Niacin

维生素 B3

Place · Level 3

NAD / NADP 两套代谢账户 · 从色氨酸也能来 · NAD+ 与长寿的新故事

Connected to · 3

synergy · 2

Riboflavin
NADH and FADH₂ feed the ETC at two entry points — B3 and B2 are the chain's twin inputs.
Chromium
Historical 'glucose tolerance factor' (GTF) paired Cr with niacin in 70s-80s marketing. EFSA 2014 + purified LMWCr studies revoked Cr's essential-nutrient status. Kept as a historical edge for context — not a clinical recommendation.

cofactor · 1

α-Lipoic Acid
On PDH/KGDH the lipoyl arm passes reducing equivalents through E3-FAD to NAD⁺ — NAD⁺ is the relay's terminal acceptor.

NAD / NADP two ledgers

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NAD / NADP 两套账户

Once B3 enters the body it contributes to the formation of NAD (nicotinamide adenine dinucleotide) and NADP. The chemical difference between them is a single phosphate group, but the biological roles are completely different:

NAD+ / NADH: catabolic-leaning. Collects electrons in the cycle (NADH) and feeds the respiratory chain to make . Also serves as substrate for sirtuins: A family of NAD⁺-powered enzymes involved in repair and 'longevity'-linked cellular upkeep. (deacetylases) and PARP (DNA repair)NADP+ / NADPH: anabolic and reductive defense. Fatty-acid synthesis, sterol synthesis, and the antioxidant system (glutathione recycling) all rely on NADPH for reducing power
A useful analogy: NAD is the 'power-transmission line', NADP is the 'power-storage and consumption side'. The two are not interchangeable — cells precisely maintain the NAD+/NADH and NADP+/NADPH ratios separately.

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Educational content, not medical advice — consult a clinician.

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