E101 - Riboflavin

At a glance

• Also called vitamin B2; provides a yellow hue and can fortify foods with a needed nutrient.
• Used in beverages, dairy products, baked goods, cereals, sauces, and confectionery.
• Approved as a color additive by the U.S. Food and Drug Administration (FDA) and authorized in the European Union (EU) as E101.
• Available in two main forms for foods: riboflavin (E101(i)) and riboflavin-5′-phosphate (E101(ii)).
• Generally stable to heat and acid but sensitive to light.

Why is Riboflavin added to food?

Food makers add riboflavin to give a natural-looking yellow color and to replace color that may fade during processing. It can also serve a second role: boosting the vitamin B2 content of a food, such as in “enriched” or “fortified” grains and beverages.¹ The FDA lists riboflavin among color additives permitted for use in foods, and in the EU it is authorized as E101.¹²

What foods contain Riboflavin?

You can find riboflavin used as a color in soft drinks, sports drinks, flavored milk and yogurt, cheeses, bakery items, breakfast cereals, soups and sauces, and sugar-coated candies. In the U.S., it may be used in foods generally, following good manufacturing practice (GMP), which means the minimum amount needed to achieve the intended effect.¹ In the EU, E101 is authorized across many food categories as listed in the food additive regulation framework.²

What can replace Riboflavin?

If a similar yellow tone is needed, formulators often consider:

• Curcumin (E100) for a bright yellow with a spice-derived origin.
• Carotene (E160a) for yellow to orange shades.
• Annatto (E160b) for yellow to orange in dairy and baked goods.
• Tartrazine (E102) for a vivid lemon-yellow synthetic option.
• The more water-soluble form riboflavin-5-phosphate (E101(ii)) when better dispersion in drinks is needed.

How is Riboflavin made?

Most food-grade riboflavin today is produced by fermentation. Manufacturers cultivate specific microorganisms—such as selected strains of Bacillus or fungi—in controlled conditions, then extract and purify the vitamin from the broth.² Older chemical synthesis routes exist but are now less common because fermentation is efficient and uses renewable feedstocks.³

Is Riboflavin safe to eat?

Regulators have reviewed riboflavin many times. The FDA permits its use as a color additive in foods, and the European Food Safety Authority (EFSA) found no safety concern for E101 at reported uses and use levels.¹² As a nutrient, riboflavin has very low toxicity and no Tolerable Upper Intake Level (UL) has been set by the U.S. National Institutes of Health (NIH).⁴

Does Riboflavin have any benefits?

Yes. Riboflavin is vitamin B2, an essential nutrient that helps your body release energy from carbohydrates, fats, and proteins. It also supports normal cell growth and the function of other B vitamins.⁴ Fortifying staple foods with riboflavin helps people meet daily needs, especially if their diets are low in natural sources like dairy, eggs, and meats.⁵

Who should avoid Riboflavin?

For most people, riboflavin in foods is well tolerated. High-dose supplements can turn urine bright yellow; this is harmless and simply reflects the vitamin’s color and your body excreting excess amounts.⁴ If you take certain medicines (for example, some tricyclic antidepressants or phenothiazines), talk with your healthcare provider—these drugs can affect riboflavin status, although typical amounts from foods are not a concern.⁴

Myths & facts

• Myth: “It’s an artificial dye.” Fact: Riboflavin is vitamin B2, a nutrient found naturally in many foods.
• Myth: “Yellow urine means harm.” Fact: Bright yellow urine after high intake is benign and expected.
• Myth: “It’s banned in Europe.” Fact: It’s authorized in the EU as E101 for many food uses.

Riboflavin in branded foods

On ingredient lists, you might see “Riboflavin,” “Vitamin B2,” or “E101.” In enriched grain products, it can appear alongside other vitamins. In drinks, dairy, and candies, it’s often used to give a warm yellow shade while also contributing a small amount of vitamin B2.

References

Footnotes

1. Color Additives Permitted for Use in Foods — U.S. FDA. https://www.fda.gov/industry/color-additive-inventories/color-additives-permitted-use-foods ↩ ↩² ↩³ ↩⁴

2. Re-evaluation of riboflavins (E 101) as a food additive — EFSA Journal 2013;11(5):3303. https://www.efsa.europa.eu/en/efsajournal/pub/3303 ↩ ↩² ↩³ ↩⁴

3. Riboflavin (INS 101) — JECFA Chemical and Technical Assessment. https://www.fao.org/3/af360e/af360e.pdf ↩

4. Riboflavin Fact Sheet for Health Professionals — NIH Office of Dietary Supplements. https://ods.od.nih.gov/factsheets/Riboflavin-HealthProfessional/ ↩ ↩² ↩³ ↩⁴

5. Enriched flour (requirements, including riboflavin) — 21 CFR 137.165, eCFR. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-B/part-137/section-137.165 ↩