The dietary supplement beta-hydroxy-beta-methylbutyrate (HMB) is claimed to increase strength, lean body mass, and decrease fat mass when used in conjunction with resistance training. Although there is some support for these claims, the evidence is not conclusive, and it is even less so for resistance trained individuals. Therefore, we aimed to further elucidate the effects of HMB supplementation in trained men. A randomized, double-blind, controlled study design was used to investigate the effects of supplementing 22 resistance trained men with 3 g.d of HMB or corn starch placebo for 9 weeks with resistance training. The effect of HMB on strength was determined using the 1-repetition maximum (1RM) method for the lower body (leg extension) and upper body (bench press, bicep preacher curl) at baseline and after the supplementation period. Body composition was assessed by skinfolds and bioelectrical impedance analysis (BIA). Overall, 9 weeks' HMB supplementation resulted in a clear-cut, trivial increase in combined averaged strength measures of 1.6% (90% confidence limits: +/-4.3%). When considered in isolation, however, leg extension 1RM increased by a substantial 9.1% (90% confidence limits: +/-7.5%), but the effect on upper-body strength was inconclusive (bench press: -1.9 +/- 9.3%; bicep curl: -1.7 +/- 4.7%). Based on BIA estimates, HMB had a decreasing (although inconclusive) influence on fat mass of -9 +/- 14%, but it had a clear, trivial effect on fat-free mass of 0.2 +/- 2.2%. The magnitude of change in body mass was trivial, but the probability of substantial reductions in skinfold thicknesses ranged from negligible to likely. In previously trained men, supplementation of HMB in conjunction with resistance training provides a substantial benefit to lower-body strength, but it has negligible effects on body composition.

High prevalence of vitamin D deficiency has been reported worldwide. Residents of Taiyuan, China, were predicted to be at high risk of vitamin D deficiency due to its high latitude, heavy air pollution, and cultural sun avoidance. This study investigated the vitamin D status of office workers, and explored the potential determinants of capillary 25-hydroxyvitamin D (25(OH)D) concentration as well as the relationship between 25(OH)D and metabolic syndrome. Two hundred participants, aged 20 to 80 years, were recruited. Capillary dried blood spot (DBS) 25(OH)D was measured; together with anthropometric (height, weight, and waist circumference), biochemical (serum lipid profile and fasting glucose) measures and a lifestyle questionnaire. Thirty-four percent of participants had 25(OH)D concentrations below 30 nmol/L, indicating deficient vitamin D status. Women’s 25(OH)D (median; 32.7 nmol/L (upper and lower quartile; 25.8, 43.8)) was significantly lower than men (44.0 nmol/L (32.3, 55.4)) (p < 0.01). Female gender, higher fasting glucose, and increased smoking (p < 0.05) were negatively associated with 25(OH)D concentration. However, there was no association found between metabolic syndrome (MetS) and 25(OH)D concentration and no significant difference in vitamin D status between men or women with MetS compared to healthy individuals. Vitamin D deficiency was common in urban residents of Taiyuan in winter and more so in women than men.

Selenium plays a role in antioxidant status and, together with iodine, in thyroid function. Iodine deficiency exists in New Zealand during pregnancy and lactation, and selenium deficiency may further affect thyroid function. This study investigated selenium intakes of pregnant and lactating women, in Palmerston North, in the North Island of New Zealand. Dietary intake was estimated using three repeated 24-h dietary recalls. Dietary intake in pregnancy was also estimated from 24-h urinary excretion of selenium. Selenium concentrations were determined in urine and breastmilk using inductively-coupled plasma mass spectrometry. Median selenium intakes based on dietary data were 51 (39, 65) μg/day in pregnancy and 51 (36, 80) μg/day in lactation, with 61% and 68% below estimated average requirement (EAR). Median daily selenium intake in pregnancy based on urinary excretion was 49 (40, 60) µg/day, with 59% below EAR. Median selenium concentration in breastmilk was 11 (10, 13) µg/L and estimated median selenium intake for infants was 9 (8, 10) µg/day, with 91% below the Adequate Intake of 12 μg/day. These pregnant and breastfeeding women were at risk of dietary selenium inadequacy. Further research is required to assess selenium status in relation to thyroid function and health in this group.

