Analysis of long-chain ω-3 fatty acid content in fish-oil supplements

BACKGROUND: Omega-3 polyunsaturated fatty acids (long-chain ω-3 PUFA) have proved to be beneficial in atherosclerosis, arrhythmia and hypertriglyceridemia in several studies, which has led national and international societies to recommend an intake of 1 g/d long-chain ω-3 PUFA for antiatherosclerotic and antiarrhythmic purposes or 2-4 g/d for a lipid lowering effect. Numerous preparations are marketed for supplementing western diet, which is low in long-chain ω-3 PUFA. Since these preparations vary in their long-chain ω-3 PUFA content, we tested nine commercially available products for their fatty acid composition. METHODS: Nine commercially available ω-3 fatty acid supplements were analyzed using capillary gas chromatography to determine their fatty acid content. RESULTS: The nine preparations showed huge differences, up to 63.7 ± 1.58 mol% (P = 0.002), in their longchain ω-3 fatty acid content. Most of them failed to achieve the daily recommended dose of 1 g, even when administered at the highest dosage according to the manufacturer's recommendations. Eight of the preparations contained either equal or significantly greater amounts of long-chain ω-3 PUFA than denoted by the manufacturer; one preparation did not provide any information. The highest percentage of DHA and EPA was detected in Omacor® (95.80 ± 0.63%) and Percucor® (76.8 ± 7.109%). CONCLUSION: Administering long-chain ω-3 fatty acid preparations may result in huge differences in terms of the actual amount ingested. It is therefore advisable to use the most standardized and purified products available. © 2007 Springer-Verlag.