Clinical trial NCT01053793: Glycemic Index and Polyphenol Bioavailability of Potatoes
Official title: A Trial to Measure the Glycemic Index and Polyphenol Bioavailability of Four Different Varieties of Potato.
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Diabetes
Insulin Resistance
Keywords: Glycemic index
Anthocyanin
Potato
Polyphenol
Lead sponsor: Guelph Food Research Centre
Sponsor class: OTHER_GOV
Collaborators: name: Nutrasource Pharmaceutical and Nutraceutical Services, Inc.
First posted: 2010-01-21
Enrollment: 10
Sex: ALL
Minimum age (years): 18
Maximum age (years): 50
Standard ages: ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: BASIC_SCIENCE

Brief summary: 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.

Detailed description: 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.

Eligibility criteria: 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

Primary outcomes:
measure: Glycemic response
timeFrame: 2 hrs
Secondary outcomes:
measure: Bioavailability of polyphenols from potatoes
timeFrame: 4 hours
Other outcomes:
Locations:
city: Guelph
country: Canada
facility: Nutrasource Diagnostic Inc
state: Ontario
Study officials:
affiliation: Agriculture and Agri-Food Canada
name: Dan Ramdath, PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: Nutracource Diagnostics Inc
name: Maggie Laidlaw, PhD
role: STUDY_DIRECTOR
References:
citation: Wolever TM, Brand-Miller JC, Abernethy J, Astrup A, Atkinson F, Axelsen M, Bjorck I, Brighenti F, Brown R, Brynes A, Casiraghi MC, Cazaubiel M, Dahlqvist L, Delport E, Denyer GS, Erba D, Frost G, Granfeldt Y, Hampton S, Hart VA, Hatonen KA, Henry CJ, Hertzler S, Hull S, Jerling J, Johnston KL, Lightowler H, Mann N, Morgan L, Panlasigui LN, Pelkman C, Perry T, Pfeiffer AF, Pieters M, Ramdath DD, Ramsingh RT, Robert SD, Robinson C, Sarkkinen E, Scazzina F, Sison DC, Sloth B, Staniforth J, Tapola N, Valsta LM, Verkooijen I, Weickert MO, Weseler AR, Wilkie P, Zhang J. Measuring the glycemic index of foods: interlaboratory study. Am J Clin Nutr. 2008 Jan;87(1):247S-257S. doi: 10.1093/ajcn/87.1.247S.
citation: Ramdath DD, Isaacs RL, Teelucksingh S, Wolever TM. Glycaemic index of selected staples commonly eaten in the Caribbean and the effects of boiling v. crushing. Br J Nutr. 2004 Jun;91(6):971-7. doi: 10.1079/bjn20041125.
citation: Wolever TM, Vorster HH, Bjorck I, Brand-Miller J, Brighenti F, Mann JI, Ramdath DD, Granfeldt Y, Holt S, Perry TL, Venter C, Xiaomei Wu. Determination of the glycaemic index of foods: interlaboratory study. Eur J Clin Nutr. 2003 Mar;57(3):475-82. doi: 10.1038/sj.ejcn.1601551.
citation: Wolever TM, Isaacs RL, Ramdath DD. Lower diet glycaemic index in African than South Asian men in Trinidad and Tobago. Int J Food Sci Nutr. 2002 Jul;53(4):297-303. doi: 10.1080/09637480220138142.