Published Article / Objective: To determine the relationship between body mass index (BMI), energy intake and levels of physical activity of HIV negative and HIV positive women. Design: Cross sectional study. Methodology: A random sample of 500 pre-menopausal women within the two age group categories of 25-34 and 35-44 years was selected. Data on physical activity was obtained using an adapted Baecke questionnaire and categorized into low, medium, and high levels of physical activity. Weight and height were used to calculate BMI. Dietary intake was determined by means of a standardized food frequency questionnaire. Results: Sixty-one percent of younger women and 38% of older women were HIV infected. The vast majority of women (91%) had low levels of physical activity, while only 9% of the sample had physical activity levels that fell within the normal to high category. More than 50% of respondents were either overweight or obese (BMI above 25 kg/m2). BMI of HIV positive younger women was, however, significantly lower than that of HIV negative women. Median energy intakes were high (more than 10 000 kJ) for both HIV positive and HIV negative women. Conclusions: Reverting to a more traditional lifestyle, including diet and physical activity, could assist in addressing unfavorable BMI parameters of these women and improve health status and quality of life of HIV infected women.

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4 pp. / Healthy bone growth and maintenance requires adequate calcium intake. You can meet your calcium needs from foods, beverages, and if necessary, supplements. This publication contains the calorie and calcium content of some foods from each group of the Food Guide Pyramid which includes bread, cereal, rice, & pasta group; vegetable group; fruit group; milk, yogurt, & cheese group; meat, poultry, fish, dry beans, eggs, & nuts group; and fats, oils & sweets.

Background: While the provision of adequate nutrition support in critically ill patients has been shown to have an impact on short-term clinical outcomes, relatively little is known about subsequent long-term outcomes. We aimed to examine the association between nutritional adequacy and long-term outcomes including survival and health-related quality of life (HRQoL) in critically ill patients requiring prolonged mechanical ventilation. Methods: The study was conducted as a retrospective cohort study on data collected prospectively in the context of a multicenter randomized controlled trial (RCT) in critically ill patients. Randomized patients who stayed in the intensive care unit (ICU) and were mechanically ventilated for >8 days were eligible for the study, but only six-month survivors were considered for the assessment of HRQoL. Nutritional adequacy was obtained from the average proportion of prescribed calories received during the first eight days of mechanical ventilation in the ICU. Survival status and HRQoL as assessed using Short-Form 36 Health Survey (SF-36) were obtained prospectively as part of the RCT protocol at three-months and six-months post ICU admission. Results: Of the 1223 patients enrolled in the randomized controlled trial, 475 met the inclusion criteria for this study. At six-month follow-up, 302 of the 475 patients were alive. Among critically ill patients with >8 days of mechanical ventilation in the ICU, survival time in those who received low nutritional adequacy was significantly shorter than for those who received high nutritional adequacy after adjusting for important covariates. Among six-month survivors, clinically meaningful and statistical significant associations between increase in scores of Physical Functioning (PF) and Role Physical domains (RP) of the SF-36 and 25% increase in nutritional adequacy were observed at three-months follow-up. No significant associations were observed at six-months. Conclusions: Our findings suggest that nutritional adequacy received as early as the first week in the ICU seems beneficial to longer survival time and faster physical recovery post ICU discharge in critically ill patients requiring prolonged mechanical ventilation in the ICU. Well-designed randomized controlled trials are needed to provide stronger assessment of the causal impact of nutrition therapy on long-term outcomes. / Thesis (Master, Community Health & Epidemiology) -- Queen's University, 2013-09-28 21:31:40.064

Gut hormones are implicated in the regulation of energy balance. The studies in this thesis have examined the effects exercise on gut hormones (acylated ghrelin and peptide YY3-36), appetite and food intake, over extended durations. Sixty-nine young, healthy, predominantly Caucasian males were recruited to six studies. The age, height and body mass of the participants were: 22.4 ± 0.3 y, 1.80 ± 0.1 m, 76.2 ± 1.0 kg (mean ± SEM). In study one, 90 min of resistance exercise did not influence appetite or energy intake over 24 h of assessment, yet stimulated a latent preference for carbohydrate rich foods. Study two demonstrated that appetite was suppressed during 60 min of swimming but was elevated after consuming a post-exercise meal. Plasma acylated ghrelin was suppressed during swimming but was unaltered after. Energy/macronutrient intake remained unchanged. In study three, 60 min of brisk walking (45 ± 2% of max) did not influence appetite, energy/macronutrient intake or plasma concentrations of acylated ghrelin during an eight hour observation period. Study four showed that 90 min of treadmill running (69 ± 1% of max) transiently suppressed appetite and acylated ghrelin but did not influence these variables, or energy/macronutrient intake within 22.5 h after exercise. The findings of study five suggest that the suppression and subsequent rebound in plasma acylated ghrelin after exercise may be related to a delayed voluntary decision to eat after. Finally, study six showed that appetite, food intake and circulating concentrations of acylated ghrelin and peptide YY3-36 are responsive to acute deficits in energy induced by food restriction but are not sensitive to equivalent energy deficits induced by exercise. This thesis has shown that exercise transiently alters circulating levels of acylated ghrelin and peptide YY3-36 in directions expected to inhibit appetite however no changes are seen after exercise. Conversely, food restriction elicits marked compensatory changes in circulating acylated ghrelin and peptide YY3-36. This thesis also demonstrates that resistance exercise, brisk walking and running do not stimulate appetite or energy intake over defined periods, even when the energy expenditure elicited is high. Swimming appears to increase appetite in the latter hours after exercise.

