Association between dietary zinc intake and mortality among Chinese adults: findings from 10-year follow-up in the Jiangsu Nutrition Study.

PURPOSE: Population studies of the association between zinc intake and mortality yield inconsistent findings. Using data from Jiangsu Nutrition Study, we aimed to assess the association between zinc intake and mortality among Chinese adults. METHODS: We prospectively studied 2832 adults aged 20 years and older with a mean follow-up of 9.8 years. At baseline, food intake was measured by 3-day weighed food record (WFR) between September and December in 2002. Death occurrence was assessed in 2012 during a household visit as well as by data linkage with the regional death registry. Hazard ratios (HRs) and 95% CI were calculated using competing risks regression (CVD and cancer mortality) and Cox proportional hazards analysis (all-cause mortality). RESULTS: During 27,742 person-years of follow-up, there were 184 deaths [63 cancer deaths and 70 cardiovascular disease (CVD) deaths]. Dietary zinc to energy ratio was positively associated with cancer and all-cause mortality. Across quartiles of the zinc to energy ratio from low to high, the HR (95% CI) for all-cause mortality was 1.00, 1.80 (95% CI 1.10-2.95), 1.55 (95% CI 0.96-2.50), and 1.85 (95% CI 1.11-3.07), respectively. Comparing the extreme quartiles of the zinc to energy ratio, the HR for cancer mortality was 2.28 (95% CI 1.03-5.04). CONCLUSION: Zinc intake was positively related to all-cause mortality and cancer mortality.

Zinc Intake, Zinc Bioavailability and Plasma Zinc in Obese Adolescents with Clinical Insulin Resistance Following Low Energy Diets.

BACKGROUND: Zinc has a critical role in metabolism and growth. This study aims to determine the effects of low-energy diets differing in macronutrient composition on zinc intake, estimated zinc bioavailability (phytate:zinc molar ratio) and plasma zinc concentration and associations between zinc status and cardiometabolic markers in obese adolescents with clinical insulin resistance (IR). METHODS: Eighty-seven obese adolescents (10-17 years, body mass index z-score 2.3 ± 0.37) with clinical IR were randomized to a low-energy diet (6.0-8.0 MJ), which was either high carbohydrate or moderate carbohydrate with increased protein. Twenty-four-hour dietary recalls were collected at 6, 9 and 12 weeks. Plasma zinc concentration and cardiometabolic markers were assessed at baseline and 12 weeks. RESULTS: Zinc intake did not differ between the 2 diet groups (p = 0.612). The high-carbohydrate group had a higher phytate intake (894 vs. 671 mg, p = 0.018) and phytate:zinc molar ratio (9.4 vs. 7.4, p = 0.009) than the increased-protein group. Plasma zinc concentration did not change from baseline in either of the diet groups, but correlated positively with zinc intake (r = 0.235, p = 0.042) and % energy from protein (r = 0.383, p = 0.001), and inversely with % energy from carbohydrate (r = -0.296, p = 0.010). CONCLUSIONS: Low energy diets for obese adolescents at risk of diabetes may need increased protein content to optimize zinc bioavailability.

Zinc supplement use and contribution to zinc intake in Australian children.

OBJECTIVE: The aims of the present study were to examine the Zn intake and characteristics of Zn supplement users and non-users and to survey Zn supplements that are commercially available. DESIGN: Cross-sectional national nutrition survey (2007 Australian Children's Nutrition and Physical Activity Survey) and a review of commercially available Zn supplements. SETTING: Australia. SUBJECTS: Children (n 4834) aged 2-16 years. RESULTS: Zn supplement use was associated with younger age, being female, having a lower BMI and consuming a vegetarian or modified diet. Supplement users had significantly higher intakes of Zn than non-users in all age and gender subgroups. Adolescent boys aged 14-16 years who did not use Zn supplements were at highest risk of inadequate Zn intake (15 % compared with 1 % of users). Conversely, children aged 2-3 years were at highest risk of exceeding the recommended upper limit of Zn intake (86-87 % of users and 64-71 % of non-users), followed by children aged 4-8 years (9-29 % of users and 3-12 % of non-users). The most common sources of Zn supplements consumed by children were multi-vitamin and mineral preparations (92 %), followed by Zn-only supplements (5 %) and Zn-containing cold and flu, or cold sore supplements (3 %). A survey of commercially available Zn supplements revealed that the median elemental Zn content was 2 and 25 mg for multi-vitamin and mineral preparations and Zn-only supplements, respectively. CONCLUSIONS: Based on these data, widespread Zn supplement use among young children is unlikely to be warranted. The impact of exceeding the upper limit of Zn intake on biomarkers of Zn toxicity requires further investigation.

