Zinc intake, status and indices of cognitive function in adults and children: a systematic review and meta-analysis

In developing countries, deficiencies of micronutrients are thought to have a major impact on child development; however, a consensus on the specific relationship between dietary zinc intake and cognitive function remains elusive. The aim of this systematic review was to examine the relationship between zinc intake, status and indices of cognitive function in children and adults. A systematic literature search was conducted using EMBASE, MEDLINE and Cochrane Library databases from inception to March 2014. Included studies were those that supplied zinc as supplements or measured dietary zinc intake. A meta-analysis of the extracted data was performed where sufficient data were available. Of all of the potentially relevant papers, 18 studies met the inclusion criteria, 12 of which were randomised controlled trials (RCTs; 11 in children and 1 in adults) and 6 were observational studies (2 in children and 4 in adults). Nine of the 18 studies reported a positive association between zinc intake or status with one or more measure of cognitive function. Meta-analysis of data from the adult’s studies was not possible because of limited number of studies. A meta-analysis of data from the six RCTs conducted in children revealed that there was no significant overall effect of zinc intake on any indices of cognitive function: intelligence, standard mean difference of <0.001 (95% confidence interval (CI) –0.12, 0.13) P=0.95; executive function, standard mean difference of 0.08 (95% CI, –0.06, 022) P=0.26; and motor skills standard mean difference of 0.11 (95% CI –0.17, 0.39) P=0.43. Heterogeneity in the study designs was a major limitation, hence only a small number (n=6) of studies could be included in the meta-analyses. Meta-analysis failed to show a significant effect of zinc supplementation on cognitive functioning in children though, taken as a whole, there were some small indicators of improvement on aspects of executive function and motor development following supplementation but high-quality RCTs are necessary to investigate this further

Adapting an international food composition table for use in rural Kenya

The objective of this project was to adapt an existing international food composition table, the International Minilist (IML), and related databases, for use in estimating dietary intakes for a study in Embu, Kenya in 1998¿2001. The IML, developed as part of the WorldFood Dietary Assessment System in 1988¿1992, contains 195 basic food ingredients that are representative of ingredients consumed in many developing countries. We reviewed the IML, as well as ancillary databases, to determine if updates were necessary. A new database containing food density information (g/mL) and weights of common household measures was created. We did not identify new food items that needed to be added to the IML for this study, in part because the basic foods consumed have changed little over the past 10 years. However, the presence of new or reformulated commercial products required several updates to the file which links Embu food ingredients to IML food ingredients. The activity of provitamin A carotenoids was reduced by 50% to agree with the lower conversion factors currently recommended. We conclude that starting with an international table such as the IML can simplify the task of estimating intakes in developing countries which do not have a comprehensive food composition table

Designing snacks to address micronutrient deficiencies in rural Kenyan schoolchildren

Three snacks were designed to improve nutrient intakes among school-age children living in rural Kenya. Snacks containing animal-source foods (milk and meat) provided more nutrients than an equicaloric vegetarian snack. The vegetarian snack provided extra vitamin A (primarily from fortified cooking fat; the milk snack was rich in calcium, vitamin A, and vitamin B-12; and the meat snack supplied vitamin B-12, iron, and zinc. When changes in intakes from baseline to the feeding period were compared across the 4 groups, total energy intake increased the most for children in the meat group and the least for children in the control group. Differences in energy intakes across the 3 feeding groups were primarily caused by decreases in home intake for the vegetarian and milk snack groups. It is important to evaluate the change in home intakes as well as intakes from the foods provided by the study when evaluating the effect of feeding programs on nutrient adequacy

Meat supplementation improves growth, cognitive, and behavioral outcomes in Kenyan children

A randomized, controlled school feeding study was conducted in rural Embu District, Kenya to test for a causal link between animal-source food intake and changes in micronutrient nutrition and growth, cognitive, and behavioral outcomes. Twelve primary schools were randomly assigned to 1 of 4 groups. Children in Standard I classes received the local plant-based dish githerias a midmorning school snack supplemented with meat, milk, or fat added to equalize energy content in all feedings. The Control children received no feedings but participated in data collection. Main outcome measures assessed at baseline and longitudinally were 24-h food intake recall, anthropometry, cognitive function, physical activity, and behaviors during school free play. For cognitive function, the Meat group showed the steepest rate of increase on Raven's Progressive Matrices scores and in zone-wide school end-term total and arithmetic test scores. The Plain githeri and Meat groups performed better over time than the Milk and Control groups (P <0.02-0.03) on arithmetic tests. The Meat group showed the greatest increase in percentage time in high levels of physical activity and in initiative and leadership behaviors compared with all other groups. For growth, in the Milk group only younger and stunted children showed a greater rate of gain in height. The Meat group showed near doubling of upper midarm muscle area, and the Milk group a smaller degree of increase. This is the first randomized, controlled feeding study to examine the effect of meat-vs. milk-vs. plant-based snacks on functional outcomes in children

