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BACKGROUND:Zinc deficiency impairs immune function and is common among children in South-East Asia. OBJECTIVES:The effect of zinc supplementation on immune function in young Laotian children was investigated. METHODS:Children (n = 512) aged 6-23 mo received daily preventive zinc tablets (PZ; 7 mg Zn/d), daily multiple micronutrient powder (MNP; 10 mg Zn/d, 6 mg Fe/d, plus 13 other micronutrients), therapeutic dispersible zinc tablets only in association with diarrhea episodes (TZ; 20 mg Zn/d for 10 d after an episode), or daily placebo powder (control). These interventions continued for 9 mo. Cytokine production from whole blood cultures, the concentrations of T-cell populations, and a complete blood count with differential leukocyte count were measured at baseline and endline. Endline means were compared via ANCOVA, controlling for the baseline value of the outcome, child age and sex, district, month of enrollment, and baseline zinc status (below, or above or equal to, the median plasma zinc concentration). RESULTS:T-cell cytokines (IL-2, IFN-γ, IL-13, IL-17), LPS-stimulated cytokines (IL-1β, IL-6, TNF-α, and IL-10), and T-cell concentrations at endline did not differ between intervention groups, nor was there an interaction with baseline zinc status. However, mean ± SE endline lymphocyte concentrations were significantly lower in the PZ than in the control group (5018 ± 158 compared with 5640 ± 160 cells/μL, P = 0.032). Interactions with baseline zinc status were seen for eosinophils (Pixn = 0.0036), basophils (Pixn = 0.023), and monocytes (P = 0.086) but a significant subgroup difference was seen only for eosinophils, where concentrations were significantly lower in the PZ than in the control group among children with baseline plasma zinc concentrations below the overall median (524 ± 44 compared with 600 ± 41 cells/μL, P = 0.012). CONCLUSIONS:Zinc supplementation of rural Laotian children had no effect on cytokines or T-cell concentrations, although zinc supplementation affected lymphocyte and eosinophil concentrations. These cell subsets may be useful as indicators of response to zinc supplementation.This trial was registered at clinicaltrials.gov as NCT02428647.

Background: Human milk is the subject of many studies, but procedures for representative sample collection have not been established. Our improved methods for milk micronutrient analysis now enable systematic study of factors that affect its concentrations.Objective: We evaluated the effects of sample collection protocols, variations in circadian rhythms, subject variability, and acute maternal micronutrient supplementation on milk vitamin concentrations.Methods: In the BMQ (Breast-Milk-Quality) study, we recruited 18 healthy women (aged 18-26 y) in Dhaka, Bangladesh, at 2-4 mo of lactation for a 3-d supplementation study. On day 1, no supplements were given; on days 2 and 3, participants consumed ∼1 time and 2 times, respectively, the US-Canadian Recommended Dietary Allowances for vitamins at breakfast (0800-0859). Milk was collected during every feeding from the same breast over 24 h. Milk expressed in the first 2 min (aliquot I) was collected separately from the remainder (aliquot II); a third aliquot (aliquot III) was saved by combining aliquots I and II. Thiamin, riboflavin, niacin, and vitamins B-6, B-12, A, and E and fat were measured in each sample.Results: Significant but small differences (14-18%) between aliquots were found for all vitamins except for vitamins B-6 and B-12. Circadian variance was significant except for fat-adjusted vitamins A and E, with a higher contribution to total variance with supplementation. Between-subject variability accounted for most of the total variance. Afternoon and evening samples best reflected daily vitamin concentrations for all study days. Acute supplementation effects were found for thiamin, riboflavin, and vitamins B-6 and A at 2-4 h postdosing, with 0.1-6.17% passing into milk. Supplementation was reflected in fasting, 24-h postdose samples for riboflavin and vitamin B-6. Maximum amounts of dose-responding vitamins in 1 feeding ranged from 4.7% to 21.8% (day 2) and 8.2% to 35.0% (day 3) of Adequate Intake.Conclusions: In the milk of Bangladeshi mothers, differences in vitamin concentrations between aliquots within feedings and by circadian variance were significant but small. Afternoon and evening collection provided the most-representative samples. Supplementation acutely affects some breast-milk micronutrient concentrations. This trial was registered at clinicaltrials.gov as NCT02756026.