The role of gut hormones in the regulation of appetite and food intake is well established. The studies presented within this thesis have examined the effects of exercise and different environmental conditions on gut hormones (acylated ghrelin and total peptide YY), appetite and food intake. Forty-two young (mean ± SEM; 22.6 ± 0.4 y), healthy and generally lean (body mass index 23.7 ± 0.3 kg m2) males were recruited into four studies. In study one, 60 minutes of high intensity (70 % of O2 max) running and cycling exercise suppressed concentrations of the appetite-stimulating hormone acylated ghrelin to a similar extent. Study two revealed that after 60 minutes running in the heat (30 °C), hunger is lower in the pre-prandial period, and energy intake lower over the 7 h trial duration compared with a similar trial conducted in temperate (20 °C) conditions. Acylated ghrelin was suppressed during running in the temperate and hot environment but this did not appear to mediate the lower energy intake observed during the hot trial. In study three, energy intake tended to be higher after 60 minutes running in a cool environment (10 °C) compared with a temperate (20 °C) environment. During and shortly after running in the cold, perceived ratings of fullness and satisfaction were lower. Acylated ghrelin concentrations appeared to be suppressed to a lesser extent during running in the cold which could mediate the elevated energy intake observed at the first meal. However, energy intake was also higher at the second meal in the cold trial when acylated ghrelin concentrations were higher in the temperate trial. Study four showed that energy intake and acylated ghrelin concentrations were lower, and total PYY tended to be lower, in normobaric hypoxia suggesting a possible role for acylated ghrelin, but not PYY, in mediating the decrease in energy intake observed in hypoxia. This thesis confirms that exercise transiently suppresses acylated ghrelin concentrations regardless of the environmental conditions (temperature and altitude) exercise is performed in. The findings support anecdotal reports that appetite and energy intake are suppressed in the heat and stimulated in the cold. These responses may be partly mediated by acylated ghrelin immediately after running but other mechanisms are likely involved thereafter. Acute hypoxic exposure suppresses acylated ghrelin concentrations; an observation which may explain the decreased energy intake in hypoxia.

Vitamin D is derived through the action of solar ultraviolet B radiation on skin and from a limited number of natural food sources, fortified foods and supplements. It is well known that vitamin D plays an active role for calcium and phosphorus absorption but there is also growing evidence of an association between vitamin D insufficiency and various chronic diseases. Middle Eastern populations are known to be at risk of vitamin D deficiency due to a diet low in vitamin D and low sunshine exposure. Obesity is also a risk factor since vitamin D is sequestered in body fat. This thesis examined dietary intake of vitamin D, obesity and other risk factors for deficiency in Middle Eastern people in the UK. A questionnaire based survey was undertaken with 242 Middle Eastern respondents. A total of 85% of the sample was estimated to have a vitamin D intake <5 µg/d. Other risk factors for vitamin D insufficiency included covering skin from sunlight (84% females); low use of supplements (18.5%) and being overweight or obese (49% males and 44% females). Vitamin D intake was lowest in those with primary (1.8 µg/d) and secondary school (2.1 µg/d) education compared to higher education (3.6 µg/d). The survey was followed by dietary assessment of 28 Iraqi adults using repeat 24 hour recalls. The results concurred with the survey: mean intake of vitamin D was (3.2±4.4 µg/d) and 78.5% were overweight or obese. Finally, overweight participants were recruited to observe the effect of fat loss on vitamin D status. Serum 25(OH)D concentrations was measured in Middle Eastern (n=12) and Caucasian adults (n=24). Firstly seasonal changes were observed between October and January (with no weight loss). Then participants were advised on weight reduction to observe the effect of fat loss on serum 25(OH)D. Vitamin D deficiency (<25 nmol/l) was observed in 67% of the Middle Eastern group in October increasing to 92% in January. Of the 36 participants, only 17 lost ≥1kg of fat mass between January and April. No difference was found in serum 25(OH)D between those that lost fat mass and those that did not, and no correlation was found between the amount of fat lost and change in 25(OH)D. In the total sample, there was a negative association between serum 25(OH)D and waist circumference and waist-hip ratio, but no correlation was found between 25(OH)D and fat mass, thus indicating a relationship with visceral fat stores rather than total fat mass.

