marker of impending overtraining.

Nutritional aspects of immunosuppression in athletes.

The literature suggests that a heavy schedule of training and competition leads to immunosuppression in athletes, placing them at a greater risk of opportunistic infection. There are many factors which influence exercise-induced immunosuppression, and nutrition undoubtedly plays a critical role. Misinterpretation of published data and misleading media reports have lead many athletes to adopt an unbalanced dietary regimen in the belief that it holds the key to improved performance. Some sports have strict weight categories, whilst in others low body fat levels are considered to be necessary for optimal performance or seen as an aesthetic advantage. This leads some athletes to consume a diet extremely low in carbohydrate content which, whilst causing rapid weight loss, may have undesirable results which include placing the athlete at risk from several nutrient deficiencies. Complete avoidance of foods high in animal fat reduces the intake of protein and several fat-soluble vitamins. On the other hand, diets with a very high carbohydrate content are usually achieved at the expense of protein. In addition, anecdotal and media reports have often promoted the supposed performance benefits of certain vitamins and minerals, yet most athletes do not realise that micronutrient supplementation is only beneficial when correcting a deficiency, and to date there is little scientific evidence to substantiate claims that micronutrients act as an ergogenic aid. Moreover, excessive intakes of micronutrients can be toxic. Deficiencies or excesses of various dietary components can have a substantial impact on immune function and may further exacerbate the immunosuppression associated with heavy training loads. This review examines the role of nutrition in exercise-induced immunosuppression and the effect of both excessive and insufficient nutrient intake on immunocompetence. As much of the present literature concerning nutrition and immune function is based on studies with sedentary participants, the need for future research which directly investigates the relationship between exercise, training, immunity and nutrition is highlighted.

Energy expenditure by heart rate in children: an evaluation of calibration techniques.

PURPOSE: To evaluate the impact of applying seven calibration equations (CE) in the estimation of free-living total energy expenditure (TEE) over 2-3 d in seven boys (mean +/- SD age 9.4+/-0.4 yr) by the Flex heart rate (HR) method. METHODS: HR and oxygen consumption were measured simultaneously for eight activities (lying, sitting, standing, arm-reaching exercise, a stooping-and-twisting exercise, stepping, treadmill walking/running, and cycle ergometry) carried out in sequence. CE were derived from various combinations of activities. Flex HRs were identified for each CE. RESULTS: There were no significant differences in TEE estimates [range (mean +/- SD); 6.65+/-0.72 to 7.27+/-0.89 MJ x d(-1)] derived from any of the CE. Mean daytime HR ranged from 86+/-4 to 122+/-15 beats x min(-1), and 82-98% of recorded daytime HR was < or = 140 beats x min(-1). As a result, within-subject CV in TEE from each of the CE ranged from 2.2% to 8.9%. Mean between-subject Flex HR ranged from 94+/-8 to 111+/-8 beats x min(-1). No significant differences were observed in corresponding TEE estimates. However, mean activity energy expenditure (AEE) ranged from 2.10+/-1.18 MJ x d(-1) (based on Flex HR 111+/-8 beats-min(-1)) to 3.55+/-1.44 MJ x d(-1) (based on Flex HR 94+/-8 beats x min(-1); NS). The corresponding estimates of resting energy expenditure (REE) were 1.89+/-0.82 MJ x d(-1) (Flex HR 111+/-8 beats-min(-1)) and 1.05+/-0.60 MJ x d(-1) (Flex HR 94+/-8 beats x min(-1)). Only the differences between the minimum and maximum estimates of REE were significant (P < 0.05). CONCLUSIONS: Unduly lengthy and complex calibration procedures for the estimation of Flex HR TEE may not be justified in most cases, particularly in sedentary children.

Boron supplementation and activated factor VII in healthy men.

OBJECTIVE: The aim of the present study was to determine whether postprandial concentrations of the active component of serine protease coagulation factor VII (VIIa) were lowered by acute boron supplementation in vivo. DESIGN: An acute, randomized, placebo-controlled, double blind, cross-over study. SETTING: Free-living population. SUBJECTS: Fifteen apparently healthy men, aged 45-65 y. INTERVENTIONS: Subjects visited the centre on two occasions, with the study days separated by a minimum of 2 weeks. Following collection of a fasting blood sample, subjects received either placebo or acute bolus of 11.6 mg boron (given as 102.6 mg sodium tetraborate decahydrate) together with a standard fat-rich meal. Blood samples were obtained at 1, 2, 4 and 6 h after the administration of the test meal, during which time subjects were at liberty to consume deionized water only. Blood samples were assayed for concentrations of insulin, glucose, lipids and boron. Measurement of the concentration of activated factor VIIa and of factor VII antigen, and of the activity of coagulation factors VII, IX and X was also carried out. RESULTS: Plasma boron concentrations were significantly higher following consumption of the boron supplement compared with placebo (0.124+/-0.02 vs 0.008+/-0.01 mg/l; P< or =0.001). There was no significant effect of acute boron supplementation on plasma insulin and glucose concentration or on blood lipid or coagulation factor profile. Factor VIIa rose significantly following consumption of the high fat meal (1.05+/-0.07 vs 1.26+/-0.07; P< or =0.001), but this increase was not altered by boron supplementation. CONCLUSIONS: Results from this study suggest that acute boron supplementation (at 11.6 mg boron) does not alter the activity of factor VIIa following consumption of a high-fat meal. SPONSORSHIP: This work was funded by Borax Europe Ltd.

