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[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. KEY WORDS: * [alpha]-lipoic acid * antioxidant * cardiovascular disease

Epidemiologic data suggest an inverse relationship between the consumption of soy isoflavones and cardiovascular disease risk. The aims of this review are to determine if isoflavones play a role in the hypocholesterolemic effect of soy and whether the studies realized with that scope were adequately designed. In humans, most studies have been performed in postmenopausal women. The results are inconsistent, however; some studies show a decrease in total cholesterol and low-density lipoprotein concentrations, and an increase in high-density lipoprotein levels, and other investigations fail to show any beneficial effect of soy isoflavones on lipid profiles. In most studies, beneficial effects could not be attributed with certainty to soy isoflavones. If these components have any health-protecting effect in humans, it is small in comparison with the effect of soy protein itself. There are currently not enough data to recommend the consumption of isoflavone supplements to lower plasma cholesterol levels. Key words: soy, isoflavones, phytoestrogens, cholesterol, triglycerides, cardiovascular disease risk doi: 10.131/nr.2003.jun.189-203

Medium-chain triglycerides (MCT) have been proposed as weight-lowering agents, although there is some concern regarding their hyperlipidemic effect. This study evaluates the effects of a combination of MCT oil, phytosterols and flaxseed oil [functional oil (FctO)] on plasma lipid concentrations and LDL particle size. Twenty-four healthy overweight men (body mass index 28.2 [+ or -] 0.4 kg/[m.sup.2]) consumed controlled diets designed to maintain weight for two periods of 29 d each. Diets contained 40% of energy as fat, 75% of which was added fat, either FctO or olive oil (OL). Body composition and blood samples were analyzed at the baseline and the endpoint of each period. Total cholesterol concentration decreased 12.5% (-0.68 mmol/L; P < 0.05) when subjects consumed FctO and 4.7% when they consumed OL. Similarly, FctO consumption lowered LDL cholesterol concentrations by 13.9%, whereas OL consumption did not. There was no difference in absolute change in LDL-cholesterol between FctO and OL consumption. Peak LDL particle size was greater in those who consumed FctO than in those who consumed OL (P < 0.05), with no effect of diet on proportion of large, medium or small particles. We conclude that those who consume a diet containing FctO have a better lipid profile than those who consume a diet rich in OL, which also leads to a larger lipoprotein particle size. Functional oil consumption can therefore help reduce the risk of cardiovascular disease. J. Nutr. 133: 1815-1820, 2003. KEY WORDS: * cholesterol * lipoproteins * low-density lipoprotein cholesterol * medium-chain triglycerides * phytosterols

Two recent reports confirm the role of n-3 polyunsaturated fatty acid (PUFA) consumption in risk reduction for sudden death. The mechanism likely involves an antiarrhythmic effect, further supporting the role of dietary n-3 PUFA in maintenance of human health. Key Words: omega-3, polyunsaturated, fatty acids, sudden death

The objective of this article is to review the existing literature concerning the effects and mechanisms of action of red wine consumption vs. other alcoholic beverages on the risk of cardiovascular disease (CVD). Of particular interest is the form and quantity of alcohol consumed. This relationship between alcohol consumption and mortality is well supported by epidemiologic studies, which have suggested that different forms of alcohol alter the relative risk values for mortality from CVD. Although not without exception, current evidence from epidemiologic and experimental studies suggests a protective effect against the development of CVD with moderate consumption of red wine. The exact nature of the protective effect remains to be established. However, mechanisms including LDL oxidation and alterations in hemostatic variables are being increasingly recognized as contributory. Key components of red wine thought to be responsible for the protective effects include phenolic compounds and alcohol content. Despite the research presented, some questions relating to the current recommendations regarding moderate alcohol consumption and cardiovascular health remain. However, collectively, the literature aids in understanding some of the ways in which alcoholic beverages and their components affect the health of our population. J. Nutr. 131: 1401-1404, 2001. KEY WORDS: * cardiovascular disease * phenolic compounds * red wine * alcohol

