Life expectancy is increasing worldwide, and there is an increasing need to delay aging and stay healthy. In this ongoing quest, scientists around the world are unraveling the biology of aging and working to find effective measures to combat it. Among them, there is an enzyme involved in energy metabolism, namely nicotinamide adenine dinucleotide (NAD+), which continues to attract the attention of scientists.
NAD+ is a key metabolite and coenzyme for a variety of metabolic and cellular processes in the body, plays an important role in many physiological processes, and is essential for maintaining human health.
With increasing age, the level of NAD+ will gradually decline, and this decline has been found to be related to a variety of human aging phenomena.
Elucidating the role of nicotinamide adenine dinucleotide in human aging is expected to reveal a promising anti-aging strategy.
The supplement Exploring NAD+ :
Combating Cellular Aging summarizes several research highlights that summarize important findings in this growing field of research.
In 2021, researchers at the Buck Institute for Research on Aging in the United States wrote in Nature Review:
A review published in Nature Reviews Molecular Cell Biology summarizes recent advances in the field of NAD+.
Multiple preclinical studies using different model systems, including rodent and human primary cells,
have confirmed that decreased NAD+ levels also associated with several age-related cellular processes,
including DNA repair, oxidative stress, and immune cell function.
A series of animal model studies have shown that nicotinamide adenine dinucleotide depletion plays a key role in many age-related processes, including cognitive decline, cancer, metabolic disease, and physical frailty.
The researchers say that increasing NAD+ levels may improve the health of several organs in the body,
including increasing energy levels, reducing muscle atrophy, and improving brain function. This makes targeting nicotinamide adenine dinucleotide metabolism a promising anti-aging strategy.
Because metabolic stress and aging can affect NAD+ levels,
scientists are also exploring ways to boost levels using NAD+ ‘s precursor, nicotinamide ribose (NR).
A study published in Scientific Reports in 2019 tested changes in nicotinamide adenine dinucleotide levels in people after ingesting an oral formulation of NR.
They recruited 140 adults aged 40 to 60 and randomly assigned them to either a placebo or a daily dose of 100 mg, 300 mg, or 1,000 mg of NR, and performed blood and urine tests on days 7, 14, 28, and 56, as well as safety assessments.
After 14 days, NAD+ levels in the blood of participants taking 300 mg and 1,000 mg of NR increased by about 51% and 142%, respectively.
Blood levels of NAD+ metabolites in the low-dose group of 100 mg increased by 22 percent after 14 days. After 56 days, higher levels of methylnicotinamide – a biomarker of increased NAD+ metabolism – detected in the urine and plasma of all participants taking NR. The study found no adverse effects.
NAD+ is also closely related to the deacetylase (sirtuin).
The family of deacetylases (SIRT1 to SIRT7) are NAD+ dependent enzymes that play a key role in skin health and aging by consuming NAD+ to regulate chemical processes.
In 2020, Shengqin Su’s team at the University of Wisconsin-Madison published a review in Photochemistry and Photobiology 3,
The known roles of SIRT3, SIRT4 and SIRT5 in skin aging and disease reviewed.
Researchers say sirtuin plays a key role in the skin’s ability to maintain balance under environmental stress and involved in skin collagen synthesis,
protection against UV rays and maintenance of the skin barrier.
In the future, the researchers will further elucidate the relationship between these proteins and NAD+ levels.
References:
- Covarrubias, A.J. et al. Nat Rev Mol Cell Biol. 22,119-141 (2021).
- D. Conze, C. Brenner & C. L. Kruger, Sci Rep. 9, 9772 (2019).
- Su, S. et al. Photochem Photobiol. 96, 973-980 (2020).
