Oxidative stress is a risk factor for chronic diseases and was previously shown to be independently associated with obesity. The authors investigated the relationship between body mass index (BMI), age and oxidative stress on 2190 subjects undergoing a health care examination. Total antioxidant status (TAS), total peroxides (TOC) and autoantibodies against oxidized LDL (oLAb) were used as oxidative stress biomarkers in addition to serum lipoproteins, bilirubin and uric acid. Gender-specific differences were observed for age, BMI, serum concentrations of bilirubin, low-density lipoprotein (LDL), uric acid and TAS, all of which were higher in males (p < 0.001), while high-density lipoprotein (HDL), HDL/LDL ratio and TOC were higher in females (p < 0.001). Total cholesterol (p < 0.05) and LDL were increased (p < 0.05), while HDL was decreased (p < 0.05) in overweight and obese subjects. This was accompanied by increased uric acid and TAS concentrations. Lowest oLAb titers were detected in obese subjects. In extremely obese subjects, increased TOC and decreased TAS were observed in spite of high uric acid levels. These results demonstrate that oxidative stress increases with increasing BMI and age, as a sequel to an impaired antioxidant status, the consumption of oLAbs, an increase of peroxides and uric acid and a disadvantaged lipid profile.

Background: Obesity increases the risk of coronary heart disease, partly due to its strong association with atherogenic dyslipidemia, characterized by high triglycerides and low high-density lipoprotein (HDL) cholesterol levels. Functional impairment of HDL may contribute to the increased cardiovascular mortality, but the effect of obesity on composition, structure, and function of HDL is not well understood. Design and Methods: We determined HDL composition, HDL subclass distribution, parameters of HDL function, and activities of most important enzymes involved in lipoprotein remodeling, including lecithin–cholesterol acyltransferase (LCAT) and cholesteryl ester transfer protein (CETP) in relatively young normal weight (n = 26), overweight (n = 22), and obese (n = 20) women. Results: Obesity (body mass index (BMI) ≥ 30) was associated with noticeable changes in LCAT and CETP activities and altered HDL composition, such as decreased apolipoprotein A-I, cholesterol, and phospholipid content, while pro-inflammatory HDL serum amyloid a content was increased. We observed a marked shift towards smaller HDL subclasses in obesity linked to lower anti-oxidative capacity of serum. LCAT activity, HDL subclass distribution, and HDL-cholesterol were associated with soluble leptin receptor, adiponectin, and liver enzyme activities. Of note, most of these alterations were only seen in obese women but not in overweight women. Conclusions: Obesity markedly affects HDL metabolism, composition, and subclass distribution linked to changes in liver and adipose tissue. HDL dysfunction may contribute to increased cardiovascular risk in obesity.

Based on animal studies, intake of probiotic bacteria was suggested to improve insulin sensitivity by reducing endotoxinemia and inflammation. The objective of this study was to determine the effects of supplementation with the probiotic strain Lactobacillus casei Shirota (LcS) over 12 wk on insulin sensitivity, β-cell function, inflammation, and endothelial dysfunction parameters in subjects with metabolic syndrome. In a randomized-controlled study, 30 subjects with metabolic syndrome either received Lactobacillus casei Shirota 3 times daily for 12 wk or served as controls with standard medical therapy. Fasting blood samples were taken and a 75-g oral glucose tolerance test was performed to derive indices for insulin sensitivity and β-cell function. In addition, parameters to assess endothelial function and inflammation markers were determined. Even though the insulin sensitivity index significantly improved after 3 mo of probiotic supplementation (0.058±0.021 vs. 0.038±0.025), the change was not significantly different compared with the control group. No improvements were seen in additional indices of insulin sensitivity (quantitative insulin sensitivity check index, insulin sensitivity by oral glucose tolerance test, and homeostasis model assessment for insulin resistance) and β-cell function (first and second phase insulin secretion, and homeostasis model assessment for β-cell function). Probiotic supplementation resulted in a significant reduction in soluble vascular cell adhesion molecule-1 (sVCAM-1) level (1,614±343 vs. 1,418±265 ng/mL). No significant changes in parameters used to assess low-grade inflammation or endothelial dysfunction were observed. Intake of LcS for 12 wk in subjects with metabolic syndrome did not improve insulin sensitivity, β-cell function, endothelial function, or inflammation markers in this trial.

The vitamin B complex comprises 8 different water-soluble constituents that humans must sequester from the diet. This pilot study compared natural versus synthetic vitamin B complexes for their bioavailability, accumulation, and their impact on antioxidants, homocysteine levels, and oxidative stress. We conducted a double-blind randomized clinical trial with thirty healthy participants. They were randomly assigned to group N (natural) and group S (synthetic). Vitamin B was ingested daily for 6 weeks in the range of about 2.5 times above the recommended daily allowance. Blood samples were taken at baseline, 1.5 h, 4 h, 7 h (diurnal), 6 w (discontinuation of supplements), and 8 w (washout). Blood levels of thiamine (B₁), riboflavin (B₂), pyridoxine (B₆), folic acid (B₉), cobalamin (B₁₂), homocysteine, total antioxidants, peroxidase activity, polyphenols, and total peroxides were determined. Compared to initial values, serum levels of each B vitamin increased at the end of the supplementation period: i.e., B₁ (+23% N; +27% S), B₂ (+14% N; +13% S), B₆ (+101% N; +101% S), B₉ (+86% N; +153% S), and B₁₂ (+16% N) (p<0.05). Homocysteine (-13% N) decreased, while peroxidase activity (+41% S) and antioxidant capacity increased (+26% N). Short-term effects were already observed after 1.5 h for B₉ (+238% N; +246% S) and after 4 h for vitamin B₂ (+7% N; +8% S), B₆ (+59% N; +51% S), and peroxidase activity (+58% N; +58% S). During the washout period, serum levels of B vitamins decreased except for thiamine and peroxidase activity, which increased further. This clinical pilot study revealed comparable bioavailability for both natural and synthetic B vitamins but did not show statistically noticeable differences between groups despite some favourable tendencies within the natural vitamin group, i.e., sustained effects for cobalamin and endogenous peroxidase activity and a decrease in homocysteine and oxidative stress levels.