Abstract available in the Current Developments in Nutrition.

The purpose of this study was to investigate if a low mixed carbohydrate plus moderate protein supplement, provided during endurance exercise, would improve time to exhaustion in comparison to a traditional 6% carbohydrate supplement in female athletes exercising at or below their ventilatory threshold. Fourteen (n = 14) trained female cyclists and triathletes cycled on two separate occasions for three hours at intensities varying between 45% - 70% VO₂max, followed by a ride to exhaustion at an intensity approximating the individual's VT (average 75.06% VO₂max). Supplements (275ml) were provided every 20 min during exercise and were composed of a 3% carbohydrate mixture + 1.2% protein (CHO+PRO) or a 6% carbohydrate-only (CHO). The CHO+PRO treatment contained a mixture of dextrose, maltodextrin, fructose, and whey protein isolate. The CHO treatment was composed of dextrose only. Time to exhaustion (TTE) was significantly greater with CHO+PRO in comparison to CHO (49.94 ± 7.01 vs 42.36 ± 6.21 min, respectively, p < 0.05). Blood glucose was signifcantly lower during the CHO+PRO (4.07 ± 0.12 mmol x L⁻¹) trial compared to CHO (4.47 ± 0.12 mmol x L⁻¹), with treatment x time interactions occurring from 118 minutes of exercise until exhaustion (p < 0.05). Heart rate was significantly lowered in the CHO+PRO treatment during exercise as compared to CHO (p < 0.05). There were no significant differences for other blood measures, ratings of perceived exertion or carbohydrate and fat oxidation between trials. Results from the present study suggest that the addition of a moderate amount of protein to a low mixed carbohydrate supplement improves endurance performance in females above that of a traditional 6% carbohydrate supplement. Improvement in performance occurred despite CHO+PRO containing a lower carbohydrate and caloric content. It is likely the greater performance seen with CHO+PRO was a result of the carbohydrate protein combination and the use of a mixture of carbohydrate sources. / text

Acute respiratory infections (ARI) are a major global cause of morbidity and mortality. Vitamin D deficiency has been reported to associate with susceptibility to ARI and with greater severity and poorer control of asthma and chronic obstructive pulmonary disease (COPD). Clinical trials of vitamin D for the prevention of ARI have yielded heterogeneous results, with some showing protection and others not. This may reflect variation in the frequency of genetic variants influencing response to vitamin D supplementation in different populations. The impact that genetic variation in the vitamin D pathway has on vitamin D status, disease phenotype and response to vitamin D supplementation in prevention of ARI has not been comprehensively investigated. Methods: I conducted: 1. A systematic review and meta-analysis of clinical studies which have investigated vitamin D as a potential therapy for ARI; 2. Three cross-sectional studies (in n=297 adult asthma patients, n=278 COPD patients, and n=272 older adults) to investigate potential environmental determinants (lifestyle and anthropometric) and genetic determinants (35 single nucleotide polymorphisms [SNP] in 11 vitamin D related genes) of serum 25-hydroxyvitamin D concentration (25[OH]D) and clinical phenotype; 3. Three prospective studies investigating the influence of genetic variation in the vitamin D pathway on a) susceptibility to ARI (main effects analysis) and b) efficacy of vitamin D supplementation for the prevention of ARI (interaction analysis). Results: My systematic review identified consistent reports of an inverse association between vitamin D status and risk of ARI in observational studies, and heterogeneous reports from clinical trials. My cross-sectional studies identified a range of classical environmental factors which predict vitamin D status in the three study populations, but did not identify any genetic variants in the vitamin D pathway that associate with vitamin D status. I identified an association between vitamin D deficiency and decreased lung function in COPD patients, but no associations between vitamin D deficiency and asthma phenotype. Finally, my analysis identified a haplotype of 5 single nucleotide polymorphisms in the vitamin D receptor (VDR) gene which significantly modify the effect of vitamin D supplementation on risk of upper respiratory infection in COPD patients. Conclusions: I identified environmental determinants that predict 25(OH)D concentrations in all three study populations, but only found an association between vitamin D deficiency and disease severity in COPD patients. Furthermore, I identified a haplotype in VDR which modifies the effect of vitamin D supplementation in COPD patients to result in a significantly reduced risk of ARI.

