Zinc status of a group of pregnant adolescents at 36 weeks gestation living in southern Ontario

Zinc deficiency in low- and middle-income countries: prevalence and approaches for mitigation

This review addresses the prevalence of zinc deficiency in Low- and Middle-income Countries (LMICs) and assesses the available strategies for its alleviation. The paucity of national-level data on the zinc deficiency in LMICs is partially a result of the lack of a reliable biomarker. Zinc deficiency appears to be a public health problem in almost all the LMICs, irrespective of the recommended indicators (plasma zinc concentration, dietary zinc adequacy and stunting prevalence) used. Based on plasma/serum zinc concentration (PZC), which is the most appropriate indicator at present, the prevalence of zinc deficiency in LMICs is of concern. Among the 25 countries for which national PZC data were available, 23 had a zinc deficiency prevalence of >20% for at least one physiological group. Zinc supplementation is largely restricted as an adjunct therapy for diarrhoea management in children, and the best platform and the most effective way of preventive zinc supplementation delivery remains to be established. Impact assessment for current zinc fortification programmes in LMICs and the effectiveness of zinc supplementation as part of a multi-micronutrient powder is to be determined. Dietary diversification, though promising for LMICs, is in the nascent stages of development at present. Inclusion of meat and animal products can be an important way of improving zinc status. Programmatic experience with the promotion of home processing techniques to increase absorbable zinc in the diet is lacking. Conventional biofortification techniques are gaining recognition in LMICs; however, transgenic biofortification as a strategy remains controversial.

Effects of Zinc Supplementation on Inflammatory Skin Diseases: A Systematic Review of the Clinical Evidence

BACKGROUND

Zinc has been used in patients with acne vulgaris for its anti-inflammatory effects; however, it is unclear if zinc supplementation is also beneficial in other inflammatory skin conditions.

OBJECTIVE

The objective of this article was to determine the effect of zinc supplementation on inflammatory dermatologic conditions.

DATA SOURCES

We searched the Cochrane Central Register of Controlled Trials, EMBASE, MEDLINE, and Ovid with no time limit up to 29 May, 2019. Trials examining supplementation with zinc in the treatment of inflammatory dermatological conditions (acne vulgaris, atopic dermatitis, diaper dermatitis, hidradenitis suppurativa, psoriasis, and rosacea) in children and adults were selected.

RESULTS

Of 229 articles, 22 met inclusion criteria. Supplementation with zinc was found to be beneficial in ten of 14 studies evaluating its effects on acne vulgaris, one of two studies on atopic dermatitis, one of one study on diaper dermatitis, and three of three studies evaluating its effects on hidradenitis suppurativa. However, the one article found on psoriasis and the one article found on rosacea showed no significant benefit of zinc treatment on disease outcome.

CONCLUSIONS AND IMPLICATIONS

Some preliminary evidence supports the use of zinc in the treatment of acne vulgaris and hidradenitis suppurativa; however, more research is needed with similar methodologies and larger sample sizes in these diseases. Further, zinc may be of some benefit in the treatment plan for atopic dermatitis and diaper dermatitis; however, additional studies should be conducted to further evaluate these potentially positive associations. To date, no evidence is available to suggest that zinc may be of benefit in rosacea and psoriasis; however, limited data are available evaluating the use of zinc in these conditions.

Including 60 mg Elemental Iron in a Multiple Micronutrient Supplement Blunts the Increase in Serum Zinc after 12 Weeks of Daily Supplementation in Predominantly Anemic, Nonpregnant Cambodian Women of Reproductive Age

BACKGROUND

Multiple micronutrient (MMN) supplementation may result in interaction effects due to competing absorptive pathways of trace elements.

OBJECTIVES

The aim of this study was to investigate the effect of MMN supplementation with or without iron on serum zinc, selenium, and copper concentrations in Cambodian women.

METHODS

In a 2 × 2 factorial double-blind randomized 12-wk trial, predominantly anemic, nonpregnant women (aged 18-45 y) received daily 60 mg of iron (Fe; n = 201); 14 other micronutrients including zinc (15 mg), selenium (65 μg), and copper (2 mg), but no iron (MMN; n = 202); 60 mg iron plus MMN (Fe + MMN; n = 206); or a placebo (n = 200). Fasting morning blood was collected at baseline and 12 wk from women in 26 villages in Kampong Chhnang province. Serum zinc, selenium, and copper concentrations (secondary outcomes of the randomized controlled trial) were measured using inductively coupled plasma mass spectrometry. Generalized linear regression was used to estimate intervention effects [β coefficient (95% CI)] for Fe (with or without MMN) and MMN (with or without Fe) after testing for the presence of an Fe × MMN interaction.

