Lactobacillus plantarum HAC01 Supplementation Improves Glycemic Control in Prediabetic Subjects: A Randomized, Double-Blind, Placebo-Controlled Trial.

A recent animal study demonstrated that administration of Lactobacillus plantarum HAC01 isolated from Korean kimchi improved glycemic control in type 2 diabetic mice. In the present study, we evaluated Lactobacillus plantarum HAC01's effects on metabolic parameters of prediabetic human subjects. Forty subjects with isolated impaired glucose tolerance were randomly assigned to receive a daily placebo (n = 20) or a dose of Lactobacillus plantarum HAC01 (n = 20) over eight weeks. The primary endpoint was a change in 2 h postprandial glucose (2h-PPG) levels and the secondary endpoints were assessment of other glucose metabolism parameters, including HbA1c, gut microbiota composition, and fecal short-chain fatty acids (SCFAs). The group with a diet supplemented with Lactobacillus plantarum HAC01 saw a significant reduction in 2h-PPG and HbA1c levels compared to the placebo group. Fasting plasma glucose, insulin, HOMA-IR, QUICKI, microbiota composition, and fecal SCFAs, however, were not significantly altered. No serious adverse effects were reported. This is the first clinical trial to show a beneficial effect of single-strain probiotic supplementation administered over eight weeks on HbA1c levels in prediabetic subjects.

Effects of Porphyra tenera Supplementation on the Immune System: A Randomized, Double-Blind, and Placebo-Controlled Clinical Trial.

OBJECTIVE: The purpose of this study was to determine if Porphyra tenera extract (PTE) has immune-enhancing effects and is safe in healthy adults. METHODS: Subjects who met the inclusion criteria (3 × 103 ≤ peripheral blood leukocyte level ≥ 8 × 103 cells/µL) were recruited for this study. Enrolled subjects (n = 120) were randomly assigned to either the PTE group (n = 60) and were given 2.5 g/day of PTE (as PTE) in capsule form or the placebo group (n = 60) and were given crystal cellulose capsules with the identical appearance, weight, and flavor as the PTE capsules for 8 weeks. Outcomes were assessed based on measuring natural killer (NK) cell activity, cytokines level, and upper respiratory infection (URI), and safety parameters were assessed at baseline and 8 weeks. RESULTS: Compared with baseline, NK cell activity (%) increased for all effector cell-to-target cell ratios in the PTE group after 8 weeks; however, changes were not observed in the placebo group (p < 0.10). Subgroup analysis of 101 subjects without URI showed that NK cell activity in the PTE group tended to increase for all effector cell/target cell (E:T) ratios (E:T = 12.5:1 p = 0.068; E:T = 25:1 p = 0.036; E:T = 50:1 p = 0.081) compared with the placebo group. A significant difference between the two groups was observed for the E:T = 25:1 ratio, which increased from 20.3 ± 12.0% at baseline to 23.2 ± 12.4% after 8 weeks in the PTE group (p = 0.036). A significant difference was not observed in cytokine between the two groups. CONCLUSION: PTE supplementation appears to enhance immune function by improving NK cell activity without adverse effects in healthy adults.