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
Deficiencies: Dermatitis, glossitis, corneal vascularization
Toxicity: None known.