Research staff conduct screening tests only on applicants who provide written consent and select research subjects who meet the selection criteria. Study subjects will visit for the first time within 4 weeks from the screening visit to reexamine the suitability of the study subject selection/exclusion criteria and then be enrolled in the human application test. The participants will be randomly assigned to the kefir lactic acid bacteria-derived whey post-biotics group and the placebo group for the first time. Complete the baseline evaluation by the date of visit. Afterwards, the participants will consume whey postbiotics derived from kefir lactic acid bacteria and a placebo product twice a day, 3g per time, for 12 weeks, and visit the institution a total of four times to perform a grip strength test, DXA. This survey will be conducted at Hanyang University Hospital. Research staff may conduct follow-up observations of study subjects as needed after final consumption of the kefir lactic acid bacteria-derived whey postbiotic group and placebo products or after early termination.
Purpose: Kefir (alcoholic fermented dairy product made by fermenting cow's milk, goat's milk, or sheep's milk) to determine the effect of 12 weeks of human consumption of whey postbiotics derived from lactic acid bacteria in improving muscle strength and intestinal microbiome in elderly people compared with placebo intake. * Primary objective: To evaluate the effectiveness of whey postbiotics derived from kefir lactic acid bacteria compared to placebo intake through the results of the grip strength test for both hands. * Secondary objective: To evaluate the effectiveness and safety of whey postbiotics derived from kefir lactobacilli for muscle strength improvement as assessed by dual energy x-ray absorptiometry (DXA), adipokines, myokines, and cytokines compared with placebo intake. The investigators aim to analyze the differences in the intestinal microbiome compared to placebo intake through fecal collection and NGS (Next Generation Sequencing). Experimental product: Kefir lactic acid bacteria-derived whey postbiotics (oral intake of 6g per day (3g twice per day)) Control product: Flavor 2.7%, Calcium carbonate 13.8%, Lactose 41.3%, Maltodextrin 10.3%, Sugar 31.23%, Carboxy methyl cellulose 0.67% (oral intake of 6g per day (3g twice per day)) Number of subjects: In this human application test, in order to calculate the number of study subjects, the investigators referred to previous studies and calculated the lean mass gain (kg) of 3.3 ± 1.5 kg (mean ± SD) after consuming whey postbiotics derived from kefir lactic acid bacteria for 12 weeks. In the placebo group, it was assumed to be 1.8 ± 1.6 kg. The statistical hypothesis test of the evaluation variable is a two-sided test. The significance level is 5%. ③ The test power is maintained at 90% and the type 2 error is set at 0.2. ④ The ratio between the test group and the control group is divided at 1:1. The calculation of the number of subjects referred to existing research, and a T-test was performed using the G power program to use the mean of the statistical difference in muscle strength improvement between the two groups divided according to the intake of whey postbiotics derived from kefir lactic acid bacteria as the mean (test power) (1-β)=0.9, significance level (α)=0.05, effect size (ES)=0.97 (Cohen's d)). The total number of research subjects required for human application testing calculated through this is 48. Here, the investigators plan to recruit a total of 60 research subjects, assuming a dropout rate of 20%. Study Design
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
60
Kefir (alcoholic fermented dairy product made by fermenting cow, goat, or sheep milk) whey derived from lactic acid bacteria postbiotics
A powder product including Flavor, Calcium carbonate, Lactose, Maltodextrin, Sugar, Carboxy methyl cellulose. This cannot be distinguished from the postbiotics by inspection.
Hanyang University
Seoul, South Korea
Grip strength test for both hands
Handgrip strength should be measured using the JAMAR grip dynamometer (Jamar, Plus+ Digital Hand Dynamometer, Preferred, USA). While the research subject is sitting, the grip strength of both hands is measured three times each, and the average value is taken as the representative value. The unit of grip strength is kg.
Time frame: 1) Day 0, 2) end of 12 weeks
Dual energy xray absorptiometry
Dexa imaging measures the whole body, lean mass, body fat mass, bone mineral content, and height using Hanyang University Hospital's DXA (Discovery W DEXA) equipment after fasting for more than 8 hours. Measurements will be taken with the study subject standing upright, rotating both feet inward about 15 degrees, and placing both hands next to the waist. Here, the investigators will measure skeletal muscle mass (SMM, kg) by subtracting bone mineral content from lean body mass. And the SMM (kg) and the height (m) will be combined to report skeletal muscle mass index (SMMI) in kg/m\^2 unit.
Time frame: Time Frame: 1) Day 0, 2) end of 12 weeks
Biomarkers from blood
All in ng/mL : 1) adipokines (leptin, adiponectin) 2) myokines (myostatin, irisin) 3) lipid analysis (TG, T-C, HDL-C, LDL-C) 4) cytokines (CRP, IL-2, IL-6, IL-1β, TNF-α, IGF-1)
Time frame: Time Frame: 1) Day 0, 2) end of 12 weeks
Confirmation of intestinal microorganisms
Stool collection is collected directly by the research subject 1 day before (24 hours) before the start of consumption of whey postbiotics derived from kefir lactic acid bacteria and after the last intake, and stored at a frozen temperature (-20℃ or lower) until the first and third visits. do. Research staff collect stool samples, store them frozen (-70°C), and then perform next-generation sequencing (NGS analysis).
Time frame: Time Frame: 1) Day 0, 2) end of 12 weeks
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