Taking a specific dose of vitamin A every day for about three weeks might make your body get rid of much less of a certain form of beta-carotene through urine, based on a small observation in two healthy adults.

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Evidence from Studies

Supporting (1)

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Community contributions welcome

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Absorption and retinol equivalence of β-carotene in humans is influenced by dietary vitamin A intake Published, JLR Papers in Press, June 1, 2003. DOI 10.1194/jlr.M300116-JLR200

Cross-Sectional Study

Human

2003 Aug

The study gave two people a vitamin A supplement for about 3 weeks and found it caused a big drop in the amount of a special marker in their urine after they ate a form of vitamin A from plants. This matches exactly what the claim says.

Contradicting (0)

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No contradicting evidence found

Gold Standard Evidence Needed

According to GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this specific claim, ordered from strongest to weakest evidence.

Source Study

Absorption and retinol equivalence of β-carotene in humans is influenced by dietary vitamin A intake Published, JLR Papers in Press, June 1, 2003. DOI 10.1194/jlr.M300116-JLR200

Score: 24

DOI: 10.1194/JLR.M300116-JLR200

Similar Assertions

Taking a lot of vitamin A every day for about three weeks might help two healthy people absorb more beta-carotene from their food, based on how much showed up in their urine over the next month.

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85%

Taking a lot of vitamin A every day for about three weeks might make your body break down beta-carotene (from food) into vitamin A less efficiently.

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83%