Using compositional principal component analysis to describe children's gut microbiota in relation to diet and body composition.

BACKGROUND: Gut microbiota data obtained by DNA sequencing are complex and compositional because of large numbers of detectable taxa, and because microbiota characteristics are described in relative terms. Nutrition researchers use principal component analysis (PCA) to derive dietary patterns from food data. Although compositional PCA methods are not commonly used to describe patterns from complex microbiota data, this approach would be useful for identifying gut microbiota patterns associated with diet and body composition. OBJECTIVES: To use compositional PCA to describe the principal components (PCs) of gut microbiota in 5-y-old children and explore associations between microbiota components, diet, and BMI z-score. METHODS: A fecal sample was provided by 319 children aged 5 y. Their primary caregiver completed a validated 123-item quantitative FFQ. Body composition was determined using DXA, and a BMI z-score was calculated. Compositional PCA identified characterizing taxa and weightings for calculation of gut microbiota PC scores at the genus level, and was examined in relation to diet and body size. RESULTS: Three gut microbiota PCs were found. PC1 (negative loadings on uncultured Christensenellaceae and Ruminococcaceae) was related to lower BMI z-scores and longer duration of breastfeeding (per month) (ß = -0.14; 95% CI: -0.26, -0.02; and ß = 0.02; 95% CI: 0.003, 0.34, respectively). PC2 (positive loadings on Fusicatenibacter and Bifidobacterium; negative loadings on Bacteroides) was associated with a lower intake of nuts, seeds, and legumes (ß = -0.05 per gram; 95% CI: -0.09, -0.01). When adjusted for fiber intake, PC2 was also associated with higher BMI z-scores (ß = 0.12; 95% CI: 0.01, 0.24). PC3 (positive loadings on Faecalibacterium, Eubacterium, and Roseburia) was associated with higher intakes of fiber (ß = 0.02 per gram; 95% CI: 0.003, 0.04) and total nonstarch polysaccharides (ß = 0.02 per gram; 95% CI: 0.003, 0.04). CONCLUSIONS: Our results suggest that specific gut microbiota components determined using compositional PCA are associated with diet and BMI z-score.This trial was registered at clinicaltrials.gov as NCT00892983.

Relative Validity and Reproducibility of a Food Frequency Questionnaire to Assess Nutrients and Food Groups of Relevance to the Gut Microbiota in Young Children.

Dietary fiber is an important nutrient for the gut microbiota, with different fiber fractions having different effects. The aim of this study was to determine the relative validity and reproducibility of a food frequency questionnaire (EAT5 FFQ) for measuring intake of fiber, and low and high fiber foods, in studies examining diet and gut microbiota in young children. One hundred parents of 5-year old children completed the 123-item EAT5 FFQ on two occasions four weeks apart. A 3-day weighed diet record (WDR) was completed on non-consecutive days between FFQ appointments. Mean correlations between the (randomly chosen) FFQ and WDR were acceptable for nutrient and food group intakes (r = 0.34 and r = 0.41 respectively). Gross misclassification was below chance (12.5%) for quartiles of nutrient (mean 5.7%) and food group (mean 5.1%) intake. 'Absolute values for surrogate categories' suggested the FFQ clearly differentiated between highest and lowest quartiles for all nutrients and food groups tested. Mean correlations between repeat administrations of the FFQ suggested very good reproducibility for nutrients (r = 0.83) and food groups (r = 0.80). The EAT5 FFQ appears to be an appropriate tool for investigating the intake of nutrients and food groups of relevance to the gut microbiota, and is the first FFQ validated to measure total, soluble and insoluble non-starch polysaccharide intakes in young children.

Effect of a Baby-Led Approach to Complementary Feeding on Infant Growth and Overweight: A Randomized Clinical Trial.