This diploma thesis deals with the issue of protein intake in fitness strength sports. Proteins are one of the most important nutrient for strength athletes because muscle mas is made up of about 20% of proteins. Because of athlete's desire for a well-balanced muscular body, they attach proteins a major role and often overstate their significance. Bodybuilding and other strength sports are often associated with extreme protein intake, which can lead to negative health effects (deficiency of some minerals, kidney load, digestive troubles, etc.). The aim of this thesis is to evaluate whether power athletes receive excess, optimum intake or lack of protein according to the current recommendations for sports nutrition. A record sheet for diet intake was used to collect the data. The protein intake of power athletes was calculated in the Nutriservis program and compared with the recommendation according to number of training lessons and the target of the athletes (fat reduction, weight maintenance or muscle growth). The diet of power athletes was also critically evaluated. The results were evaluated by relevant text commentaries and summarized using a graph. The result is that 45% of strength athletes consume excess protein and their intake is higher than 2.0 g protein/kg/day. However, it was also found...

It is highly recommended for women to take multivitamin/mineral supplements during the periconceptional and prenatal periods. Studies have confirmed that taking prenatal multivitamins prevents maternal iron deficiency anemia, and reduces the risk for neural tube defects (NTDs). To date, research aimed at optimizing the use of multivitamins before and during pregnancy has been minimal. My thesis focused on two challenges of periconceptional and prenatal multivitamin supplementation. The first challenge was gastrointestinal (GI) adverse events such as nausea and constipation which may be attributed to iron content and tablet size. Pregnant women are highly susceptible to GI adverse events since 80% experience nausea and vomiting of pregnancy. A prospective, randomized, controlled, open-label study was conducted to investigate whether a low-iron, small-tablet prenatal multivitamin can reduce GI adverse events, and improve supplement tolerability and adherence, relative to a high-iron, small-tablet prenatal multivitamin. We determined that low iron dose did not produce a significant difference, while small tablet size could be considered an important factor. Moreover, our results confirmed that adherence was poor in pregnant women. We were prompted to identify determinants which could predict adherence to prenatal multivitamins. Our retrospective study determined that predictors of adherence are rooted in women’s prior experiences with multivitamin use. The second challenge we addressed was achieving adequate blood folate concentrations for prevention of NTDs. If adherence is poor, standard dosing of 0.4-1 mg folic acid may not produce the blood folate concentrations needed in women prior to conception. We investigated the pharmacokinetics of 5 mg folic acid. Our prospective, parallel, open-labeled study, comparing a single dose of 5 mg to 1.1 mg folic acid, confirmed that folic acid follows linear (proportional) pharmacokinetics. However, our prospective, randomized, controlled, open-labeled, multiple-dose study determined that repeated use of folic acid at these 2 doses followed non-linear pharmacokinetics. Nevertheless, our data confirmed that 5 mg folic acid can produce higher blood folate concentrations, with a faster rate, which can counter the effect of poor adherence. In conclusion, optimal use of prenatal multivitamins requires improvements in supplement tolerability, adherence, and pharmacokinetics which depend on supplement formulations, and individualized assessment and counseling.

Maternal and child undernutrition are a significant problem in the developing world, with serious consequences for human health and socio-economic development. In Cambodia, 55% of children, 43% of women of reproductive age, and 50% of pregnant women are anemic. Current prevention and control practices rely on supplementation with iron pills or large-scale food fortification, neither of which are affordable or feasible in rural Cambodia. In the study areas, 97% of women did not meet their daily iron requirements. The current research focuses on the design and evaluation of an innovative iron supplementation technique. A culturally acceptable, inexpensive and lightweight iron ingot was designed to resemble a fish species considered lucky in Khmer culture. The ingot, referred to as ‘try sabay’ or ‘happy fish’, was designed to supply iron at a slow, steady rate. Iron leaching was observed in water and soup samples prepared with the iron fish when used concurrently with an acidifier. More than 75% of daily iron requirements can be met with regular use. Its use in the common pot of soup or boiled water provides supplementation to the entire family. The effectiveness of the iron fish was investigated in a randomized community trial involving 310 women in rural Cambodia. Blood samples were taken at baseline and every three months thereafter, over a 12-month trial period. Significant increases in hemoglobin concentrations were observed in women allocated an iron fish when compared to controls throughout the study, with an endline difference of 11.6 g/L. Significant improvements in serum ferritin concentration were observed at 9 months (6.9 ng/mL) and endline (30.8 ng/mL) in women who used an iron fish regularly when compared to the control group. Overall, use of the iron fish led to a two-fold reduction in the prevalence of anemia. The supplement was used daily by 94% of the households at the end of the trial. The study highlights the acceptability and effectiveness of a fish-shaped iron ingot as a means of improving dietary iron content. It offers a promising, simple solution to iron deficiency anemia if the project can be scaled-up for use throughout the country. / Canadian Institutes of Health Research, University of Guelph, International Development Research Centre (Canada)

