Protein Requirements of Pre-Menopausal Female Athletes: Systematic Literature Review

This systematic literature review aimed to determine the protein requirements of pre-menopausal (e.g., 18–45 years) female athletes and identify if the menstrual cycle phase and/or hormonal contraceptive use influence protein requirements. Four databases were searched for original research containing pre-menopausal female athletes that ingested protein alongside exercise. The Academy of Nutrition and Dietetics Quality Criteria Checklist was used to determine study quality. Fourteen studies, which included 204 recreationally active or competitive females, met the eligibility criteria for inclusion in this review, and all were assessed as positive quality. The estimated average requirement (EAR) for protein intake of pre-menopausal recreational and/or competitive female athletes is similar for those undertaking aerobic endurance (1.28–1.63 g/kg/day), resistance (1.49 g/kg/day) and intermittent exercise (1.41 g/kg/day) of ~60–90 min duration. The optimal acute protein intake and influence of menstrual cycle phase or hormonal contraceptive use on protein requirements could not be determined. However, pre- and post-exercise protein intakes of 0.32–0.38 g/kg have demonstrated beneficial physiological responses in recreational and competitive female athletes completing resistance and intermittent exercise. The protein requirements outlined in this review can be used for planning and assessing protein intakes of recreational and competitive pre-menopausal female athletes

Investigating the relationship between maternal iodine intake in pregnancy and iodine status or thyroid function of mothers and infants: a prospective cohort study.

Iodine is crucial for thyroid hormone production which is essential for growth and development. Iodine deficiency in pregnancy can lead to cognitive impairment, poor growth, congenital abnormalities and in severe situations cretinism. Mild iodine deficiency re-emerged in Australia in the last decade. To address this issue, in 2009 mandatory iodine fortification of bread was implemented and in 2010 routine iodine supplementation in pregnancy was recommended. Since mandatory iodine fortification there has been limited data on the iodine intake and iodine status of Australians, including pregnant women. Intervention trials in iodine deficient populations have shown a higher maternal and infant urine iodine concentration (UIC) in iodine supplemented groups compared to controls, with the effect on thyroid function being less clear. However, no studies have assessed the relationships between maternal iodine intake from food and supplements in pregnancy and maternal or infant iodine status and thyroid function in mildly iodine deficient or sufficient populations. The primary aims of the thesis were to examine the associations between maternal iodine intake/iodine status/thyroid function in pregnancy and markers of maternal and infant iodine status/thyroid function. The secondary aims were to examine the associations between maternal iodine intake/thyroid function in pregnancy and pregnancy/birth outcomes, infant growth and the general health of pregnant and postnatal women. 783 pregnant women in South Australia participated in the study. An iodine specific food frequency questionnaire (I-FFQ) was developed and validated to assess dietary iodine intake at baseline (<20 weeks’ gestation) and 28 weeks’ gestation. Maternal UIC, maternal thyroid function and the general health and wellbeing of pregnant and postpartum women was assessed at baseline, 28 weeks’ gestation and 3 months postpartum. Breast milk iodine concentration (BMIC) was assessed at birth and 3 months postpartum. Thyroid stimulating hormone (TSH) was collected from newborn screening at birth. Pregnancy/birth outcome data and infant anthropometrics at birth were collected from the women’s and infant’s medical records and infant UIC, infant thyroid function and infant growth was measured at 3 months of age. Based on the median UIC, pregnant women in this study were classified as iodine sufficient, both with or without the use of iodine supplements during pregnancy. Maternal iodine intake in pregnancy was positively associated with maternal UIC and BMIC (Chapter 4), while no association was found with maternal thyroid function (Chapter 4), infant UIC, infant thyroid function (Chapter 5) or clinical outcomes (Chapter 6). At 28 weeks’ gestation maternal free triiodothyronine (fT3) was positively associated with infant fT3 at 3 months of age, while maternal fT3 and thyroglobulin (Tg) was inversely associated with infant TSH at 3 months of age (Chapter 5). Furthermore, markers of maternal thyroid function at 28 weeks gestation was associated with the mental and physical health of women at 3 months postpartum as well as the severity of stress at 28 weeks gestation (Chapter 6). In summary, maternal iodine intake in pregnancy is not associated with maternal or infant thyroid function in an iodine sufficient population, although maternal thyroid function at 28 weeks’ gestation is associated with infant thyroid function at 3 months of age and with aspects of the general health and wellbeing of pregnant and postnatal women. Further research is needed to better understand these relationships in populations with various iodine status and their impact on infant development.Thesis (Ph.D.) -- University of Adelaide, School of Paediatrics and Reproductive Health, 201

Long term weight maintenance after advice to consume low carbohydrate, higher protein diets – A systematic review and meta analysis

Abstract not availableP.M. Clifton, D. Condo, J.B. Keog

Nutritional intake, sports nutrition knowledge and energy availability in female Australian rules football players