Importance: Baby-led approaches to complementary feeding, which promote self-feeding of all nonliquid foods are proposed to improve energy self-regulation and lower obesity risk. However, to date, no randomized clinical trials have studied this proposition. Objective: To determine whether a baby-led approach to complementary feeding results in a lower body mass index (BMI) than traditional spoon-feeding. Design, Setting, and Participants: The 2-year Baby-Led Introduction to Solids (BLISS) randomized clinical trial recruited 206 women (168 [81.6%] of European ancestry; 85 [41.3%] primiparous) in late pregnancy from December 19, 2012, through March 17, 2014, as part of a community intervention in Dunedin, New Zealand. Women were randomized to a control condition (n = 101) or the BLISS intervention (n = 105) after stratification for parity and education. All outcomes were collected by staff blinded to group randomization, and no participants withdrew because of an adverse event. Data were analyzed based on intention to treat. Interventions: Mothers in the BLISS group received lactation consultant support (≥5 contacts) to extend exclusive breastfeeding and delay introduction of complementary foods until 6 months of age and 3 personalized face-to-face contacts (at 5.5, 7.0, and 9.0 months). Main Outcomes and Measures: The primary outcome was BMI z score (at 12 and 24 months). Secondary outcomes included energy self-regulation and eating behaviors assessed with questionnaires at 6, 12, and 24 months and energy intake assessed with 3-day weighed diet records at 7, 12, and 24 months. Results: Among the 206 participants (mean [SD] age, 31.3 [5.6] years), 166 were available for analysis at 24 months (retention, 80.5%). The mean (SD) BMI z score was not significantly different at 12 months (control group, 0.20 [0.89]; BLISS group, 0.44 [1.13]; adjusted difference, 0.21; 95% CI, -0.07 to 0.48) or at 24 months (control group, 0.24 [1.01]; BLISS group, 0.39 [1.04]; adjusted difference, 0.16; 95% CI, -0.13 to 0.45). At 24 months, 5 of 78 infants (6.4%) were overweight (BMI≥95th percentile) in the control group compared with 9 of 87 (10.3%) in the BLISS group (relative risk, 1.8; 95% CI, 0.6-5.7). Lower satiety responsiveness was observed in BLISS infants at 24 months (adjusted difference, -0.24; 95% CI, -0.41 to -0.07). Parents also reported less food fussiness (adjusted difference, -0.33; 95% CI, -0.51 to -0.14) and greater enjoyment of food (adjusted difference, 0.25; 95% CI, 0.07 to 0.43) at 12 months in BLISS infants. Estimated differences in energy intake were 55 kJ (95% CI, -284 to 395 kJ) at 12 months and 143 kJ (95% CI, -241 to 526 kJ) at 24 months. Conclusions and Relevance: A baby-led approach to complementary feeding did not result in more appropriate BMI than traditional spoon-feeding, although children were reported to have less food fussiness. Further research should determine whether these findings apply to individuals using unmodified baby-led weaning. Trial Registration: http://anzctr.org.au Identifier: ACTRN12612001133820.

Anticipatory guidance to prevent infant sleep problems within a randomised controlled trial: infant, maternal and partner outcomes at 6 months of age.

OBJECTIVE: To evaluate the effectiveness of sleep education delivered antenatally and at 3 weeks postpartum to prevent infant sleep problems at 6 months of age. DESIGN: Sleep intervention within a randomised controlled trial for the Prevention of Overweight in Infancy (POI) study. PARTICIPANTS: 802 families were randomly allocated to one of four groups: usual care (control), sleep intervention (sleep), food, activity and breastfeeding intervention (FAB), and combined group receiving both interventions (combination). INTERVENTIONS: All groups received standard Well Child care. The sleep intervention groups (sleep and combination) received an antenatal group education session (all mothers and most partners) emphasising infant self-settling and safe sleeping, and a home visit at 3 weeks reinforcing the antenatal sleep education. FAB and combination groups received four contacts providing education and support on breast feeding, food and activity up to 4 months postpartum. OUTCOME MEASURES: Here we report secondary sleep outcomes from the POI study: the prevalence of parent-reported infant sleep problems and night waking, and differences in sleep duration. Additional outcomes reported include differences in infant self-settling, safe sleep practices, and maternal and partner reports of their own sleep, fatigue and depression symptoms. RESULTS: Linear or mixed linear regression models found no significant intervention effects on sleep outcomes, with 19.1% of mothers and 16.6% of partners reporting their infant's sleep a problem at 6 months. Actigraphy estimated the number of night wakings to be significantly reduced (8%) and the duration of daytime sleep increased (6 min) in those groups receiving the sleep intervention compared with those who did not. However, these small differences were not clinically significant and not observed in 24 hours infant sleep diary data. No other differences were observed. CONCLUSION: A strategy delivering infant sleep education antenatally and at 3 weeks postpartum was not effective in preventing the development of parent-reported infant sleep problems.

