Human Clinical Study Ⅰ(17):
Zenk et al. (2002) divided 42 subjects randomly into three groups including a S100 Milk Protein Concentrate (MPC) group (4g daily), a glucosamine sulfate group (1.5g daily) and a placebo control group for a six week clinical study(17). The Western Ontario and McMaster Universities Arthritis Index (WOMAC)(21) was the major functional assessment tool. Assessment was carried out at the beginning of the study and in the second, fourth and sixth weeks. Vital signs (e.g. blood pressure, pulse and body temperature), weight and adverse reactions were also assessed. Blood tests were carried out at the beginning of study and in the sixth week, in order to monitor differential blood counts and blood chemistry.
 

WOMAC results showed that the arthritic symptoms of subjects in the S100 MPC group and glucosamine group were significantly relieved. In addition, the S100 MPC group showed persistent improvement, while the glucosamine group only showed the greatest improvement in the second week (Fig. 4).

Effect size assessment of the study was calculated by the formula(22) of Hedges and Cohen. Results of the study showed that the scores of the S100 MPC group were higher than that of glucosamine for every individual item scored (effect sizes of both were greater than 0.8), and in WOMAC scores, 60% of the scores for the S100 MPC group were higher than those of the glucosamine group (Fig. 5). The WOMAC treatment effect size scores for all items were more than 1.3 for the S100 MPC group, which showed that the ability to relieve arthritic symptoms was far superior to glucosamine.

 

Human Clinical Study Ⅱ(18):

Colker et al. (2002) divided 31 subjects randomly into an ordinary drink group (control group) and a S100 MPC drink group (treatment group) for a six weeks study in which 12 ounces of each beverage was consumed daily. WOMAC and the Knee Osteoarthritis Outcome Score(23) (KOOS) were major functional assessment tools. Other items such as vital signs, weight, blood analysis and adverse reactions were also assessed.

KOOS and WOMAC results both showed that S100 MPC significantly improved indexes of pain, knee joint discomfort, daily activities and total WOMAC scores (Fig. 6).

 

Human Clinical Study Ⅲ(24):

Ziegenfuss et al. (2019) conducted an 8-week study involving 58 participants with mild to moderate knee pain during activity. The participants were randomly assigned to either a placebo group (PLA, daily supplementation of 4000 mg microcrystalline cellulose) or a S100 milk protein concontrate group (MPC, daily supplementation of 4000 mg S100 MPC). The efficacy was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the 6-minute walk test, while other parameters such as vital signs, weight, blood analysis, and adverse reactions were also evaluated.

According to WOMAC scores, the group supplemented with S100 milk protein concontrate showed a significant reduction in knee pain during activities such as descending stairs, getting in and out of vehicles, shopping, and getting in and out of bed, compared to the placebo group (refer to Table 1). Additionally, the S100 MPC supplementation group exhibited a substantial decrease of approximately 35% in the total WOMAC score, indicating a significant improvement in joint discomfort symptoms among the participants.

The results of the 6-minute walk test showed a significant increase in walking distance for participants supplemented with S100 milk protein concontrate after 8 weeks (refer to Table 2). This suggests that supplementation with S100 milk protein concontrate effectively improves joint discomfort and enhances walking performance in the study participants.