Young adulthood is an important stage in the accrual of bone mass. Young women are often unaware of the need, and how to optimize modifiable risk factors, particularly intake of nutrients associated with good bone health. In this study, an accessible way to estimate osteoporosis risk, quantitative ultrasound (QUS), is compared to the gold-standard technique dual X-ray absorptiometry (DXA) in a group of 54 healthy young women (18–26 years) from Manawatu, New Zealand, and the relationship with nutrient intake is investigated. Broadband ultrasound attenuation and speed of sound (BUA, SOS) were assessed by QUS calcaneal scans and bone mineral concentration/density (BMC/BMD) were determined by DXA scans of the lumbar spine and hip (total and femoral neck). Dietary intake of energy, protein, and calcium was estimated using three-day food diaries and questionnaires. DXA mean Z-scores (>−2.0) for the hip (0.19) and spine (0.2) and QUS mean Z-scores (>−1.0) (0.41) were within the expected ranges. DXA (BMD) and QUS (BUA, SOS) measurements were strongly correlated. Median intakes of protein and calcium were 83.7 g/day and 784 mg/day, respectively. Protein intake was adequate and, whilst median calcium intake was higher than national average, it was below the Estimated Average Requirement (EAR). No significant relationship was found between dietary intake of calcium or protein and BMD or BMC. To conclude, QUS may provide a reasonable indicator of osteoporosis risk in young women but may not be an appropriate diagnostic tool. Increased calcium intake is recommended for this group, regardless of BMD.

Iodine and selenium are required for thyroid function. This study investigated iodine and selenium intakes in healthy, women aged 50–70 years (n = 97) from three cities in the North Island of New Zealand, after mandatory fortification of bread with iodised salt. Iodine and selenium concentrations were determined in 24-h urine samples; daily intakes were extrapolated from amounts in urine (90% and 55% of daily intake, respectively). Three day diet diaries (3DDD) also estimated selenium and iodine (excluding iodised salt) intake. Median urinary iodine concentration (UIC) was 57 (41, 78) µg/L, indicating mild iodine deficiency. Estimated median iodine intake based on urine was 138 (100, 172) µg/day, below Recommended Dietary Intake (RDI) (150 µg/day) with 25% below Estimated Average Requirement (EAR) (100 µg/day). Estimated median selenium intake was 50 (36, 71) µg/day based on urine and 45 (36, 68) µg/day using 3DDD, below RDI (60 µg/day) with 49%–55% below EAR (50 µg/day). Median bread intakes were low at 1.8 (1.1, 2.7) serves/day; 25% consumed ≤1 serve/day. Although population iodine intakes improved following mandatory fortification, some had low intakes. Selenium intakes remain low. Further research should investigate thyroid function of low consumers of iodine fortified bread and/or selenium in New Zealand.

We determined the reliability of a 60-min treadmill protocol in the heat when spaced >4 weeks apart, longer than the test–retest duration of 1 week found in the literature. Nine unacclimated, trained males (age: 31 ± 8 y; VO₂peak: 60 ± 6 ml∙kg⁻¹∙min⁻¹) undertook a 15 min self-paced time-trial pre-loaded with 45 min of running at 70% of individual ventilatory threshold (11.2 ± 0.3 km∙h⁻¹) in 30 ± 1°C (53 ± 5% relative humidity). They repeated this following 40 ± 14 and 76 ± 26 days, with pre-trial standardization of diet and exercise for 48 h. When considering trial 1 as a familiarization, change in core temperature (∆T_core) during the first 45 min (∆2.0 ± 0.2°C) between trials 2 and 3 yielded bias and 95% limits of agreement (LoA) of −0.10 ± 0.43°C, standard error of measurement (SEM) of 0.13°C and intraclass correlation coefficient (ICC) of 0.75, more reliable than measures of baseline T_core (36.9 ± 0.2°C; LoA: −0.23 ± 0.90°C; SEM: 0.22°C; ICC: 0.03) and T_core at 45 min during exercise (38.9 ± 0.4°C; LoA: 0.32 ± 1.12°C; SEM: 0.28°C; ICC: 0.15). The coefficient of variation (CV) between trials 2 and 3 for distance run during the 15 min time-trial was 2.1 ± 2.0% with LoA of 0.001 ± 0.253 km and SEM of 0.037 km. This protocol is reliable spaced ~5 weeks apart when considering the most commonly accepted limit of <5% CV for performance, reinforced by reliability of the ΔT_core being 0.1 ± 0.4°C.