Folate intake in North America has drastically increased over the past decade due to folic acid fortification and widespread supplemental use. The role of folate in breast cancer is highly controversial and the effects of folic acid supplementation on breast cancer patients are currently unknown. An animal study was performed to determine the effects of folic acid supplementation on the progression of the mammary tumors in the DMBA-carcinogen model. Folic acid supplementation was associated with more rapid sentinel tumor progression and with higher sentinel tumor weight, volume, and area, although no clear dose-responsive relationship was observed. Folic acid supplementation was associated with an increased expression of proapoptotic protein PARP and decreased expression of proliferation protein PCNA. These data suggest that folic acid supplementation may promote the progression of established mammary tumors. Whether or not folic acid supplementation may adversely affect the outcome of patients with breast cancer warrants further studies.

Folate intake in North America has drastically increased over the past decade due to folic acid fortification and widespread supplemental use. The role of folate in breast cancer is highly controversial and the effects of folic acid supplementation on breast cancer patients are currently unknown. An animal study was performed to determine the effects of folic acid supplementation on the progression of the mammary tumors in the DMBA-carcinogen model. Folic acid supplementation was associated with more rapid sentinel tumor progression and with higher sentinel tumor weight, volume, and area, although no clear dose-responsive relationship was observed. Folic acid supplementation was associated with an increased expression of proapoptotic protein PARP and decreased expression of proliferation protein PCNA. These data suggest that folic acid supplementation may promote the progression of established mammary tumors. Whether or not folic acid supplementation may adversely affect the outcome of patients with breast cancer warrants further studies.

It is highly recommended for women to take multivitamin/mineral supplements during the periconceptional and prenatal periods. Studies have confirmed that taking prenatal multivitamins prevents maternal iron deficiency anemia, and reduces the risk for neural tube defects (NTDs). To date, research aimed at optimizing the use of multivitamins before and during pregnancy has been minimal. My thesis focused on two challenges of periconceptional and prenatal multivitamin supplementation. The first challenge was gastrointestinal (GI) adverse events such as nausea and constipation which may be attributed to iron content and tablet size. Pregnant women are highly susceptible to GI adverse events since 80% experience nausea and vomiting of pregnancy. A prospective, randomized, controlled, open-label study was conducted to investigate whether a low-iron, small-tablet prenatal multivitamin can reduce GI adverse events, and improve supplement tolerability and adherence, relative to a high-iron, small-tablet prenatal multivitamin. We determined that low iron dose did not produce a significant difference, while small tablet size could be considered an important factor. Moreover, our results confirmed that adherence was poor in pregnant women. We were prompted to identify determinants which could predict adherence to prenatal multivitamins. Our retrospective study determined that predictors of adherence are rooted in women’s prior experiences with multivitamin use. The second challenge we addressed was achieving adequate blood folate concentrations for prevention of NTDs. If adherence is poor, standard dosing of 0.4-1 mg folic acid may not produce the blood folate concentrations needed in women prior to conception. We investigated the pharmacokinetics of 5 mg folic acid. Our prospective, parallel, open-labeled study, comparing a single dose of 5 mg to 1.1 mg folic acid, confirmed that folic acid follows linear (proportional) pharmacokinetics. However, our prospective, randomized, controlled, open-labeled, multiple-dose study determined that repeated use of folic acid at these 2 doses followed non-linear pharmacokinetics. Nevertheless, our data confirmed that 5 mg folic acid can produce higher blood folate concentrations, with a faster rate, which can counter the effect of poor adherence. In conclusion, optimal use of prenatal multivitamins requires improvements in supplement tolerability, adherence, and pharmacokinetics which depend on supplement formulations, and individualized assessment and counseling.

