Anthocyanins do not influence long-chain n-3 fatty acid status: studies in cells, rodents and humans

Abstract

Increased tissue status of the long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) is associated with cardiovascular and cognitive benefits. Limited epidemiological and animal data suggest that flavonoids, and specifically anthocyanins, may increase EPA and DHA levels, potentially by increasing their synthesis from the shorter-chain n-3 PUFA, α-linolenic acid. Using complimentary cell, rodent and human studies we investigated the impact of anthocyanins and anthocyanin-rich foods/extracts on plasma and tissue EPA and DHA levels and on the expression of fatty acid desaturase 2 (FADS2), which represents the rate limiting enzymes in EPA and DHA synthesis. In experiment 1, rats were fed a standard diet containing either palm oil or rapeseed oil supplemented with pure anthocyanins for 8 weeks. Retrospective fatty acid analysis was conducted on plasma samples collected from a human randomized controlled trial where participants consumed an elderberry extract for 12 weeks (experiment 2). HepG2 cells were cultured with α-linolenic acid with or without select anthocyanins and their in vivo metabolites for 24 h and 48 h (experiment 3). The fatty acid composition of the cell membranes, plasma and liver tissues were analyzed by gas chromatography. Anthocyanins and anthocyanin-rich food intake had no significant impact on EPA or DHA status or FADS2 gene expression in any model system. These data indicate little impact of dietary anthocyanins on n-3 PUFA distribution and suggest that the increasingly recognized benefits of anthocyanins are unlikely to be the result of a beneficial impact on tissue fatty acid status.

Effects of the flavonol quercetin andα-linolenic acid onn-3 PUFA status in metabolically healthy men and women: a randomised, double-blinded, placebo-controlled, crossover trial

“…In contrast to our study, the applied doses of flavonoids in cell culture and animal studies were higher (e.g. about 500 mg/d) (62) . Thus, possibly a pharmacological dose is needed to exert similar effects in humans.…”

“…Moderate wine drinking has been associated with increased levels of EPA and DHA in plasma fatty acids in epidemiological studies (15,59,60) , and a cohort study shows a significant association between erythrocyte levels of EPA and DHA in wine drinkers but not in beer or spirit drinkers (16) , which suggests that components in wine only, not ethanol, affect the metabolism of n-3 PUFA. Animal studies show that consumption of flavonoids increases conversion of ALA, further supporting the hypothesis that ethanol does not play a major role in the association between wine drinking and increased n-3 PUFA metabolism (17,61,62) . Quercetin, ubiquitous in plants, is among the most potent antioxidants of plant origin and a predominant flavonoid in human nutrition (18) .…”

Extract of oats as a modulator of fatty acid composition of geese tissues in the conditions of physiological stress

“…It is also known that fatty acid synthase (FAS) is a multienzymic complex that catalyses the synthesis of de novo fatty acids. Inhibition of these enzymes, in turn, may be subject to inhibition by the action of natural flavonoids (Brand et al, 2010;Vauzour et al, 2015;Zhang et al, 2016), which may lead to a decrease in the unsaturation of lipids and, consequently, increase tissue resistance to the action of free radicals.…”

Acción de flavonoides sobre la conversión de ácidos grasos poliinsaturados de cadena larga a partir de ácidos grasos esenciales

“…En contraste a estudios previos que evaluaron la acción de alimentos ricos en antocianinas sobre el metabolismo de los AGPI 13,53 , el suministro de antocinianinas no influyó en el perfil lipídico y la expresión génica de FADS2 (gen de la desaturasa 2, o Δ6D) en ratas 54 , estas divergencias probablemente se expliquen en función el perfil de antocianinas empleado por Vauzour et al, rico en delfinina 3 glucósico 54 , mientras que en trabajos previos la antocianina predominante era la cianidina 3 glucósido 13,53 . Así mismo Vauzour et al 54 , no encontraron variaciones en el perfil lipídico en el plasma de mujeres post menopáusicas al suministrar un extracto de sauco rico en antocianinas, no obstante, en este grupo etario el nivel de estrógenos es menor que en mujeres en edad fértil.…”

“…Así mismo Vauzour et al 54 , no encontraron variaciones en el perfil lipídico en el plasma de mujeres post menopáusicas al suministrar un extracto de sauco rico en antocianinas, no obstante, en este grupo etario el nivel de estrógenos es menor que en mujeres en edad fértil. Al respecto existe evidencia que la síntesis de AGPI n-3 está ligada al estrógeno 55 , ello explicaría por qué la concentración de AGPI n-3 es más alta en mujeres que en hombres.…”