Artificial sweeteners like sucralose are found in many foods and drinks. Sucralose might
affect hormones and cause health changes.
To see if sucralose changes how medicines are absorbed and processed, how hormones are
secreted, gut bacteria, and how fat cells are metabolized.
People ages 18-60 who:
- Are black or Hispanic
- Weigh more than 110 pounds
- Have a body mass index of 25-40
- Do not have a condition that requires drug treatment
Participants will be screened with:
- Medical history
- Physical exam
- Blood, heart, and urine tests
Participants must not eat or drink anything with artificial sweeteners throughout the study.
Over 7 days, Participants will answer questions, and give daily urine samples and 1 stool
sample. Participants will repeat these throughout the study.
Overnight Visit 1: participants will fast starting the night before. They will get breakfast
at the visit. The visit includes:
- An IV will be placed in the arm. Participants will get 2 tablets of medicines. Blood
will be drawn several times over 24 hours.
- A piece of fat tissue may be taken from the abdomen (biopsy).
- Participants will have a sweet drink. Blood samples will be taken over 2 hours.
Then participants will be randomly assigned to take either a sucralose capsule or placebo.
They will take it twice a day for 2 weeks. They will complete two 24-hour food diaries.
Overnight Visit 2 repeats Visit 1 except the biopsy.
Then participants will take the capsules for another 2 weeks.
Overnight Visit 3 repeats Visit 1.
Participants may be contacted by phone within 4 weeks after they finish.
- Canagliflozin (sold as InvokanaTM) is a new medicine for diabetes. But it might increase
the bone fracture risk in people with diabetes.
- To see if Invokana has negative side effects on bone health.
- Healthy men ages 18 45.
- Participants will be screened with a medical history, physical exam, and blood tests. A
nutritionist will discuss their dietary history and the study dietary requirements.
Participants will get a food diary to record what they eat and drink on 3 separate days.
- Participants will have a DEXA scan x-ray test of bone health. Participants will lie
still on a table while a small camera passes over the body.
- Participants will have 2 stays in the clinic. They will be 1 week apart and each last 6
overnights starting on a Sunday.
- Before each stay, participants will:
- Pick up food each day for 7 days. They will get breakfast, lunch, dinner, and snacks.
They must eat only the food provided during these times.
- Collect their urine twice.
- During the stays, participants will:
- Be evaluated by a doctor and have blood drawn.
- On each Monday, participants will:
- Skip breakfast
- At about 8 a.m. take a placebo pill in one stay, the study drug in the other stay.
- Drink 6 ounces of water every 2 hours for 4 hours.
- An intravenous (IV) catheter will be inserted into an arm. Blood will be drawn every 2
hours from 8 a.m. until noon.
- Get lunch.
- Have blood testing again at 8pm and midnight.
- Repeat the testing days 2 5.
- Have urine collected.
- Artificial sweeteners, such as sucralose (brand name Splenda), are very commonly found in
products such as diet soft drinks. Recently, researchers learned that these sweeteners may
affect hormones in the body, especially when they are consumed in combination with real
sugar. Changes in hormone levels may, in turn, result in changes in blood sugar, appetite,
and weight. Researchers are interested in studying the effects of artificial sweeteners on
the metabolism and hormonal levels of healthy volunteers.
- To study the effects that artificial sweeteners have on hormone levels, blood sugar, and
- To evaluate whether artificial sweeteners change the rate at which food passes out of
the stomach into the gut, or the rate at which the body absorbs sugar from the gut.
- To evaluate the effects that different amounts of artificial sweeteners have on hormone
- Healthy volunteers between 18 and 45 years of age.
- This study will require one screening visit and four testing visits, scheduled on
- At the screening visit, eligible participants will be screened with a physical
examination, medical history, blood samples, and body measurements (including height,
weight, body circumferences, and skin folds). Participants will also be asked about how
much artificial sweetener they typically consume and will have taste tests, in which a
small amount of flavored liquid is placed on the tongue and participants will name the
flavor and rate its intensity.
- Participants will have four glucose tolerance tests on four different days. In
preparation for the test, participants will not eat or drink anything but water for 12
hours prior to the test. Blood will be drawn before the test, and participants will
drink one of the following study liquids, selected at random:
- Plain water
- Water mixed with sucralose (the amount found in one 12 oz diet soft drink)
- Water mixed with sucralose (the amount found in 2.5 12 oz diet soft drinks)
- Water mixed with sucralose (the amount found in 3.7 12 oz diet soft drinks)
- Ten minutes after drinking the study liquid, participants will have a sugary drink that
will allow researchers to measure sugar absorption and the speed with which food leaves
- In addition, participants will complete questionnaires about hunger levels before
drinking the sugar solution and at regular intervals for 2 hours afterward. Blood
samples will be taken at regular intervals as well.
This study will determine whether resting beta cells (cells in the pancreas that produce
insulin) for 2 weeks will improve the ability of patients with Type 2 diabetes mellitus
(T2DM) to make insulin. Beta cells can rest by giving patients insulin shots. The study will
also examine how teenagers with T2DM feel about having diabetes and explore differences
between young people with and without T2DM.
This study includes patients 12 to 25 years of age with T2DM who are overweight and who were
diagnosed within 2 years of enrolling in the study. Healthy individuals of normal weight or
who are overweight are also eligible. Candidates are screened with a medical history,
physical examination and laboratory tests.
Participants with T2DM are assigned to one of two groups. Group 1 takes an anti-diabetes
medicine called metformin and follows a diet prescribed by a study staff dietitian for 2
weeks. Group 2 takes metformin, follows the prescribed diet, and receives insulin through a
pump under the skin for 2 weeks. During these two weeks, all participants have the following
- Frequent blood sugar checks.
- Oral glucose tolerance test (routine diabetes test in which blood samples are drawn
before and several times after the subject drinks a sugary solution).
- Arginine stimulation to test the response of the body to arginine, a normal ingredient
of food that stimulates the release of insulin. Two catheters are placed into veins in
the arms, one to administer a liquid containing arginine, the other to draw the blood
- Ultrasound of the blood vessels in the neck to check for hardening of the arteries.
- Metabolism test to measure the amount of oxygen used during rest. The subject breathes
normally during rest while wearing a canopy over his or her head for about 20 minutes.
- MRI scans of the abdomen to examine the amount of fat in the belly (at the beginning and
end of the study)
- DEXA scan to determine percent body fat.
- Tests to explore quality of life and feelings about health, work or school, friends and
- Exercise testing on a treadmill or stationary bicycle.
- Genetic studies for information on diabetes and obesity.
Normal volunteers have blood draws, oral glucose tolerance testing, MRI scan, DEXA scan,
psychological testing, exercise testing, and genetic testing.