Three experiments were conducted to determine the effects of source (experiment 1), frequency, and level (experiments 2 and 3) of energy supplementation on performance, forage utilization and intake, productivity, rumen fermentation, and nutrient digestibility of growing beef cattle fed stockpiled forage. In experiment 1 (EXP1) and experiment 2 (EXP2), 45 cross bred yearling steers were managed on stockpiled crested wheatgrass pasture over 70 days during summer/fall of 2011 and 2012. Steers were stratified by IBW (EXP1 = 334±1.2 kg; EXP2 = 358±1.8 kg) and allocated randomly to 1 of 9 crested wheatgrass pastures (5 steers/pasture). Each pasture was randomly assigned to 1 of 3 replicated (n = 3) treatments. In EXP1, two isonitrogenous and isocaloric by-product feed pellets that differed in starch and degradable fiber content were used in one of three supplementation strategies: 1) no supplement (CON), or supplemented at 0.6 % of BW with 2) low starch/high fibre (LS/HF) pellet (40.3% starch; 29.5% NDF DM basis) pellet, or 3) high starch/low fibre (HS/LF; 48.6% starch; 22.8% NDF DM basis) pellet. In EXP2 a by-product feed pellet was formulated to provide ruminal and post-ruminal energy (30.3 % NDF; 32.0 % starch; 7.2 % fat) supplementation strategies included: 1) daily (DLY) supplementation at 0.6 % of BW, 2) low-alternate (LA) supplementation at 0.9 % of BW, and 3) high-alternate (HA) supplementation at 1.2 % of BW. There was no effect (P > 0.05) of treatment on forage utilization in either experiment. In EXP 1, final BW and ADG were not different (P > 0.05) between LS/HF (435 kg; 1.4 kg d-1) and HS/LF (439 kg; 1.5 kg d-1). However, supplemented cattle had higher (P < 0.05) final BW and ADG than CON cattle (402 kg; 1.0 kg d-1). Supplementation increased production costs by 450 %. In EXP 2, no difference (P > 0.05) was observed for final BW and ADG among DLY (435 kg; 1.1 kg d-1), LA (424 kg; 0.9 kg d-1), and HA (428 kg; 1.0 kg d-1). Production costs were reduced by 23 % with alternate supplementation and LA had 19 % less production costs than HA. In experiment three (EXP 3), four ruminally cannulated beef heifers were individually fed a stockpiled grass hay and offered the same pelleted supplement as in EXP2. Treatments consisted of 4 supplementation strategies: 1) no supplement (CON), 2) daily (DLY) supplementation at 0.6% BW, 3) low-alternate (LA) supplementation at 0.9 % of BW, and 4) high-alternate (HA) supplementation at 1.2 % of BW. Forage intake, rumen fermentation parameters, and apparent total tract digestibility were measured. Three data sets were analyzed: 1) overall (average of all collection days), 2) day of supplementation (DS) and 3) non-supplementation day (NSD) for alternating treatments. Overall, hay DMI (kg d-1) was lower (P = 0.04) for DLY (7.1) vs. CON (8.1), but no different (P ≥ 0.11) for DLY vs. LA (6.9), or vs. HA (6.4). On DS, hay DMI (kg d-1) of DLY (7.3) differed (P < 0.05) vs. HA (6.0), but was not different (P = 0.16) vs. LA (6.4). On NSD, hay DMI (kg d-1) of DLY (7.0) was not different (P ≥ 0.48) to those of LA (7.3) and HA (6.9). Overall, total VFA concentration (mM) was lower (P < 0.01) for CON (69.2) vs. DLY (77.1); but not different (P ≥ 0.45) for DLY vs. LA (75.8) or HA (75.1). Rumen NH3 (mg/dL) was lower (P < 0.01) for CON (3.4) and higher (P < 0.01) for LA (5.8) vs. DLY (4.6), but not different (P = 0.37) for DLY vs. HA (4.3). Overall, ruminal pH was lower (P ≤ 0.04) for DLY (6.65) vs. CON (6.75) and HA (6.72), but similar (P = 0.18) for DLY vs. LA (6.70). On DS, ruminal pH was lower (P = 0.04) for HA (6.59) vs. DLY (6.64), but higher (P < 0.01) on NSD for HA (6.85) vs. DLY (6.67). Apparent DM, OM and GE digestibility coefficients were lower (P ≤ 0.03) for CON and LA vs. DLY, but no difference (P ≥ 0.36) for DLY vs. HA. These results indicate that beef steers grazing stockpiled crested wheatgrass were limited in energy intake and that supplementation of metabolizable energy improved animal performance regardless of the source of energy. Reducing the frequency of energy supplementation and level offered on alternate days do not affect animal performance and reduces the production costs of the system. Negative effects of alternate day supplementation on forage intake and rumen fermentation are reduced when a lower level is offered relative to simply doubling the daily amount of supplement.