Study of the oxidation of omega-3 food supplements available on the Belgian market

Details

Supervisors

Dierge, Emeline

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en sciences agronomiques, à finalité spécialisée

Abstract

enLong-chain omega-3 fatty acids, particularly EPA and DHA, play a central role in human health, yet their intake remains insufficient in the Belgian population. In response to this nutritional gap, dietary supplements represent an increasingly popular alternative source. However, their high polyunsaturated fatty acid content makes them particularly susceptible to lipid oxidation, a process that compromises both their nutritional quality and consumer safety. This study assessed the oxidative quality and nutritional compliance of 22 omega-3 dietary supplements available on the Belgian market, covering three lipid sources - fish oil, algal oil, and krill oil at two time points: at the time of purchase (T1) and after 18 weeks of storage under manufacturer-recommended conditions (T2). Primary and secondary oxidation markers (peroxide value, p-anisidine value, and total oxidation) were determined, along with EPA and DHA content expressed as a percentage of label claim compliance. At the time of purchase, 47.4% of measurements exceeded the GOED voluntary threshold for primary oxidation, positioning Belgium among the markets with the highest reported rates of PV non-compliance. Secondary oxidation remained within acceptable limits across all products. After 18 weeks, primary oxidation progressed significantly, with the non-compliance rate rising to 76.8%, while secondary oxidation remained stable, suggesting that supplements were still in an early ascending phase of the oxidation kinetics. Nutritional compliance in EPA+DHA was largely preserved, with no supplement showing a significant decrease in fatty acid content over the study period. The influence of oil source, antioxidant systems, packaging, and price on oxidative stability revealed no significant differences, consistent with most published surveys. Krill oil supplements could not be included in comparative oxidative analyses due to matrix-specific analytical interferences. These findings raise genuine public health concerns regarding the oxidative quality of omega-3 supplements available to Belgian consumers, in a context where no legally binding oxidative quality standards currently exist at the European Union level.