Effect of vegetarian diets on zinc status: a systematic review and meta-analysis of studies in humans.

Plant-based diets contain less saturated fat and cholesterol and more folate, fibre and phytochemicals than omnivorous diets, but some micronutrients, especially zinc, are poorly bioavailable. The findings of studies exploring the zinc intake and zinc status in populations that habitually consume vegetarian diets are inconsistent. This study aims to investigate the effects of plant-based diets on dietary zinc intake and status in humans using systematic review and meta-analysis techniques. Thirty-four studies were included in the systematic review. Of these, 26 studies (reporting 48 comparisons) compared males and/or females consuming vegetarian diets with non-vegetarian groups and were included in meta-analyses. Dietary zinc intakes and serum zinc concentrations were significantly lower (-0.88 ± 0.15 mg day(-1), P < 0.001 and -0.93 ± 0.27 µmol L(-1), P = 0.001 respectively; mean ± standard error) in populations that followed habitual vegetarian diets compared with non-vegetarians. Secondary analyses showed greater impact of vegetarian diets on the zinc intake and status of females, vegetarians from developing countries and vegans. Populations that habitually consume vegetarian diets have low zinc intakes and status. Not all vegetarian categories impact zinc status to the same extent, but a lack of consistency in defining vegetarian diets for research purposes makes dietary assessment difficult. Dietary practices that increase zinc bioavailability, the consumption of foods fortified with zinc or low-dose supplementation are strategies that should be considered for improving the zinc status of vegetarians with low zinc intakes or serum zinc concentrations at the lower end of the reference range.

Daily consumption of Lactobacillus gasseri CP2305 improves quality of sleep in adults - A systematic literature review and meta-analysis.

BACKGROUND & AIM: The gut-brain axis is one of the proposed interactions between the brain and peripheral intestinal functions; of particular interest is the influence of food components on the gut-brain axis mediated via the gut microbiome. Probiotics and paraprobiotics have been proposed to interact with the intestinal environment and provide health benefits such as improving sleep quality. The aim of this research was to undertake a systematic literature review and meta-analysis to evaluate the current evidence regarding the effects of Lactobacillus gasseri CP2305 on sleep quality for the general population. METHODS: A systematic literature search was conducted of peer-reviewed articles published up to 04 November 2022. Randomised controlled trials were identified that investigated the effects of Lactobacillus gasseri CP2305 on sleep parameters in adults. Meta-analysis of the change in the Pittsburgh Sleep Quality Index (PSQI) global score was conducted. Quality assessments of individual studies were conducted using the Cochrane Risk of Bias and Health Canada tools. RESULTS: Seven studies were included in the systematic literature review; six studies included data for meta-analysis to quantify the effect of L. gasseri CP2305 on sleep quality. The ingestion of L. gasseri CP2305 resulted in significant improvement in the PSQI global score compared to control (-0.77, 95% CI: -1.37 to -0.16, P = 0.01). In the two studies that included electroencephalogram (EEG) data, output was significantly improved for at least half of the measured EEG outcomes after consumption of L. gasseri CP2305. No serious concerns were found in the potential biases of included studies, indirectness of the included evidence, and other methodological issues. CONCLUSION: The present systematic review and meta-analysis indicates significant improvement in sleep quality of adults with mild to moderate stress as an effect of daily consumption of L. gasseri CP2305. Based on existing evidence, the relationship between L. gasseri CP2305 and enhanced sleep quality is plausible, however further investigations are required to confirm the mechanisms of actions for this effect.

A randomized controlled trial in young women of the effects of consuming pork meat or iron supplements on nutritional status and feeling of well-being.

