Dietary α‐linolenic acid increases brain but not heart and liver docosahexaenoic acid levels

Abstract

Fish oil-enriched diets increase n-3 FA in tissue phospholipids; however, a similar effect by plant-derived n-3 FA is poorly defined. To address this question, we determined mass changes in phospholipid FA, individual phospholipid classes, and cholesterol in the liver, heart, and brain of rats fed diets enriched in flax oil (rich in 18:3n-3), fish oil (rich in 22:6n-3 and 20:5n-3), or safflower oil (rich in 18:2n-6) for 8 wk. In the heart and liver phospholipids, 22:6n-3 levels increased only in the fish oil group, although rats fed flax oil accumulated 20:5n-3 and 22:5n-3. However, in the brain, the flax and fish oil diets increased the phospholipid 22:6n-3 mass. In all tissues, these diets decreased the 20:4n-6 mass, although the effect was more marked in the fish oil than in the flax oil group. Although these data do not provide direct evidence for 18:3n-3 elongation and desaturation by the brain, they demonstrate that 18:3n-3-enriched diets reduced tissue 20:4n-6 levels and increased cellular n-3 levels in a tissue-dependent manner. We hypothesize, based on the lack of increased 22:6n-3 but increased 18:3n-3 in the liver and heart, that the flax oil diet increased circulating 18:3n-3, thereby presenting tissue with this EFA for further elongation and desaturation.

Vegetable oils rich in alpha linolenic acid allow a higher accretion of n-3 LCPUFA in the plasma, liver and adipose tissue of the rat

“…EPA normally competes with ARA to be incorporated into membrane phospholipids (Sun et al, 2008), an effect that is notorious when higher amounts of ALA are provided, such as in the case of ChO. Less competence is observed for SO and SIO, but irrelevant for CO. DHA is almost exclusively accumulated in the brain, retina and gonads (Innis and Dyer, 2002;Barceló-Coblijn et al, 2005). The presence of this n-3 LCPUFA in the liver reflects the active conversion of ALA into DHA, and its presence in plasma shows its active transport to the target tissues.…”

Substitution of dietary oleic acid for myristic acid increases the tissue storage of α-linolenic acid and the concentration of docosahexaenoic acid in the brain, red blood cells and plasma in the rat

“…When the diet contains DHA, ALA did not contribute appreciably to DHA within brain phospholipids of adult rats (Demar et al, 2005). However, some recent results have suggested that DHA could be synthesized directly in the brain from ALA (Barcelo-Coblijn et al, 2005). We cannot confirm these results, since we were not able to measure desaturase activities in the brain (data not shown).…”

“…In many countries, however, the intakes of both a-linolenic acid (ALA; C18:3 n-3) and DHA (Burdge and Calder, 2005;Denomme et al, 2005) are lower than the current dietary recommendations (Simopoulos et al, 1999). Various dietary strategies have been proposed to increase their cellular level: (i) consumption of oils rich in ALA (Harper et al, 2006), but the rate of in vivo conversion of ALA to highly unsaturated fatty acids (FA) is low (Burdge and Calder, 2005;Hussein et al, 2005), and its effective conversion to DHA in mammalian tissues, although recently quantified in the plasma of rats as 10-fold higher than brain consumption rates (Igarashi et al, 2007), is controversial (Barcelo-Coblijn et al, 2005;Lin and Salem, 2005), because of the competition of multiple substrates for D6-desaturase (D' Andrea et al, 2002); (ii) consumption -E-mail: Vincent.Rioux@agrocampus-rennes.fr of fish, fish oil or microalgae oil (Geppert et al, 2005) directly providing the long-chain (n-3) derivatives; and (iii) consumption of both ALA and long-chain (n-3) derivatives, by using, for example, products from breeding animals that have been fed with extruded linseeds (Weill et al, 2002).…”

Nuevas fuentes dietarias de acido alfa-linolénico: una visión crítica

“…En el cerebro la conversión de ALA en DHA es particularmente importante, especialmente porque este es el tejido que contiene el mayor contenido de DHA en el organismo (7,8). Es así como al estudiar la biotransformación del ALA se observa un incremento significativo de la formación de DHA, situación que no se observa con sus intermediarios (EPA y DPA) (37).…”

“…Estudios realizados en animales Se han realizado numerosos estudios sobre la conversión del ALA en diferentes modelos animales (ratas, hámster, conejos, cerdos, primates, entre otros) los que han permitido establecer varios aspectos, siendo los más importantes; (i) el ALA se convierte en sus derivados metabólicos en muy baja cantidad (6 al 0,05%) y (ii) el ALA cuando es metabolizado se transforma rápidamente en EPA, pero no de igual forma en DHA, indicando limitaciones importantes dentro de la propia vía metabólica de los AGPICL ω-3 (37,39).…”