Nicotinamide adenine dinucleotide, or NAD+ is an essential molecule for the creation of energy in the human cell and regulates critical cellular processes like glycolysis, the energy generating pathway in humans and all other lifeforms that we are aware of. In this process, NAD+ is an electron carrier that accepts a pair of high energy electrons and helps to pass energy from glucose to other pathways in the cell. While exercise is considered a frontline modality to combat age-related muscle decline, nutritional strategies may also offer an effective countermeasure to age-associated morbidities and promote healthy muscle aging.
NAD+, is a coenzyme that is found in every cell of the body where it is involved in hundreds of critical metabolic processes. It is modulated by conditions of metabolic stress and is reported to decline with aging in preclinical models. NAD+ turns nutrients into cellular energy and activates sirutins, a set of proteins that regulate cellular health. While NR and NMN (another precursor to NAD+) are found in the foods we eat, so far there’s no food that gives us enough to boost NAD+ levels so it may be worth considering supplementation with NAD+ precursors.
Unfortunately, you can’t just take NAD+ itself because it won’t enter the cells where it can do its job. The way around this is to introduce smaller precursors like nicotinamine mononucleotide (NMN) and/or nicotinamine riboside (NR) that can enter the cell where they are converted to NAD+ by natural cellular processes. Both NMN and NR are precursor molecules to NAD+ that is available on the supplement market from several manufacturers. NR can enter cells directly while NMN requires a conversion step to gain entry.
Does it really work though?
One recent study evaluated whether oral NR supplementation in aged participants could increase the number and quality of the molecules in skeletal muscle and whether it could alter muscle mitochondrial transformation of energy. In this study supplementation with 1g daily NR for 21 days increased the quantity and quality of NAD+ in human skeletal muscle. The same study demonstrated that NR dosing depressed levels of circulating pro-inflammatory cytokines like TNF-a and IL-6 that may otherwise enhance the disease state. This is important because chronic inflammation seems to be a consistent feature of aging. While more studies are needed, it does appear that oral NR is available to human skeletal muscle and has anti-inflammatory properties, both of which may be beneficial in the context of aging, muscle or inflammatory disease groups.