Nucleosides + nucleotides as dietary supplements rather than de novo synthesis substrates. CDP-choline (citicoline) — provides cytidine + choline; stroke recovery + cognitive enhancement; raises both phosphatidylcholine + acetylcholine biosynthesis. Uridine — converted to UMP/UDP/UTP; precursor for membrane phosphatidylcholine via Kennedy pathway; bipolar + sleep claims. NAD-precursor stack: NMN (nicotinamide mononucleotide), NR (nicotinamide riboside), NAAD, NaMN — bypass the rate-limiting NAMPT step; longevity + mitochondrial health claims; oral PK + tissue NAD+ elevation under active research. Inosine — degraded to uric acid; gout precursor + claimed performance enhancer (debated). Adenosine + adenosine-cousins (cordycepin = 3'-deoxyadenosine — covered in mushroom pathway).
Organ Systems
nervous
musculoskeletal
Pathway Steps
dietary-nucleoside → cellular-nucleotide-pool — via salvage pathway phosphorylation; CDP-choline directly provides Kennedy-pathway intermediate. Cells obtain nucleotides by de novo synthesis or by salvaging dietary/recycled nucleosides and bases — the salvage pathway being far more energy-efficient. Rapidly dividing tissues (gut, immune cells) rely heavily on salvage, which is why dietary nucleotides are added to infant formula and why antimetabolite drugs target these pathways.
Known Modulators
cdp choline (substrate) — phosphatidylcholine + acetylcholine biosynthesis. citicoline; stroke recovery + cognitive enhancement; raises CNS PC + ACh in chronic dosing
uridine (substrate) — UMP pool + Kennedy pathway PC synthesis. OTC; mood + cognitive claims; converts to UMP via uridine kinase
naad (substrate) — NAD biosynthesis (de novo). NaAD — NaMN → NAAD → NAD pathway intermediate; lab/research reagent
nad plus (substrate) — direct NAD+ replacement (poor oral PK). NAD+ oral has minimal bioavailability — IV NAD+ infusions widely marketed despite limited efficacy data
namn (substrate) — NAD biosynthesis (de novo, NaMN). nicotinic acid mononucleotide; de novo pathway intermediate