To assist with the evaluation of zinc (Zn) intervention programs, information is needed on the magnitude and velocity of response of plasma Zn concentration following changes in Zn intake. Our objective in this study was to measure plasma Zn concentration of healthy adult men before and after initiation and discontinuation of 1 of 2 dosages of Zn supplements or placebo. We conducted a randomized, double-blind, placebo-controlled trial in 58 apparently healthy males aged 19-54 y. Participants received 1 of 3 liquid supplements daily for 21 d: 10 or 20 mg Zn/d, as Zn sulfate, or placebo. Fasting plasma Zn concentrations were measured on 14 occasions before, during, and after supplementation. Data were analyzed using mixed-model ANCOVA. The plasma Zn concentration was related to day of study (P < 0.0001) and study group (P < 0.0001). Controlling for baseline concentrations, plasma Zn concentrations were consistently elevated above baseline by d 5 among individuals in both of the Zn-supplemented groups compared with those receiving placebo supplements, regardless of their initial plasma Zn concentration. There were no significant group-wise differences between those who received either 10 or 20 mg/d Zn. Plasma Zn concentrations of supplemented individuals declined following withdrawal of supplementation and within 2 wk no longer differed from those of the placebo group. Change in the plasma Zn concentration is a useful indicator to monitor compliance with, and possibly effectiveness of, Zn supplementation programs. To ensure accurate interpretation of the results, samples should be collected while the intervention is still in progress. J. Nutr. 140: 2128-2133, 2010. doi: 10.3945/jn.110.122812

A survey indicated that high-dose vitamin A (HD-VA) supplements had no apparent effect on vitamin A (VA) status, assessed by serum retinol concentrations, of Zambian children < 5 y of age. To explore possible reasons for the lack of response, we quantified absorption, retention, and urinary elimination of either a single HD-VA supplement (209.8 [micro]mol; 60 mg) or a smaller dose of stable isotope (SI)-labeled VA (17.5 [micro]mol; 5 mg), which was used to estimate VA pool size, in 3- to 4-y-old Zambian boys (n = 4 for each VA dose). A tracer dose of [14C2]-labeled VA (0.925 kBq; 25 nCi) was coadministered with the HD-VA supplement or SI-labeled VA, and 24-h stool and urine samples were collected for 3 and 7 consecutive days, respectively, and 24-h urine samples at 4 later time points. Accelerator MS was used to quantify 14C in stool and urine. Estimates of absorption, retention, and the urinary elimination rate (UER) were 83.8 [+ or -] 7.1%, 76.3 [+ or -] 6.7%, and 1.9 [+ or -] 0.6%/d, respectively, for the HD-VA supplement and 76.5 [+ or -] 9.5%, 71.1 [+ or -] 9.4%, and 1.8 [+ or -] 1.2%/d, respectively, for the SI-labeled VA. Mean estimates of absorption, retention, and the UER did not differ by size of the VA dose administered. Estimated absorption and retention were negatively associated with reported fever (r = -0.83; P = 0.011). The HD-VA supplement and SI-labeled VA were adequately absorbed, retained, and utilized in apparently healthy Zambian preschool-age boys; absorption and retention may be affected by recent fever. J. Nutr. 140:1588-1594, 2010. doi: 10.39454/jn.110.125500.

Deficiencies of multiple micronutrients (MMN) usually coexist in developing countries, but supplements have usually provided only 1 or 2 micronutrients (MN). To inform policy, in this article we compared the relative benefits of supplying MMN vs. a placebo or 1 or 2 MN on the following: children's growth, health, and development; pregnancy outcome; nutritional status; and HIV/AIDS mortality and morbidity in adults. Sufficient data were available to perform random-effects meta-analyses of randomized controlled trials (RCT) for the effects of MMN on child growth and nutritional status. Results for other outcomes are presented as effect sizes (ES) when available. In children, MMN interventions resulted in small but significantly greater improvements in length or height (ES = 0.13; 95% CI: 0.055, 0.21) and weight (ES = 0.14; 95% CI: 0.029, 0.25), hemoglobin (ES = 0.39; 95% CI: 0.25, 0.53), serum zinc (ES = 0.23; 95% Cl: 0.18, 0.43), serum retinol (ES = 0.33; 95 % CI: 0.050, 0.61), and motor development. A Cochrane review reported that compared with no supplementation or a placebo, MMN supplementation during pregnancy reduced the relative risk of low birth weight (0.83), small-for-gestational age (0.92), and anemia (0.61); however, MMN were not more effective than iron +folic acid alone. There is some evidence that MMN supplementation improves CD4 counts and HIV-related morbidity and mortality in adults. The efficacy of MMN varies across trials, but overall there is evidence that outcomes are better than when providing [less than or equal to] 2 MN. The policy implications of these studies are discussed.

