Vitamin B2 (Riboflavin) 101: RDA, Testing, and Supplementing

Vitamin B2, also called riboflavin, was the second vitamin to be discovered. It is critical for human health and involved in numerous bodily processes. B2 is naturally yellow and has also been used as a food coloring agent. This article will discuss what B2 is, including its role in the body. We'll then discuss B2 deficiency, how to test for it, and food and supplement sources.

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What is (Riboflavin) Vitamin B2?

Vitamin B2 is a water-soluble vitamin. Riboflavin is an essential part of many coenzymes. Coenzymes are compounds that bind to an enzyme and assist in a reaction. There are two riboflavin-containing coenzymes called flavocoenzymes: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).

Vitamin B2's (Riboflavin’s) Role in The Body

Vitamin B2, through the actions of FMN and FAD, affects food and drug metabolism, energy production, antioxidant functions, methylation processes, and other vitamin interactions.

Food and Drug Metabolism

Flavocoenzymes are a required part of protein, carbohydrate, and fat metabolism. They also help play a role in drug and toxin metabolism that takes place in the liver.

Energy Production

The body’s energy unit of measurement is adenosine triphosphate, also called ATP. FAD is a necessary part of the production of ATP. ATP is used for muscular contractions, nerve impulses, and the creation of various chemicals in the body, amongst other things. Each cell in the body requires 100 to 150 moles, or units, of ATP per day to function correctly.

Antioxidant Function

Glutathione is the most potent antioxidant that our bodies produce. Antioxidants fight and reduce compounds called free radicals, damaging DNA and cell membranes and leading to premature aging and certain diseases. FAD is required for the production of glutathione. Additionally, FAD is required to produce uric acid, an important water-soluble antioxidant. Uric acid aids in tissue repair and blood vessel integrity.

Vitamin Interactions

Flavocoenzymes are essential for converting B12, B6, niacin, and folate into their active forms in the body. There also seems to be a connection between riboflavin and iron. Studies have shown that improving riboflavin levels can increase hemoglobin, the iron-dependent oxygen taxi in the body, which transports oxygen around the body.

Methylation

Methylation is an umbrella term for biochemical processes in the body that affect DNA production, hormone metabolism, and detoxification. The primary enzyme, methylenetetrahydrofolate reductase (MTHFR), requires FAD to function correctly. This enzyme plays an essential role in lowering homocysteine levels. Homocysteine is an amino acid that can cause blood clotting and may increase the risk for cardiovascular events, including heart attack and stroke.

What Causes Vitamin B2 (Riboflavin) Deficiency?

Ariboflavinosis is the medical term for a B2 deficiency. While a B2 deficiency is rare in the United States, it is common worldwide in low to middle-income countries. However, subclinical deficiencies are estimated to be widespread but go undetected due to a lack of testing. B2 deficiencies usually are concurrent with other water-soluble vitamin deficiencies. High alcohol intake, anorexia, those who avoid dairy products, and highly active people may be at risk for B2 deficiency.

Additionally, hypothyroidism and adrenal insufficiency hinder the formation of flavocoenzymes and thus can cause B2 deficiency symptoms even with adequate b2 levels. Lastly, B2 is sensitive to light and rapidly becomes inactivated in the presence of light. Extensive use of light therapy to treat newborn jaundice and in the treatment of skin disorders can lead to B2 deficiency.  

Vitamin B2 (Riboflavin) Deficiency Symptoms

Symptoms of B2 deficiency include:

• Sore throat
• Swelling and redness in the lining of the mouth and throat
• Cheilosis (cracked and swollen lips)
• Angular stomatitis (cracks and sores on the corners of the mouth)
• Redness and swelling of the tongue
• Seborrheic dermatitis (scaling, moist, inflamed skin)
• Vascularization of the cornea (blood vessels in the clear part of the eye)
• Anemia (normochromic, normocytic anemia)

How to Test Vitamin B2 (Riboflavin) Levels

B2 levels can be tested in the blood or urine.

Access Medical Laboratories offers a B2 test in the blood. Blood levels should be between 106-638 nanomoles/liter (nmol/L).

Urinary measurements of B2 reflect dietary intake since B2 is not readily stored in the body. B2 levels in the urine should be at or above 120 micrograms (mcg)/day. Levels below 40 mcg/day indicate a B2 deficiency.

How to Get Enough Vitamin B2 (Riboflavin) from Your Diet

The Food and Nutrition Board at the Institute of Medicine of the National Academies created Dietary Reference Intake (DRI) measurements for vitamins and minerals. One DRI is the Recommended Daily Allowance (RDA). The RDA is defined as the average daily intake amount needed to achieve nutritional adequacy for nearly all healthy people. When there is not enough evidence to formulate an RDA, an Adequate Intake (AI) is formed. AI is defined as the average daily intake assumed to meet nutritional requirements for nearly all healthy people in a specific population.

AIs were developed for birth through 1 year. From birth to six months, the AI for males and females is 0.3mg, and from seven months to one year is 0.4 mg for males and females.

Pregnant and lactating women often have different RDAs due to their unique nutritional requirements. RDA for pregnant women ages 14-50 is 1.4 mg, and for lactating women aged 14-50 is 1.6mg.

B2 can be found in foods and supplements.

B2 is found naturally in many foods. In the United States and other countries, poor sources of B2, such as cereals and grain products, have been fortified with the vitamin.

It’s important to note that gut bacteria found in the microbiome of the large intestine can also produce B2. Higher levels of B2 are produced from vegetable-rich diets as opposed to meat-based diets.

B2 (Riboflavin) Supplements

B2 is found in multivitamins, b-complexes, and as a stand-alone vitamin supplement. Most supplements contain riboflavin in free form, although some contain riboflavin 5’-phosphate. Most multivitamins contain 1.3 mg of riboflavin, the RDA for adult males.

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Summary

Vitamin B2 is crucially essential for many biological processes in the body. Its impressive list of effects makes this water-soluble vitamin necessary for human health. Knowing levels of b2, therefore, can be an important marker to evaluate not just to rule out deficiencies but also to assess if striving for optimal health. Once the B2 level is known, food and supplementation recommendations can be made to suit the individual's needs.