Acute nicotinamide riboside supplementation increases human cerebral NAD levels in vivo.

Purpose: The purpose of this study was to determine the effect of acute nicotinamide riboside (NR) supplementation on cerebral nicotinamide adenine dinucleotide (NAD) levels in the human brain in vivo by means of downfield proton MRS (DF H MRS).

Methods: DF H MRS was performed on 10 healthy volunteers in a 7.0 T MRI scanner with spectrally selective excitation and spatially selective localization to determine cerebral NAD levels on two back-to-back days: once after an overnight fast (baseline) and once 4 h after oral ingestion of nicotinamide riboside (900 mg). Additionally, two more baseline scans were performed following the same paradigm to assess test-retest reliability of the NAD levels in the absence of NR.

Results: NR supplementation increased mean NAD concentration compared to the baseline (0.458 ± 0.053 vs. 0.392 ± 0.058 mM; p < 0.001). The additional two baseline scans demonstrated no differences in mean NAD concentrations (0.425 ± 0.118 vs. 0.405 ± 0.082 mM; p = 0.45), and no difference from the first baseline scan (F(2, 16) = 0.907; p = 0.424).

Conclusion: These preliminary results confirm that acute NR supplementation increases cerebral NAD levels in healthy human volunteers and shows the promise of DF H MRS utility for robust detection of NAD in humans in vivo.