High doses of riboflavin and the elimination of dietary red meat promote the recovery of some motor functions in Parkinson's disease patients. C.G. Coimbra and V.B.C. Junqueira. Brazilian Journal of Medical and Biological Research, 36 (10): 1409, 2003.
Figure 2. Dependency of hemin catabolism on riboflavin bioavailability. The elimination of hemin requires cyclic reduction of heme oxygenase by flavoprotein cytochrome P450 reductase that, in turn, utilizes both flavin mononucleotide (FMN) and flavin-adenine dinucleotide (FAD) as prosthetic groups. Average or increased red meat consumption may overload the capacity of this chain of reactions already compromised by impaired intestinal absorption of riboflavin (with decreased FMN and FAD synthesis), leading to increased hemin (iron) delivery to the CNS and increased utilization of riboflavin for hemin inactivation. Modified from Figure 1, box 21-1, page 783 of Ref. 2.