Eating frequency in relation to BMI in very young children: a longitudinal analysis.

OBJECTIVE: Eating less frequently is associated with increased obesity risk in older children but data are potentially confounded by reverse causation, where bigger children eat less often in an effort to control their weight. Longitudinal data, particularly in younger children, are scarce. We aimed to determine whether eating frequency (meals and snacks) at 2 years of age is associated with past, current or subsequent BMI. DESIGN: Cohort analysis of a randomised controlled trial. Eating frequency at 2 years of age was estimated using 48 h diaries that recorded when each child ate meals and snacks (parent-defined) in five-minute blocks. Body length/height and weight were measured at 1, 2 and 3·5 years of age. Linear regression assessed associations between the number of eating occasions and BMI Z-score, before and after adjustment for potential confounding variables. SETTING: Prevention of Overweight in Infancy (POI) study, Dunedin, New Zealand. SUBJECTS: Children (n 371) aged 1-3·5 years. RESULTS: On average, children ate 5·5 (sd 1·2) times/d at 2 years of age, with most children (88-89 %) eating 4-7 times/d. Eating frequency at 2 years was not associated with current (difference in BMI Z-score per additional eating occasion; 95 % CI: -0·02; -0·10, 0·05) or subsequent change (0·02; -0·03, 0·06) in BMI. Similarly, BMI at age 1 year did not predict eating frequency at 2 years of age (difference in eating frequency per additional BMI Z-score unit; 95 % CI: -0·03; -0·19, 0·13). CONCLUSIONS: Number of eating occasions per day was not associated with BMI in young children in the present study.

Three-year follow-up of a randomised controlled trial to reduce excessive weight gain in the first two years of life: protocol for the POI follow-up study.

BACKGROUND: The Prevention of Overweight in Infancy (POI) study was a four-arm randomised controlled trial (RCT) in 802 families which assessed whether additional education and support on sleep (Sleep group); food, physical activity and breastfeeding (FAB group); or both (Combination group), reduced excessive weight gain from birth to 2 years of age, compared to usual care (Control group). The study had high uptake at recruitment (58 %) and retention at 2 years (86 %). Although the FAB intervention produced no significant effect on BMI or weight status at 2 years, the odds of obesity were halved in those who received the sleep intervention, despite no apparent effect on sleep duration. We speculate that enhanced self-regulatory behaviours may exist in the Sleep group. Self-regulation was not measured in our initial intervention, but extensive measures have been included in this follow-up study. Thus, the overall aim of the POI follow-up is to determine the extent to which augmented parental support and education on infant sleep, feeding, diet, and physical activity in the first 2 years of life reduces BMI at 3.5 and 5 years of age, and to determine the role of self-regulation in any such relationship. METHODS/DESIGN: We will contact all 802 families and seek renewed consent to participate in the follow-up study. The families have received no POI intervention since the RCT finished at 2 years of age. Follow-up data collection will occur when the children are aged 3.5 and 5 years (i.e. up to 3 years post-intervention). Outcomes of interest include child anthropometry, body composition (DXA scan), diet (validated food frequency questionnaire), physical activity (accelerometry), sleep (questionnaire and accelerometry), and self-regulation (questionnaires and neuropsychological assessment). DISCUSSION: Our follow-up study has been designed primarily to enable us to determine whether the intriguing benefit of the sleep intervention suggested at 2 years of age remains as children approach school age. However, cohort analyses will also investigate how BMI, self-regulation, and sleep consolidation develop during the early years. This information will be valuable to researchers and policy makers progressing the field of early childhood obesity prevention. TRIAL REGISTRATION: ClinicalTrials.gov number NCT00892983 .

Nut-enriched bread is an effective and acceptable vehicle to improve regular nut consumption.

