The PRO Health Study is a single-center, prospective, double-blind, randomized, placebo-controlled trial of streptococcus-containing supplementation in healthy adults.

Upon enrollment, healthy adults will enter a 1-week lead-in period which serves as an opportunity to collect baseline saliva samples and complete daily logs. Subjects that meet eligibility criteria on Day 7 will be randomized into 1 of 2 groups, receiving either a placebo-control or a streptococcus-containing probiotic supplement. Supplementation will begin on Day 8 and will continue for a total of 14 consecutive days. Participants will be observed for an additional 2 weeks following cessation of supplementation. The total duration of the study will be approximately 5 weeks. Saliva samples will be collected on 7 occasions and participants will be asked to complete questionnaires and daily diet and health logs throughout the course of the study.

Inclusion Criteria:

• Healthy adults;
• Age 21-45 years of age;
• BMI between 18-30;
• No history of infectious disease; heart, metabolic, autoimmune endocrine, liver, or kidney diseases; GI related conditions such as malabsorption disease, Crohn's disease, colitis, inflammatory bowel disease; Type 1 or 2 diabetes mellitus, any type of cancer, heart disease;
• Practices good oral hygiene according to the American Dental Association with brushing teeth between 1-2 times per day;
• Willingness to only use the study toothpaste to brush or clean teeth and refrain from using any other oral-care products such as other toothpaste, mouthwash, rinses and breath-sprays during the five-week study period;
• Willingness to limit consumption of raw onions or garlic and fermented foods such as sauerkraut, pickles, miso, and kimchi during the five-week study period;
• Non-alcohol consumers or those who consume alcohol in moderation defined as having up to 1 drink per day for women and up to 2 drinks per day for men;
• Willingness to avoid binge drinking during the study period defined by the Centers for Disease Control and Prevention as: This pattern of drinking usually corresponds to 5 or more drinks on a single occasion for men or 4 or more drinks on a single occasion for women, generally within about 2 hours;
• Willingness to refrain from drinking any alcohol within 24 hours of each saliva sample collection;
• Willingness to refrain from using illicit drugs during the five-week study;
• Willingness to refrain from using tobacco (smoking or chewing) or smoking marijuana during the five-week study period;
• Willingness to refrain from intake of probiotics, kombucha, or yogurt during the five-week study period;
• Willingness to refrain from consuming more than 1 package of sugary candy and from chewing more than 1 package of chewing gum during the five-week study period;
• Willingness to refrain from having any non-emergency, elective oral surgeries, dental procedures or dental teeth cleanings during the five-week study period.

Exclusion Criteria:

• Currently pregnant or plans to become pregnant several weeks prior to enrollment and during the five-week study period;
• History of periodontal disease, or gingivitis;
• Dental trauma or injury to the teeth and/or periodontium (gums, periodontal ligament, alveolar bone), and nearby soft tissues such as the lips, tongue within the past 4 weeks;
• Any oral surgery or intensive procedures made to the oral cavity (such as fillings, wisdom tooth extraction, root canal, dental implants, etc.) within the past 4 weeks;
• Routine dental cleaning within the past 4 weeks;
• Use of probiotics, kombucha, or yogurt/kefir within the past 7 days of enrollment;
• Use of probiotics containing S. salivarius within the past 8 weeks of enrollment;
• Use of oral or IV antibiotics within the past 8 weeks of enrollment;
• Consumption of more than one package of sugary candy (hard candy, gummy candy, mints, etc.) per day;
• Use of more than one package of chewing gum (sugary or sugarless) per day;
• Use of mouthwashes, mouth-rinses or breath-sprays more than three times per day;
• Current tobacco (smoking or chewing) or E-cigarette users or individuals who quit using less than one year before enrolling in the study;
• Frequent marijuana smoking or vaping, or use of other illicit drugs (must be no more than 12 times within the past year and no more than once per month);
• Marijuana smoking or vaping or use of other illicit drugs within the past 4 weeks;
• Excessive alcohol drinkers: For men, heavy drinking is typically defined as consuming 15 drinks or more per week. For women, heavy drinking is typically defined as consuming 8 drinks or more per week;
• Individuals who live within the same household or who are in intimate relationships with current or past study participants (to avoid horizontal transfer of the oral microbiome);
• Anyone the investigator feels isn't an applicable participant.

Participants, investigators, and data evaluators will be blinded to the treatment assignments.