The abstract submission has been made with the following details:

Congress: IUNS 2017 BUENOS AIRES, ARGENTINA
Contact details
Reference number: 233593
Name: Sherry
Surname: Tanumihardjo
Abstract submission details
Number: 144/3360
Title: Biological evidence for or against high dose supplementation
Type: Abstract Talk (SPEAKERS OF SYMPOSIA)
Area: Track 3: Public Health Nutrition and Environment
Format: ORAL
Principal author: Sherry Tanumihardjo
Biological evidence for or against high dose supplementation
Symposium ID (144/...) and Title of the Symposium to which the talk belongs
144/Track 3 Integration to effective implementation (I-to-I): Risk:benefit of high dose vitamin A supplementation programs
Abstract (max. 500 words)
The World Health Organization (WHO) recommends high dose capsules of retinyl palmitate be orally administered to children between 6 and 59 months of age for the prevention of mortality. Infants less than 12 months are to receive 100,000 IU and those 12-59 months receive 200,000 IU. These capsules should be targeted in areas of the world that are at risk for vitamin A deficiency based on a variety of factors. Other high dose supplementation programs in different age- or vulnerable groups have been tested and sometimes implemented in many countries. However, currently evidence on their efficacy to improve infant and childhood mortality is not supported by reviews of randomized controlled trials. One of the most debated interventions is neonatal supplementation. Trials indicated mixed results on infant mortality, and a meta-analysis of human trials indicated no overall effect of neonatal supplementation on death within 6 mo of birth. High dose supplements have transient effects on serum retinol and tissue stores of vitamin A, with the exception of the liver where increases may last for several months on the background of low dietary intake in humans. In swine models, vitamin A is well-absorbed, appears in serum primarily as retinyl esters, and is taken up dose dependently in all tissues. Nonetheless, enhancement in piglets did not persist in serum, lung, kidney, spleen, or adrenal gland. It has long been considered that circulating retinyl esters disrupt membranes and are the major cause of symptoms of hypervitaminosis A or toxicity. After high-dose supplements, elevated esters persisted for approximately 12 hours before being sequestered in the liver for storage. Elevated circulating esters were associated with hypervitaminosisA in Zambian children at a cutoff of 5% of total vitamin A, but the current cutoff used in adults, i.e., 10% retinyl esters of total vitamin A, has not been validated. In piglets, vitamin A storage was enhanced for more than 10 days after high-dose supplements compared with placebo. In the same study, once liver reserves reached 0.7 micromol/g liver, vitamin A concentrations plummeted. It is not known whether this was due to the high dose capsule administered 7 days prior or if it reflects a biological response at this liver reserve, which was referred to as excessive vitamin A status in the past. No group of piglets reached a mean concentration of >1 micromol/g liver, which currently defines hypervitaminosis. Short-term impacts of retinoid signaling and longer follow-up after high dose supplements need to be evaluated.
Keywords (5 keywords maximum)
animal models catabolism circulating retinyl esters hypervitaminosis supplementation
Conflict of Interest disclosure
No conflicts of interest
Further collaborators (N/A if not applicable)
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