Tocopherols in Seafood and Aquaculture Products

Abstract

Fish products contain various nutritionally beneficial components, namely, ω3-polyunsaturated fatty acids (ω3-PUFA), minerals, and vitamins. Particularly, tocopherols (α-, β-, γ-, and δ-tocopherol) can be provided by seafood and aquaculture products. Hence, this review shows the various aspects of tocopherols in seafood and aquaculture products. For tocopherol determination in these products, HPLC methods coupled with diode array detection in the UV area of the spectrum or fluorescence detection have been shown as sensitive and accurate. These newest methods have helped in understanding tocopherols fate upon ingestion by seafood organisms. Tocopherols pass through the intestinal mucosa mainly by the same passive diffusion mechanism as fats. After absorption, the transport mechanism is thought to consist of two loops. The first loop is dietary, including chylomicrons and fatty acids bound to carrier protein, transporting lipids mainly to the liver. The other is the transport from the liver to tissues and storage sites. Moreover, tocopherol levels in fish organisms correlate with diet levels, being adjusted in fish body depending on diet concentration. For farmed fish species, insufficient levels of tocopherols in the diet can lead to poor growth performance or to nutritional disease. The tocopherol quantity needed as a feed supplement depends on various factors, such as the vitamer mixture, the lipid level and source, the method of diet preparation, and the feed storage conditions. Other ingredients in diet may be of great importance, it has been proposed that α-tocopherol may behave as a prooxidant synergist at higher concentrations when prooxidants such as transition metals are present. However, the antioxidant action of tocopherols outweighs this prooxidant effect, provided that adequate conditions are used. In fact, muscle-based foods containing higher levels of tocopherol show, for instance, higher lipid stability. Besides, tocopherols are important not only from the nutritional point of view but also from the physiological one, since they are involved in many metabolic processes in the human organism. Moreover, synergistic interactions with selenium and ascorbic acid have been reported. It deserves attention that there is evidence tocopherols taken with food can prevent heart disease, while no such evidence was found for α-tocopherol as supplement. From this perspective, eating fish is advisable, since, for instance, a 100 g serving of salmon may provide nearly 14% of recommended dietary allowance.

Integrated utilization of microalgae cultured in aquaculture wastewater: wastewater treatment and production of valuable fatty acids and tocopherols

“…Amounts of αtocopherol in our cultures were 2.7-6-fold higher than the recommended dose. Now feed is supplemented with αtocopherol in a synthetic form (α-tocopheryl acetate) (Hamre 2011), but interest in natural vitamin E supplements is increasing (Afonso et al 2013).…”

Influence of bioaccessibility of total mercury, methyl-mercury and selenium on the risk/benefit associated to the consumption of raw and cooked blue shark (Prionace glauca)

“…The estimated MeHg probabilities must be balanced with the probability of exceeding the Se RDA, given the effects of Se on MeHg toxicity (Ralston and Raymond, 2010;Afonso et al, 2012). Nevertheless, the Se daily requirements could be met only for high consumption frequencies, exceeding a daily meal of blue shark.…”

“…Among mineral elements, selenium (Se) assumes particular importance. This metalloid is essential for normal functioning of many systems in human body, mostly due to its antioxidant capacity, since its presence is related with the reduction of certain types of cancer and other diseases, and its deficiency can have adverse consequences (Pedrero and Madrid, 2008;Ralston and Raymond, 2010;Afonso et al, 2012). Fish is considered the best source of Se in human diet, due to its ability to accumulate considerable amounts of this element (Navarro-Alarcon and CabreraVique, 2008;Aomori and Hokkaido, 2012).…”

“…Recent studies have shown that Se-enriched diets not only prevent MeHg toxicity, but can also rapidly reverse some of its most severe symptoms (Ralston and Raymond, 2010).This demonstrates the importance of maintaining sufficient amounts of Se in the organism (Ralston and Raymond, 2010;Afonso et al, 2012).…”

Shellfish: Nutritive Value, Health Benefits, and Consumer Safety

“…Vitamin B 12 (cobalamin) deficiency may cause health disorders such as megaloblastic anemia and neuropsychiatric disorders (Hamed and others ). The tocopherols are powerful antioxidants (Alfonso and others ). Iodine available from shellfish is a key constituent of thyroid hormones (Institute of Medicine, IOM ; Wardlaw and Smith ; James ).…”