Norwegian scientists have found an explanation for how NAD molecule depletion affects the ageing process.
Nicotinamide adenine dinucleotide (NAD) is a molecule found in every living cell of the body; made from Vitamin B3 (niacin), it plays an important role in creating energy in the body, as well as pertaining DNA.
The researchers from the University of Bergen, whose study was published in Nature Metabolism, showed for the first time how mitochondria act as ‘reservoirs to hold NAD; scientists believe this finding may lead the way for new therapeutic options to combat ageing and age-related diseases.
Lead author Prof Mathias Ziegler told medicalnewstoday.com: ‘NAD is an essential molecule that plays critical roles in all living cells – bacteria, plants and animals. The fundamental role of NAD is in the retrieval of energy from food sources to make it available for cellular functions. Metaphorically speaking, NAD acts like a rechargeable battery, storing energy retrieved from nutrients and then passing it on to fuel energy-demanding processes. The most important of such processes takes place in mitochondria, the cell’s powerhouse.’
However, as the amount of NAD in the mitochondrial ‘reservoirs’ depletes with age, cells may not have enough NAD to function adequately.
Prof Ziegler noted: ‘In our study, we established and investigated for the first time a cellular model system that resembled the situation of chronically diminished NAD levels, thereby enabling us to study the mechanistic consequences.’
They found mitochondria act as a reservoir to hold NAD and supply it to the cell as needed. Previous studies had demonstrated mitochondrial NAD plays an important protective role in situations of cellular stress; but how NAD exerts this role remained unknown.
Ziegler’s team revealed mitochondria ‘can supply NAD when the demand for this molecule is excessive in other parts of the cell’; they also discovered that if mitochondria does not have enough NAD stored up, it can have a fatal consequence for the cell.
He summed up: ‘Our study connects two hallmarks of ageing, mitochondrial dysfunction and dysregulated NAD levels, indicating excessive consumption of mitochondrial NAD might constitute a key factor leading to dysfunctional mitochondria and thus ageing- associated diseases.”
Foods rich in NAD+ precursors include dairy products, fish, poultry and green vegetables.
