Effects of cold‐pressed and vitamin E‐enriched flaxseed oils on lipid profile and antioxidant status in high‐fat fed rats

Abstract

In this study we evaluate whether cold-pressed flaxseed oil (CFO), vitamin E-enriched hot pressed and totally refined flaxseed oils (HRFOs) characterized by different qualities of micronutrients have beneficial effects on lipid profile and antioxidant status in high-fat fed rats. Male Wistar rats were fed synthetic diets containing 10% of HRFO, CFO, low-dose (100 mg/100 g oil) vitamin E-enriched HRFO (L-HRFO) or high-dose (200 mg/100 g oil) vitamin E-enriched HRFO (H-HRFO), respectively for 4 wk. The results showed that plasma triglycerides (TG), total cholesterol (TC), and low-density lipoprotein cholesterol levels in CFO group decreased by 12, 21, and 18% compared with HRFO group ( p < 0.05), the total hepatic lipids, TC and TG levels in CFO group were also lower significantly than those in HRFO group, but no significant differences were observed in plasma and hepatic lipid profiles among HRFO, L-HRFO, and H-HRFO groups. T-AOC levels significantly increased by 11, 12, and 22% in CFO, L-HRFO and H-HRFO groups compared with HRFO group, which was negatively correlated with the MDA levels and similar changes were observed for GSH and vitamin E levels in plasma. The CFO had a significantly higher cholesterol secretion than HRFO, L-HRFO, and H-HRFO. These results indicated that CFO had a more beneficial effect on improving lipid status and preventing oxidative stress than HRFO, and vitamin E-enriched HRFO decreased the lipid peroxidation concentration though there was no significant effect on lipid profiles.Practical applications: The cold-pressed and vitamin E-enriched HRFOs characterized by different qualities of micronutrients reduced the risk factors of cardiovascular disease. This could provide a theoretical basis for the development of high value-added functional food ingredients based on flaxseed oil or a-linolenic acid.

Effect of dietary eicosapentaenoic and docosahexaenoic acid on expression of rat liver genes controlling cholesterol homeostasis and on plasma cholesterol level

“…The same is true regarding plasma LDL-C in the present experiment (0.75 mmol/l; Figure 2): the results of the similar experiments with the FO-fed rats are between 1.84 mmol/l (Xiao et al 2012) and 0.23 mmol/l (Popovic et al 2011), the value reported by Campioli et al 2012 (0.81 mmol/l) being very similar to our data.…”

“…Similarly to the present study (Figure 2), FO in the rat diet decreased plasma TC also in most of the recent studies (Lu et al 2011;Takahashi 2011;Campioli et al 2012;Ferramosca et al 2012;Xiao et al 2012). However, Yamazaki et al (2011) and Campioli et al (2012) did not find differences in TC between the FO-fed rats and the control rats.…”

“…Plasma cholesterol. Plasma TC level of the FOfed rats in the present experiment (1.07 mmol/l; Figure 2) is approximately in the middle of the range of the results of similar experiments (FO-fed rats; all data recalculated to mmol/l): 3.22 (Lu et al 2011) → 2.45 (Ferramosca et al 2012) → 2.36 (Xiao et al 2012) → 2.04 (Campioli et al 2012) → 1.01 (Yamazaki et al 2011) → 0.98 (Takahashi 2011) → 0.54 (Popovic et al 2011).…”

“…due to different qualities of micronutrients: addition of the cold-pressed flaxseed oil to a rat diet decreased plasma TC in comparison with the control rats fed a diet with totally refined flaxseed oil in an experiment of Xiao et al (2012).…”

“…Fish oil (FO) in the rat diet decreased plasma TC in most of the recent studies (Lu et al 2011;Ferramosca et al 2012;Xiao et al 2012). On the other hand, regarding studies in humans, EPA/DHA either reduced TC and LDL-C (Lopez-Huertas 2009) or increased both TC and LDL-C and HDL-C (Maki et al 2003) or no change in TC and slight increases in HDL-C and LDL-C, respectively were established (Eslick et al 2009).…”