A recent study warns that omega-3 supplements, which are commonly used for health benefits, may become rancid and lose nutritional value.

These algae and seafood supplements, such as fish oil, deteriorate as they oxidize, potentially reducing their health benefits.

Leigh A. Frame, Associate Professor of clinical research and leadership at George Washington University in the US said, "Our study suggests many of these supplements are not fresh -- and thus may not provide a potential health benefit.”

Over a six-year period, 72 popular supplement brands were tested for rancidity of omega-3, which is valued for its cardiovascular and overall health benefits.

The study found that 45% of tested supplements were rancid, despite adhering to GOED's recommended rancidity limits. Flavored supplements frequently mask rancidity, making precise oxidation levels difficult to determine.

"Flavouring is potentially masking the freshness of omega-3 supplements in two ways," said lead author Jacob Hands, medical student at the varsity's School of Medicine and Health Sciences.

If fish oil supplements are fresh, they won't have a fishy taste or smell, he explained.

"Flavouring can mask those aspects but also makes it difficult for researchers to determine the level of oxidation and the quality of the supplement."

According to Frame, third-party testing can confirm supplement purity, but even tested brands cannot guarantee freshness.

Caution is advised, especially when it comes to flavored fish oil supplements, because their impact on freshness and health benefits is unknown, as Frame and H have noted.ands.