Nicotinamide Adenine Dinucleotide, after water, is the most prevalent molecule in the human body. Hence, you cannot overstate its importance. Proteins like the sirtuins use this to fix damages in DNA. NAD+ is also essential for mitochondria which synthesize energy on the cellular level to be used by the body.
Inside mitochondria, the powerhouse of the cell, NAD+ has a vital role in cell function. Metabolic processes like the Krebs Cycle, the electron transport chain, and glycolysis, all require its active participation to occur.
As a coenzyme, Nicotinamide Adenine Dinucleotide possesses the ability to alter enzyme activity, cell signaling, and gene expression. As it binds to enzymes, NAD+ is involved in metabolism by transferring electrons from molecule to molecule.
You can think of this transferring of electrons as the recharging of a battery. As the electrons use up their energy, the battery starts losing its charge. Once expended, these electrons need a little energy boost to get back to their starting position—the NAD+ acts like this booster inside our cells.
The current aging theory suggests that DNA damage is the primary cause of aging. DNA damage is unavoidable; many stressors in our environment, such as pollution and radiation, impair the accurate replication of DNA. The cells in our bodies are equipped with the molecular machinery to take care of this DNA damage. However, as this process uses up the Nicotinamide Adenine Dinucleotide coenzyme and energy molecules, it depletes a good amount of the cell’s valuable reserves.
As we age, our bodies produce more PARP or Poly (ADP-ribose) polymerase, a critical DNA repairing protein. This increased level of PARP causes a reduction in the level of NAD+ over time. If the amount of the coenzyme is not restored in the body, it hinders DNA damage repair.
Sirtuins are newly-discovered enzymes that help cells with damage repair as well as a timely stress response. These enzymes also contribute to insulin secretion and diseases relating to aging such as diabetes and neurodegenerative problems. Because of their role in cellular well-being, they are popularly known as the “longevity genes” and also as the “guardian of genes.”
NAD+ activates sirtuins.
David Sinclair, a Harvard NAD researcher and geneticist, explains that the levels of Nicotinamide Adenine Dinucleotide steadily decline in the body with age, which causes a reduction in sirtuin activity. That’s why in old age, our bodies become susceptible to multiple diseases that aren’t present in younger individuals due to the lack of proper DNA and cellular damage repair. The only way to prevent this from happening is to naturally lift up the levels of NAD+ in the body to stop or, in some cases, even reverse the process and signs of aging.
Human beings synthesize Nicotinamide Adenine Dinucleotide by using small components called precursors as raw materials. These are extracted from the food that we eat. The five precursors found in our bodies include tryptophan, nicotinamide, nicotinic acid or niacin, nicotinamide riboside, and lastly nicotinamide mononucleotide. Of these five nicotinamide, niacin, and nicotinamide riboside are all types of vitamins B3.
Numerous biochemical pathways are available in our bodies for synthesizing NAD+; all of these result in the same end product. First up is the De novo pathway, which roughly translates as “from scratch” in English. Starting with tryptophan, the first NAD+ precursor, the pathway moves its way up.
Next comes the salvage pathway. To stop proteins from reaching concerningly high levels, the body degrades them all from time to time. During this process of protein degradation, enzymes use a few of these degradation products to fuel new protein synthesis. Therefore, this pathway salvages products formed during Nicotinamide Adenine Dinucleotide degradation to make new molecules of the enzyme.
There are numerous ways to increase levels of NAD+ in the body. The practice of calorie restriction and fasting has proven to raise levels of NAD+ and sirtuin. Studies on mice have shown that reduced calorie intake causes a slowing down effect on the ageing process due to higher levels of the coenzyme.
Nutritional coenzymes can be obtained from food, but often the concentration is too low. But you can compensate for this deficiency by taking NMN, which has shown to enhance Nicotinamide Adenine Dinucleotide levels.