NAD⁺ Pool

The consumed cosubstrate for sirtuin histone deacetylases. Chronically depleted in this clinical context through three simultaneous drains.

Why NAD⁺ Is Critical

Sirtuin family HDACs (SIRT1, SIRT3, SIRT6, SIRT7) remove acetyl groups from histones — specifically from pro-inflammatory gene promoters where NF-κB has placed acetylation marks. This is the deacetylation side of the chromatin remodeling work that butyrate's HDAC inhibition and pterostilbene's SIRT1 activation complement from opposite directions.

NAD⁺ is not a cofactor — it is a consumed cosubstrate:

NAD⁺ + Acetyl-Histone → [SIRT] → Deacetylated-Histone + Nicotinamide (NAM) + O-acetyl-ADP-ribose

One molecule of NAD⁺ consumed per deacetylation event. When NAD⁺ is depleted, sirtuin activity collapses regardless of enzyme expression level.

The Three Simultaneous Drains

1. PARP Hyperactivation (Primary Drain)

PARP1 and PARP2 are DNA repair enzymes that consume NAD⁺ massively when oxidative DNA damage is present:

Single strand break → PARP activation → PAR chain synthesis from NAD⁺
One strand break can consume 80% of cellular NAD⁺ within minutes
Chronic low-level oxidative DNA damage from 4-HNE = chronic low-level PARP activation = chronic NAD⁺ drain
This drain cannot be outpaced by simple NAD⁺ precursor supplementation unless the oxidative DNA damage is also addressed

Therefore: [[Phase 0 - Source Control and Redox]] reducing oxidative damage is as important for NAD⁺ restoration as NMN/NR supplementation. Sulforaphane → Nrf2 → antioxidant upregulation → reduced oxidative DNA damage → reduced PARP activation → NAD⁺ spared.

2. CD38 Upregulation (Inflammatory Drain)

CD38 is an ectoenzyme that degrades NAD⁺ to cyclic ADP-ribose and nicotinamide. Inflammation directly upregulates CD38 expression. More systemic inflammation → more CD38 activity → faster NAD⁺ degradation.

This creates a vicious cycle: NAD⁺ depletion → reduced sirtuin-mediated inflammatory gene deacetylation → more inflammation → more CD38 → more NAD⁺ depletion.

3. Sirtuin Consumption (Functional Drain)

The sirtuins themselves consume NAD⁺ during their beneficial activity. The paradox: the more effectively sirtuins deacetylate pro-inflammatory marks, the more NAD⁺ they consume. Supplementing NAD⁺ precursors is therefore essential even as sirtuins are activated.

Synthesis Pathways

Preiss-Handler Pathway

Nicotinic acid (niacin, vitamin B3) → NaMN → NaAD → NAD⁺ Most direct dietary route. Niacin specifically also induces ABCA1 (efferocytosis connection → [[Efferocytosis Failure]]) and has broad lipid-modifying effects.

Salvage Pathway

Nicotinamide (NAM, released by sirtuins) → NMN → NAD⁺ [requires NAMPT enzyme] This pathway regenerates NAD⁺ from the nicotinamide released during sirtuin activity. NAMPT is the rate-limiting enzyme. NMN supplementation feeds directly into this pathway.

De Novo Synthesis

Tryptophan → kynurenine → quinolinic acid → NAD⁺ Requires B6, B2, iron, copper. Diverted under chronic inflammation — IDO1 activation shunts tryptophan toward kynurenine for immunosuppression rather than NAD⁺ production. Another reason inflammation reduces NAD⁺ availability.

NMN and NR Supplementation

NR (Nicotinamide Riboside): Converts to NMN → NAD⁺. Well-absorbed orally.
NMN (Nicotinamide Mononucleotide): More direct precursor. Debated whether it enters cells as NMN or must be converted to NR first — recent data suggests direct NMN transport via Slc12a8 transporter in some tissues.
Dosing: 300–500mg daily. Higher doses (1g+) used in some longevity protocols.

Interaction with berberine: Berberine activates AMPK which can interfere with mTOR. Don't take simultaneously with NMN/NR — AMPK and mTOR pathways interact in ways that can partially cancel autophagy induction. Separate timing by several hours.

Connections

[[One Carbon Metabolism]] — parallel epigenetic substrate system
[[Phase 3 - Epigenetic Reprogramming]] — where NAD⁺ is used
[[Phase 0 - Source Control and Redox]] — reducing PARP drain
[[Epigenetic Transmission]] — what NAD⁺-dependent sirtuins are repairing