Evidence to Underpin Vitamin A Requirements and Upper Limits in Children Aged 0 to 48 Months: A Scoping Review

Area of Science:

• Nutritional Science
• Public Health
• Pediatrics

Background:

• Vitamin A deficiency poses significant health risks to young children in low- and middle-income countries.
• Accurate nutrient requirements and safe upper intake levels for vitamin A are crucial for this vulnerable population.

Purpose of the Study:

• To conduct a scoping review to identify, quantify, and map existing research on vitamin A for children aged 0-48 months.
• To inform the updating of nutrient requirements and upper limits for vitamin A in young children.
• To identify research gaps and guide future systematic reviews.

Main Methods:

• Comprehensive literature searches were performed in Medline, EMBASE, and Cochrane Central databases up to March 19, 2021.
• Titles, abstracts, and a subset of full texts were independently assessed in duplicate.
• Included studies were categorized by research question, methodology, and date, with data extraction and risk of bias assessment.

Main Results:

• The review identified studies on vitamin A supplementation, food fortification (staple foods, complementary foods, biofortified crops, fortified drinks), and their health outcomes.
• Recent isotopic tracer and modeling studies show potential for quantifying the impact of various food-based approaches on vitamin A status.
• Evidence from systematic reviews and trials on adverse events related to high vitamin A intake was found, useful for setting upper limits.

Conclusions:

• A comprehensive database of relevant research has been compiled.
• The findings highlight the need for full systematic reviews to address specific questions for setting vitamin A requirements and upper limits.
• This scoping review provides a foundation for future evidence-based recommendations on vitamin A intake for children.