Safety, Tolerability and Host Response to Lactobacillus Johnsonii

Healthy adult volunteers from 18-50 years of age will be recruited through the University of
Florida and randomly distributed into two groups. This study is divided into 3 phases:
baseline, intervention (study treatment) and washout. Participants will receive either the
probiotic or placebo during the intervention phases. During the baseline phase, blood and
fecal samples will be collected about 1 week before intervention initiation. On the day of a
scheduled blood draw, the participant will need to arrive fasted overnight, and a light
breakfast will be provided after blood draw. Starting on day 1 of the intervention phase, a
second baseline blood sample will be collected and the participant will begin the study
intervention (probiotic or placebo). Participants will consume 1 capsule (probiotic or
placebo) daily for 8 weeks, and blood and stool samples will be collected and processed (on
or around weeks 2, 4 and 8 of the intervention phase). A Fisher Scientific commode specimen
collection system will be provided for stool collections. The stool collection kit may be
taken home (participants will be asked to drop off the stool within 4 hours of defecation)
for fecal sample collection or may use the restroom in the clinical lab at the Food Science
and Human Nutrition Building in which kits will be provided for use. In the wash-out phase,
participants will not consume the capsule (either the probiotic or placebo), but will provide
blood and stool samples (on or around week 12). Throughout the study, participants will
provide a total of 5 stool samples and 6 blood samples. Participants will be asked to
complete daily and weekly questionnaires throughout all phases of the study, which will ask
about quality of life (physical functioning, mental functioning, level of sleep, etc.),
gastrointestinal function, and dietary intake. These assessments will be self-reported via
online questionnaires. In the event that internet access is not available for a portion of
the study, paper copies of the questionnaires may be provided.

Inclusion Criteria:

- To participate in the study individuals must

- be 18-50 years old.

- be willing to complete multiple questionnaires via computer.

- be willing to take the probiotic or placebo capsule daily for 8 weeks.

- be willing to provide 1 stool during weeks 0, 2, 4, 8 and 12 of the study.

- be willing to provide blood samples at weeks -1, 0, 2, 4, 8 and 12 of the study.

- have daily access to a computer with internet access for the entire 13-wk study.

- be willing to provide a social security number

Exclusion Criteria:

- To participate in the study individuals must NOT

- currently take medications for constipation, diarrhea or psychological disorders
(depression, anxiety, insomnia etc.).

- have taken antibiotics within the past four weeks prior to randomization.

- currently take probiotic supplements and do not want to discontinue a minimum of
two weeks prior to the study

- have had or are currently being treated for any diseases or illnesses such as
gastrointestinal disease (gastric ulcers, Crohn's, ulcerative colitis, etc.),
chronic disease like diabetes or kidney disease, immune-compromising diseases or
conditions (HIV, AIDS, hepatitis, cancer, transplant patient etc.)

- currently receive medical treatment for stress induced symptoms/disorders

- be a current smoker