Vitamin B2 (Riboflavin)

Riboflavin is needed for the formation of flavin mononucleotide (FMN, seen in Complex I of the ETS) and flavin adenine dinucleotide (FAD, from Step 6 of the Krebs). Below is a diagram that shows their structures.

Riboflavin is light-sensitive! That’s why you won’t see milk in a clear bottle or container.

Good sources: Milk, eggs, liver, green leafy veggies, and whole & enriched grains.

DRI: 0.9-1.3 mg per day

Functions: The 2 co-enzymes discussed above (FMN and FAD).

All known functions:

Essential to the production of energy from food in the form of ATP (adenosine triphosphate)
Active form is FAD (flavin adenine dinucleotide) and FMH (flavin mononucleotide, also calledriboflavin 5’-phosphate) which are cofactors for oxidation-reduction reactions in energy production
FAD assists methylation reactions throughout body
Coenzymes derived from riboflavin are called flavins
Enzymes that use a flavin coenzymes are called flavoproteins
Flavins metabolize drugs and toxins
Low B2 can impair methylation reactions in the brain, which may present clinically as depression
Activates glutathione reductase, which regenerates the antioxidant glutathione
Key role in iron utilization
Aids in mobilization of ferritin from tissues; helpful for anemia
FAD is a cofactor for methylenetetrahydrofolate reductase (MTHFR) so for people who arehomozygous for 677C→T MTHFR gene, riboflavin may lower their homocysteine
Recycles folate into a usable methyl-donor form (converts 5,10-methylene TH4-folate to 5-methylTH4-folate)
People with 677C→T MTHFR gene tend to respond well to B2 therapy to lower blood pressure
Cofactor to xanthine oxidase, which synthesizes uric acid and aids in purine catabolism
Cofactor to pyridoxal 5’-phosphate oxidase, which converts vitamin B6 into its active form
Cofactor in the conversion of retinol (vitamin A) to retinoic acid
Cofactor to kynurenine mono-oxygenase, which converts tryptophan into niacin containing enzymesNAD and NADP
Cofactor to NAD(P):quinine oxidoreductase which aids in detoxification and chemoprevention
Cofactor to protoporphyrinogen oxidase which synthesizes hemoglobin
Cofactor to dihydrolipoyl dehydrogenase which aids energy metabolism
Cofactor to fatty acyl-CoA-dehygrogenase which aids in fatty acid oxidation
Cofactor to succinate dehydrogenase which is used in the Krebs cycle for energy production
Cofactor to NADH dehydrogenase (also called ubiquinone oxidoreductase) which functions inmitochondrial respiration
Cofactor to sphinganine oxidase which synthesizes sphingosine (component of nerve tissue)
Cofactor to monoamine oxidase which aids in metabolism of several neurotransmitters such asserotonin, melatonin, epinephrine and norepinephrine
Role in mitochondrial energy metabolism may explain its efficacy in migraine prophylaxis
Role in glutathione reductase implicates riboflavin deficiency in cataract formation
Minimizes pain associated with inflammation
Augments the antinociceptive (painkiller) effects of morphine