Introduction: The longevity gene-associated Nicotinamide Adenine Dinucleotide (NAD)-dependent sirtuin plays an important role in genomic stability, antioxidant potential, DNA repair, and mitochondrial and energy metabolism. Since tuna meat is known to contain NAD precursors, we postulate that it may increase sirtuin levels in human cells. Methods: We investigated in vitro whether tuna meat regulates mitochondrial function and energy metabolism in human Peripheral Blood Mononuclear Cells (PBMCs). Mitochondrial NAD activity, sirtuin expression, energy production, and antioxidant activity in PBMCs were analyzed after the in vitro treatment of cells with a digestive enzyme tuna hydrolysate, hot water tuna extract, or control. In a clinical study, 84 healthy volunteers consumed edible tuna meat three times a week for three weeks, and the level of sirtuin 2 in PBMCs was analyzed. Results: Both digestive enzyme tuna hydrolysate and hot water tuna extract significantly increased NAD level, sirtuin 1 and 2 expression, and mitochondrial ATP production in PBMCs. Tuna hydrolysates showed high antioxidant capacity in vitro. In the clinical study, in the group that consumed 80 to 120 grams of tuna, sirtuin 2 levels in PBMCs were significantly increased by approximately 2-fold after consuming tuna meat for 3 weeks compared to the initial stage. Discussion: Our present study indicates that tuna may enhance longevity gene-related sirtuin activity, its associated mitochondrial activity, and anti-oxidative potential in PBMCs. Conclusion: Our studies underscore the benefits of tuna meat as a dietary choice and provide scientific support for the promotion of healthy ageing.
Suzuki-Takahashi et al. (Mon,) studied this question.