PURPOSE: Consuming 30 g of nuts/day is recommended to reduce chronic disease. However, nut consumption appears far from ideal among several populations. A potential strategy to increase consumption is to add nuts to a staple, for example, bread. Whether the health benefits and acceptability of nuts persist in this form is currently unknown. Thus, we examined the effects of consuming three nut-enriched breads on postprandial glycaemia, satiety, gastrointestinal tolerance, dietary intakes, and acceptance. METHODS: In this controlled, crossover study, 32 participants were randomly allocated to receive one of four breads for 8 days each. Three breads contained either 30 g of finely sliced hazelnuts, 30 g semi-defatted hazelnut flour, or 15 g of each (amounts per 120 g bread) and were compared with a control nut-free bread. Blood glucose response was measured over 120 min, along with ratings of gastrointestinal discomfort. Appetite ratings and diet diaries were completed during each treatment period. RESULTS: Area under the blood glucose curve was significantly lower for the nut breads compared to the control bread (all P < 0.001), with no significant differences between the nut breads (all P ≥ 0.130). There were no significant differences in satiety (all P ≥ 0.135) or gastrointestinal symptoms (all P ≥ 0.102) between the breads. Acceptance was highest for the finely sliced hazelnut bread. Furthermore, consuming hazelnut-enriched bread improved diet quality, increasing monounsaturated fat, vitamin E, and dietary fibre intakes. CONCLUSION: Bread appears to be an effective and acceptable vehicle for increasing nut consumption, resulting in improved postprandial glycaemia and diet profiles. Long-term studies are now required.

Baby-Led Introduction to SolidS (BLISS) study: a randomised controlled trial of a baby-led approach to complementary feeding.

BACKGROUND: In 2002, the World Health Organization recommended that the age for starting complementary feeding should be changed from 4 to 6 months of age to 6 months. Although this change in age has generated substantial debate, surprisingly little attention has been paid to whether advice on how to introduce complementary foods should also be changed. It has been proposed that by 6 months of age most infants will have developed sufficient motor skills to be able to feed themselves rather than needing to be spoon-fed by an adult. This has the potential to predispose infants to better growth by fostering better energy self-regulation, however no randomised controlled trials have been conducted to determine the benefits and risks of such a "baby-led" approach to complementary feeding. This is of particular interest given the widespread use of "Baby-Led Weaning" by parents internationally. METHODS/DESIGN: The Baby-Led Introduction to SolidS (BLISS) study aims to assess the efficacy and acceptability of a modified version of Baby-Led Weaning that has been altered to address potential concerns with iron status, choking and growth faltering. The BLISS study will recruit 200 families from Dunedin, New Zealand, who book into the region's only maternity hospital. Parents will be randomised into an intervention (BLISS) or control group for a 12-month intervention with further follow-up at 24 months of age. Both groups will receive the standard Well Child care provided to all parents in New Zealand. The intervention group will receive additional parent contacts (n = 8) for support and education on BLISS from before birth to 12 months of age. Outcomes of interest include body mass index at 12 months of age (primary outcome), energy self-regulation, iron and zinc intake and status, diet quality, choking, growth faltering and acceptability to parents. DISCUSSION: This study is expected to provide insight into the feasibility of a baby-led approach to complementary feeding and the extent to which this method of feeding affects infant body weight, diet quality and iron and zinc status. Results of this study will provide important information for health care professionals, parents and health policy makers. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12612001133820 .

Development and pilot testing of Baby-Led Introduction to SolidS--a version of Baby-Led Weaning modified to address concerns about iron deficiency, growth faltering and choking.

BACKGROUND: In Baby-Led Weaning (BLW), infants are offered 'finger' foods from the start of the complementary feeding period instead of being spoon-fed. Healthcare professionals have expressed concerns about adequacy of iron and energy intake, and about choking, for infants following Baby-Led Weaning. METHODS: We developed a modified version of BLW, Baby-Led Introduction to SolidS (BLISS), to address these concerns. In a 12-week pilot study, families who had chosen to use a BLW approach were assigned to BLISS (n = 14) or BLW (n = 9). BLISS participants received 2 intervention visits, resources and on-call support. BLW participants received no intervention. Participants were interviewed weekly for 12 weeks and completed a three-day weighed record or three 24-h iron questionnaires. RESULTS: Compared to the BLW group, the BLISS group were more likely to introduce iron containing foods during the first week of complementary feeding, and to offer more serves per day of iron containing foods at 6 months (2.4 vs 0.8 serves/day; P = 0.001); and less likely to offer high-choking-risk foods (3.24 vs 0.17 serves/day; P = 0.027). CONCLUSIONS: This pilot study suggests BLISS may result in higher iron intakes and lower choking risk than unmodified BLW. However, the results need to be confirmed in a large randomised controlled trial.

