Probiotics have been recognized as functional foods with beneficial effects against obesity and cardiometabolic diseases, such as dyslipidemia, type 2 diabetes and the reduction of visceral fat mass, body weight and waist circumference.

In previous studies, it was shown that capsule/powder probiotic or postbiotic supplementation containing a single strain probiotic, could reduce anthropometric parameters, including the visceral fat area, and contribute to type 2 diabetes management in subjects with abdominal obesity. Similar findings were found when this single strain probiotic was delivered through enriched seafood sticks. Results showed that enriched seafood sticks significantly reduced insulin concentrations and HOMA-IR, pulse pressure, waist circumference, body weight and triglycerides.

These findings suggest that this specific single strain probiotic as a probiotic or postbiotic, could be a complementary strategy in the management of cardiometabolic disease risk factors.

Probiotics have mostly been studied incorporated in dairy food matrix. Other food matrices, such as chewing gum, have scarcely been exploited by the food industry. Chewing gum as a novel vehicle for probiotics presents the ability to release active ingredients into the oral cavity with a steady and rapid action. Furthermore, it has a high acceptance amongst adults and children and present few side effects.

No previous randomized controlled trials have examined the effect of a probiotic chewing gum on anthropometric adiposity biomarkers and glucose homeostasis in abdominally obese individuals.

The main objective of the present study is to evaluate the efficacy of single strain probiotic in the reduction of waist circumference in abdominally obese individuals.

The specific objectives:

• To evaluate the efficacy of single strain probiotic in the improvement of other anthropometric biomarkers (waist-hip-ratio, body weight, BMI, total fat mass, visceral fat index, free fat mass, lean body mass, conicity index, visceral adipose tissue and subcutaneous fat).
• To evaluate the efficacy of single strain probiotic in the management of glucose homeostasis.
• To evaluate the efficacy of single strain probiotic in the management of serum lipid levels.
• To evaluate the efficacy of single strain probiotic in the reduction of blood pressure and pulse pressure.
• To asses Quality of life after single strain probiotic supplementation.
• To identify changes in caloric intake and subjective satiety after single strain probiotic supplementation.
• To identify changes in gastrointestinal health after single strain probiotic supplementation.
• To identify changes in the oral microbiome after single strain probiotic supplementation.
• To identify changes in the gastrointestinal microbiome after single strain probiotic supplementation.

A total of 120 adult volunteers will be included in the intervention (60 in each arm of the intervention).

During the CHOICE study, there will be 6 visits in total. Of these visits, 3 will be face-to-face and 3 by telephone. The study visits will be the following: screening visit (V0, face-to-face): to check inclusion/exclusion criteria and, in case of satisfying the inclusion criteria; basal visit (V1, face-to- face); visits during the intervention (V2, V3 and V4 via telephone); final study visit (V5, face-to-face).

In visits V0, V1 and V5 volunteers must present themselves in fasting conditions of 8 hours to obtain blood samples. In visits V1 and V5 volunteers must bring saliva and faeces samples.

In order to measure the changes in visceral adipose tissue, up to five days prior to the visit V1 and approximately up to 3 days prior after the V5, volunteers must have a Nuclear Magnetic Resonance (NMR) for measuring visceral fat.

CHOICE Study

Visit 0 (V0, week -1): Recruitment and selection

• Information to the volunteer and signature of the informed consent.
• Revision of the inclusion/exclusion criteria.
• Elaboration of study clinical history.
• Vital signs (blood pressure/resting heart rate).
• Checking the concomitant medication.
• Anthropometry (waist circumference; hip; body weight and composition; height).
• Blood sample extraction.
• Delivery of the 3-day dietary record and the material for feaces and saliva sample recollection for V1.
• Schedule the first visit and instructions (fasting).