The high prevalence of vitamin B-12 deficiency in many regions of the world is becoming recognized as a widespread public health problem, but it is not known to what extent this deficiency results from a low intake of the vitamin or from its malabsorption from food. In rural Kenya, where a previous study identified a high prevalence of inadequate vitamin B-12 intakes, this study examined whether plasma vitamin B-12 concentrations were associated with dietary sources of the vitamin at baseline and could be increased by supplementation with animal source foods (ASF). The 4 experimental groups in 503 school children were: 1) control (no food provided); 2) githeri (a maize and bean staple with added oil); 3) githeri + meat (githeri + minced beef); or 4) githeri + milk (githeri + milk). Feedings were isocaloric. Dietary data were collected at baseline, and biochemical data at baseline and after 1 and 2 y of feeding. Baseline plasma vitamin B-12 concentration was 193.6 [+ or -] 105.3 pmol/L and correlated with % energy from ASF (r = 0.308, P < 0.001). The odds ratio for low plasma vitamin B-12 (

The essential design and quality control aspects of dietary assessment, randomized controlled trials (RCT) in developing countries and their subsequent meta-analysis are reviewed. Dietary assessment protocols consist of three stages: measurement of food intakes using a method appropriate for the study objectives, calculation of nutrient intakes and finally an evaluation of their nutrient adequacy. The latter may involve: 1) assessment of dietary diversity (average number of different foods consumed per day) and selected indices of dietary quality such as intakes of animal source foods (g/d); 2) percentage of energy from protein, fat and animal protein; 3) selected nutrient densities; and 4) dietary phytate:zinc molar ratio, as well as the prevalence of inadequate nutrient intakes calculated using a probability approach. To establish causality between the nutrient inadequacies identified and adverse health outcomes, RCT must be undertaken. A prerequisite of RCT is double-blind randomization, a procedure designed to eliminate biases arising from baseline confounding variables, unintended interventions and ascertainment bias. Results from existing RCT can be summarized via meta-analysis to gain a better understanding of the population relationship. Meta-analysis is a statistical technique involving linear models or generalized linear models, which can be performed after locating the individual studies, and selecting and abstracting all the necessary data. KEY WORDS: * dietary assessment * probability analysis * randomized clinical trials * double blinding * meta-analysis

To improve standardization of a folate bioassay, folate-depleted rats were repleted with a folate-free amino acid-based diet supplemented with 29 levels of folic acid. Growth was the main response variable and body tissue folate concentrations were also assessed. Because a positive correlation was observed between low levels of dietary folic acid and growth and little or no correlation was observed between high levels and growth, six regression models with a steep slope for low levels and a shallow or zero slope for high levels of dietary folic acid were evaluated. The model referred to as the 'two-phase regression' or 'change-point' model best described the relationship. Depleted rats needed 674 + or - 71 nmol folic acid/kg diet to reach their full growth potential. This value is biologically sensible, and this regression model is well established in the statistical literature. The change-point model is highly recommended to characterize the growth response, because growth is a functional response and, in the range of 226 to 680 nmol folic acid/kg, this response is linear, which is an additional advantage. Linear responses are easier to interpret because of complicated issues of interpretation and confidence intervals with nonlinearities. Linear regressions described serum and liver folate responses, whereas exponentials described whole blood and carcass folate responses. Depleted rats needed 5920 and 5780 nmol folic acid/kg diet to maximize their whole blood and carcass folates, respectively.