OBJECTIVES: Limited information is available on the role of pork meat in influencing iron status. The aim of this study was to determine the effect of consuming pork meat as compared to iron supplementation on nutritional status and feeling of well-being. METHODS: Young women were randomly assigned to a control diet (CG), a pork-containing diet (PG), or a control diet with iron supplementation (SG) for 12 weeks. Sixty-five women aged 24.6 ± 4.4 years (mean ± SD) completed the trial. RESULTS: Serum ferritin concentrations were increased significantly (p = 0.001) in participants assigned to the SG as compared with the other groups, as assessed by repeated-measures analysis of variance. At week 12, hemoglobin concentrations were significantly higher in PG and SG as compared with CG. Plasma zinc concentrations at the end of the intervention were similar to baseline concentrations for individuals in the CG and PG but were decreased significantly (p < 0.05) in SG. Plasma-, erythrocyte-folate, and serum vitamin B6 and B12 concentrations were not significantly affected by the intervention, although the concentrations of vitamins B6 and B12 tended to increase in PG. Well-being, as measured using the Health Survey Short Form (SF-36) and its 8 multi-item scales, showed significant improvement in vitality in SG (p < 0.05) and bodily pain in PG (p < 0.05). No significant relationships were observed between these health concept scores and biomarkers of nutritional status. CONCLUSIONS: Consumption of pork meat by young women maintains hemoglobin levels to the same extent as low-dose iron supplementation and enhances the components of well-being, mainly their perception of bodily pain.

Vitamin B12 status, cognitive decline and dementia: a systematic review of prospective cohort studies.

Poor vitamin B12 status may lead to the development of cognitive decline and dementia but there is a large variation in the quality, design of and results reported from these investigations. We have undertaken a systematic review of the evidence for the association between vitamin B12 status and cognitive decline in older adults. A database search of the literature to 2011 was undertaken, using keywords related to vitamin B12 and cognition. All prospective cohort studies assessing the association of serum vitamin B12 or biomarkers were included. Quality assessment and extraction of the data were undertaken by two researchers. The quality assessment tool assigns a positive, neutral or negative rating. Of 3772 published articles, thirty-five cohort studies (n 14 325 subjects) were identified and evaluated. No association between serum vitamin B12 concentrations and cognitive decline or dementia was found. However, four studies that used newer biomarkers of vitamin B12 status (methylmalonic acid and holotranscobalamin (holoTC)) showed associations between poor vitamin B12 status and the increased risk of cognitive decline or dementia diagnosis. In general, the studies were of reasonable quality (twenty-one positive, ten neutral and four negative quality) but of short duration and inadequate subject numbers to determine whether an effect exists. Future studies should be of adequate duration (at least 6 years), recruit subjects from the seventh decade, choose markers of vitamin B12 status with adequate specificity such as holoTC and/or methylmalonic acid and employ standardised neurocognitive assessment tools and not screening tests in order to ascertain any relationship between vitamin B12 status and cognitive decline.

The effect of zinc supplementation on glucose homeostasis: a randomised double-blind placebo-controlled trial.

AIMS: The burden and health costs of Type 2 Diabetes Mellitus continue to increase globally and prevention strategies in at-risk people need to be explored. Previous work, in both animal models and humans, supports the role of zinc in improving glucose homeostasis. We, therefore, aimed to test the effectiveness of zinc supplementation on glycaemic control in pre-diabetic adults. METHODS: We conducted a randomized, double-blind, placebo-controlled trial across 10 General Practitioner (GP) practices in NSW, Australia. The trial is known as Zinc in Preventing the Progression of pre-Diabetes (ZIPPeD)Study. Pre-diabetic (haemoglobin A1c [HbA1c] 5.7-6.4%, 39-46 mmol/mol) men and women (N = 98) were all assigned to a free state government telephone health coaching service (New South Wales Get Healthy Information and Coaching Service) and then randomised to either daily 30 mg zinc gluconate or placebo. Blood tests were collected at baseline, 1, 6 and 12 months for the primary outcomes (HbA1c, fasting blood glucose (FBG)); secondary outcomes included Homeostasis Model Assessment 2 (HOMA 2) parameters, lipids, body weight, height, waist circumference, blood pressure and pulse. RESULTS: The baseline-adjusted mean group difference at 6 months, expressed as treatment-placebo, (95% CI) was -0.02 (-0.14, 0.11, p = 0.78) for HbA1c and 0.17 (-0.07, 0.42; p = 0.17) for FBG, neither of which were statistically significant. There were also no significant differences between groups in any of the secondary outcomes. Zinc was well tolerated, and compliance was high (88%). CONCLUSION: We believe our results are consistent with other Western clinical trial studies and do not support the use of supplemental zinc in populations with a Western diet. There may still be a role for supplemental zinc in the developing world where diets may be zinc deficient. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry, ACTRN12618001120268. Registered on 6 July 2018.