The effect of low-dose fish oil supplementation on serum growth factors in healthy humans.

OBJECTIVE: To examine the effect of low-dose fish oil supplementation on specific growth factors, purported to play a central role in lesion formation, and also on the total growth factor activity of serum, as assessed by the induction of DNA synthesis in cultured human arterial smooth muscle cells. DESIGN: Randomized placebo-controlled double-blind intervention study. SETTING: Free-living population. SUBJECTS: Sixty-three healthy volunteers, 37 males and 26 females. INTERVENTIONS: Four treatment regimes with subjects receiving 0, 0.3,0.6 or 0.9 g/day of n-3 PUFA for an 8 week period. Blood samples were taken at baseline and following the 8 week intervention. All samples were analysed in batch following completion of the study. RESULTS: Consumption of fish oil had no effect on serum platelet-derived growth factor (PDGF), or transforming growth factor beta (TGFbeta) concentration. Furthermore, fish oil supplementation did not alter the total growth factor activity of serum. CONCLUSIONS: Results indicate that low-dose fish oil supplementation, equivalent to about two portions of fatty fish per week and providing less than 1 g n-3 PUFA/day, does not alter the levels of the major serum growth factors and does not modify total serum growth factor activity in healthy human volunteers. SPONSORSHIP: European Union shared cost project (FAIR-CT-95-0085).

Frequency of fruit and vegetable consumption and blood antioxidants in the Caerphilly cohort of older men.

OBJECTIVE: To assess the number of portions of fruit and vegetables consumed daily by a large representative sample of older men, and to determine how blood antioxidant (vitamins E, A and carotenoids) concentrations vary with fruit and vegetable consumption. DESIGN: Cross-sectional study of free-living men. SUBJECTS: Men aged 55-69 y (dietary data, n=1957; blood data, n=1874) participating in Phase III (1989-1993) of the Caerphilly and Speedwell Collaborative Heart Disease Studies. METHODS: Dietary data were obtained by semi-quantitative food-frequency questionnaire and blood samples were analysed for antioxidant vitamins. Men were subdivided into groups on the basis of portions per day of fruit and vegetables. Within these sub-groups, mean and 95% ranges of intakes and of blood antioxidant levels were obtained. Log transformations were performed where appropriate. RESULTS: Only 4.3% of the men met the recommended target of five portions, while 33.3% of the men consumed one or fewer portions of fruit and vegetables per day. Those men who consumed the poorest diets with respect to fruit and vegetable intakes were more likely to be from lower socio-economic classes, drink more alcohol and be current smokers. Fruit and vegetable intake reflected plasma concentrations of antioxidants, which showed a dose-response relationship to frequency of consumption. CONCLUSIONS: Older men in the UK consume much less fruit and vegetables than current recommendations. Major difficulties are likely to be encountered in trying to meet a dietary target that is clearly much higher than the fruit and vegetable consumption of large sections of the older population in the UK. SPONSORSHIP: This work was supported by the Medical Research Council.

An evaluation of the sensitivity and specificity of energy expenditure measured by heart rate and the Goldberg cut-off for energy intake: basal metabolic rate for identifying mis-reporting of energy intake by adults and children: a retrospective analysis.

OBJECTIVE: To identify adults and children as under- (UR), acceptable (AR), or over-reporters (OR) of energy intake (EI) using energy expenditure measured by doubly labelled water (DLW) (EE(DLW)), and to use this as a reference to determine the sensitivity and specificity of (i) EE measured by heart rate (EE(HR)), and (ii) the Goldberg cut-off technique for classifying subjects into the same categories. DESIGN: Retrospective analysis of a dataset comprising concurrent measurements of EE(DLW), EE(HR), basal metabolic rate (BMR), and EI by weighed record (EI(WR)) on 14 adults and 36 children. EI by diet history (EI(DH)) was also measured in the children only. EI(WR):EE(DLW) provided the reference definition of subjects as UR, AR or OR. Three strategies for classifying mis-reporters based on EE(HR) and Goldberg cut-offs were then explored. Sensitivity and specificity were calculated respectively as the proportion of UR and non-UR correctly identified. RESULTS: Approximately 80% of all subjects were AR. For EI(WR) and EI(DH) respectively, the sensitivity of EE(HR) was 0.50 and 1.00, and specificity was 0.98 and 1.00. Although designating subjects as having low, medium or high activity levels (EE(HR):BMR(meas)) and calculating cut-offs based on appropriate WHO physical activity level PALs did not change sensitivity, specificity dropped to 0.98 (EI(WR)) and 0.97 (EI(DH)). Cut-offs based on a PAL of 1.55 reduced sensitivity to 0.33 (EI(WR)) and 0.00 (EI(DH)), but specificity remained unchanged. The sensitivity of all cut-offs based on physical activity level (PALs) for EI(WR) was 0.50 (adults) and 0.25 (children). CONCLUSIONS: If the precision of EE(HR) was improved, it may be useful for identifying mis-reporters of EI.

