Different formulations of omega-3 supplements are now available such as ethyl esters, triacylglycerides, free fatty acids, phospholipids and monoacylglycerides which allow these compounds to be tested as sustainable dietary supplements.

During the last decade, essential polyunsaturated fatty acids (PUFAs) such as the eicosatetraenoic acid (EPA) and docosahexaenoic acid (DHA) derived from marine sources have been investigated as nonpharmacological dietary supplements to improve different pathological conditions, as well as aging. 

This study aimed to determine the effects of dietary n-3 PUFA monoacylglycerides (MAG, both EPA and DHA) on the mitochondrial metabolism and oxidative stress of a short-lifespan model, Drosophila melanogaster, sampled at five different ages. 

The results showed that diets supplemented with MAG-EPA and MAG-DHA increased median lifespan by 14.6% and decreased mitochondrial proton leak increasing mitochondrial coupling. 

Superoxide dismutase

The flies fed on MAG-EPA also had higher electron transport system capacity and mitochondrial oxidative capacities. Moreover, both n-3 PUFAs delayed the occurrence of lipid peroxidation, but only flies fed the MAG-EPA diet showed maintenance of superoxide dismutase activity during aging. 

The study, therefore, highlights the potential of n-3 PUFA monoacylglycerides as nutraceutical compounds to delay the onset of senescence by acting directly or indirectly on the mitochondrial metabolism and suggests that Drosophila could be a relevant model for the study of the fundamental mechanisms linking the effects of n-3 PUFAs to aging.

Results demonstrate that n-3 PUFAs modulate mitochondrial functions and antioxidant capacities of Drosophila thorax muscle during aging. Notably, MAG-EPA has more potent effects than MAG-DHA, which translates into increased mitochondrial oxidative

In turn, these improved capacities could explain the increased lifespan observed in Drosophila. Minor effects were also detected with MAG-DHA, as well as similarly increased longevity with MAG-EPA.

Although they could not ascertain the precise effects of MAG-EPA, our study suggests that this n-3 PUFA primarily modulates mitochondrial metabolism. These effects could be related to changes in mitochondrial membrane composition this n-3 PUFA primarily modulates post-translational modifications of mitochondrial enzymatic complexes mitochondrial metabolism.

These effects could be related to changes in mitochondrial membrane composition or to post-translational modifications of mitochondrial enzymatic complexes and anti-oxidant enzymes, as already suggested. 

Another possibility would be that 3 PUFAs affect the regulation of mitochondrial ROS. Since n-3 PUFA decreased proton leak (which is involved in the modulation of ROS production) affected SOD activity, one interesting research avenue would be the contribution of n-3 PUFA on mitochondrial ROS production/detoxification during aging in Drosophila.  Additionally, Drosophila could be a relevant model for the metabolism of n-3 PUFAs, as physiological and metabolic effects can be detected in this organism after dietary intervention.