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What is Riboflavin (Vitamin B2), Food Sources and Supplement Forms + Role and Function in the Body + Needs, Deficiency/Toxicity

What is riboflavin?

Riboflavin has long been called vitamin B2 and is a B-complex vitamin meaning that it plays a key role in energy metabolism. The name riboflavin refers both to a component of its molecular structure and also its yellow color: ribo- with respect to the ribose (a simple sugar) portion of the molecule and flavin from the Latin word for yellow, flavus.

 

What foods have riboflavin?

Better sources of riboflavin include rapidly growing, green leafy vegetables, beef liver, beef, and dairy products (see Riboflavin in Foods Table). About ½ to ¼ of the riboflavin Americans consume is provided by milk and milk products.Meats are also a primary supplier of dietary riboflavin along with fortified and enriched foods (breads, breakfast cereals).

 
 

Is riboflavin stable during cooking and storage?

Riboflavin appears to be more stable than vitamin C and thiamin with regard to cooking and storage. However, significant riboflavin losses in foods are experienced when foods are exposed directly to light (e.g., sunlight). This was a bigger concern back when milk was packaged in clear glass bottles and delivered to your doorstep usually before people got out of bed. The milk would then be exposed to the morning sunlight until it was brought in the house. As most milk producers no longer package their product in clear containers such as glass bottles this helps milk retain most of its riboflavin. Sun drying and cooking foods in an open pot can lead to significant riboflavin losses as well. Also, like other water-soluble vitamins, riboflavin can be washed away during boiling and thawing (thaw drip).

 

How much riboflavin do we need?

The RDA for adults is 1.1 to 1.3 mg of riboflavin for adult women and men. Meanwhile the RDA for pregnant and lactating women is 1.4 mg and 1.6 mg. LIke other vitamins, the RDAs can be viewed as good minimum intake levels. Because riboflavin is important in energy operations it is more appropriate to express recommendations for more athletic people based on level of additional calories burned during exercise and sport training/competition. Here recommendations 0.6 grams of riboflavin would be recommended for every 1000 calories expended daily. Thus athletes expending 3000 to 6000 calories daily would have a recommendation of 1.8 and 3.6 mg. See DRI/RDA Table for minimum recommended levels across the lifespan.

 

Where is riboflavin in our body?

Riboflavin in foods is well absorbed from our digestive tract. Although riboflavin is found in most cells in the body, higher concentrations will be found in very active tissue, such as the heart, liver, and kidneys. This makes sense due to riboflavin’s heavy involvement with aerobic energy metabolism. Riboflavin status is typically assessed by taking a sample of blood and assessing the activity of process that requires riboflavin to operation efficiently. Because of its water solubility, riboflavin is lost from the body in urine which is visually obvious as urine turns a bright yellow a short time after ingesting riboflavin supplements.

 

What does riboflavin do in the body? Riboflavin functions in the cells as an essential component of two coenzymes, FAD and FMN , which are often referred to as flavins. With regard to energy metabolism, FAD (flavin adenine dinucleotide) serves as one of the electron carriers in aerobic energy metabolism.FAD transfers electrons from reactions in the Kreb’s cycle and also the breakdown of fatty acids, a pathway that researchers call β-oxidation (see Riboflavin Role Figure). FMN (flavin mononucleotide), on the other hand, also functions in electron transfer as a key component of the electron-transport chain in the mitochondria in our cells. Beyond energy metabolism FAD and FMN are used in many of our cell systems such as amino acid and steroid hormone metabolism. As you might have guessed, these and other riboflavin-requiring cell activities involve the transfer of electrons from one molecule to another. That is what riboflavin-based co-enzymes do: they transfer electrons.

 

What happens if too little or too much riboflavin is consumed?

Deficiency of riboflavin rarely occurs by itself. However, if a diet contains very little riboflavin, a person would begin to show deficiency signs after a couple of months, such as inflammation of the mouth and tongue. Other signs of riboflavin deficiency include dryness and cracking at the corners of the mouth, lesions on the lips, accumulation of fluid in tissue (edema), anemia, and neurological disorders, as well as mental confusion. On the other hand, there does not appear to be great concern regarding riboflavin toxicity because of its rapid removal from the body in urine. See DRI/RDA Table for recommended levels across the lifespan.