Analysis of omega-3 fatty acid content of South African fish oil supplements

Abstract

IntroductionSubstantial evidence describes the protective effects of marine-derived omega-3 (n-3) polyunsaturated fatty acids (PUFA) on cardiovascular diseases as well as many other conditions. Numerous fatty acid preparations are marketed for supplementing the Western diet, which is low in n-3 fats. Since these preparations may vary in their n-3 PUFA content, we tested 45 commercially available products on the South African market for their fatty acid composition.MethodForty-five commercially available n-3 fatty acid supplements were analysed using gas–liquid chromatography to determine their fatty acid content.ResultsMore than half of the n-3 supplements available on the South African market contained ≤ 89% of the claimed content of EPA and/or DHA as stated on the product labels. To meet ISSFAL’s recommendation of 500 mg EPA + DHA/day can cost consumers between R2 and R5 per person per day (R60 to R150 p/p/month). Regarding rancidity, the majority of capsules contained conjugated diene (CD) levels higher than that of vegetable oil obtained from opened containers (three months) used for domestic cooking purposes, despite the addition of vitamin E as antioxidant.ConclusionSince no formal regulatory structure for dietary supplements currently exists in South Africa, consumers depend on self-regulation within the nutraceutical industry for assurance of product quality, consistency, potency and purity. Our results indicate that more than half of the n-3 fatty acid supplements on the South African market do not contain the claimed EPA and/or DHA contents as stated on product labels, and they contained CD levels higher than that in unused vegetable oils obtained from opened containers used for domestic cooking purposes.

Analysis of the omega-3 fatty acid content of South African fish oil supplements : a follow-up study : cardiovascular topics

“…CD values were compared against reference values as described by Opperman et al 13 Peroxide levels were determined spectrophotometrically as described by Khodaparast et al 15…”

Replacement of Reduced Highly Unsaturated Fatty Acids (HUFA Deficiency) in Dilative Heart Failure: Dosage of EPA/DHA and Variability of Adverse Peroxides and Aldehydes in Dietary Supplement Fish Oils

“…The data derived from fish oils acquired in 13 countries are also compatible with peroxide values of dietary supplement ω-3 oils on the Norwegian Health Care Market, where only 4 of 56 had peroxide values <5 mEq/kg and 28 had <10 mEq/kg [41] as specified by the European Pharmacopeia [42]. The problem of oxidation products in dietary supplement fish oils has been addressed also in a South African study, where the conjugated diene level was used as an indication of rancidity [43]. In the present study, alkenals were determined, which are part of VOCs and responsible for the adverse smell and other potentially harmful effects.…”

Microwave‐Assisted, Base‐Catalyzed Synthesis of Fatty Acid Methyl Esters from Seeds and Fish Oil Supplements

“…Several publications have studied the correctness of the manufacturers' information in fish oil supplements (Opperman et al, ; Osadnik and Jaworska, ; Yi et al, ). For example, Osadnik et al found that, for the majority of their tested products in the Polish market, there was consistency in the total amount of DHA and EPA claimed on the label, while Opperman's group reported that the n‐3 supplements available in the South African market contained ≤89% of the stated content.…”

“…Although there are several studies that analyze dietary supplements to provide guidance for consumers, many of them have limitations. For example, in their extraction and derivatization of the FA, they follow multistep procedures and/or involve long heating times (among others, Opperman et al, ), high temperatures (Rincón‐Cervera et al, ), costly automated instrumentation (Roberts, et al, ; Stuff and Whitecavage, ), high‐resolution equipment (Osadnik and Jaworska, ), or special analysis software (Kanable et al, ). Many of them have been conducted in other countries and only concentrate in supplements obtained in local markets (Opperman et al, ; Osadnik and Jaworska, ; Yi et al, ).…”