Cigarette smoking leads to oxidative stress and high cholesterolemia, which are key drivers of cardiovascular disease (CVD). Whey is known for its antioxidant and hypolipidemic properties. This study investigated whether whey protein concentrate (WPC) and hydrolysate of WPC (HWPC) can alleviate CVD risk in South Korean smokers by lowering oxidative stress and blood lipids.
Methods A total of 25 male smokers were screened, of which 18 eligible participants (72.0%), randomly assigned to either the WPC (n=9) or the HWPC (n=9) group, completed the 8-week intervention. Before (week 0, baseline) and after the intervention, participants visited the laboratory for blood collection and anthropometric measurements (body weight, height, waist circumference, body fat mass, nutritional intake). Blood samples were analyzed for plasma lipid profiles, plasma fat-soluble antioxidants, and leukocyte oxidative DNA damage using the comet assay.
Results There were no significant differences in anthropometric measurements, dietary food intake, plasma conjugated dienes, total radical-trapping antioxidant potential, and erythrocytes’ glutathione peroxidase and catalase activities in both WPC and HWPC groups. However, we observed a significant decrease in the tail moments of leukocytes, low-density lipoprotein cholesterol, atherogenic index, and high coenzyme Q10 levels in both groups. In the WPC group, total cholesterol decreased, while plasma retinol, α-tocopherol, lycopene, α-carotene, and β-carotene increased.
Conclusion WPC or HWPC significantly decreases blood cholesterol levels and oxidative DNA damage and increases plasma fat-soluble antioxidant levels. Thus, WPC or HWPC might be used as oral supplementation to lower the risk for CVD in South Korean male smokers.
Numerous clinical trials have examined the beneficial effects of Juglans regia leaf extract (JRLE) in patients with type 2 diabetes mellitus (T2DM); however, the results of these studies are inconsistent. Therefore, we conducted the current systematic review and meta-analysis to evaluate the effect of JRLE on glycemic control and lipid profile in T2DM patients. We searched online databases including PubMed, Scopus, EMBASE, and Web of Science for randomized controlled clinical trials that examined the effect of JRLE on glycemic and lipid indices in T2DM patients. Data were pooled using both fixed and random-effect models and weighted mean difference (WMD) was considered as the overall effect size. Of the total records, 4 eligible studies, with a total sample size of 195 subjects, were included. The meta-analysis revealed that JRLE supplementation significantly reduces fasting blood glucose (WMD, −18.04; 95% confidence interval [CI], −32.88 mg/dL, −3.21 mg/dL; p = 0.017) and significantly increases fasting insulin level (WMD, 1.93; 95% CI, 0.40 U/L, 3.45 U/L; p = 0.014). Although the overall effect of JRLE supplementation on hemoglobin A1c was not significant, a significant reduction was seen in studies with an intervention duration of > 8 weeks (WMD, −0.64; 95% CI, −1.16%, −0.11%; p = 0.018). Moreover, we also found no significant change in lipid parameters. Our findings revealed a beneficial effect of JRLE supplementation on glycemic indices in T2DM patients, but no significant improvement was found for lipid profile parameters.
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