Effects of Products Containing Bacillus subtilis var. natto on Healthy Subjects with Neck and Shoulder Stiffness, a Double-Blind, Placebo-Controlled, Randomized Crossover Study.

Plain Language Summary

Neck and shoulder stiffness and pain are common complaints, and causative factors include muscle tension and reduced blood flow around the neck and shoulders. NKCP® is as a food supplement that contains bacillopeptidase F, a protease (enzyme) that is isolated and purified from the culture of the probiotic bacterium B. subtilis var. natto, which is used to ferment soy beans to natto, a traditional Japanese food. Various health benefits have been attributed to natto, and NKCP® has been shown to have blood thinning properties. This double-blind, placebo controlled crossover study aimed to evaluate the effects of NKCP® on healthy individuals with neck and shoulder stiffness and pain. Subjects received either NKCP® or placebo for 4 weeks, then had a 4 week washout period where they received neither test supplement, and then received the other test supplement for another 4 weeks. Shoulder and neck symptoms were assessed prior to starting the trial, and at 4, 8 and 12 weeks, through subjective reporting and a muscle hardness meter to measure muscle stiffness. Neck and shoulder stiffness and pain were improved after taking NKCP® but not significantly more than in the placebo group. Headaches improved significantly more in the NKCP® group compared to the placebo group. No significant changes were observed for lower back pain, cold hands and feet, eyestrain, and dry eye.