In order to fully exploit the nutrient density concept, thorough understanding of the biological activity of single nutrients in their interaction with other nutrients and food components from whole foods is important This review provides a narrative overview of recent insights into nutrient bioavailability from complex foods in humans, highlighting synergistic and antagonistic processes among food components for two different food groups, ie, dairy, and vegetables and fruits For dairy, bioavailability of vitamins A, B2, B12 and K, calcium, phosphorous, magnesium, zinc and iodine are discussed, whereas bioavailability of pro-vitamin A, folate, vitamin C and K, potassium, calcium, magnesium and iron are discussed for vegetables and fruits Although the bioavailability of some nutrients is fairly well-understood, for other nutrients the scientific understanding of uptake, absorption, and bioavailability in humans is still at a nascent stage Understanding the absorption and bioavailability of nutrients from whole foods in interaction with food components that influence these processes will help to come to individual diet scores that better reflect absorbable nutrient intake in epidemiologic studies that relate dietary intake to health outcomes Moreover, such knowledge may help in the design of foods, meals, and diets that aid in the supply of bioavailable nutrients to specific target groups

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Bioavailability of Micronutrients From Nutrient-Dense Whole Foods : Zooming in on Dairy, Vegetables, and Fruits

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

Background Adequate iodine intake is important for children and women of childbearing age because iodine is vital for fetal brain development and early life. Objective Iodine status of children (n = 1875), adolescents (n = 557) and women of childbearing age (n = 567) was assessed using urinary iodine concentrations (UIC) from duplicate spot samples collected in the Canadian Health Measures Survey, cycle 5 (2016 - 2017). Methods Daily iodine intakes were estimated from urinary iodine and creatinine concentrations using a formula based on iodine absorption and predicted 24-h creatinine excretion. Usual UIC and iodine intakes, adjusted for within-person variation, were estimated using the National Cancer Institute method. Iodine status was assessed by (1) comparing median UIC with WHO/UNICEF/ICCIDD reference ranges and (2) estimating the prevalence of inadequate and excessive intakes using the Estimated Average Requirement (EAR) and Tolerable Upper Intake Level (UL) cut-point method, respectively. Results Median UIC for males or females 6 - 11 y or 12 - 19 y were ≥100 µg/L, the lower cut-off for adequate intakes. For women 20 - 39 y, median UIC (95% CI) of an unadjusted sample was 81 µg/L (67, 95) and for usual UIC 108 µg/L (84, 131). Percentage of children 3 y with iodine intakes ≥ EAR was 82% (75, 89). The corresponding estimates for males 4 - 8 y, 9 - 13 y and 14 - 18 y were 93% (88, 97), 91% (87, 96) and 84% (76, 91), respectively. Estimates for females were 4 - 8 y 86% (83, 89), 9 - 13 y 87% (80, 95), 14 - 18 y 68% (55, 80) and 19 - 39 y 68% (59, 76). For all sex-age groups, 91 - 100% had iodine intakes ≤ UL. Conclusions Iodine intakes may be insufficient for some women of childbearing age. Public health policies and programs should continue to recommend that all women who could become pregnant, or women who are pregnant or breastfeeding, take a daily multivitamin-mineral supplement containing iodine.

Iodine Status of Canadian Children, Adolescents and Women of Childbearing Age.

Combining ion chromatography with mass spectrometry and inductively coupled plasma-mass spectrometry: Annual review 2020

https://academic.oup.com/ajcn/article-pdf/115/1/298/42749507/nqab327.pdf

Sarah Bürki

Papers

Iodine bioavailability from cow milk: a randomized, crossover balance study in healthy iodine-replete adults.