Using the AUSDRISK score to screen for pre-diabetes and diabetes in GP practices: a case-finding approach.

OBJECTIVE: To identify the optimal AUSDRISK threshold score to screen for pre-diabetes and diabetes. METHODS: A total of 406 adult patients not diagnosed with diabetes were screened in General Practices (GP) between May and October 2019. All patients received a point of care (POC) HbA1c test. HbA1c test results were categorised into diabetes (≥6.5% or ≥48 mmol/mol), pre-diabetes (5.7-6.4% or 39-47 mmol/mol), or normal (<5.7% or 39 mmol/mol). RESULTS: Of these patients, 9 (2%) had undiagnosed diabetes and 60 (15%) had pre-diabetes. A Receiver Operator Characteristic (ROC) curve was constructed to predict the presence of pre-diabetes and diabetes; the area under the ROC curve was 0.72 (95%CI 0.65-0.78) indicating modest predictive ability. The optimal threshold cut point for AUSDRISK score was 17 (sensitivity 76%, specificity 61%, + likelihood ratio (LR) 1.96, - likelihood ratio of 0.39) while the accepted cut point of 12 performed less well (sensitivity 94%, specificity 23%, +LR=1.22 -LR+0.26). CONCLUSIONS: The AUSDRISK tool has the potential to be used as a screening tool for pre-diabetes/diabetes in GP practices. A cut point of ≥17 would potentially identify 75% of all people at risk and three in 10 sent for further testing would be positive for prediabetes or diabetes. IMPLICATIONS FOR PUBLIC HEALTH: Routine case-finding in high-risk patients will enable GPs to intervene early and prevent further public health burden from the sequelae of diabetes.

Zinc transporter genes are coordinately expressed in men and women independently of dietary or plasma zinc.

The zinc transporter (ZnT; SLC30) and Zrt- and Irt-like protein (Zip, SLC39) zinc transporter families are integral to the maintenance of intracellular zinc concentrations. Few studies have examined the expression patterns of zinc transporter genes in human primary tissues. This study investigated the expression levels of a range of zinc transporter mRNA in the peripheral blood mononuclear cells of healthy men and women (n = 40) using quantitative real-time PCR. It also explored the relationships among zinc transporter expression levels, plasma zinc concentrations, and dietary zinc intake. The relative expression of the zinc transporter mRNA varied considerably, with ZnT7, ZnT1, and Zip1 being the most abundantly expressed. ZnT1 and Zip1 mRNA were highly correlated with one another (r = 0.9; P < 0.001) and with ZnT5, ZnT7, Zip3, and Zip10 (P < 0.001). When analyzed by gender, a correlation between the mRNA of ZnT7 and Zip3 (r = 0.6; P < 0.01) was demonstrated only in women. Zip10 mRNA was correlated with ZnT1 and Zip1 (r = 0.9; P < 0.001) in men only. In a regression analysis, plasma zinc variability was not significantly explained by dietary zinc intake, gender, age, or any individual or combination of zinc transporters. This study expands what is known about both the levels of zinc transporter gene transcription in humans and the extent of its variation in healthy men and women. The positive association between the mRNA of ZnT1 and Zip1, which have reciprocal roles in zinc transport across the plasma membrane, provides insight into the coordinated control of zinc homeostasis in humans.

Evaluation of the micronutrient composition of plant foods produced by organic and conventional agricultural methods.