Glucose is the primary fuel for the brain and also important for exercising muscle. The purpose of the thesis was to investigate the effects of the glycaemic index (GI) of mixed meals on appetite, cognitive performances and metabolic responses during intermittent exercise in recreationally active adults. Study one investigated whether a low GI (LGI) breakfast (GI = 42.5) could suppress appetite and reduce energy intake (EI) of 12 recreationally active females (28.2 ± 8.0 years) more than a high GI (HGI) breakfast (GI = 73.5). Area under the curve of the appetite score (AS AUC) following LGI breakfast was significantly greater than the HGI trial during the 60-min postprandial (pp) period (2568 ± 1027 vs. 2198 ± 821 mm∙min, p = 0.025). The HGI breakfast facilitated a stronger appetite suppressing effect up to eight hours post breakfast than the LGI trial (18834 ± 3906 vs. 21278 ± 3610 mm∙min, p = 0.028). The EI on the LGI trial day was significantly higher than on the pre-trial day (2,215 ± 576 vs. 1,748 ± 464 kcal, corrected p = 0.008). Fourteen recreationally active males (34.5 ± 8.9 years) in study two consumed the LGI (GI = 41.3) and HGI (GI = 74.3) breakfasts in the laboratory and then prescribed LGI and HGI meals in the free living environment. In line with study one, the AS AUC was significantly smaller following HGI than LGI breakfast over the 60-min pp period (2,989 ± 1,390 vs. 3,758 ± 1,290 mm∙min, p = 0.027). The HGI meals (GI = 76.9) suppressed appetite more than the LGI meals (GI = 39.6) over 12 hours on the trial day (35,454 ± 9,730 vs. 41,244 ± 8,829 mm∙min, p = 0.009) although energy balance was not different between trials. Study three investigated whether following a LGI breakfast (GI = 42.2) providing 1 g CHO kg-1 BM could result in a better vigilance and attention than a HGI breakfast (GI = 72.4), and reduced lunch EI in 16 recreationally active males (24.4 ± 3.6 years). A significant trial x time effect in the interference time of the Stroop Colour Word Task (SCWT) (p = 0.039) showed that the LGI breakfast maintained the attentional performance up to 90-min pp. Both high pre-task glucose concentration ([Glucose]) at 15-min pp and low pre-task [Glucose] at 105-min pp in the HGI trial were associated with unfavourable outcomes in vigilance in the Rapid Information Processing Task (RIPT). The LGI pre-task [Glucose] returning back to fasting level at 60-min pp was associated positively with the response time. The pre-lunch AS was a significant predictor of the lunch EI per fat free mass which explained 21% and 26% of variance in the LGI and HGI trials respectively. No significant difference was found in the ad libitum lunch EI between trials. Sixteen recreationally active males (27.8 ± 7.7 years) in study four consumed a LGI (GI = 42) and a HGI breakfast (GI = 72.8) providing 1.2 g CHO kg-1 BM consumed 60 minutes prior to intermittent running on two separate mornings. Better attentional performance at 150-min pp was found following LGI than HGI breakfast. The significant trial x time interaction in the SCWT (p = 0.045) showed the shortest interference time performed after the last exercise session in the LGI trial. The amounts of CHO and fat being oxidized were comparable between trials during three sessions of 16-min intermittent running with an average intensity of 65% V̇O2max. In conclusion, the pre-meal appetite sensation is more predictive of the subsequent meal EI than the pre-meal [Glucose]. The meal strategy for weight management in recreationally active adults may focus on greater appetite suppression by selecting HGI foods whilst maintaining healthy eating guidelines. Recreationally active males performing sports requiring high levels of vigilance and selective attention with low physical activity levels can benefit up to 60–90 min pp from the LGI breakfast. Their attentional performance can benefit from the LGI breakfast with moderate to high intermittent intensities in the late exercise period at 150–min pp. Recreationally active adults should consider the timing of meal consumption in relation to performing intermittent exercise, in order to maximize the advantages from the LGI or HGI breakfasts for cognitive performance or appetite suppression. They may be more liberal in pre-exercise food choices if substrate oxidation during intermittent running is only of their concern.