RESULTS

A total of 760 women completed the trial. Zinc deficiency prevalence at baseline was 45% (inflammation-adjusted serum zinc <10.7 μmol/L). A significant Fe × MMN interaction (P = 0.02) was detected in the 2 × 2 analysis with serum zinc concentration as the outcome: the MMN group had a higher mean serum zinc concentration at 12 wk (12.3 μmol/L; 95% CI: 12.2, 12.4 μmol/L) compared with all other groups, and the Fe + MMN group had a higher mean serum zinc concentration (11.6 μmol/L; 95% CI: 11.5, 11.7 μmol/L) compared with the Fe group (11.0 μmol/L; 95% CI: 10.9, 11.0 μmol/L) and the placebo group (11.2 μmol/L; 95% CI: 11.1, 11.4 μmol/L).

CONCLUSIONS

The inclusion of 60 mg iron in the daily MMN formulation may be interfering with the absorption and/or metabolism of supplemental zinc in Cambodian women. This is of particular concern when MMN supplementation is implemented in populations with risk of zinc deficiency. This trial was registered at clinicaltrials.gov as NCT-02481375.

Zinc absorption by young adults from supplemental zinc citrate is comparable with that from zinc gluconate and higher than from zinc oxide

The water-soluble zinc salts gluconate, sulfate, and acetate are commonly used as supplements in tablet or syrup form to prevent zinc deficiency and to treat diarrhea in children in combination with oral rehydration. Zinc citrate is an alternative compound with high zinc content, slightly soluble in water, which has better sensory properties in syrups but no absorption data in humans. We used the double-isotope tracer method with (67)Zn and (70)Zn to measure zinc absorption from zinc citrate given as supplements containing 10 mg of zinc to 15 healthy adults without food and compared absorption with that from zinc gluconate and zinc oxide (insoluble in water) using a randomized, double-masked, 3-way crossover design. Median (IQR) fractional absorption of zinc from zinc citrate was 61.3% (56.6-71.0) and was not different from that from zinc gluconate with 60.9% (50.6-71.7). Absorption from zinc oxide at 49.9% (40.9-57.7) was significantly lower than from both other supplements (P < 0.01). Three participants had little or no absorption from zinc oxide. We conclude that zinc citrate, given as a supplement without food, is as well absorbed by healthy adults as zinc gluconate and may thus be a useful alternative for preventing zinc deficiency and treating diarrhea. The more insoluble zinc oxide is less well absorbed when given as a supplement without food and may be minimally absorbed by some individuals. This trial was registered at clinicaltrials.gov as NCT01576627.

Nutrition intervention strategies to combat zinc deficiency in developing countries

Widespread zinc deficiency is likely to exist in developing countries where staple diets are predominantly plant based and intakes of animal tissues are low. The severe negative consequences of zinc deficiency on human health in developing countries, however, have only recently been recognized. An integrated approach employing targeted supplementation, fortification and dietary strategies must be used to maximize the likelihood of eliminating zinc deficiency at a national level in developing countries. Supplementation is appropriate only for populations whose zinc status must be improved over a relatively short time period, and when requirements cannot be met from habitual dietary sources. As well, the health system must be capable of providing consistent supply, distribution, delivery and consumption of the zinc supplement to the targeted groups. Uncertainties still exist about the type, frequency, and level of supplemental zinc required for prevention and treatment of zinc deficiency. Salts that are readily absorbed and at levels that will not induce antagonistic nutrient interactions must be used. At a national level, fortification with multiple micronutrients could be a cost effective method for improving micronutrient status, including zinc, provided that a suitable food vehicle which is centrally processed is available. Alternatively, fortification could be targeted for certain high risk groups (e.g. complementary foods for infants). Efforts should be made to develop protected fortificants for zinc, so that potent inhibitors of zinc absorption (e.g. phytate) present either in the food vehicle and/or indigenous meals do not compromise zinc absorption. Fortification does not require any changes in the existing food beliefs and practices for the consumer and, unlike supplementation, does not impose a burden on the health sector. A quality assurance programme is required, however, to ensure the quality of the fortified food product from production to consumption. In the future, dietary modification/diversification, although long term, may be the preferred strategy because it is more sustainable, economically feasible, culturally acceptable, and equitable, and can be used to alleviate several micronutrient deficiencies simultaneously, without danger of inducing antagonistic micronutrient interactions. Appropriate dietary strategies include consumption of zinc-dense foods and those known to enhance zinc absorption, reducing the phytic acid content of plant based staplesviaenzymic hydrolysis induced by germination/fermentation or nonenzymic hydrolysis by soaking or thermal processing. All the strategies outlined above should be integrated with ongoing national food, nutrition and health education programmes, to enhance their effectiveness and sustainability, and implemented using nutrition education and social marketing techniques. Ultimately the success of any approach for combating zinc deficiency depends on strong advocacy, top level commitment, a stable infrastructure, long term financial support and the capacity to control quality and monitor and enforce compliance at the national or regional level. To be cost effective, costs for these strategies must be shared by industry, government, donors and consumers.