The aim of the present analysis was to evaluate the micronutrient content of plant foods produced by organic and conventional agricultural methods. Studies were identified from a search of electronic databases (1980-2007, inclusive) as well as manual searches. A total of 66 studies (describing 1440 micronutrient comparisons) were identified. Thirty-three studies (908 comparisons) satisfied the screening criteria which considered cultivar, harvesting, and soil conditions. In studies that satisfied the screening criteria, the absolute levels of micronutrients were higher in organic foods more often than in conventional foods (462 vs 364 comparisons, P=0.002), and the total micronutrient content, expressed as a percent difference, was higher in organic (+5.7%, P<0.001) as compared to conventionally grown produce. The micronutrient content of food groups was more frequently reported to be higher for organic vegetables and legumes compared to their conventional counterparts (vegetables, 267 vs 197, P<0.001; legumes, 79 vs 46, P=0.004). This trend was supported by a mean percent difference in micronutrient content favoring organic vegetables (+5.9%, P<0.001) and legumes (+5.7%, P<0.001). Further research is required to determine the effect of organic agricultural methods on a broader range of nutrients and their potential impact on health.

Zinc in Preventing the Progression of pre-Diabetes (ZIPPeD Study) - study protocol for a randomised placebo-controlled trial in Australia.

BACKGROUND: Diabetes is increasing in incidence, morbidity and treatment costs globally, hence prevention strategies need to be explored. Animal studies and some human data have shown that zinc can improve glycaemic control, but the impact of this effect in a pre-diabetic population remains uncertain. This study is designed to investigate whether zinc gluconate and lifestyle coaching can improve glucose handling and ultimately reduce diabetes incidence in an at-risk pre-diabetic population in Australia. METHODS/DESIGN: The study will be a randomised, placebo-controlled, double-blind clinical trial. The study will be conducted at the Hunter New England Local Health District New South Wales (NSW), Australia. Pre-diabetic (haemoglobin A1c [HbA1c] 5.7-6.4) male and female participants (n = 410) aged 40-70 years will be recruited through the Diabetes Alliance Network, a collaboration of diabetes specialists and general practitioner practices. All participants will be given routine care to encourage healthy lifestyle changes using a telephone coaching service (Get Healthy Information and Coaching Service, NSW Health) and then randomised to receive a supplement, either zinc gluconate (equivalent to 30 mg of elemental zinc) or placebo of identical appearance for 12 months. The identity of the supplements will be blinded to both research personnel and the participants. Participants will be asked to complete medical, lifestyle and dietary surveys and will have baseline and final visits at their general practitioner practice. Primary outcomes will be HbA1c and insulin sensitivity collected at baseline and at 1, 6 and 12 months; secondary outcomes will include fasting blood glucose, fasting cholesterol, blood pressure and body mass index. The primary efficacy endpoint will be judged at 6 months. DISCUSSION: This study will generate new evidence about the potential for health coaching, with or without zinc supplementation, to improve glucose handling and ultimately to reduce progression from pre-diabetes to diabetes. TRIAL REGISTRATION: Australian and New Zealand Clinical Trials Registry, ACTRN12618001120268 . Registered on 6 July 2018.

Zinc status at baseline is not related to acute changes in serum zinc concentration following bouts of running or cycling.

Zinc status is implicated in physiological functions related to exercise performance and physical activity. We have previously demonstrated significant changes in serum zinc concentrations following a bout of aerobic exercise, suggestive of a relationship between zinc metabolism and exercise-related functions. In the present study, we aim to determine the association between pre-exercise serum zinc concentration and immediate changes in serum zinc concentration following an aerobic exercise bout. We have previously conducted a systematic literature search of PubMed, Web of Science, Scopus and SPORTDiscus, for studies that investigated the acute effects of aerobic exercise on zinc biomarkers. In the current study, we undertook a secondary analysis using mixed effects meta-regression modelling to determine the relationship between baseline serum zinc concentration and the change in serum zinc concentration immediately after exercise. Meta-regression models revealed no significant relationship between baseline serum zinc concentration and the change in serum zinc concentration following a bout of exercise when all comparisons were included (slope -0.11 ±â€¯0.07 [standard error]; P > 0.05). When comparisons were stratified by exercise modality, no significant relationships were observed for exercise bouts involving cycling or running. The current analyses were limited by the available literature and low statistical power of the meta-regression models. Based on the current available data, the present analysis revealed limited evidence for a relationship between pre-exercise serum zinc concentration and immediate changes in serum zinc levels following a bout of aerobic exercise. Subgroup meta-regression analyses stratified by the mode of exercise bouts did not differ from the overall results. This suggests that zinc status at baseline is not related to acute changes in serum zinc concentration following bouts of aerobic exercise.

