Supplementation of female rats with alpha-linolenic acid leads to the same omega-6/omega-3 LC-PUFA accretion in mother tissues and in fetal and newborn brains.
Supplementation of female rats with alpha-linolenic acid leads to the same omega-6/omega-3 LC-PUFA accretion in mother tissues and in fetal and newborn brains.
Year: 2003
Authors: A Valenzuela, R von Bernhardi, V Valenzuela, G Ramfrez, S J Alarcon.
Publication Name: Ann. Nutr. Metab.
Publication Details: Volume 48; 28-35.
Abstract:
It is well established that arachidonic acid (AA), an omega-6 fatty acid (n6), and docosahexaenoic acid (DHA), an omega-3 fatty acid (n3), are fundamental for the structure and function of the nervous system. Although a considerable amount of AA and DHA are incorporated into the central nervous system after birth, the majority is accreted during the last stage of pregnancy. Research has suggested that maternal supplementation of AA and DHA before and during pregnancy may be the best way to provide these fatty acids to the developing fetus. Western diets provide adequate amounts of LA, from which AA can be synthesized, however, consumption of n3 fatty acids remains low. It has therefore been suggested that an intake of 2.22g/d of ALA, the parent n3 fatty acid, and 300mg of DHA/d for pregnant and nursing women may be required. However, it remains unclear whether supplementing the maternal diet with ALA or preformed DHA results in the same bioequivalence for DHA accretion during fetal brain development. In this study, the impact of supplementing the maternal diet with either ALA or DHA, before and during pregnancy, on DHA accretion in different tissues of maternal, fetal, newborn, and weaning brain of the rat was assessed. Recently weaned female Wistar rats (n=90, 22-25d of age) were fed a standard synthetic diet for 40d. Rats were then randomly allocated to one of three experimental groups for an additional 40d period. In addition to the standard synthetic diet, the following fatty acids were incorporated into the experimental diets as ethyl esters (dissolved in 1.0ml of triglyceride fraction of coconut oil) and administered via gastric instillation: 1) DHA (n=30; 6mg/kg DHA-EE in 1.0ml), 2) ALA (n=30; 60mg/kg ALA-EE in 1.0ml), or 3) Control (n=30; 1.0ml of coconut fraction only). On days 0 and 40 of the supplementation period, blood was obtained from 10 rats from each group for subsequent analysis, and 5 rats/group were sacrificed for brain tissue samples. Remaining rats were then mated, in which supplementation continued until delivery. On days 16 and 19 of gestation, 4 mothers from each group were sacrificed for analysis of fetal and maternal brain tissue. The same procedure was followed for 2d pups and 21d weaning rats. Fatty acid composition of blood plasma, erythrocytes, liver, visceral adipose tissue, and brain segments (frontal cortex, hippocampus, and cerebellum) was analyzed in samples obtained from the various time periods. It was reported that supplementation with both ALA and DHA induced a similar accretion of DHA in plasma, erythrocytes, liver, and brain tissues of the dams, without an effect on AA content. However, DHA concentration in maternal adipose tissue was increased only in the DHA group and only after direct supplementation with DHA. Furthermore, DHA accretion in tissues obtained from the frontal cortex, hippocampus, and cerebellum of fetuses and newborn rats was higher in the ALA and DHA supplemental groups in comparison to the control group, however, no significant difference was found between either the ALA or DHA group. These data suggest that maternal DHA or ALA supplementation results in similar bioequivalence for DHA accretion in the dams, and in rat fetal and newborn brain tissues. However, the authors noted that consideration must be given to the fact that DHA and ALA used in this study were in the form of ethyl esters, which allow for rapid hydrolysis and absorption, in comparison to DHA and ALA used in previous studies which were in the more common form of triacylglycerols and phospholipids (that found in foods and in supplements).
