Here is the complete guide to vitamin A, an essential nutrient for vision and immunity, whose management in plant-based diets relies on a fascinating metabolic conversion.

The complete guide to vitamin A: everything you need to know about plant carotenoids

In plant-based nutrition, we do not talk so much about “vitamin A” as about “provitamin A”. Indeed, vitamin A in its active form (retinol) is found only in animal products. Vegetarians and vegans rely on carotenoids, such as beta-carotene, which our body converts into vitamin A according to its needs.

This is excellent news: unlike animal-derived retinol, there is no risk of toxicity from overdosing on plant beta-carotene. However, this conversion requires a few preparation tricks to be truly effective. Here is how to support your visual and immune health thanks to plants.

What does vitamin A actually do in your body?

Vitamin A is a fat-soluble vitamin (which dissolves in fats) essential for many biological functions:

Night vision: It is an essential component of rhodopsin, a protein present in the retina that allows us to see in low-light conditions.
Immune defense: It maintains the integrity of mucous membranes (natural barriers against viruses) and stimulates the production of white blood cells.
Skin health: It promotes cellular regeneration and wound healing. It is often used in dermatology to combat acne and skin aging.
Cell growth: It plays a key role in cell differentiation and is particularly important for embryonic development.

Nutritional needs and the concept of RE (retinol equivalent)

Since the body must convert plant pigments into vitamin A, the unit RE (Retinol Equivalent) is used to measure requirements.

Recommended nutritional intake (RNI)

Profile	Daily requirement (in µg RE)
Adult man	750 µg RE
Adult woman	650 µg RE
Pregnant / breastfeeding woman	700 to 950 µg RE

The conversion factor: About 6 to 12 mg of beta-carotene are required to produce 1 mg of vitamin A. This is why plant sources must be consumed in generous quantities and, above all, with a source of fat to optimize this conversion.

Bioavailability: how to maximize absorption?

Beta-carotene is trapped inside plant cell walls. To release and convert it, two rules are fundamental:

Light cooking: Unlike vitamin C, beta-carotene is better absorbed when vegetables are cooked. Heat breaks down fibers and makes the pigment more accessible.
Adding fat: Vitamin A is fat-soluble. Eating raw carrots without any fat source results in almost no absorption. A drizzle of olive oil, a few nuts, or an avocado in the same meal can triple conversion efficiency.

Top 10 best plant-based sources of vitamin A

Plant sources are easy to identify: they are generally fruits and vegetables that are orange, red, or dark green in color.

Food	Serving	Beta-carotene content (µg)
1. Sweet potato (cooked)	150 g	15,000 µg
2. Carrot (cooked)	100 g	8,000 µg
3. Pumpkin / Kabocha squash	150 g	6,000 µg
4. Spinach (cooked)	150 g	5,500 µg
5. Kale	100 g	5,000 µg
6. Dried apricots	5 units	1,500 µg
7. Melon	1/4 fruit	1,200 µg
8. Red bell pepper (raw)	100 g	1,000 µg
9. Mango	1/2 fruit	800 µg
10. Fresh parsley	1 bunch	500 µg

Signs of deficiency: visual and skin warnings

Vitamin A deficiency is rare in developed countries but can occur in cases of fat malabsorption or extremely unbalanced diets:

Night blindness: Difficulty or inability to see in low light.
Xerophthalmia: Severe eye dryness that may damage the cornea.
Dry and rough skin: “Toad skin” sensation (hyperkeratosis).
Increased susceptibility to infections: Repeated colds and bronchitis.

FAQ: common questions about plant-based vitamin A

Should vegans take retinol supplements?

No. Beta-carotene from fruits and vegetables is more than sufficient if you regularly consume colorful vegetables with a little fat. Supplementing with pure retinol is actually discouraged without medical advice, as excess intake can be toxic to the liver.

Can you get an orange skin tone from eating too many carrots?

Yes! This is called carotenemia. It is a harmless skin discoloration (especially on the palms of the hands) caused by excess beta-carotene. It is absolutely not dangerous and disappears once consumption is reduced.

Is carrot juice a good source?

It is an excellent source because juicing breaks down the fibers, massively releasing carotenoids. Just remember to add a drop of flaxseed oil or eat a few almonds at the same time to aid absorption.

What is the impact of freezing on vitamin A?

Vitamin A and carotenoids withstand freezing very well. Frozen vegetables (spinach, carrots, squash) retain almost all their provitamin A, making them a practical option all year round.

Scientific references and sources

ANSES: Nutritional references for vitamins and minerals (2021).
EFSA (European Food Safety Authority): “Scientific Opinion on Dietary Reference Values for vitamin A” (2015).
The American Journal of Clinical Nutrition: “Beta-carotene bioavailability from vegetables”.
National Institutes of Health (NIH): Vitamin A Fact Sheet for Health Professionals.
Food Chemistry: “Effects of thermal processing on carotenoids in vegetables”.