Lower Serum Zinc Concentration Despite Higher Dietary Zinc Intake in Athletes: A Systematic Review and Meta-analysis.

BACKGROUND: Zinc is an essential trace element that has been implicated in numerous biological functions, including immunity, energy metabolism and antioxidative processes. Recent evaluations of the literature have provided evidence of significant acute changes in zinc metabolism following a bout of aerobic exercise. OBJECTIVE: The aim of this study was to determine the zinc status of trained athletes compared with control populations, as described in cross-sectional studies. DESIGN: We conducted a systematic literature search of the PubMed, Scopus, SPORTDiscus and Cochrane Library electronic databases from inception to 28 January 2016 to identify cross-sectional studies that determined the zinc status of athletes compared with a control population. Meta-analysis of the differences in serum zinc concentration and dietary zinc intake between groups were conducted. RESULTS: Twelve studies were included in the systematic review. Of the included studies, nine and eight studies provided sufficient data for the meta-analysis of serum zinc concentration and dietary zinc intake, respectively. Serum zinc concentration was significantly lower in athletes [- 0.93 µmol/L, 95% confidence interval (CI) - 1.62 to - 0.23] despite significantly higher dietary zinc intake compared with the control population (2.57 mg/day, 95% CI 0.97-4.16). Data on erythrocyte and urinary zinc from the included studies were insufficient for meta-analysis. CONCLUSIONS: Despite higher total dietary zinc intake, athletes generally have lower serum zinc concentration, which suggests that athletes have higher requirement of zinc than those who are physically inactive. Further investigations of zinc metabolism during exercise and dietary zinc requirement in active populations are needed to establish evidence-based recommendations.

Modifiable "Predictors" of Zinc Status in Toddlers.

Suboptimal zinc status is common in very young children and likely associated with increased risk of infection and detrimental effects on growth. No studies have determined potentially modifiable "predictors" of zinc status in toddlers from high-income countries. This cross-sectional analysis of 115 toddlers from the Baby-Led Introduction to SolidS (BLISS) study used weighed diet records (three non-consecutive days) to assess dietary intake, and a venous blood sample (trace-element free techniques) to assess plasma zinc, at 12 months of age. "Predictors" of plasma zinc were determined by univariate analysis and multiple regression. Mean (SD) plasma zinc was 9.7 (1.5) µmol/L, 60% were below the IZiNCG reference limit of <9.9 µmol/L. Median (25th, 75th percentiles) intake of zinc was 4.4 (3.7, 5.4) mg/day. Red meat intake (p = 0.004), consumption of zinc-fortified infant formula (3-6 mg zinc/100 g) (p = 0.026), and food fussiness (p = 0.028) were statistically significant "predictors" of plasma zinc at 12 months. Although higher intakes of red meat, and consumption of infant formula, are potentially achievable, it is important to consider possible barriers, particularly impact on breastfeeding, cost, and the challenges of behavior modification. Of interest is the association with food fussiness-further research should investigate the direction of this association.

Modified Version of Baby-Led Weaning Does Not Result in Lower Zinc Intake or Status in Infants: A Randomized Controlled Trial.

