Survey of mercury in fish oil supplements

The Food Standards Agency (FSA) has conducted a survey to establish the concentrations of mercury in a range of commercial fish oil dietary supplements. This work follows a previous survey by the FSA of imported fish and shellfish, UK farmed fish and their products, which highlighted that some larger predatory fish accumulate higher levels of mercury.

Total mercury was measured in 100 samples of fish oil dietary supplements, including cod liver oil, halibut oil, tuna oil, salmon oil and shark oil.

Only nine samples in the survey contained detectable levels of mercury. There is no regulatory limit for mercury in dietary supplements or fish oils.

Dietary exposure estimates based on the levels found showed that more than 500 capsules would need to be consumed per adult per day, in addition to the rest of the diet, before the safety guideline for mercury intake is exceeded.

The levels of mercury found in this survey do not pose a risk to consumer safety.