A combination of flaxseed oil and astaxanthin alleviates atherosclerosis risk factors in high fat diet fed rats.

Atherosclerosis is the most common pathologic process underlying cardiovascular disease. Both flaxseed oil (FO) and astaxanthin (ASX) are believed to benefit cardiovascular system. The combined effect of FO and ASX on the atherosclerosis risk factors in rats fed a high fat diet was investigated. Astaxanthin was dissolved in flaxseed oil to a final concentration of 1 g per kg (FO plus ASX). Male Sprague Dawley rats were fed a rodent diet contained 20 per cent fat whose source was lard (HFD) or 75 per cent lard and 25 per cent FO plus ASX (50 mg ASX per kg diet) or 50 per cent lard and 50 per cent FO plus ASX (100 mg ASX per kg diet) or FO plus ASX (200 mg ASX per kg diet) for 10 weeks.The combination of FO and ASX significantly increased the antioxidant defense capacity and decreased lipid peroxidation in plasma. Evident decreases in the levels TG, TC and LDL C contents, as well as IL 6 and CRP were also observed in plasma of FO and ASX fed rats. The combination of FO and ASX can improve oxidative stress, lipid abnormalities and inflammation, providing evidence that the combination of FO and ASX could be a promising functional food in cardiovascular health promotion. (Authors abstract)

Flaxseed oil (FO) is one of the most important specialty oils, which contains high levels of alpha  linolenic acid (ALA, 18 3 n 3). ALA itself may exert various biological functions by competing with linoleic acid or interaction with ion channels and nuclear receptors. ALA has been widely reported to have many beneficial effects on blood lipid profiles and inflammation, which suggest that FO are beneficial for atherosclerosis prevention. Astaxanthin (ASX) is a lipophilic xanthophyll carotenoid and found in a variety of living organism including microalgae, fungi and crustaceans. It has a wide range of biological effects such as anti-cancer, anti-diabetes and neuroprotective actions. In addition, ASX has also been reported to reduce blood pressure, LDL oxidation as well as inflammatory, and thus, combining its protection against oxidative stress, provides overall cardiovascular benefits. In this study, whether the combination of FO and ASX is able to reduce atherosclerosis risk factors in rats fed a high fat diet was studied.
High consumption of dietary fat is a known cause of increased plasma oxidative stress, whereas in this experiment, the combination of FO and ASX remarkably elevated the plasma SOD, CAT and GPx activities as well as GSH level, which led to the pronounced enhancement of total antioxidant capability. As a result, lipid peroxidation levels in plasma markedly declined with the supplement of FO and ASX. The levels of TG, TC and LDL C in plasma declined in response to the consumption of FO and ASX combination and both of FO and ASX undoubtedly contributed to these beneficial changes. ALA has been shown to suppress the expression and activities of numerous hepatic fatty acid syntheses such as fatty acid synthase (FAS), malic enzyme and glucose 6 phosphate dehydrogenase, and hence decrease fatty acid synthesis in liver. ALA sharply enhances hepatic peroxisomal and mitochondrial fatty acid oxidation rate by increasing the expression and activities of a series of fatty acid oxidation enzymes. As a peroxisome proliferator activated receptor alpha (PPAR alpha ) agonist, ASX also shows the similar action on inducing fatty acid oxidation. In addition, the hypocholesterolemic effects of FO and ASX are likely owing to elevated hepatic expression of LDL receptor as well as declined cholesterol biosynthesis.
In the present experiment, when the lard was replaced with the combination of FO and ASX, both the plasma levels of IL 6 and CRP declined, which implied that the FO and ASX combination is fully competent to improve inflammation status. In conclusion, supplement of FO and ASX combination has satisfactory efficacy at ameliorating oxidative stress, lipid profile and inflammation, which suggested that the combination of FO and ASX might contribute to prevent atherogenesis and then reduce the incidence of CVD. In addition, the presence of astaxanthin in FO lowers the lipid oxidation rate of FO and, on the other hand, astaxanthin is stable in FO in room temperature. This makes the combination of FO and ASX very promising functional food in cardiovascular health promotion. (Editors comments)