Biomarkers of Nutrition for Development (BOND)—Vitamin A Review

Tanumihardjo, Sherry A.; Russell, Robert M.; Stephensen, Charles B.; Gannon, Bryan M; Craft, Neal E.; Haskell, Marjorie J; Lietz, Georg; Schulze, Kerry; Raiten, Daniel J.

doi:10.3945/jn.115.229708

Cited by 366 publications

(449 citation statements)

References 259 publications

(366 reference statements)

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“…In some cases, using more sensitive methodology (e.g., modified relative dose response (MRDR), isotope dilution tests [90]) on randomly selected subsamples may be important, especially if widespread fortification programs are in place.…”

Section: Discussionmentioning

confidence: 99%

Vitamin A Supplementation Programs and Country-Level Evidence of Vitamin A Deficiency

Wirth¹,

Petry²,

et al. 2017

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Vitamin A supplementation (VAS) programs targeted at children aged 6–59 months are implemented in many countries. By improving immune function, vitamin A (VA) reduces mortality associated with measles, diarrhea, and other illnesses. There is currently a debate regarding the relevance of VAS, but amidst the debate, researchers acknowledge that the majority of nationally-representative data on VA status is outdated. To address this data gap and contribute to the debate, we examined data from 82 countries implementing VAS programs, identified other VA programs, and assessed the recentness of national VA deficiency (VAD) data. We found that two-thirds of the countries explored either have no VAD data or data that were >10 years old (i.e., measured before 2006), which included twenty countries with VAS coverage ≥70%. Fifty-one VAS programs were implemented in parallel with at least one other VA intervention, and of these, 27 countries either had no VAD data or data collected in 2005 or earlier. To fill these gaps in VAD data, countries implementing VAS and other VA interventions should measure VA status in children at least every 10 years. At the same time, the coverage of VA interventions can also be measured. We identified three countries that have scaled down VAS, but given the lack of VA deficiency data, this would be a premature undertaking in most countries without appropriate status assessment. While the global debate about VAS is important, more attention should be directed towards individual countries where programmatic decisions are made.

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Section: Discussionmentioning

confidence: 99%

Vitamin A Supplementation Programs and Country-Level Evidence of Vitamin A Deficiency

Wirth¹,

Petry²,

et al. 2017

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“…Concerning RET concentration, it is acknowledged that it is tightly regulated [79] with concentrations ranging from 2 to 4 µM at fast in adults [80]. Its concentration only changes in response to extreme VA dietary events or in disease states [79], and in the postprandial period when a meal rich in VA is provided to subjects deficient in VA.…”

Section: Physiological Regulation Of Blood Vitamin a Concentrationsmentioning

confidence: 99%

“…Its concentration only changes in response to extreme VA dietary events or in disease states [79], and in the postprandial period when a meal rich in VA is provided to subjects deficient in VA. This last observation is assumed to be due to the fact that when hepatic VA stores are very low, free RBP accumulates in the liver [81].…”

Section: Physiological Regulation Of Blood Vitamin a Concentrationsmentioning

confidence: 99%

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Genetic Variations Associated with Vitamin A Status and Vitamin A Bioavailability

2017

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Blood concentration of vitamin A (VA), which is present as different molecules, i.e., mainly retinol and provitamin A carotenoids, plus retinyl esters in the postprandial period after a VA-containing meal, is affected by numerous factors: dietary VA intake, VA absorption efficiency, efficiency of provitamin A carotenoid conversion to VA, VA tissue uptake, etc. Most of these factors are in turn modulated by genetic variations in genes encoding proteins involved in VA metabolism. Genome-wide association studies (GWAS) and candidate gene association studies have identified single nucleotide polymorphisms (SNPs) associated with blood concentrations of retinol and β-carotene, as well as with β-carotene bioavailability. These genetic variations likely explain, at least in part, interindividual variability in VA status and in VA bioavailability. However, much work remains to be done to identify all of the SNPs involved in VA status and bioavailability and to assess the possible involvement of other kinds of genetic variations, e.g., copy number variants and insertions/deletions, in these phenotypes. Yet, the potential usefulness of this area of research is exciting regarding the proposition of more personalized dietary recommendations in VA, particularly in populations at risk of VA deficiency.

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“…Concerning RET concentration, it is acknowledged that it is tightly regulated [79] with concentrations ranging from 2 to 4 μM at fast in adults [80]. Its concentration only changes in response to extreme VA dietary events or in disease states [79], and in the postprandial period when a meal rich in VA is provided to subjects deficient in VA.…”

Section: Physiological Regulation Of Blood Vitamin a Concentrationsmentioning

confidence: 99%

Nutrigenetics

2018

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Biomarkers of Nutrition for Development (BOND)—Vitamin A Review

Cited by 366 publications

References 259 publications

Vitamin A Supplementation Programs and Country-Level Evidence of Vitamin A Deficiency

Vitamin A Supplementation Programs and Country-Level Evidence of Vitamin A Deficiency

Genetic Variations Associated with Vitamin A Status and Vitamin A Bioavailability

Nutrigenetics

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