Glycemic Index and Polyphenol Bioavailability of Potatoes

A Trial to Measure the Glycemic Index and Polyphenol Bioavailability of Four Different Varieties of Potato.

The purpose of this study is to determine the glycemic index of four varieties of potatoes and to determine the bioavailability of polyphenols contained in these potatoes.

Ten healthy persons will have a fasting blood sample drawn and asked to randomly consume a 50g glucose drink (2 occasions), or 50g carbohydrate equivalent of cooked purple, red, yellow and white potatoes. Further blood samples will be obtained at 15,30, 45, 60, 90, 120, 180, 240 mins. Bloods from the first 2 hours will be analyzed for glucose and insulin to determine the glycemic response. Hourly blood samples will be analyzed for polyphenol to determine the bioavailability of polyphenols from the different potato variety. Urine samples will be collected before ingestion of the food items and again at 4 hours, and will be used to determine polyphenol bioavailability.

Inclusion Criteria:

• healthy, non-smoker on no medication
• normal glucose tolerance
• willing to have a catheter inserted in forearm

Exclusion Criteria:

• abnormal glucose tolerance
• abnormal BMI
• on medication for a chronic disorder