Here is the complete guide to vitamin B2 (or riboflavin), the vitamin of “clarity” and vitality, essential for transforming your nutrients into usable energy.

The complete guide to vitamin B2: the engine of cellular respiration

Riboflavin, or vitamin B2, is easy to recognize: it is what gives a fluorescent yellow color to certain dietary supplements or to urine after heavy consumption. In the body, it acts as an electron carrier essential for the “respiration” of your cells.

For vegetarians and vegans, vitamin B2 requires particular attention. While it is ubiquitous in animal milk, it is more dispersed in the plant kingdom (almonds, mushrooms, green vegetables). This guide helps you identify the best sources to maintain healthy skin and keep your metabolism at its peak.

What is vitamin B2 actually used for in your body?

Vitamin B2 is a cofactor for many enzymes involved in energy production:

Macronutrient metabolism: It helps break down carbohydrates, fats, and proteins to extract energy (ATP).
Skin and mucous membrane health: It is fundamental for tissue renewal. A deficiency often appears first at the corners of the lips or on the tongue.
Antioxidant protection: It participates in the recycling of glutathione, one of the most powerful antioxidants produced by our body to protect our cells.
Activation of other vitamins: Without B2, your body has great difficulty converting vitamin B6 and vitamin B9 (folates) into their active forms.
Vision: It helps maintain normal vision and protects the cornea.

Nutritional requirements: a stable daily intake

Like all B vitamins, it is water-soluble. The body does not store it, and excess is eliminated each day.

Recommended nutritional intakes (RNI)

Profile	Recommended daily requirement
Adult man	1.6 mg
Adult woman	1.3 mg
Pregnant / breastfeeding woman	1.6 mg to 1.7 mg
Athlete (higher needs)	2.0 mg+

Did you know? Riboflavin is extremely sensitive to light. This is why bottles of fortified plant milk or oils are often opaque: exposure to daylight can destroy vitamin B2 in just a few hours.

Vitamin B2 resistance to heat

Unlike vitamin B1 or vitamin C, vitamin B2 resists cooking heat relatively well. However:

Leaching: It escapes into cooking water. If you boil your broccoli and discard the water, you lose part of the riboflavin.
UV sensitivity: This is its main weakness. Store your seeds, nuts, and cereals in opaque containers or in a closed cupboard.

Top 10 best plant-based sources of vitamin B2

Without dairy products, vegans should rely on mushrooms, nuts, and fermented foods.

Food	Serving	Vitamin B2 intake (mg)
1. Nutritional yeast / brewer’s yeast	1 tbsp	0.5 mg (30% of recommended intake)
2. Almonds (with skin)	30 g	0.35 mg
3. Button mushrooms (cooked)	100 g	0.30 mg
4. Spinach (cooked)	150 g	0.25 mg
5. Wheat germ	2 tbsp	0.15 mg
6. Tempeh	100 g	0.12 mg
7. Quinoa (cooked)	150 g	0.15 mg
8. Avocado	1/2 fruit	0.10 mg
9. Sesame seeds (Tahini)	1 tbsp	0.10 mg
10. Broccoli (steamed)	150 g	0.15 mg

Signs of deficiency: skin warning signals

A mild deficiency (ariboflavinosis) may occur in cases of very restricted diets or malabsorption:

Cheilitis: Cracks and redness at the corners of the lips.
Glossitis: Red, swollen, or painful tongue.
Seborrheic dermatitis: Oily and scaly skin, often around the nose or ears.
Eye fatigue: Increased sensitivity to light (photophobia) and red eyes.
Anemia: Because iron metabolism is disrupted by lack of B2.

FAQ: common questions about vitamin B2

Why is my urine neon yellow after taking vitamins?

This is completely normal. The name “riboflavin” comes from the Latin flavus, meaning yellow. Your body simply eliminates the excess that your cells could not absorb. It is not dangerous, just a sign that your body is saturated with B2.

Do vegans often have B2 deficiencies?

Studies show that some vegans have borderline intake if they do not regularly consume nuts, mushrooms, or fortified foods. Regular use of nutritional yeast and fortified plant beverages usually solves the issue.

Does coffee destroy vitamin B2?

No, unlike vitamin B1, riboflavin is not particularly affected by caffeine or tea tannins.

Does B2 help with migraines?

Yes, several clinical studies have shown that high doses of riboflavin (under medical supervision) can reduce the frequency and intensity of migraines by improving the energy metabolism of neurons.

Scientific references and sources

ANSES: Nutritional references for vitamin B2 (Updated 2021).
EFSA (European Food Safety Authority): “Scientific Opinion on Dietary Reference Values for riboflavin”.
National Institutes of Health (NIH): Riboflavin Fact Sheet for Health Professionals.
Linus Pauling Institute: “Riboflavin – Micronutrient Information Center”.
Journal of Nutrition: “Riboflavin status of vegetarians”.