Visit 1 (V1, week 0): Basal visit

• NMR (±5 days V1).
• Revision of study clinical history.
• Vital signs (blood pressure/resting heart rate).
• Checking the concomitant medication.
• Anthropometry (waist circumference; hip; body weight and composition).
• Blood sample extraction.
• Abdominal fat Ultrasound.
• Checking the 3-day dietary record.
• Checking the Three Factor Eating Questionnaire (TFEQ).
• Checking the Bing Eating Scale (BES).
• Checking the satiety scale (VAS) and gastrointestinal health information.
• Collection of feaces samples.
• Collection of saliva samples.
• Delivery of the 3-day dietary record and the material for saliva and feaces sample for V5.
• Schedule the next telephone visit and also the final visit and instructions (fasting).

Visit 2 (V2, week 3): Follow-up during the intervention

• Checking the concomitant medication.
• Record adverse effects.
• Checking adherence to product consumption (treatment compliance)
• Checking the satiety scale.
• Checking the gastrointestinal health.
• Schedule the next visit and instructions.

Visit 3 (V3, week 6): Follow-up during the intervention

• Checking the concomitant medication.
• Record adverse effects.
• Checking adherence to product consumption (treatment compliance)
• Checking the satiety scale.
• Checking the gastrointestinal health.
• Schedule the next visit and instructions.

Visit 4 (V4, week 9): Follow-up during the intervention

• Checking the concomitant medication.
• Record adverse effects.
• Checking adherence to product consumption (treatment compliance)
• Checking the satiety scale.
• Checking the gastrointestinal health.
• Schedule the next visit and instructions (fasting).

Visit 5 (V2, week 12): Final visit

• NMR (±3 days before V5).
• Revision of study clinical history.
• Vital signs (blood pressure/resting heart rate).
• Anthropometry (waist circumference; hip; body weight and composition)
• Checking the concomitant medication.
• Blood sample extraction.
• Abdominal fat Ultrasound.
• Checking the 3-day dietary record.
• Checking the TFEQ.
• Checking the BES.
• Record of adverse effects.
• Checking the treatment compliance
• Checking the satiety scale. (VAS)
• Collection of feaces samples.
• Collection of saliva samples.

Inclusion Criteria:

1. Male and female subjects ≥ 18 years old.
2. Established diagnosis of abdominal obesity: waist circumference (WC) ≥ 102 cm for men and ≥ 88 cm for women.
3. Voluntary, written, signed, informed consent to participate in the study.
4. Agreement to comply with the protocol and study restrictions.
5. Females of child-bearing potential require to provide a negative urine pregnancy test.

Exclusion Criteria:

1. WC < 102 cm for men, <88 cm for women, and >150 cm.
2. BMI ≥ 40 kg/m2.
3. Diagnosed and pharmacologically-treated type 1 or type 2 diabetes (fasting blood glucose ≥ 7 mmol/l).
4. Subjects with serious autoimmune disease, cardiovascular disease, liver dysfunction/disease, kidney dysfunction/disease, dementia, pancreatic disease, history of cancer within past 5 years, anemia, or any other disease or condition which, in the Investigator's opinion, could interfere with the results of the study or the safety of the subject.
5. Immunosuppression or ongoing therapy causing immunosuppression.
6. Pharmacologically-treated (medication/supplements) dyslipidemia.
7. Subjects consuming antibiotics in the previous 1 month.
8. Subjects consuming probiotics and prebiotics at least 1 month prior to inclusion in the study or during the intervention period.
9. Use of drugs or supplements to manage body weight or body fat in the last 3 months.
10. Use of laxatives or fiber supplements in the past 4 weeks.
11. History of chronic active inflammatory disorders.
12. History of bariatric surgery.
13. History of any chronic gastrointestinal disease (e.g. IBD).
14. Regular use of systemic or inhaled corticosteroids, or systemic immunomodulatory drugs.
15. Significant change in tobacco, snuff, nicotine and e-cigarette use habits in the past 3 months or planned cessation of the use of these products during the trial.
16. Active or recent (last 3 months) participation in a weight loss program (diet and/or exercise).
17. Weight change (increase or loss) of 3 kg during the past 3 months.
18. Pregnant or planning pregnancy during the study or breastfeeding.
19. Participation in a clinical trial with an investigational product or drug within 60 days prior to screening.
20. Illicit drug users.
21. Alcohol abusers.
22. Known hypersensitivity to any ingredients in the active or placebo products.