Nutritional status in pregnant adolescents: a systematic review of biochemical markers

Adolescent pregnancy is a major public health challenge for many industrialized countries and is associated with significant medical, nutritional, social and economic risk for mothers and their infants. Despite this, relatively little is known about the nutritional status of this population. The aim of this paper was to conduct a systematic review of the current evidence relating to the biochemical markers of nutritional status of pregnant adolescents living in industrialized countries. Six papers were identified that fulfilled the inclusion criteria, the majority of which were conducted in the United States. The studies were of variable quality and most failed to control for potential confounders which may have strongly influenced the findings. Due to limited research, conclusions cannot be drawn about the zinc and calcium status of pregnant adolescents, and data on folate and vitamin B(12) status appeared conflicting. There was some consensus among studies, however, to suggest that indicators of anaemia and iron status were compromised in pregnant adolescents, particularly during the third trimester of pregnancy. Chronological age did not appear to influence nutritional status, although there was some evidence to suggest that increasing gynaecologic age may positively influence plasma ferritin levels. Current research is limited by sampling and measurement bias, and research is urgently required to address these limitations. Further consideration should also be made of the influence of the role of socio-economic support on pregnant adolescents' nutritional status. The achievement of improved nutrition in pregnancy among adolescents requires multidisciplinary collaborations of adolescent healthcare providers, academics, professional organizations, policymakers, industry and service users. Only once this is achieved can adolescent nutrition, and adolescent nutrition in pregnancy, be significantly and sustainably optimized.

Zinc and copper metabolism in pregnancy and lactation of adolescent women

OBJECTIVE

Pregnant and lactating adolescent women are at risk of zinc and copper deficiency but their capacity for metabolic adaptation is poorly known. This study investigated the effect of pregnancy and lactation on zinc and copper metabolism in adolescent women by comparing biochemical indices between groups in different reproductive states.

METHODS

Habitual dietary intake and biochemical indices (zinc, copper, alkaline phosphatase, and ceruloplasmin in plasma; zinc [E-Zn], metallothionein [E-MT], and superoxide dismutase [E-SOD] in erythrocytes) and their relation were compared among non-pregnant non-lactating adolescents (NPNLs; n = 26), third-trimester pregnant adolescents (PAs; n = 26), and lactating adolescents up to 3 mo postpartum (LAs; n = 21).

RESULTS

Zinc and copper intakes were not different across groups (on average, 8.7 and 1.0 mg/d, respectively). PAs had lower plasma zinc but higher plasma copper, alkaline phosphatase, and ceruloplasmin levels than did LAs and NPNLs (P < 0.05). E-SOD and E-Zn were similar in all groups but E-MT was higher in the PA and LA groups than in the NPNL group (P < 0.05). Correlations between plasma copper and ceruloplasmin and between E-MT and E-Zn were observed in the LA and NPNL groups (r > or = 0.64, P < 0.01) but not in the PA group. In contrast, correlations between plasma alkaline phosphatase and plasma zinc, between E-MT and plasma zinc, and between E-SOD and E-Zn were observed only in the PA group (r > or = 0.46, P < 0.05).

CONCLUSION

Zinc and copper biochemical responses to pregnancy and lactation in the adolescent women studied appeared qualitatively similar to those described in previous studies in adult women. However, the significant correlations observed between the activity of zinc-dependent enzymes and plasma (or erythrocyte) zinc suggest that a poor maternal zinc status may limit the metabolic adaptation capacity of these adolescent women especially during pregnancy.

