Efficacy of daily and weekly multiple micronutrient food-like tablets for the correction of iodine deficiency in Indonesian males aged 6-12 mo

Nutrient intakes of pregnant and lactating women in Indonesia and Malaysia: Systematic review and meta-analysis

Introduction

Optimizing dietary intake during pregnancy and lactation is crucial to the growth and development of children and their lifelong health. We performed a systematic review and meta-analysis to describe the nutrient intakes of pregnant and lactating women in Indonesia and Malaysia, countries that are experiencing rapid nutrition transition in Southeast Asia.

Methods

We screened 2,258 studies published between January 1980 and March 2021. The nutrient intakes of pregnant and lactating women were quantitatively analyzed to calculate the percentage of adequacy using national recommended daily allowances or nutrient intakes (RDA/RNI) and estimated average requirements (EAR) for micronutrients. Standardized mean differences (SMD) between dietary intake and RDA/RNI were determined for selected nutrients.

Results

Fifty-three studies were included and showed that energy and macronutrient intakes among pregnant and lactating women in both countries were below the RDA/RNI. In addition, most studies reported that women failed to meet the EAR for vitamin D (<70% EAR), vitamin E (<50% EAR), and water-soluble vitamins (<80% EAR) except for vitamin C and A among Malaysians. Moreover, calcium, potassium, and iron intakes of pregnant women were <60% EAR in Indonesia and <80% EAR in Malaysia. Phosphorus intake among pregnant women in both countries and sodium intake among Malaysian pregnant women exceeded 100% EAR. Indonesian lactating women had <60% EAR for calcium and potassium intakes, while Malaysian women had more than 100% EAR. For 21 studies reporting overall protein intakes, the standard mean difference (SMD) was −2.26 (95% CI; −2.98, −1.54) below the RDA/RNI for pregnant women and −0.67 SMD (95% CI −15.7, −11.5) for lactating women. When the four studies from Malaysia were analyzed separately, protein intakes of pregnant women were above the RNI. Moreover, low intakes of vitamin D, vitamin C, calcium, and iron, but sufficient intakes in vitamin A, zinc, and phosphorus were observed in pregnant women in both countries.

Conclusion

Dietary intakes of energy, macronutrients, and micronutrients (vitamin D, vitamin E, water-soluble vitamins, calcium, and iron) of pregnant and lactating women in Indonesia and Malaysia were below the recommendations. Important heterogeneities were observed even between these two countries for specific essential nutrient intakes. Innovative research and targeted programs to address specific deficiencies should be prioritized.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021252204, identifier: CRD42021252204.

The Role of Iodine for Thyroid Function in Lactating Women and Infants

Iodine is a micronutrient needed for the production of thyroid hormones, which regulate metabolism, growth, and development. Iodine deficiency or excess may alter the thyroid hormone synthesis. The potential effects on infant development depend on the degree, timing, and duration of exposure. The iodine requirement is particularly high during infancy because of elevated thyroid hormone turnover. Breastfed infants rely on iodine provided by human milk, but the iodine concentration in breast milk is determined by the maternal iodine intake. Diets in many countries cannot provide sufficient iodine, and deficiency is prevented by iodine fortification of salt. However, the coverage of iodized salt varies between countries. Epidemiological data suggest large differences in the iodine intake in lactating women, infants, and toddlers worldwide, ranging from deficient to excessive intake. In this review, we provide an overview of the current knowledge and recent advances in the understanding of iodine nutrition and its association with thyroid function in lactating women, infants, and toddlers. We discuss risk factors for iodine malnutrition and the impact of targeted intervention strategies on these vulnerable population groups. We highlight the importance of appropriate definitions of optimal iodine nutrition and the need for more data assessing the risk of mild iodine deficiency for thyroid disorders during the first 2 years in life.

The challenges of iodine supplementation: a public health programme perspective

An adequate iodine intake during pregnancy, lactation and early childhood is particularly critical for optimal brain development of the foetus and of children 7-24 months of age. While the primary strategy for sustainable elimination of iodine deficiency remains universal salt iodisation, the World Health Organization and the United Nations Children's Fund recommend a complementary strategy of iodine supplements as a temporary measure when salt iodisation could not be implemented. This article aims to review current evidence on efficacy and implications of implementing iodine supplementation as a public health measure to address iodine deficiency. Iodine supplementation seems unlikely to reach high coverage in a rapid, equitable and sustained way. Implementing the programme requires political commitment, effective and efficient supply, distribution and targeting, continuous education and communication and a robust monitoring system. Thus, universal salt iodisation should remain the primary strategy to eliminate iodine deficiency.

Methods of assessment of iodine status in humans: a systematic review

BACKGROUND

Biomarkers of iodine status are required to study iodine deficiency disorders in different parts of the world and to evaluate the effects of fortification strategies.

OBJECTIVE

The objective was to assess the usefulness of biomarkers of iodine status in humans by systematically reviewing intervention studies that altered iodine status.

DESIGN

We performed a structured search for iodine intervention studies on Ovid MEDLINE, EMBASE (Ovid), and the Cochrane Library. Studies were assessed for inclusion and validity, with independent duplication. A random-effects meta-analysis was performed.

RESULTS

Twenty-one intervention studies (12 randomized controlled trials, 3 controlled clinical trials, and 6 before-after studies) were included in the review. Urinary iodine (in children and adolescents and in those with low and moderate baseline iodine status), thyroglobulin (in children and adolescents but not in pregnant and lactating women), serum thyroxine (in children and adolescents, adults, women, and those with moderate baseline thyroxine status but not in pregnant and lactating women), and serum thyroid-stimulating hormone (in pregnant and lactating women but not in children and adolescents or those at moderate baseline status), but not triiodothyronine, proved to be useful biomarkers of iodine status.

CONCLUSIONS

Despite the high risk of bias of many of the included studies, the results suggested that urinary iodine, thyroglobin, serum thyroxine, and thyroid-stimulating hormone are useful biomarkers of iodine status, at least in some groups. High-quality controlled studies measuring relevant long-term outcomes are needed to address which biomarker is the most appropriate for assessing iodine intake in some population groups and settings.