Medium chain fatty acids (MCFA) are readily oxidized in the liver. Animal and human studies have shown that the fast rate of oxidation of MCFA leads to greater energy expenditure (EE). Most animal studies have also demonstrated that the greater EE with MCFA relative to long-chain fatty acids (LCFA) results in less body weight gain and decreased size of fat depots after several months of consumption. Furthermore, both animal and human trials suggest a greater satiating effect of medium-chain triglycelides (MCT) compared with long-chain triglycerides (LCT). The aim of this review is to evaluate existing data describing the effects of MCT on EE and satiety and determine their potential efficacy as agents in the treatment of human obesity. Animal studies are summarized and human trials more systematically evaluated because the primary focus of this article is to examine the effects of MCT on human energy metabolism and satiety. Hormones including cholescytokinin, peptide YY, gastric inhibitory peptide, neurotensin and pancreatic polypeptide have been proposed to be involved in the mechanism by which MCT may induce satiety; however, the exact mechanisms have not been established. From the literature reviewed, we conclude that MCT increase energy expenditure, may result in faster satiety and facilitate weight control when included in the diet as a replacement for fats containing LCT. J. Nutr. 132: 329-332, 2002. KEY WORDS: * medium-chain triglycerides * satiety * energy expenditure * obesity

Mechanisms explaining the decrease in circulatory cholesterol levels after weight loss remain ill defined. The objective was to examine effects of weight loss as achieved through energy restriction upon human in vivo cholesterol biosynthesis. Six subjects (64-77 y, body mass index, 30.3 [+ or -] 3.8 kg/[m.sup.2]) were recruited into a two-phase prospective clinical trial. In the first phase, subjects complied with American Heart Association (AHA) Step I diets for 3 mo with no change in their usual energy intake. After this weight-stable phase, subjects consumed an AHA Step I diet with a targeted reduction in energy intake of [approximately]1000 kJ/d for 6 mo to achieve negative energy balance leading to weight loss. The incorporation rate of deuterium from body water into erythrocyte membrane free cholesterol over 24 h was utilized as an index of cholesterogenesis at the end of both phases. Subjects' mean weights decreased (P < 0.05) from 89.3 [+ or -] 12.5 kg to 83.2 [+ or -] 11.5 kg (6.8 [+ or -] 2.6% of initial body weight) across phases. Circulating concentrations of total and LDL-cholesterol, and triglycerides also decreased (P < 0.05) across phases. HDL-cholesterol concentrations were unchanged (P > 0.05). Cholesterol fractional synthetic rate (FSR) after phase 2 (3.04 [+ or -] 1.90%/d) was lower (P < 0.05) than that after phase 1 (8.42 [+ or -] 3.90%/d). Absolute synthesis rate (ASR) after phase 2 [0.59 [+ or -] 0.38 g/(kg [multiplied by] d)] also was lower (P < 0.05) than that after phase 1 [1.66 [+ or -] 0.84 g/(kg [multiplied by] d)]. These data suggest that, in obese men, energy restriction resulting in even modest weight loss suppresses endogenous cholesterol synthesis, which contributes to a decline in circulating lipid concentrations. KEY WORDS: weight loss; energy restriction; cholesterol; deuterium; humans

Research has determined that plant sterol esters are effective in maintaining healthful cholesterol levels. Studies using margarine containing sitostanol-ester and soybean oil sterol-ester showed that both were equally effective in decreasing low-density lipoprotein and blood total cholesterol levels. Neither of the two esters affected high-density lipoprotein cholesterol levels.

Skinfold calipers are a better method than bioelectrical impedance analysis (BIA) for determining changes in the body composition due to anorexia nervosa. BIA is unable to record changes due to hydration differences, and to determine the water distribution in the intracellular and extracellular compartments. BIA uses regression analysis, and the body composition values are adjusted toward the group mean position. Values varying from the mean give wrong estimates of body fatness. Modifications incorporated in BIA, to make it more sensitive to hydration, fail to give satisfactory results.

To study the influence of dietary fatty acid composition on energy metabolism, forty male rats were fed elemental diets containing 42% of energy as fish oil, safflower oil, olive oil or beef tallow for 12 wk. Food intakes and body weights were measured daily. Energy expenditure and body composition were determined using doubly labeled water on the final 2 d. Pooled fecal energy losses differed in response to dietary manipulation, with losses greatest in rats fed beef tallow and least in those fed olive oil. Higher lean body mass gains and lower fat mass gains were observed in rats fed diets containing fish oil, compared with rats fed olive oil or beef tallow. Total energy gains in rats fed olive oil (3632 + or - 145 kJ) and beef tallow (3850 + or - 136 kJ) were higher than those in rats fed fish oil (2905 + or - 196 kJ). Energy efficiency in both the olive oil and beef tallow groups was also higher than that in the fish oil group. There were no differences in energy expenditure measured by doubly labeled water technique among the four groups. The data suggest that dietary fatty acid composition alters the efficiency of energy substrate accretion in rats.