Riboflavin, also known as vitamin B 2, is an essential nutrient required for life. This vitamin works with two enzymes critical to the body's production of adenosine triphosphate (ATP)—its main energy source. Vitamin B 2 is also used to process amino acids and fats and to activate vitamin B 6 and folate.

Preliminary evidence suggests that riboflavin supplements may offer benefits for two illnesses: migraine headaches and cataracts.

Requirements/Sources

The official US and Canadian recommendations for daily intake of riboflavin are as follows:

  • Infants
    • 0-6 months: 0.3 mg
    • 7-12 months: 0.4 mg
  • Children
    • 1-3 years: 0.5 mg
    • 4-8 years: 0.6 mg
    • 9-13 years: 0.9 mg
  • Males
    • 14 years and older: 1.3 mg
  • Females
    • 14-18 years: 1.0 mg
    • 19 years and older: 1.1 mg
  • Pregnant Women: 1.4 mg
  • Nursing Women: 1.6 mg

Riboflavin is found in organ meats (such as liver, kidney, and heart) and in many vegetables, nuts, legumes, and leafy greens. The richest sources are torula (nutritional) yeast, brewer's yeast, and calf liver. Almonds, wheat germ, wild rice, and mushrooms are good sources as well.

Although serious riboflavin deficiencies are rare, slightly low levels can occur in children, the elderly, and those in poverty.1-4 Oral contraceptives used in the 1970s and 1980s appeared to reduce levels of riboflavin.5,6,7 But, it is not clear whether today’s versions of those medications, which contain much lower levels of estrogen, would have the same effect.

Therapeutic Dosages

For migraine headaches, the typical recommended dosage of riboflavin is much higher than nutritional needs: 400 mg daily. For cataract prevention, riboflavin may be taken at the nutritional dosages described. Since the B vitamins tend to work together, many nutritional experts recommend taking B 2 with other B vitamins, perhaps in the form of a B-complex supplement.

Therapeutic Uses

Preliminary evidence suggests that riboflavin supplements taken at high dosages may reduce the frequency of migraine headaches.8

One very large study suggests that riboflavin at nutritional doses may be helpful for cataracts, but in this study it was combined with another B vitamin—niacin ( vitamin B3)—so it's hard to say which vitamin was responsible for the effect.9

Riboflavin has also been proposed as a treatment for sickle-cell anemia,10HIV infection,11 and as a performance enhancer for athletes, but there is no real evidence that it is effective for these uses.

What Is the Scientific Evidence for Vitamin B 2 ?

Migraine Headaches

According to a 3-month, double-blind, placebo-controlled study of 55 people with migraines, riboflavin can significantly reduce the frequency and duration of migraine attacks.12 This study found that, when given at least 2 months to work, a daily dose of riboflavin (400 mg) can produce dramatic migraine relief. The majority of the participants experienced a greater than 50% decrease in the number of migraine attacks as well as the total days with headache pain. However, a larger and longer study is needed to follow up on these results.

Cataracts

Riboflavin supplements may help prevent cataracts, but the evidence isn't yet clear. In a large, double-blind placebo-controlled study, 3,249 people were given either placebo or one of four nutrient combinations ( vitamin A - zinc, riboflavin- niacin, vitamin C - molybdenum, or selenium - beta-carotene - vitamin E) for a period of 6 years.13 Those receiving the riboflavin-niacin supplement showed a significant (44%) reduction in the incidence of cataracts. However, it is unclear whether the benefits seen in this group were due to niacin, riboflavin, or the combination of the two. Strangely, there was a small, but statistically significantly higher incidence of a special type of cataract (called a subcapsular cataract) in the niacin-riboflavin group.

Safety Issues

Riboflavin seems to be an extremely safe supplement.