Current physical activity recommendations are being met by less than 21 % of children between 5-15 y. Recent Government initiatives are aiming to increase children’s participation in exercise. However, the effects on an imposed bout of exercise-induced energy expenditure (EE) on energy intake (EI) and appetite (hunger, fullness and prospective consumption) in normal weight children have received a limited research focus to date. Therefore, this thesis aimed to investigate how an imposed bout of exercise-induced energy expenditure (EE) on energy intake (EI) and appetite in normal weight children The first study investigated whether 17 habitually active girls were able to accurately increase their EI to match the EE following 60 min moderate intensity walking exercise. On average 17% of the EE was compensated for by an increase in EI. However, the ranged for EI change was -160% to +166% indicating large individual responses. The second study investigated whether 30 min of maximal sprint intermittent sprint cycling exercise would significantly alter EI or appetite in 13 boys and 13 girls. In the boys, hunger and prospective consumption were suppressed whilst fullness increased immediately following the exercise, whilst EI was significantly increased in response to the exercise condition. No significant changes to appetite or EI were observed in the girls. The third study investigated whether a mid-morning snack, moderate intensity cycling exercise (energy matched to snack) or both would alter EI or appetite in 20 boys and 18 girls. Irrespective of sex, hunger and prospective consumption were suppressed whilst fullness increased following the mid-morning snack, however this change in appetite did not alter EI as no significant differences were found between conditions. The fourth study investigated whether 99 recreational sports players (males/females, adults/children) were able to conceptualise their EE following 1 h habitual training into quantifiable amounts of food (chocolate) or drink (sports drink). Only 36 % of the EE from the exercise was met by the estimated amounts of food or drink. Age, sex nor sports participation significantly altered the participants’ accuracy of estimation. The fifth study investigated whether sex or dietary restraint impacted brain activation responses to visual food stimuli in 15 boys and 14 girls between a fed and fasted condition. Significant differences in brain activation were found between conditions, sexes and dietary restraint, potentially suggesting the differences observed in the previous experimental studies could be attributed to neurological alterations between participants. In conclusion, the findings presented demonstrate the changes in EI between young adolescents in response to an imposed bout of exercise are extremely variable. Whilst eating behaviours failed to correspond to the EI differences observed between participants, potentially brain activation differences may be responsible. The sex of the participant is more likely to impact EI and appetite following maximal sprint intensity exercise, more so than a bout of moderate intensity exercise. Future research should focus on determining what underpins the variable change in EI between participants following a bout of exercise.

While obesity is a world leading health problem, the most efficient treatment option for severely obese patients is Roux-Y gastric bypass (RYGB) surgery. However, there are large inter-individual differences in weight loss after RYGB surgery. The reasons for this are not yet elucidated and the role of genetics in weight loss-regulation is still not fully understood. The main aim for this thesis was to investigate the effects of common obesity-associated genetic variants and their effect on weight loss and food intake. We examined if the weight loss two years following RYGB surgery depends on the  FTO genotype, as well as pre-surgery vitamin D status. For FTO AA-carriers, the surgery resulted in a 3% per-allele increased excess BMI loss (EBMIL; P=0.02). When split by vitamin D baseline status, the EBMIL of vitamin D deficient patients carrying AA exceeded that of vitamin D deficient patients carrying TT by 14% (P=0.03). No such genotypic differences were found in patients without pre-surgery vitamin D deficiency. As the influence of individual single nucleotide polymorphisms may be small, we identified a novel method to combine SNPs into a genetic risk score (GRS). Using the random forest model, SNPs with high impact on weight loss after RYGB surgery were filtered out. An up to 11% lower EBMIL with higher risk score was estimated for the GRS model (p=0.026) composed of seven BMI-associated SNPs (closest genes: MC4R, TMEM160, PTBP2, NUDT3, TFAP2B, ZNF608 and MAP2K5). Pre-surgical hunger feelings were found to be associated with EBMIL and the SNP rs4846567. Before surgery, patients filled out the Three Factor Eating Questionnaire and were genotyped for known BMI and waist-hip ratio (WHR) associated SNPs. Patients with the lowest hunger scores had up to 32% greater EBMIL compared to the highest scoring patients (P=0.002). TT-allele carriers of rs4846567 showed a 58% lower hunger feelings. TT- carriers also showed a 51% decrease in disinhibition, but no significant impact on cognitive restraint was observed. Due to the association of eating behaviour and weight loss, acute effects on DNA methylation in response to a food intake intervention of a standardized meal were also investigated. After food intake, 1832 CpG sites were differentially methylated compared to the baseline after multiple testing correction. When adjusted for white blood cell fractions, 541 CpG sites remained. This may be interpreted as that the immune system is playing an active role in the response to food intake and highlights the dynamic nature of DNA-methylation. These findings will contribute to a better care for morbidly obese patients. Post-surgical treatment may be optimized so that patients with a less favourable genetic profile may receive additional support for weight loss and weight management. This may be considered as a step in the transition towards personalized medicine.