NAD+, also known as coenzyme I, stands for nicotinamide adenine dinucleotide. It is a crucial coenzyme in the tricarboxylic acid cycle, promoting the metabolism of sugars, fats, and amino acids, participating in energy synthesis, and existing in every cell to engage in thousands of reactions.
A large body of experimental data shows that NAD+ is extensively involved in various basic physiological activities within organisms, thereby intervening in critical cellular functions such as energy metabolism, DNA repair, genetic modification, inflammation, biological rhythms, and stress resistance.
Research indicates that NAD+ levels in the human body decline with age. This decrease in NAD+ levels can lead to multiple functional declines, such as neurodegeneration, vision loss, obesity, and cardiac dysfunction. Hence, how to increase NAD+ levels in the body has been a hot topic in biomedical research.
Many studies have shown that increasing NAD+ can extend the lifespan of various organisms: Yeast, a single-celled organism with a short lifespan, has its lifespan extended when supplemented with NAD+, evidenced by an increase in cell replication ability; studies on worms have shown that NAD+ can extend their lifespan by at least 10%. These effects also extend to mammals.
In a recent study on elderly men, supplementing NAD+ significantly increased their NAD+ levels by 59% within just two hours, while markers of oxidative stress decreased. In this study, the isometric muscle torque peak (a measure of muscle strength) of men increased by 8%, and exercise-related fatigue improved by 15%.
Studies on mouse models of Alzheimer's disease have shown that supplementing NAD+ can improve the condition. In a recent study, it reversed cognitive deficits in mice, thereby improving memory. The pathology observed in the brains of Alzheimer's patients (amyloid plaques) was also reduced in these animals. Previous studies have found similar results.
Sirtuins can improve metabolism and help prevent weight gain, metabolic syndrome, and type 2 diabetes. By enhancing the activity of sirtuins, NAD+ can boost metabolism and prevent excessive weight gain in mice; in animal models of type 2 diabetes, this improved metabolism helps control blood sugar levels and counteract the damage caused by hyperglycemia.
Improving metabolism and reducing weight helps lower the risk of cardiovascular diseases. NAD+ also has a protective function for the cardiovascular system. In a recent study, mice with heart disease had their NAD+ levels reduced by 30%. If left untreated, they usually develop heart failure, but NAD+ significantly alleviated the decline in heart function.
Sleep patterns change with age, largely due to disruptions in circadian rhythms that control sleep/wake cycles. NAD+ has shown the ability to balance circadian rhythms by stimulating the key cellular protein Sirt1. In an animal study, mice lacking Sirt1 experienced a decline in sleep quality. Increasing NAD+ levels can help boost SIRT1 and other sirtuins, aiding in the restoration of normal sleep/wake cycles.