Glycemic Index - Variability Among Individuals

Obesity Clinical Trial

Official title:

Evaluation of Glycemic Index to Assess Diet Associated Chronic Disease Risk

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01023646
• Other study ID #: R01DK073321
• Secondary ID: R01DK073321
• Status: Completed
• Phase: N/A
• First received: November 30, 2009
• Last updated: April 24, 2017
• Start date: December 2007
• Est. completion date: December 2016

Study information

• Verified date: April 2017
• Source: Tufts University
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

The purpose of this study is to determine the variability in glycemic index determinations for individual foods and food combinations. The study will also evaluate the changes in insulin and free fatty acid levels, plasma lipid and lipoprotein profiles, C-reactive protein-a marker of inflammation and glycosylated hemoglobin- a marker of glucose metabolism during a five-hour period after eating the food or foods. Additionally, supplementary data on variation in oral sensation, habitual food intake, food preferences and genes mediating sensory perception and dietary behaviors (supported by a grant from the Tufts Ross Aging Initiative) will be related to the outcomes on the present study.

Description:

The objective of this proposal is to investigate the intra-individual reproducibility (within the same individual, when repeatedly measured) and inter-individual variability (among individuals) of glycemic index (GI) and glycemic load (GL) value determinations for individual foods and food combinations. The specific aims to accomplished this objective are to evaluate reproducibility and variability of GI value determinations in volunteers differing in biologic characteristics - body mass index (BMI), age and gender; assess the effect of macronutrient amounts and combinations, and fiber on variability of GI and GL value determinations; assess the effect of prior meal macronutrient composition ('second meal' effect) on GI value determinations; and relate these data to chronic disease risk factors monitored prior to and during the intervention period. These aims will be accomplished by assessing intra-individual reproducibility and inter-individual variability of repeated GI value determinations for white bread, commonly used as a reference food, relative to glucose, in volunteers selected to represent a range of BMI's (18-24.9, 25-29.9, 30-35) and ages (18-49.9, 50-85 y), and on the basis of gender, and relate these data to body composition and insulin sensitivity (Phase I). This work will then be extended to address issues related to variability potentially introduced by differences in macronutrient and fiber combinations and loads (Phase II), and finally by 'second meal' effects (Phase III). Prior to each set of food challenges (glucose and test food[s] in random order) volunteers will be characterized on the basis of fasting HbA1c; lipids and lipoproteins; insulin, glucose and C-reactive protein. During the 5-hour challenge (sampling at 0, 15, 30, 45, 60, and every 30 minutes thereafter) volunteers will be monitored for changes in blood glucose, insulin, triglycerides, total, low density lipoprotein and high density lipoprotein cholesterol, and non-esterified fatty acid levels. Additionally, supplementary data on variation in oral sensation, habitual food intake, food preferences and genes mediating sensory perception and dietary behaviors (supported by a grant from the Tufts Ross Aging Initiative) will be related to the outcomes on the present study. The concepts of both GI and GL are in the public domain and it has been suggested that the concepts be incorporated into U.S. federal dietary guidance (U.S. Dietary Guidelines and Dietary References Intakes) formulated to promote health and reduce chronic disease risk. This proposal addresses some of the understudied areas for which additional information would be useful in order to determine whether GI and GL should be used to classify foods on an individual basis, as has been suggested, and when formulating dietary guidance for the general population.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 124
• Est. completion date: December 2016
• Est. primary completion date: November 2015
• Accepts healthy volunteers: Accepts Healthy Volunteers
• Gender: All
• Age group: 18 Years to 85 Years

Eligibility

Inclusion Criteria:

• For Phase 1 (Study 1) a total of seventy five volunteers will be included in the study. This study will be conducted in adult men and women (18-85 y) free of known chronic disease with BMI 18 to 35 kg/m2.

• For Phase 2 (Studies 2, 3, 4, and 5) a total of 80 volunteers will be included, 20 volunteers per study. Phase 2 studies will be conducted in adult men and women (50 - 85 y) free of known chronic disease and with a BMI of 25 to 35 kg/m2.

• For Phase 3 (Study 6) a total of 20 volunteers will be included in the study. Phase 3 study will be conducted in adult men and women (50-85 y) free of known chronic disease and with a BMI of 25 to 35 kg/m2.

Exclusion criteria:

• BMI = 35 kg/m2 for Phase I, and BMI = 25 to = 35 kg/m2 for Phase II and III

• Renal disease, as defined by a history of chronic kidney disease or by glomerular filtration rate of < 60 ml.min/1.73 m2 calculated from screening blood tests.

• Liver disease, as defined by a history of chronic hepatitis B or C, cholestatic or cirrhotic liver disease, nonalcoholic fatty liver disease, elevations of serum glutamate pyruvate transaminase (SGPT) or serum glutamate oxaloacetate transaminase (SGOT) greater than 1.5 times the upper limit of normal at screening, bilirubin greater than 2 mg/dL (in the absence of benign causes of elevated bilirubin such as Gilbert's syndrome) at screening, or albumin below the lower limit of normal.

• Untreated hypertension, defined as systolic blood pressure (SBP) > 140 mm and diastolic blood pressure (DBP) > 90 mm.

• Irritable bowel syndrome.

• Malabsorptive disorder and inflammatory bowel disease.

• Disorders of esophageal and gastrointestinal motility, and previous esophageal or gastric resection.

• History of chronic pancreatitis, or history of acute pancreatitis within the last year.

• Hypothyroidism or hyperthyroidism, as defined as screening thyroid-stimulating hormone (TSH) outside of normal ranges.

• Anemia, as defined by screening hematocrit of 34% for women and 38% for men.

• Smoking within the past 6 months.

• Diabetes.

• Fasting glucose = 125 mg/dL.

• Pregnancy.

• Breastfeeding.

• History of polycystic ovary syndrome

• History of autoimmune or other connective tissue disorders associated with chronic inflammation, such as rheumatoid arthritis.

• Alcohol consumption > 7 drinks/week.

• Use of medications or supplements known to affect glucose metabolism.

• