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Retinoic acid

Overview

Retinoic acid on this page is all-trans-retinoic acid, the acid metabolite made from vitamin A. The structure shown is that isomer (C20H28O2). Foods are not recorded here as containing it. They supply preformed vitamin A, mainly retinol and retinyl esters, or provitamin A carotenoids such as beta-carotene. After absorption those precursors are oxidised to retinoic acid, and that last step is irreversible [1,2].

Beta-carotene can be cleaved to retinal before that oxidation [2]. The acid then acts as a local signal and is cleared by CYP26 enzymes, so a circulating vitamin A measurement is not a tissue retinoic acid measurement [1]. A serving of liver, egg yolk, butter or a carotenoid vegetable is a precursor exposure. Tretinoin is the drug name for this same molecule at a medicinal dose. The 9-cis and 13-cis isomers are different structures and are not this page.

Dietary Origin

The foods below are linked as precursors, not as foods that contain retinoic acid. Animal foods in this set are dominated by preformed vitamin A. Leafy greens, carrots and sweet potatoes are dominated by beta-carotene. Figures are the per-100 g panels already on those food pages.

Preformed vitamin A: beef liver 4,968 µg RAE; ghee (anhydrous butter oil) 840 µg RAE; unsalted butter 684 µg RAE; egg yolk 381 µg RAE. Grass-fed butter uses that same unsalted-butter panel, so it is not a separate vitamin A assay. Beta-carotene: sweet potato 8,509 µg and 709 µg RAE; carrots 8,285 µg and 835 µg RAE; spinach 5,626 µg; romaine lettuce 5,226 µg; Swiss chard 3,647 µg; kale 2,873 µg. Many other foods record a trace of vitamin A or beta-carotene. Those traces are not linked here.

Research Spotlights & Evidence Checks

🔎 Evidence Check · food-constituent

Do these foods contain retinoic acid?

No. They supply retinol, retinyl esters or beta-carotene. Retinoic acid is formed afterwards by oxidation, and that step is irreversible [1,2].

Read the evidence

Intestinal absorption covers dietary vitamin A and provitamin A carotenoids. Beta-carotene can be cleaved to retinal, and retinal can be oxidised to retinoic acid [1,2]. That sequence is why the foods are dietary precursors. It is not a measurement of retinoic acid in the food, and a vitamin A blood value does not stand in for the acid in a tissue [1].

🔎 Evidence Check · supplemental-formulation

Is a tretinoin medicine the same exposure as these foods?

No. Tretinoin is a medicinal dose of all-trans-retinoic acid. A food portion is the precursor, not that dose [1].

Read the evidence

The drug uses the same all-trans molecule this page identifies. A prescribed dose is a different exposure from liver, egg yolk, butter or a carotenoid vegetable. High-dose oral retinoid medicines are teratogenic; that warning belongs to the medicine and to excess preformed vitamin A, not to a recipe. This page does not set a dietary requirement for retinoic acid.

Recipes

Recipes are listed when a food is tagged as containing the substance. These foods supply precursors, so they are connected under Foods.

no recipes found (no foods contain this substance)

Foods

11 food relationships

Butter

Dairy fat providing vitamin A and culinary saturated fat

Dietary precursorButter → provides Preformed vitamin A (retinol and retinyl esters) → Oxidation to retinal, then to retinoic acid → Retinoic acid

Unsalted butter records 684 µg RAE vitamin A per 100 g and 158 µg beta-carotene. The dominant precursor is preformed vitamin A. The food is not recorded as containing retinoic acid.

Carrots

Beta-carotene source with food matrix effects on absorption

Dietary precursorCarrots → provides Beta-carotene → Cleavage to retinal, then oxidation to retinoic acid → Retinoic acid

Raw carrots record 8,285 µg beta-carotene and 835 µg RAE vitamin A per 100 g. The dominant precursor is beta-carotene. The food is not recorded as containing retinoic acid.

Egg Yolks

Nutrient-dense part of eggs with choline, lutein, and fat-soluble vitamins

Dietary precursorEgg Yolks → provides Preformed vitamin A (retinol and retinyl esters) → Oxidation to retinal, then to retinoic acid → Retinoic acid

Raw egg yolk records 381 µg RAE vitamin A per 100 g and 88 µg beta-carotene. The dominant precursor is preformed vitamin A. The food is not recorded as containing retinoic acid.

Ghee

Heat-stable clarified butter with butyrate and fat-soluble vitamins

Dietary precursorGhee → provides Preformed vitamin A (retinol and retinyl esters) → Oxidation to retinal, then to retinoic acid → Retinoic acid

Anhydrous butter oil records 840 µg RAE vitamin A per 100 g. That is a retinol precursor. The food is not recorded as containing retinoic acid.

Grass-Fed Butter

Butyrate, CLA, vitamins A/D/K2, selenium, and C15:0

Dietary precursorGrass-Fed Butter → provides Preformed vitamin A (retinol and retinyl esters) → Oxidation to retinal, then to retinoic acid → Retinoic acid

This page uses the unsalted-butter panel, 684 µg RAE vitamin A per 100 g, not a separate grass-fed vitamin A assay. The dominant precursor is preformed vitamin A. The food is not recorded as containing retinoic acid.

Kale

Leafy green rich in iron, magnesium, zinc, quercetin, and carotenoids

Dietary precursorKale → provides Beta-carotene → Cleavage to retinal, then oxidation to retinoic acid → Retinoic acid

Raw kale records 2,873 µg beta-carotene and 241 µg RAE vitamin A per 100 g. The dominant precursor is beta-carotene. The food is not recorded as containing retinoic acid.

Liver

Nutrient-dense organ meat with bioavailable B12, retinol, iron, and CoQ10

Dietary precursorLiver → provides Preformed vitamin A (retinol and retinyl esters) → Oxidation to retinal, then to retinoic acid → Retinoic acid

Beef liver records 4,968 µg RAE vitamin A per 100 g, with 232 µg beta-carotene. The dominant precursor is preformed vitamin A. The food is not recorded as containing retinoic acid.

Romaine Lettuce

Crisp salad lettuce providing vitamin K, folate and carotenoids

Dietary precursorRomaine Lettuce → provides Beta-carotene → Cleavage to retinal, then oxidation to retinoic acid → Retinoic acid

Raw romaine records 5,226 µg beta-carotene and 436 µg RAE vitamin A per 100 g. The dominant precursor is beta-carotene. The food is not recorded as containing retinoic acid.

Spinach

Leafy green rich in iron, magnesium, folate, and carotenoids

Dietary precursorSpinach → provides Beta-carotene → Cleavage to retinal, then oxidation to retinoic acid → Retinoic acid

Raw spinach records 5,626 µg beta-carotene and 469 µg RAE vitamin A per 100 g. The dominant precursor is beta-carotene. The food is not recorded as containing retinoic acid.

Sweet Potatoes

Root vegetable rich in beta-carotene, fibre, and potassium

Dietary precursorSweet Potatoes → provides Beta-carotene → Cleavage to retinal, then oxidation to retinoic acid → Retinoic acid

Raw sweet potato records 8,509 µg beta-carotene and 709 µg RAE vitamin A per 100 g. The dominant precursor is beta-carotene. The food is not recorded as containing retinoic acid.

Swiss Chard

Leafy green rich in iron, magnesium, folate, and carotenoids

Dietary precursorSwiss Chard → provides Beta-carotene → Cleavage to retinal, then oxidation to retinoic acid → Retinoic acid

Raw Swiss chard records 3,647 µg beta-carotene and 306 µg RAE vitamin A per 100 g. The dominant precursor is beta-carotene. The food is not recorded as containing retinoic acid.

References

[1] Duester (2008). Retinoic acid synthesis and signaling during early organogenesis. Retinol is oxidised to retinaldehyde and then to retinoic acid; the second step is irreversible, and CYP26 enzymes clear the acid. Tissue signalling is local, not a circulating vitamin A result.

[2] Harrison (2012). Mechanisms involved in the intestinal absorption of dietary vitamin A and provitamin A carotenoids. Dietary vitamin A is absorbed as retinol and retinyl esters. Provitamin A carotenoids such as beta-carotene can be cleaved to retinal. The review is about absorption and cleavage, not a measurement of retinoic acid in food.