Nicotinamide riboside (NR) is a NAD+ precursor vitamin that is increasingly attracting the attention of research and supplement industry. Keeping NAD+ levels up while we age promotes health at the mitochondrial level. It is known for a long time that NR is present in cow milk, the concentration however of NR and other NAD+ precursors in milk was so far unknown.
This recently published study found that raw cow milk typically contained ∼12 μmol of NAD+ precursor vitamins/L, of which 60% was present as nicotinamide and 40% was present as NR. Nicotinic acid and other NAD+ metabolites were below the limits of detection.
The study purpose was to not only determine the amount of NAD+ precursor vitamin concentration in samples of raw milk from individual cows but also in commercially available cow milk. The commercial milk showed an average 8.3 μmol of NAD+ precursor vitamins/L with fluctuation among various brands tested. NR content was an average 3.2 μmol / L of milk.
We can use the molar mass of NR (255 g/mol) to calculate how many milligram of NR a liter of milk contains: commercial milk has on average 0.8mg of NR / Liter. To put that to perspective Niagen supplements on the market provide 250 milli grams of Nicotinamide Riboside per portion. That would require drinking some 300L of milk.
The researchers also noted that NR is more stable in milk than water. The ability of milk to bind and preserve the integrity of NR makes dairy products potentially good sources of supplemented NR. Further research is however needed to maximize NR concentration of conventional and organic milk to reach supplement product levels.