Risk of suboptimal iron and zinc nutriture among adolescent girls in Australia and New Zealand: causes, consequences, and solutions

Surveys in Australia, New Zealand and other industrialised countries report that many adolescent girls have dietary intakes of iron and zinc that fail to meet their high physiological requirements for growing body tissues, expanding red cell mass, and onset of menarche. Such dietary inadequacies can be attributed to poor food selection patterns, and low energy intakes. Additional exacerbating non-dietary factors may include high menstrual losses, strenuous exercise, pregnancy, low socioeconomic status and ethnicity. These findings are cause for concern because iron and zinc play essential roles in numerous metabolic functions and are required for optimal growth, immune and cognitive function, work capacity, sexual maturation, and bone mineralization. Moreover, if adolescents enter pregnancy with a compromised iron and zinc status, and continue to receive intakes of iron and zinc that do not meet their increased needs, their poor iron and zinc status could adversely affect the pregnancy outcome. Clearly, intervention strategies may be needed to improve the iron and zinc status of high risk adolescent subgroups in Australia and New Zealand. The recommended treatment for iron deficiency anaemia and moderate zinc deficiency is supplementation. Although dietary intervention is often recommended for treating non-anaemic iron deficiency and mild zinc deficiency, it is probably more effective and appropriate for prevention than for the treatment of suboptimal iron and zinc status. Many of the strategies for enhancing the content and bioavailability of dietary iron are also appropriate for zinc.

The role of zinc in the growth and development of children

This review concerns the importance of zinc in growth, development, and cognitive function in children and the deleterious consequences of its deficiency on children's health. Possible strategies to overcome zinc deficiency and the results of some supplementation trials are discussed.

Are changes in food consumption patterns associated with lower biochemical zinc status among women from Dunedin, New Zealand?

Reductions in red meat and increases in cereals in the diet may compromise the intake and bioavailability of Zn. In this cross-sectional study of 330 premenopausal New Zealand women aged 18--40 years, we have assessed the inter-relationships among dietary intakes (via computer-administered food-frequency questionnaire), biochemical Zn status, and anthropometric indices, and compared our results with earlier data. Fasting serum (12.00 (sd 1.36) micromol/l) and hair Zn (2.71 (sd 0.36) micromol/g) were lower than those for young Dunedin, New Zealand, women in 1973 (non-fasting serum Zn 18.6 (sd 4.6) micromol/l, hair Zn 2.99 (sd 0.35) micromol/g). Further, our mean serum Zn was at the 25th percentile of the US National Health and Nutrition Examination Survey (NHANES) (1976--1980) reference sample for women aged 20--44 years. Meat-poultry-fish contributed only 28 % total Zn in the present study, a level comparable with that from cereals-nuts-legumes (27 %), compared to about 40 % in 1989. Significant negative correlations existed between serum Zn and dietary [phytate]:[Zn] molar ratios (r -0.163, 35 % had diets with [phytate]:[Zn] >15, a level said to compromise Zn status. Mean serum Zn of a subgroup of non-oral contraceptive users free of infection was higher in the red-meat eaters (n 149) compared with non-red-meat eaters (n 48) (12.2 v. 11.8 micromol/g, In contrast, serum Zn was lower in those with dietary [phytate]:[Zn] ratios >15 v. <15 (i.e. 11.9 v. 12.3 micromol/l, We postulate that the lower biochemical Zn status of these New Zealand women may be associated in part with changes in food selection patterns, which have led to a reduction in the bioavailability of dietary Zn.

Drug and environmental factors associated with adverse pregnancy outcomes. Part III: Folic acid: pharmacology, therapeutic recommendations, and economics

OBJECTIVE

To review folic acid's mechanism of action, adverse effects, therapeutic recommendations, compliance, and cost.

DATA SOURCES

A MEDLINE search was conducted through December 1997. Additional sources were obtained from Current Contents and citations from the references obtained. Search terms included folate, folic acid, neural tube defect, homocysteine, and methylenetetrahydrofolate reductase.

STUDY SELECTION

Animal and human studies examining the effects of folate were reviewed.

DATA EXTRACTION

Data collected included mechanism of action, safety issues, dosing recommendations, compliance with recommendations, and economics.

DATA SYNTHESIS

Folic acid decreases neural tube defect risk through an effect on methionine-homocysteine metabolism. In addition, increased folate intake may reduce cardiovascular morbidity and mortality. Since toxicity is minimal, everyone can potentially benefit from increased folate consumption. To help achieve this, the Food and Drug Administration has mandated that cereal grain be fortified with 140 micrograms of folic acid per 100 g of grain, which will add approximately 0.1 mg of folate to the average diet. Studies recommend supplementing with 0.2 mg to promote optimal homocysteine concentrations and for preventing neural tube defects.

CONCLUSIONS

Despite fortification, most women will still receive less folate than the 0.4 mg/d recommended by the Public Health Service. All population groups would benefit from increased folate intake. Current studies indicate 200 micrograms/d may be the minimum effective amount of fortification needed for normalizing homocysteine concentrations and preventing a significant number of neural tube defects; thus, a higher level of food fortification may be warranted.