Prolonged suppression of the innate immune system in the horse following an 80 km endurance race.

REASONS FOR PERFORMING STUDY: An increased susceptibility to bacterial and viral infections of the respiratory tract, which results in a loss of performance, has been reported in racehorses. Much research has focused on the influence of high-intensity exercise of a short duration on immune system function in horses, but scant attention has been given to prolonged endurance exercise as an immune modulator. OBJECTIVES: The objective of this study was to evaluate the effect of an 80 km endurance race on the monocyte and neutrophil oxidative burst, serum cortisol, glutamine and plasma glucose concentrations in 8 endurance-trained horses (mean +/- s.d. age 9.4 +/- 2.2 years). METHODS: Blood samples were drawn from the horses prior to and following an 80 km ride. RESULTS: Mean time for completion of the 80 km race was 306 +/- 40 mins. Immediately post race mean serum cortisol concentration, blood monocyte and neutrophil counts were higher and blood lymphocyte counts and plasma glucose concentration were lower compared with prerace values (P < 0.05). Neutrophil and monocyte oxidative burst activity decreased following the race and had not regained prerace values after 3 days of rest (P < 0.05). CONCLUSIONS: The present study indicates that long duration exercise in horses has a negative impact on the function of the innate immune system that lasts several days post race. Precise mechanisms instigating the fall in innate immune system function are unclear and multifactorial, but may be attributed, at least in part, to a high serum cortisol response during very prolonged exercise. POTENTIAL CLINICAL RELEVANCE: A prolonged bout of exercise results in a long-term suppression of the innate immune system function in horses which may, in part, account for the observed increase of infectious episodes in horses during training.

Hematological recovery in male ultramarathon runners: the effect of variations in training load and running time.

AIM: Haematological response to the 2001 downhill Comrades Marathon was compared in high (>120 km/w in training; 3 weeks of pre-race taper) and low (<80 km/w in training; 2 weeks of pre-race taper) training status groups. METHODS: Full blood counts, differential lymphocyte counts (CD3, CD4, CD8, CD19, CD56), serum cortisol, C-reactive protein (CRP) and creatine kinase (CK) were measured in blood samples donated 21 hours before and 16 hours after a 90 km ultramarathon. RESULTS: Despite significantly faster mean race finishing time (8.03 h vs 10.53 h; p<0.001) and greater percentage incidence (55.6% vs 40%) of post-race upper respiratory tract infection (URTI) in the highly trained group, these faster runners did not show evidence of a slower post-race recovery in terms of total leukocyte, neutrophil, total or differential lymphocyte counts (p>0.05). CRP concentrations were, however, markedly higher in the slower, less trained group (65.3+/-10.7 vs 38.3+/-5.9; p<0.01). CONCLUSIONS: Despite greater systemic evidence of post-race muscle inflammation and an acute phase response in the slower runners in a downhill ultramarathon race, the haematological recovery of well trained runners who undergo a 3-week taper period prior to the ultramarathon is not different to that in less trained runners who spend almost 3 hours longer on the road. The higher prevalence of post-race URTI symptoms in the fast, well trained group does not appear to be related to lymphocyte recovery in peripheral blood.

Therapeutic potential of cannabinoid medicines.

Cannabis was extensively used as a medicine throughout the developed world in the nineteenth century but went into decline early in the twentieth century ahead of its emergence as the most widely used illicit recreational drug later that century. Recent advances in cannabinoid pharmacology alongside the discovery of the endocannabinoid system (ECS) have re-ignited interest in cannabis-based medicines. The ECS has emerged as an important physiological system and plausible target for new medicines. Its receptors and endogenous ligands play a vital modulatory role in diverse functions including immune response, food intake, cognition, emotion, perception, behavioural reinforcement, motor co-ordination, body temperature, wake/sleep cycle, bone formation and resorption, and various aspects of hormonal control. In disease it may act as part of the physiological response or as a component of the underlying pathology. In the forefront of clinical research are the cannabinoids delta-9-tetrahydrocannabinol and cannabidiol, and their contrasting pharmacology will be briefly outlined. The therapeutic potential and possible risks of drugs that inhibit the ECS will also be considered. This paper will then go on to review clinical research exploring the potential of cannabinoid medicines in the following indications: symptomatic relief in multiple sclerosis, chronic neuropathic pain, intractable nausea and vomiting, loss of appetite and weight in the context of cancer or AIDS, psychosis, epilepsy, addiction, and metabolic disorders.