the effect of cranberry extract supplementation on cardiovascular risk factors in obese, insulin resistant humans

Conditions: Insulin Resistance; Atherosclerosis

Summary: the purpose of this study is to determine the health benefits of cranberry extract in people who are at risk for diabetes and heart problems.

this study will be a double-blinded, randomized, placebo-controlled, pilot study in which subjects with pre-diabetes will be randomized to receive either placebo or cranberry extract for a total of 8 weeks of treatment. each subject will continue on the same dosage of cranberry extract or matching placebo for the entire duration of treatment. comparisons for insulin sensitivity, endothelial function, and markers of inflmmation and oxidative stress will be made between the 2 groups pre and post intervention.

Eligibility criteria:
inclusion criteria: * are 20 years of age or older * not being treated with diabetes medication. however, if you are taking metformin for pre-diabetes and are willing to stop taking the medication 2 weeks before and during the study that is ok. we will request clearance from your prescribing physician prior to stopping metformin and enrolling in the study. * have a blood sugar of 100-125 mg/dl (fasting) or 140-199 mg/dl after a 2 hour glucose tolerance test (determined by tests done at the screening visit) * have a fasting insulin more than or equal to 5 µiu/ml (determined by tests done at the screening visit) * have a body mass index (bmi) ≥ 30 and ≤ 45. exclusion criteria: * have a prior history of type 2 diabetes * are pregnant or breastfeeding. * are a woman able to have children and are not using birth control (i.e. barrier method, intrauterine and cervical devices, birth control pills, hormonal injections (depo provera® ), condoms with spermicidal gel or foam, contraceptive patch (ortho evra), diaphragm, or abstinence), or have had a tubal ligation or hysterectomy, or not at least 2 years past menopause. - all women able to have children will have a pregnancy test at the screening visit. if you become pregnant during the study, you will be dropped from the study. * have type 1 diabetes. * are taking steroids (except topical or inhaled steroids). - other medications that may affect your blood sugar (i.e. certain blood pressure medications) are acceptable if the dose has not changed in the previous 6 months and the dose will not change during the study. * have a history or evidence of stomach or intestinal problems, e.g. irritable bowel syndrome; inflammatory bowel disease; ulcerative colitis or crohn's disease; diverticulosis or diverticulitis; narrowing of the intestines, partial or complete removal of the stomach or small bowel; autonomic neuropathy consisting of difficulty swallowing; delayed stomach emptying or diarrhea; chronic, severe constipation; stomach or colon ulcers, or gi bleeding. * use laxatives or cathartics on a chronic basis. * take medications known to damage the kidneys, such as certain antibiotics, methicillin, and cyclosporin. * have any evidence of kidney disease. * have significant heart problems and/or history (within the last 6 months) of significant heart problems. * have evidence within the previous 6 months of liver disease such as hepatitis; jaundice; cirrhosis. * have clinically significant lung, neurologic, blood-related, immune system-related, cancer-related or metabolic disease. * have had a recurrence of cancer within the past five years, other than treated basal cell carcinoma. * are planning surgery during the study period. * have a history of substance abuse or alcoholism within the past 5 years, or significant psychiatric disorder that would interfere with your ability to complete the study. * have donated blood during the month before entering the study or are planning to donate blood during the study. * have participated in other studies using a research medication during the previous 3 months. * are currently smoking or have smoked within the past 6 months. - no smoking will be allowed during the study. * have had a fluctuation in body weight \>5% in the previous 2 months. * are taking prescription or over-the-counter medication for weight loss. * are taking weight loss or herbal supplements. * are taking prescription or over-the-counter anti-inflammatory medications (such as naproxen, aspirin, ibuprofen). * are allergic to cranberries

Keywords: cranberry extract