Vitamin B2 (Riboflavin): Importance, History, and Daily Recommendations

What is Vitamin B2 and its Importance

Vitamin B2, also known as riboflavin, is a water-soluble vitamin essential for various functions in the body. It plays a crucial role in energy production, cellular growth and development, and the maintenance of healthy skin and eyes. Additionally, riboflavin acts as an antioxidant, helping to protect the body from damage caused by free radicals.

Brief History and Discovery

The discovery of riboflavin dates back to the early 20th century. In 1920, British biochemist Sir Frederick Gowland Hopkins found that certain food factors, which he called "accessory food factors," were essential for growth and health in animals. This discovery laid the groundwork for the identification of riboflavin.

In 1933, scientists Kuhn, Gyorgy, and Wagner-Jauregg successfully isolated riboflavin as a yellow-green, fluorescent substance from milk. They named it "riboflavin," derived from the Latin word "flavus," meaning yellow, and the sugar "ribose," which is part of its chemical structure.


Riboflavin is found in various food sources, both animal and plant-based. Some of the most significant sources of riboflavin include:

  • Dairy products: milk, yogurt, and cheese
  • Meat and poultry: beef, chicken, and turkey
  • Fish: salmon, trout, and mackerel
  • Eggs
  • Green vegetables: spinach, asparagus, and broccoli
  • Grains: whole grains, enriched bread, and fortified cereals
  • Nuts and seeds: almonds, sunflower seeds, and chia seeds

It is important to note that riboflavin is sensitive to light, and prolonged exposure to sunlight can reduce its content in food. To preserve riboflavin, store foods in a dark, cool place.

Functions in the Body

Riboflavin has several important functions in the body:

  1. Energy production: Riboflavin is a vital component of two coenzymes, flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD), which are involved in cellular respiration and energy production. These coenzymes help break down carbohydrates, fats, and proteins to release energy.
  2. Antioxidant activity: Riboflavin acts as an antioxidant, neutralizing harmful free radicals and reducing oxidative stress in the body, which can contribute to chronic diseases and aging.
  3. Cellular growth and development: Riboflavin plays a role in the synthesis of nucleic acids, which are essential for cellular growth and division.
  4. Maintenance of skin, eyes, and mucous membranes: Riboflavin is necessary for maintaining healthy skin, eyes, and mucous membranes in the body. It aids in the production of collagen, a structural protein that supports the skin's elasticity and firmness. Additionally, riboflavin supports good vision by contributing to the maintenance of the cornea and retina.
  5. Conversion of other B vitamins: Riboflavin helps in the conversion of other B vitamins, such as vitamin B6 (pyridoxine) and vitamin B9 (folate), into their active forms. This conversion is crucial for the proper functioning of these vitamins in the body.

Recommended Daily Intake of Riboflavin

The recommended daily intake (RDI) of riboflavin varies depending on age, sex, and life stage. The following values are based on the Dietary Reference Intakes (DRIs) established by the Institute of Medicine:
Infants (0-6 months): 0.3 mg/day (Adequate Intake)
Infants (7-12 months): 0.4 mg/day (Adequate Intake)
Children (1-3 years): 0.5 mg/day
Children (4-8 years): 0.6 mg/day
Children (9-13 years): 0.9 mg/day
Adolescents (14-18 years): 1.0 mg/day (females) and 1.3 mg/day (males)
Adults (19 years and older): 1.1 mg/day (females) and 1.3 mg/day (males)
Pregnant women: 1.4 mg/day
Lactating women: 1.6 mg/day

It is essential to consume riboflavin-rich foods regularly, as the body does not store this water-soluble vitamin in large amounts. In most cases, a well-balanced diet can provide the necessary amount of riboflavin to meet the RDI. However, individuals with certain medical conditions, strict vegetarians, and vegans may need to supplement riboflavin to meet their needs.

Recap and Conclusion

Vitamin B2, or riboflavin, is an essential nutrient that plays a significant role in energy production, cellular growth and development, and the maintenance of healthy skin and eyes. Its discovery in the early 20th century contributed to our understanding of the importance of vitamins in overall health.

Riboflavin is found in a variety of animal and plant-based foods, including dairy products, meat, fish, eggs, green vegetables, grains, nuts, and seeds. The recommended daily intake of riboflavin varies depending on age, sex, and life stage, but most individuals can obtain sufficient amounts through a well-balanced diet.

William H. McDaniel, MD

Dr. Robert H. Shmerling is the former clinical chief of the division of rheumatology at Beth Israel Deaconess Medical Center (BIDMC), and is a current member of the corresponding faculty in medicine at Harvard Medical School.

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