Lactation Consultant Support from Late Pregnancy with an Educational Intervention at 4 Months of Age Delays the Introduction of Complementary Foods in a Randomized Controlled Trial.

BACKGROUND: Although the WHO recommends that complementary feeding in infants should begin at 6 mo of age, it often begins before this in developed countries. OBJECTIVE: Our objective was to determine whether lactation consultant (LC) support, with educational resources given at 4-mo postpartum, can delay the introduction of complementary foods until around 6 mo of age. METHODS: A total of 802 mother-infant pairs were recruited from the single maternity hospital serving Dunedin, New Zealand (59% response rate) and randomly assigned to the following: 1) usual care (control group); 2) infant sleep education intervention (Sleep); 3) food, activity, and breastfeeding intervention (FAB); or 4) combination (both) intervention (Combo). Certified LCs delivered 3 intervention sessions (late pregnancy and 1-wk and 4-mo postpartum). The 4-mo contact used educational resources focused on developmental readiness for complementary foods. Age when complementary foods were introduced was obtained from repeated interviews (monthly from 3- to 27-wk postpartum). RESULTS: A total of 49.5% and 87.2% of infants received complementary foods before 5 and 6 mo of age, respectively. There was evidence of group differences in the number of infants introduced to complementary foods before 5 mo (P = 0.006), with those receiving support and resources (FAB and Combo groups combined; 55.6%) more likely to wait until at least 5 mo compared with controls (control and Sleep groups combined; 43.3%) (OR: 1.52; 95% CI: 1.08, 2.16). However, there was no evidence they were more likely to wait until 6 mo of age (P = 0.52). Higher maternal age, higher parity, and a less positive attitude toward breastfeeding were positively associated, and drinking alcohol during pregnancy was negatively associated, with later age of introduction of complementary foods. CONCLUSIONS: Providing an LC and educational resources at 4-mo postpartum to predominantly well-educated, mainly European, women can delay the introduction of complementary foods until 5 mo of age, but not until the WHO recommendation of 6 mo. This trial was registered at clinicaltrials.gov as NCT00892983.

Parent-led or baby-led? Associations between complementary feeding practices and health-related behaviours in a survey of New Zealand families.

OBJECTIVE: To determine feeding practices and selected health-related behaviours in New Zealand families following a 'baby-led' or more traditional 'parent-led' method for introducing complementary foods. DESIGN, SETTING AND PARTICIPANTS: 199 mothers completed an online survey about introducing complementary foods to their infant. Participants were classified into one of four groups: 'adherent baby-led weaning (BLW)', the infant mostly or entirely fed themselves at 6-7 months; 'self-identified BLW', mothers reported following BLW at 6-7 months but were using spoon-feeding at least half the time; 'parent-led feeding', the mother reported not having tried BLW; and 'unclassified method', the mother reported they were not following BLW at 6-7 months but reported the infant mostly or entirely fed themselves at 6-7 months. RESULTS: 8% were following 'adherent BLW', 21% 'self-identified BLW' and 0% were following the 'unclassified method'. Compared with 'self-identified BLW' and 'parent-led feeding', a higher proportion of the 'adherent BLW' met the WHO recommendations to exclusively breastfeed for 6 months and to introduce complementary foods at 6 months. The 'adherent BLW' group was more likely to have family foods (p=0.018), and less likely (p=0.002) to have commercially prepared baby food. Both BLW groups were more likely to share meals with the family compared with 'parent-led feeding'. In contrast to 'self-identified BLW' and 'parent-led feeding', the 'adherent BLW' group did not offer iron-fortified cereal as a first food. CONCLUSIONS: This study suggests that although many parents consider they follow BLW, a very few are following it strictly. The extent to which BLW was followed was associated with potential benefits (eg, sharing family meals) and risks (eg, low iron first foods) highlighting the importance for health professionals and researchers of accurately determining the extent of adherence to BLW.

How feasible is Baby-led Weaning as an approach to infant feeding? A review of the evidence.