This study aimed to assess nutritional intake, sports nutrition knowledge and risk of Low Energy Availability (LEA) in female Australian rules football players. Victorian Football League Women\u27s competition (VFLW) players (n = 30) aged 18-35 (weight: 64.5 kg &plusmn; 8.0; height: 168.2 cm &plusmn; 7.6) were recruited from Victoria, Australia. Nutritional intake was quantified on training days using the Automated 24 h Dietary Assessment Tool (ASA24-Australia), and sports nutrition knowledge was measured by the 88-item Sports Nutrition Knowledge Questionnaire (SNKQ). The risk of LEA was assessed using the Low Energy Availability in Females Questionnaire (LEAF-Q). Daily mean carbohydrate intake in the current investigation was 3 g&sdot;kg-1&sdot;d-1, therefore, below the minimum carbohydrate recommendation for moderate exercise of approximately one hour per day (5-7 g&sdot;kg-1&sdot;d-1) and for moderate to intense exercise for 1-3 h per day (6-10 g&sdot;kg-1&sdot;d-1) for 96.3% and 100% of players, respectively. Daily mean protein intake was 1.5 g&sdot;kg-1&sdot;d-1, therefore, consistent with recommendations (1.2-2.0 g&sdot;kg-1&sdot;d-1) for 77.8% of players. Daily mean calcium intake was 924.8 mg&sdot;d-1, therefore, below recommendations (1000 mg&sdot;d-1) for 65.5% of players, while mean iron intake was 12.2 mg&sdot;d-1, also below recommendations (18 mg&sdot;d-1) for 100% of players. Players answered 54.5% of SNKQ questions correctly, with the lowest scores observed in the section on supplements. Risk of LEA was evident in 30% of players, with no differences in carbohydrate (p = 0.238), protein (p = 0.296), fat (p = 0.490) or energy (p = 0.971) intakes between players at risk of LEA and those not at risk. The results suggest that female Australian rules football players have an inadequate intake of carbohydrate and calcium and low sports nutrition knowledge. Further investigation to assess the risk of LEA using direct measures is required

The Impact of Shiftwork on Skeletal Muscle Health

(1) Background: About one in four workers undertake shift rosters that fall outside the traditional 7 a.m.–6 p.m. scheduling. Shiftwork alters workers’ exposure to natural and artificial light, sleep patterns, and feeding patterns. When compared to the rest of the working population, shiftworkers are at a greater risk of developing metabolic impairments over time. One fundamental component of metabolic health is skeletal muscle, the largest organ in the body. However, cause-and-effect relationships between shiftwork and skeletal muscle health have not been established; (2) Methods: A critical review of the literature was completed using online databases and reference lists; (3) Results: We propose a conceptual model drawing relationships between typical shiftwork consequences; altered light exposure, sleep patterns, and food and beverage consumption, and drivers of skeletal muscle health—protein intake, resistance training, and hormone release. At present, there is no study investigating the direct effect of shiftwork on skeletal muscle health. Instead, research findings showing that acute consequences of shiftwork negatively influence skeletal muscle homeostasis support the validity of our model; (4) Conclusion: Further research is required to test the potential relationships identified in our review, particularly in shiftwork populations. Part of this testing could include skeletal muscle specific interventions such as targeted protein intake and/or resistance-training

Development and validation of an iodine-specific FFQ to estimate iodine intake in Australian pregnant women

Adequate iodine is important during pregnancy to ensure optimal growth and development of the offspring. We validated an iodine-specific FFQ (I-FFQ) for use in Australian pregnant women. A forty-four-item I-FFQ was developed to assess iodine intake from food and was administered to 122 pregnant women at 28 weeks gestation. Iodine supplement use was captured separately at 28 weeks gestation. Correlation between iodine intake from food estimated using the I-FFQ and a 4&nbsp;d weighed food record as well as correlation between total iodine intake and 24&nbsp;h urinary iodine excretion (UIE), 24&nbsp;h urinary iodine concentration (UIC), spot UIC and thyroid function were assessed at 28 weeks gestation. A moderate correlation between the two dietary methods was shown r0&middot;349, P0&middot;001), and it was strengthened with the addition of iodine supplements r 0&middot;876, P&nbsp;0&middot;001). There was a fair agreement (k=&nbsp;0&middot;28, P&nbsp;0&middot;001) between the two dietary measures in the classification of women as receiving adequate (&nbsp;&ge;&nbsp;160&nbsp;&mu;g/d) or inadequate (160&nbsp;&mu;g/d) iodine intake from food, but the limits of agreement from the Bland&ndash;Altman plot were large. Total iodine intake was associated with 24&nbsp;h UIE (&beta;&nbsp;=&nbsp;0&middot;488, P 0&middot;001) but not with spot UIC. Iodine intake from food using the I-FFQ was assessed at study entry (&nbsp;20 weeks gestation) in addition to 28 weeks gestation, and there was a strong correlation in iodine intake at the two time points (r 0&middot;622, P&nbsp;0&middot;001), which indicated good reproducibility. In conclusion, the I-FFQ provides a valid tool for estimating iodine intake in pregnant women and can be used to screen women who are at risk of inadequate intake

The Impact of Dietary Factors on the Sleep of Athletically Trained Populations: A Systematic Review

Many athletic populations report poor sleep, especially during intensive training and competition periods. Recently, diet has been shown to significantly affect sleep in general populations; however, little is known about the effect diet has on the sleep of athletically trained populations. With sleep critical for optimal recovery and sports performance, this systematic review aimed to evaluate the evidence demonstrating that dietary factors influence the sleep of athletically trained populations. Four electronic databases were searched from inception to May 2022, with primary research articles included if they contained a dietary factor(s), an outcome measure of sleep or sleepiness, and participants could be identified as ‘athletically trained’. Thirty-five studies were included, with 21 studies assessed as positive quality, 13 as neutral, and one as negative. Sleep or sleepiness was measured objectively in 46% of studies (n = 16). The review showed that evening (≥5 p.m.) caffeine intakes >2 mg·kg−1 body mass decreased sleep duration and sleep efficiency, and increased sleep latency and wake after sleep onset. Evening consumption of high glycaemic index carbohydrates and protein high in tryptophan may reduce sleep latency. Although promising, more research is required before the impact of probiotics, cherry juice, and beetroot juice on the sleep of athletes can be resolved. Athletic populations experiencing sleep difficulties should be screened for caffeine use and trial dietary strategies (e.g., evening consumption of high GI carbohydrates) to improve sleep