School snacks containing animal source foods improve dietary quality for children in rural Kenya

Provision of a snack at school could help alleviate the micronutrient malnutrition that is common among schoolchildren in developing countries. The Child Nutrition Project was designed to compare the efficacy of three school snacks in improving growth and cognitive function of children in rural Kenya. The snacks provided 20% of the children's energy requirement, and were composed of equicaloric portions of githeri (a vegetable stew) alone (Energy group), githeri plus milk (Milk group) or githeri plus meat (Meat group). A fourth group of children served as Controls. When nutrient intakes from three, 24-h dietary recalls collected before feeding were compared to three, 24-h recalls conducted after feeding began, intakes of vitamin B-12, riboflavin, vitamin A and calcium increased more in the Milk group than in the Control group, whereas intakes of vitamin B-12, vitamin A, calcium, available iron and available zinc increased more than those of Controls for children in the Meat group. At most of the time points examined, total energy intake increased more for the Meat group than for the other two feeding groups, because the additional energy provided by the Milk and Energy snacks was partially balanced by a decrease in the energy content of foods consumed at home. This decrease did not occur to the same extent for the Meat group, so both dietary quantity and dietary quality improved. For the Milk group, only dietary quality improved. For the Energy group, there were no significant changes in the total day's diet compared to the Control group

Ultraconserved elements (UCEs) resolve the phylogeny of Australasian smurf-weevils.

Weevils (Curculionoidea) comprise one of the most diverse groups of organisms on earth. There is hardly a vascular plant or plant part without its own species of weevil feeding on it and weevil species diversity is greater than the number of fishes, birds, reptiles, amphibians and mammals combined. Here, we employ ultraconserved elements (UCEs) designed for beetles and a novel partitioning strategy of loci to help resolve phylogenetic relationships within the radiation of Australasian smurf-weevils (Eupholini). Despite being emblematic of the New Guinea fauna, no previous phylogenetic studies have been conducted on the Eupholini. In addition to a comprehensive collection of fresh specimens, we supplement our taxon sampling with museum specimens, and this study is the first target enrichment phylogenomic dataset incorporating beetle specimens from museum collections. We use both concatenated and species tree analyses to examine the relationships and taxonomy of this group. For species tree analyses we present a novel partitioning strategy to better model the molecular evolutionary process in UCEs. We found that the current taxonomy is problematic, largely grouping species on the basis of similar color patterns. Finally, our results show that most loci required multiple partitions for nucleotide rate substitution, suggesting that single partitions may not be the optimal partitioning strategy to accommodate rate heterogeneity for UCE loci

Phylogenetic tree results of the Eupholini weevils, branch colors correspond to species clades: LEFT: SVDQuartets species tree.

<p>Dashed lines denote nodes that differ between trees. Node values indicate bootstrap support values. RIGHT: ASTRAL species tree, input trees derived from multi-partitioned MrBayes analyses of individual gene trees. Node values indicate support values of MrBayes posterior (minus burn-in) used as ASTRAL bootstrap replicates.</p

Linear regression of logit proportion of UCE loci captured verses specimen age.

<p>Number of UCE loci and specimen age for; <i>Xylocopa</i> (carpenter bees) from Blaimer et al. 2016, <i>Aphelocoma</i> (scrub-jays) from McCormack et al. 2016, Eupholini (smurf weevils) from this study. Specimen age is in years from when individual was first collected and preserved. Regressions show a decline in the number of UCE loci captured as specimen age increases, the rate of decline is similar between studies.</p

LEFT: ASTRAL species tree derived from multi-partitioned RAxML trees.

<p>Node values indicate bootstrap support values. RIGHT: ASTRAL species tree, input trees derived from multi-partitioned MrBayes analyses of individual gene trees. Node values are derived from posterior distribution of MrBayes trees (minus burn-in) where each sample of the MCMC generation represents a bootstrap sample to ASTRAL.</p