Baby-Led Weaning (BLW) is an alternative method for introducing complementary foods to infants in which the infant feeds themselves hand-held foods instead of being spoon-fed by an adult. The BLW infant also shares family food and mealtimes and is offered milk (ideally breast milk) on demand until they self-wean. Anecdotal evidence suggests that many parents are choosing this method instead of conventional spoon-feeding of purées. Observational studies suggest that BLW may encourage improved eating patterns and lead to a healthier body weight, although it is not yet clear whether these associations are causal. This review evaluates the literature with respect to the prerequisites for BLW, which we have defined as beginning complementary foods at six months (for safety reasons), and exclusive breastfeeding to six months (to align with WHO infant feeding guidelines); the gross and oral motor skills required for successful and safe self-feeding of whole foods from six months; and the practicalities of family meals and continued breastfeeding on demand. Baby-Led Weaning will not suit all infants and families, but it is probably achievable for most. However, ultimately, the feasibility of BLW as an approach to infant feeding can only be determined in a randomized controlled trial. Given the popularity of BLW amongst parents, such a study is urgently needed.

School playgrounds and physical activity policies as predictors of school and home time activity.

BACKGROUND: Previous work has suggested that the number of permanent play facilities in school playgrounds and school-based policies on physical activity can influence physical activity in children. However, few comparable studies have used objective measures of physical activity or have had little adjustment for multiple confounders. METHODS: Physical activity was measured by accelerometry over 5 recess periods and 3 full school days in 441 children from 16 primary schools in Dunedin, New Zealand. The number of permanent play facilities (swing, fort, slide, obstacle course, climbing wall etc) in each school playground was counted on three occasions by three researchers following a standardized protocol. Information on school policies pertaining to physical activity and participation in organized sport was collected by questionnaire. RESULTS: Measurement of school playgrounds proved to be reliable (ICC 0.89) and consistent over time. Boys were significantly more active than girls (P < 0.001), but little time overall was spent in moderate-vigorous physical activity (MVPA). Boys engaged in MVPA for 32 (SD 17) minutes each day of which 17 (10) took place at school compared with 23 (14) and 11 (7) minutes respectively in girls. Each additional 10-unit increase in play facilities was associated with 3.2% (95% CI 0.0-6.4%) more total activity and 8.3% (0.8-16.3%) more MVPA during recess. By contrast, school policy score was not associated with physical activity in children. CONCLUSION: The number of permanent play facilities in school playgrounds is associated with higher physical activity in children, whereas no relationship was observed for school policies relating to physical activity. Increasing the number of permanent play facilities may offer a cost-effective long-term approach to increasing activity levels in children.

Increased blood pH but not performance with sodium bicarbonate supplementation in elite rugby union players.

PURPOSE: This study investigated the effect of ingesting 0.3 g/kg body weight (BW) of sodium bicarbonate (NaHCO3) on physiological responses, gastrointestinal (GI) tolerability, and sprint performance in elite rugby union players. METHODS: Twenty-five male rugby players, age 21.6 (2.6) yr, participated in a randomized, double-blind, placebo-controlled crossover trial. Sixty-five minutes after consuming 0.3 g/kg BW of either NaHCO3 or placebo, participants completed a 25-min warm-up followed by 9 min of high-intensity rugby-specific training followed by a rugby-specific repeated-sprint test (RSRST). Whole-blood samples were collected to determine lactate and bicarbonate concentrations and pH at baseline, after supplement ingestion, and immediately after the RSRST. Acute GI discomfort was assessed by questionnaire throughout the trials, and chronic GI discomfort was assessed during the 24 hr postingestion. RESULTS: After supplement ingestion and immediately after the RSRST, blood HCO3⁻ concentration and pH were higher for the NaHCO3 condition than for the placebo condition (p < .001). After the RSRST, blood lactate concentrations were significantly higher for the NaHCO3 than for the placebo condition (p < .001). There was no difference in performance on the RSRST between the 2 conditions. The incidence of belching, stomachache, diarrhea, stomach bloating, and nausea was higher after ingestion of NaHCO3 than with placebo (all p < .050). The severity of stomach cramps, belching, stomachache, bowel urgency, diarrhea, vomiting, stomach bloating, and flatulence was rated worse after ingestion of NaHCO3 than with placebo (p < .050). CONCLUSIONS: NaHCO3 supplementation increased blood HCO3⁻ concentration and attenuated the decline in blood pH compared with placebo during high-intensity exercise in well-trained rugby players but did not significantly improve exercise performance. The higher incidence and greater severity of GI symptoms after ingestion of NaHCO3 may negatively affect physical performance, and the authors strongly recommend testing this supplement during training before use in competitive situations.