The Influence of Probiotics on Body Weight and Composition

The purpose of this study is to evaluate the addition of two different probiotic interventions to a comprehensive behavioral lifestyle intervention on body weight loss and overall health in overweight adults.

This is a randomized, double-blinded, placebo-controlled study. After obtaining informed consent, healthy overweight adults aged 18 to 75 years (n=76/intervention group with n=228 total/study) will be randomized to one of three groups: Lactobacillus, a blend of Bifidobacterium and Lactobacillus, or placebo. Participants will consume 1 capsule per day of probiotic or placebo for 12 weeks. Participants will attend weekly behavioral lifestyle intervention meetings, which will address dietary and physical activity contributions to weight loss, in groups of approximately 20 subjects during the 12 intervention weeks.

Participants will complete daily questionnaires throughout the week before and during the intervention period which address subject compliance and bowel habits. A dual X-ray absorptivity scan will be done to measure body composition during the week before the intervention and during the 12th week of the intervention period (± 1 week). Blood samples will be collected via a finger prick at the baseline and final time points. Blood samples will be used to measure cardiovascular and metabolic markers of health. Stool samples will be collected from 25 subjects per intervention group during the week before the intervention period and the 12th week of the intervention period. Dietary intake will be assessed during the week before the intervention period and during the week of the final appointment (± 1 week). Gastrointestinal symptoms and physical activity questionnaires will be completed upon providing consent to the study, being randomized to an intervention, and during the last week of the intervention period. Questionnaires regarding income, weight control strategies, and quality of life will be completed during randomization and during the last week of the intervention period. Stool samples will be collected from a subgroup of participants during the week before the intervention period and during the 12th week of the intervention period. These samples will be used to detect the presence and/or abundance and/or survival of the probiotic microorganisms at the end of the digestive tract.

Eligibility Criteria:
Inclusion Criteria:

To participate in the study you must:

* Be age 18 to 75 years
* Have a BMI ≥ 25
* Be willing to receive random assignment to probiotic or placebo supplementation
* Be willing to and able to complete the Informed Consent Form in English
* Be willing to complete questionnaires, records, and diaries associated with the study and to complete all study visits
* Be committed to losing weight over the 12-week study period
* Be willing to discontinue consumption of fermented foods or probiotics (e.g., yogurts with live, active cultures or supplements).
* Be willing to provide a social security number (SS#) to receive study payment? Note: the subject can still participate if unwilling to provide SS#, but no financial reimbursement can be provided.

Exclusion Criteria:

To participate in the study you must NOT:

* Have used another investigational product within 3 months of enrolling in the study
* Be pregnant or breast-feeding or planning on becoming pregnant in the next 18 months
* Be allergic to milk, soy, or yeast
* Have gained or lost at least 10 lbs in the previous 3 months
* Have had uncontrolled angina (severe chest pain) within the past 6 months
* Have insulin-dependent diabetes (oral medications are not exclusionary)
* Use weight-loss medications
* Have had cancer treatment (radiation, chemotherapy, or surgery) within the past 6 months or any other treatment or condition known to weaken the immune system (e.g., systemic corticosteroids or HIV/AIDS)
* Be currently being treated for or have any of the following physician-diagnosed diseases or conditions: inflammatory bowel disease, celiac disease, short bowel syndrome, or any other malabsorptive syndrome?
* Have any physical condition deemed likely to significantly interfere with your ability to participate in a lifestyle intervention involving eating and physical activity changes
* Be currently participating in Weight Watcher's or another weight loss program