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The objective of this study was to examine the effects of the antioxidant alpha-lipoic acid (ALP) versus a medium chain triglyceride oil mixture (MCTo), which was designed to increase energy expenditure and to improve lipid profiles containing medium chain triglycerides, phytosterols, and omega-3 fatty acids in the form of flaxseed oil. A total of 48 hamsters were fed a) hypercholesterolemic (HC) control, b) HC MCTo, c) HC ALP, or d) HC MCTo/ALP diet for 4 weeks. No differences were observed on food intake, body weight, total body water, lean and fat mass, and tissue thiobarbituric acid reactive substances (TBARS). ALP alone had no effect on total cholesterol (TC); however, MCTo feeding increased TC with (P < 0.03) and without (P < 0.003) ALP when compared with control. ALP increased HDL levels compared with control (P < 0.04) and MCTo/ALP (P < 0.007) groups. MCTo, with (P < 0.0001) or without (P < 0.006) ALP, increased non-HDL cholesterol levels versus control. The non-HDL:HDL cholesterol ratio was decreased by ALP compared with MCTo (45%) and MCTo/ALP (68%) (P < 0.0001), a similar trend was seen when compared with the HC control (22%) group (P < 0.14). Triglyceride levels were not altered by any dietary treatment. Liver and heart tissue reduced glutathione (GSH) was increased (P < 0.05) by all three treatments when compared with control. Both tissues showed an increase (P < 0.05) in oxidized glutathione (GSSG) when fed ALP as compared with other treatments. Hamsters fed ALP had a lower (P < 0.05) GSH/GSSG ratio compared with other treatment groups. In conclusion, MCTo feeding does not elicit beneficial effects on circulating plasma lipids and measures of body composition. In addition, our results do not clearly support an improvement in oxidative status through supplementation of ALP. However, our results do support the existence of beneficial effects of ALP on circulating lipoprotein content in the hamster.

Alpha-lipoic acid (ALA) has been identified as a powerful antioxidant found naturally in our diets, but appears to have increased functional capacity when given as a supplement in the form of a natural or synthetic isolate. ALA and its active reduced counterpart, dihydrolipoic acid (DHLA), have been shown to combat oxidative stress by quenching a variety of reactive oxygen species (ROS). Because this molecule is soluble in both aqueous and lipid portions of the cell, its biological functions are not limited solely to one environment. In addition to ROS scavenging, ALA has been shown to be involved in the recycling of other antioxidants in the body including vitamins C and E and glutathione. Not only have the antioxidant qualities of this molecule been studied, but there are also several reports pertaining to its blood lipid modulating characteristics, protection against LDL oxidation and modulation of hypertension. Therefore, ALA represents a possible protective agent against risk factors of cardiovascular disease (CVD). The objective of this review is to examine the literature pertaining to ALA in relation to CVD and describe the most powerful actions and potential uses of this naturally occurring antioxidant. Despite the numerous studies on ALA, many questions remain relating to the use of ALA as a supplement. There is no consensus on dosage, dose frequency, form of administration, and/or preferred form of ALA. However, collectively the literature increases our understanding of the potential uses for supplementation with ALA and identifies key areas for future research.

α-Lipoic acid (ALA) has been identified as a powerful antioxidant found naturally in our diets, but appears to have increased functional capacity when given as a supplement in the form of a natural or synthetic isolate. ALA and its active reduced counterpart, dihydrolipoic acid (DHLA), have been shown to combat oxidative stress by quenching a variety of reactive oxygen species (ROS). Because this molecule is soluble in both aqueous and lipid portions of the cell, its biological functions are not limited solely to one environment. In addition to ROS scavenging, ALA has been shown to be involved in the recycling of other antioxidants in the body including vitamins C and E and glutathione. Not only have the antioxidant qualities of this molecule been studied, but there are also several reports pertaining to its blood lipid modulating characteristics, protection against LDL oxidation and modulation of hypertension. Therefore, ALA represents a possible protective agent against risk factors of cardiovascular disease (CVD). The objective of this review is to examine the literature pertaining to ALA in relation to CVD and describe the most powerful actions and potential uses of this naturally occurring antioxidant. Despite the numerous studies on ALA, many questions remain relating to the use of ALA as a supplement. There is no consensus on dosage, dose frequency, form of administration, and/or preferred form of ALA. However, collectively the literature increases our understanding of the potential uses for supplementation with ALA and identifies key areas for future research. [ABSTRACT FROM AUTHOR]