Vitamin B2 (Riboflavin)

One liter of fresh milk and two eggs
November 7, 2013

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.

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