Omega-3 fish oil supplements are one of the most commonly consumed dietary supplements. It’s rich in omega-3 fatty acids, which is extremely important for your health. However, as with most things, these supplements run a risk of becoming rancid and when they do they could cause more harm than good.
According to a new report from Labdoor, over 10 percent of the fish oil supplements that the organisation tested turned out to be rancid.
“The majority of products passed oxidation assays, although 1454 products recorded peroxide levels at or above the upper limit,” the report states.
All supplements will come with a “best-before” date on their label, and although they will not expire in the traditional sense of becoming unsafe to digest, they will become worthless if taken beyond that date.
Rancid Omega-3 capsules reveal that storage and best-before dates are key.
Research published this week found that many common Omega-3 fish oil supplements are rancid, which arises when a product becomes oxidised.
Fish oil is particularly susceptible to oxidising, which happens faster when exposed to heat, air or light.
“For us, they would start to smell and feel off,” said Labdoor research director Dan Mark.
Whether rancid fish oil is harmful remains unclear.
So far, sporadic studies have shown that highly oxidised fish oil capsules can have a negative impact on cholesterol levels.
At least two comparative studies to date show that consuming rancid fish oil can increase bad cholesterol levels.
And in animal studies, oxidized fatty acids have been found to cause organ damage, inflammation, and atherosclerosis, among other problems.
As fish oil oxidizes, new by-products begin to form in the oil called lipid peroxides, as well as harmful aldehydes and ketones, said Omega 3 Innovations.
The health site added: “These oxidation by-products are what gives off the unpleasant smell and taste of spoiled fish.
“The rate at which the omega-3 molecules oxidize depends on a number of factors, including how the fish were harvested and the oil processed. But once an oil has started to oxidize, there is no going back.
“At that point, it’s simply a matter of time before the oil goes rancid and counteracts the benefits of omega-3 fish oil.”