BACKGROUND: Little is known about zinc intakes and status during complementary feeding. This is particularly true for baby-led approaches, which encourage infants to feed themselves from the start of complementary feeding, although self-feeding may restrict the intake of zinc-rich foods. OBJECTIVE: To determine the zinc intakes, sources, and biochemical zinc status of infants following Baby-Led Introduction to SolidS (BLISS), a modified version of Baby-Led Weaning (BLW), compared with traditional spoon-feeding. DESIGN: Secondary analysis of the BLISS randomized controlled trial. PARTICIPANTS/SETTING: Between 2012 and 2014, 206 community-based participants from Dunedin, New Zealand were randomized to a Control or BLISS group. INTERVENTION: BLISS participants received eight study visits (antenatal to 9 months) providing education and support regarding BLISS (ie, infant self-feeding from 6 months with modifications to address concerns about iron, choking, and growth). MAIN OUTCOME MEASURES: Dietary zinc intakes at 7 and 12 months (weighed 3-day diet records) and zinc status at 12 months (plasma zinc concentration). STATISTICAL ANALYSES PERFORMED: Regression analyses were used to investigate differences in dietary intakes and zinc status by group, adjusted for maternal education and parity and infant age and sex. RESULTS: There were no significant differences in zinc intakes between BLISS and Control infants at 7 (median: 3.5 vs 3.5 mg/day; P=0.42) or 12 (4.4 vs 4.4 mg/day; P=0.86) months. Complementary food groups contributing the most zinc at 7 months were "vegetables" for Control infants, and "breads and cereals" for BLISS infants, then "dairy" for both groups at 12 months. There was no significant difference in mean±standard deviation plasma zinc concentration between the Control (62.8±9.8 µg/dL [9.6±1.5 µmol/L]) and BLISS (62.8±10.5 µg/dL [9.6±1.6 µmol/L]) groups (P=0.75). CONCLUSIONS: BLISS infants achieved similar zinc intake and status to Control infants. However, the BLISS intervention was modified to increase iron intake, which may have improved zinc intake, so these results should not be generalized to infants following unmodified BLW.

Comparison of 4 diets of varying glycemic load on weight loss and cardiovascular risk reduction in overweight and obese young adults: a randomized controlled trial.

BACKGROUND: Despite the popularity of low-glycemic index (GI) and high-protein diets, to our knowledge no randomized, controlled trials have systematically compared their relative effects on weight loss and cardiovascular risk. METHODS: A total of 129 overweight or obese young adults (body mass index, > or =25 [calculated as weight in kilograms divided by the square of height in meters]) were assigned to 1 of 4 reduced-fat, high-fiber diets for 12 weeks. Diets 1 and 2 were high carbohydrate (55% of total energy intake), with high and low GIs, respectively; diets 3 and 4 were high protein (25% of total energy intake), with high and low GIs, respectively. The glycemic load was highest in diet 1 and lowest in diet 4. Changes in weight, body composition, and blood chemistry profile were studied. RESULTS: While all groups lost a similar mean +/- SE percentage of weight (diet 1, -4.2% +/- 0.6%; diet 2, -5.5% +/- 0.5%; diet 3, -6.2% +/- 0.4%; and diet 4, -4.8% +/- 0.7%; P = .09), the proportion of subjects in each group who lost 5% or more of body weight varied significantly by diet (diet 1, 31%; diet 2, 56%; diet 3, 66%; and diet 4, 33%; P = .01). Women on diets 2 and 3 lost approximately 80% more fat mass (-4.5 +/- 0.5 [mean +/- SE] kg and -4.6 +/- 0.5 kg) than those on diet 1 (-2.5 +/- 0.5 kg; P = .007). Mean +/- SE low-density-lipoprotein cholesterol levels declined significantly in the diet 2 group (-6.6 +/- 3.9 mg/dL [-0.17 +/- 0.10 mmol/L]) but increased in the diet 3 group (+10.0 +/- 3.9 mg/dL [+0.26 +/- 0.10 mmol/L]; P = .02). Goals for energy distribution were not achieved exactly: both carbohydrate groups ate less fat, and the diet 2 group ate more fiber. CONCLUSION: Both high-protein and low-GI regimens increase body fat loss, but cardiovascular risk reduction is optimized by a high-carbohydrate, low-GI diet.

Plasma/Serum Zinc Status During Aerobic Exercise Recovery: A Systematic Review and Meta-Analysis.

