Flaxseed and its contribution to body growth and brain of Wistar rats during chidhood and adolescence

Objectives: To evaluate the effect of flaxseed upon body growth and brain of rats. Methods: Experimental phase lasted 52 days, using 42 Wistar rats which were divided into four groups: Control (CG, n of 12), 10% casein diet; Flaxseed (GL, n of 12), 10% flaxseed diet plus casein; Modified Control (GCM, n of 12), 10% casein diet with changes in lipid and fiber comparable to GL; Non-protein (GA, n of 6), diet without protein. Considering food intake, protein intake and weight variation, the Protein Efficiency Ratio (PER) was calculated. Net Protein Retention (NPR) and the Food Efficiency Ratio (CEA) were also determined relative to brain weight at 30 days of life (M30) and at 52 days (M52). Analysis of Variance (ANOVA), Test of Sheffe and post test of Bonferroni were used, p ≤0.05. Results: GL had lower food intake, protein and weight variation than GC, but had higher values than GCM. Concerning PER, GL was lower than GC and similar to the GCM, as well as CEA. As for NPR, GL had lower values than the CG and GCM. At M30, GL was superior to GC in relation to brain weight. Likewise, the same was observed at M52. Conclusion: Flaxseed promoted adequate growth and better brain development in animals, which might be explained by increased incorporation of omega-3 into these tissues. (Authors abstract)
Polyunsaturated fatty acids (PUFAs) of n3 series, found in the brain and retina, contribute to the process of myelination, development of visual function, psychomotor development and various aspects of neural function in relation to behavior. Its importance in the development of central nervous system of infants is well documented. Approximately 20% of alpha-linolenic acid contained in flaxseed is converted in the body into EPA and DHA. Phospholipid membranes of the brain are highly enriched with DHA, which can affect brain function and behavior and also promote fetal development. This study was designed to evaluate the effect of flaxseed consumption on body growth and brain development of rats from childhood to adolescence. The flaxseed diet promoted adequate growth in animals and better brain growth, and contributed to increased omega-3 fatty acid incorporation to this tissue, suggesting a better development of the animals fed this diet both during childhood and adolescence. Food intake of animals fed on flaxseed was below the GC and higher than GCM, reflecting a lower protein intake by GL when compared to GC and a higher consumption when compared to the GCM. This inferiority in relation to GC can be justified by the high-fiber diet and fats present in flaxseed. Fibers are found in large quantities in flaxseed (28%) which are soluble and insoluble, causing animals to have a greater satiety, thus leading to lower consumption. One method for assessment of growth and protein utilization used in this experiment was PER. PER value above 2 is related to a good quality and high protein. The GL group exhibited a PER greater than 2. By observing the averages for the relative brain weight of animals at day 30 of life (M30), the largest percentage of brain weight was on GL when compared to GC and it was observed homogeneity between GL and GCM. This result of relative brain weight of GL can be attributed to large amounts of fatty acids from omega-3 family in flaxseed. The FS diet was offered since the gestation and lactation of the pups until 52 days of their life (M52), which generated a greater aggregation of these fatty acids in brain tissue, thus increasing its weight due to a higher content of DHA absorbed by the brain during development of central nervous system. This study confirms previous research that has shown higher levels of omega-3 long-chain (EPA and DHA) in the brain and spinal cord of animals following a flaxseed diet. (Editors comments)