MCPD esters and glycidyl esters in food supplements of fish oils, algae oils, and krill oils

2-Monochloropropane-1,3-diol fatty acid esters (2-MCPDE), 3-monochloropropane-1,2-diol fatty acid esters (3MCPDE), and glycidol fatty acid esters (GE) are known for their occurrence in vegetable oils, but little is known about their occurrence in oils from marine origin which are often consumed for their proportionally high levels of polyunsaturated fatty acids. A total of 52 samples of supplements entirely or partly based on marine oils originating from fish (liver), algae and krill were investigated. The samples were purchased in 2018 and 2020 from stores in the Netherlands and online, and were analyzed by GC-MS/MS. Mean (and median) concentrations of 3MCPDE, 2-MCPDE and GE were 1431 (365), 225 (72) and 261 (140) mu g/kg oil. Highest levels were observed in fish oil, and lowest levels in krill-based oils. Concentrations of 2-MCPDE were on average 5.8 times lower than of 3-MCPDE. Besides some exceptions, concentrations of the analytes were lower in 2020 than in 2018. Several samples from 2018 and one sample from 2020 exceeded the current EU maximum limits. Exposure estimates show that consumption of the supplements contributes to exposure to the process contaminants, but in itself is below the Tolerable Daily Intake (TDI) established for 3-MCPDE by the European Food Safety Authority (EFSA). This study shows that marine oil supplements are contaminated by these compounds, and efforts should be made by industries to control or even lower the levels.

Automated summary

This study investigated the occurrence of 2-MCPDE, 3-MCPDE, and GE in marine oil supplements derived from fish liver, algae, and krill. The results showed that fish oil had the highest levels, while krill-based oils had the lowest levels. The concentrations of the analytes were generally lower in 2020 compared to 2018.