Is zinc a limiting nutrient in the diets of rural pregnant Malawian women?

Pregnant women consuming plant-based diets are at risk of Zn deficiency; Zn requirements for fetal growth and maternal tissue accretion are high. Therefore we have studied, at 24 and 33 weeks gestation, the Zn status of eighty-seven pregnant rural Malawian women (mean age 22.7 years) who consume maize-based diets, using anthropometry, dietary intake data, plasma and hair Zn concentrations, and infection status via serum C-reactive protein, leucocyte count, and malaria blood smear. Of the women, 12% were stunted (height-for-age Z score < -2 SD) and 20% lost weight over the 9-week period; weight gain averaged 0.13 kg/week. Mean plasma Zn concentration declined significantly from 24 to 33 weeks (7.9 (SD 2.2) v. 6.6 (SD 2.0) mumol/l; P < 0.0003). Both plasma and hair Zn values were very low; nearly 50% of the women had both plasma and hair Zn values below acceptable cut-off values. No significant differences in biochemical Zn indices existed between those who tested positive and negative for infection. Cereals (mainly maize) provided more than two-thirds of mean energy intake compared with less than 5% from flesh foods. As a result about 60% of the subjects had dietary phytate:Zn molar ratios greater than 15, and more than 35% had inadequate Zn intakes based on probability estimates and WHO basal requirements. Biochemical evidence of Zn deficiency was attributed in part to low intakes of poorly available Zn. The anthropometric, biochemical, and dietary data together indicate that Zn deficiency may be a factor limiting pregnancy outcome in rural Malawian women.

Zinc and copper concentrations in serum from Spanish women during pregnancy

A cross-sectional study of serum zinc (Zn) and copper (Cu) levels in 31 healthy pregnant women and 51 healthy, nonpregnant controls living in the Mediterranean area of Granada, Spain, was performed. The subjects were divided into two groups: Group A, consisted of pregnant women in three categories according to the trimester of pregnancy, and Group B consisted of nonpregnant women acting as controls. In pregnant women, serum Zn levels were found from 0.300-1.340 mg/L and serum Cu from 0.936-2.304 mg/L, whereas in the nonpregnant women group, the mean serum levels were 0.947+/-0.265 mg/L for Zn and 1.092+/-0.365 mg/L for Cu. Serum Zn progressively decreased with gestation. Mean Zn levels were 0.829+/-0.253, 0.846+/-0.329, and 0.620+/-0.142 mg/L, corresponding to the first, second, and third trimesters of pregnancy, respectively. Serum Zn concentrations were significantly lower in pregnant women as compared to controls: 0.712+/-0.236 mg/L vs 0.947+/-0.265 mg/L, respectively (p < 0.05). In contrast, Cu levels increased with period of gestation from 1.053+/-0.498 mg/L in the first trimester to 1.616+/-0.304 mg/L in the second and 1.689+/-0.344 mg/L in the third. Serum Cu levels in the second and third trimesters of pregnancy were significantly higher (p < 0.05) than those determined during the first trimester and for nonpregnant controls. Both Zn and Cu during pregnancy did not appear to be dependent on the subject's age (p > 0.05).

Iron and zinc status of young women aged 14 to 19 years consuming vegetarian and omnivorous diets

OBJECTIVE

To assess the iron and zinc status of young females, aged 14 to 19 years, consuming vegetarian and omnivorous diets.

METHODS

Dietary intakes (via 3-day weighed food records), BMI, and laboratory indices of iron and zinc status were compared in a convenience sample of 79 lacto-ovo-vegetarians (LOV), 16 semi-vegetarians (SV), and 29 omnivorous (OM) females.

RESULTS

Twenty-nine percent LOV, 44% SV, and 17% OM had low iron stores (i.e., plasma ferritin < 12 micrograms/L); only 3% had anemia. As well, 24% LOV, 33% SV, and 18% OM had serum zinc < 10.71 mumol/L and 14% LOV, 14% SV, and 17% OM had hair zinc < 1.68 mumol/g. Intakes of iron and ascorbic acid from the weighed food records were associated with serum iron (p < 0.04) and total iron binding capacity (negatively; p < 0.02), respectively, whereas Phy:Zn molar ratios were associated with serum zinc (negatively; p < 0.04). Z-scores for BMI were associated with serum zinc (p < 0.02) and diet type (p < 0.001); serum AP activity was associated with age (p < 0.0001) and oral contraceptive use (p < 0.04).

CONCLUSIONS

Suboptimal iron and zinc status was attributed to low intakes of poorly available iron and zinc in all dietary groups.