BACKGROUND: Exercise and the subsequent recovery processes have been proposed to induce disturbances in zinc homeostasis. We previously reported acute increase in serum zinc concentration immediately after aerobic exercise; the change in the indices of zinc status during exercise recovery was not explored. OBJECTIVE: The aim of the current analysis is to determine the changes in zinc biomarkers during recovery from an aerobic exercise bout. METHODS: We conducted a systematic literature search on PubMed, Web of Science, Scopus and SPORTDiscus electronic databases from inception to 20 December 2014 to identify studies that investigated the acute effects of exercise on selected indices of zinc status. Meta-analyses were conducted to determine the change in serum zinc concentration during exercise recovery, defined as up to 4 h following exercise cessation, compared to pre-exercise levels. RESULTS: Forty-five studies were included in the systematic literature review, of which 12 studies (providing 18 comparisons) reported serum zinc levels after the cessation of exercise. During exercise recovery, serum zinc concentration was significantly lower than pre-exercise values (-1.31 ± 0.22 µmol/L, P < 0.001; mean ± SE). Secondary analyses showed a significant decrease of serum zinc levels in all categories of participants' training status, mode of exercise and time of blood collection. Insufficient data were available for meta-analysis of other zinc biomarkers. CONCLUSIONS: The present analysis showed that serum zinc levels decrease significantly during exercise recovery, compared to pre-exercise levels. This extends our previous report of an increase in serum zinc immediately after exercise. We postulate that the exercise-induced fluctuations in zinc homeostasis are linked to the muscle repair mechanisms following exercise; the potential for zinc to enhance the exercise recovery process remains to be determined.

Quantifiable effects of regular exercise on zinc status in a healthy population-A systematic review.

Zinc is an essential mineral of which its functions have potential implications on exercise performance and beneficial adaptations of physical activity. While the effects of aerobic exercise on zinc metabolism acutely have been well described, the effect of long-term exercise training on zinc status remains unclear. The present review aims to determine the effects of exercise training on markers of zinc status in an apparently healthy adult population. We conducted a systematic literature search on PubMed, Scopus, SPORTDiscus and Cochrane Library from inception to 28 January 2016 to identify interventional or cohort studies that investigated the effects of exercise training on indices of zinc status. Pairwise comparisons of mean differences in within-group change were calculated and summarised visually in forest plots. Six studies satisfied the inclusion criteria for the systematic review, of which 5 studies included data on changes in serum zinc concentrations and 3 studies provided changes in dietary zinc intake. Two comparisons showed significantly higher increase of serum zinc concentrations in the exercise group compared to control, while one comparison reported significantly lower change in serum zinc for the exercising group. The exercise groups consumed significantly higher dietary zinc compared to controls in two comparisons. The present review revealed an incomplete evidence base in evaluating the effect of long-term exercise training on markers of zinc status. Further well-designed investigations are required to elucidate the relationship for establishment of dietary recommendation in populations who are continuing exercise interventions.

Interrelationships among mediators of cellular zinc homeostasis in healthy and type 2 diabetes mellitus populations.

SCOPE: The involvement of zinc in multiple physiological systems requires tight control of cellular zinc concentration. This study aims to explore the relationships among selected mediators of cellular zinc homeostasis in an apparently healthy (AH) population and a cohort with type 2 diabetes mellitus (T2DM). METHODS AND RESULTS: Baseline data of three trials forming two cohorts, AH (n = 70) and T2DM (n = 42), were used for multivariate analyses to identify groupings within ten zinc transporter and metallothionein (MT) gene expressions, stratified by health status. Multiple regression models were used to explore relationships among zinc transporter/MT groupings and plasma zinc. Gene expression of zinc transporters and MTs, with the exception of ZnT6, were significantly lower in the T2DM cohort (p < 0.01). Cluster analysis showed that the groupings of zinc transporters and MTs were largely similar between the two cohorts, with the exception for ZnT1 and ZIP7. Zinc transporters and MTs were significant determinants of plasma zinc (r2 = 0.48, p = 0.001) in the AH cohort, but not in the T2DM cohort. CONCLUSION: The current study suggests altered cellular zinc homeostasis in T2DM and supports the use of multiple zinc transporters and MTs groupings to further understand zinc homeostasis in health and T2DM.