'Riboflavin, an essential nutrient, is a constituent of two coenzymes: riboflavin-5'-phosphate [flavin mononucleotide (FMN)] and flavin adenine dinucleotide (FAD), which are essential components of a number of oxidative enzyme systems. Various foods such as bakery, cereal and pasta products are commonly enriched by the addition of 2 to 5 mg per kg products. Also, many commonly used vitamin supplements contain riboflavin. The amount of riboflavin-5'-phosphate added to food is minuscule.
The Recommended Dietary Allowance of riboflavin is 0.6mg per 1000kcal for persons of all ages with an additional 0.3mg daily for pregnant and 0.5mg for lactating women. A recent U.S. survey of over 20,000 persons, 1 to 74 years of age, revealed a mean average intake of 1.92 and a median of 1.69mg per day.
The acute toxicity in animals of riboflavin or FMN given orally is extremely low, with LD50 values several orders of magnitude greater than the dietary requirements or the estimated addition to food. The relative insolubility of riboflavin limits the absortion when large amounts are ingested. No reports have come to the attention of the Select Committee suggesting carcinogenic, mutagenic, or teratogenic effects of riboflavin. Normal reproductive performance was observed in three generations of rats fed several hundred times their daily requirements. Toxic effects in man have not been reported apart from rare instances of sensitivity.
In light of these considerations, the Select Committee concludes that: There is no evidence in the available information on riboflavin or riboflavin-5'-phosphate that demonstrates or suggest reasonable grounds to suspect, a hazard to the public when they are used at levels that are now current or that might reasonably be expected in the future.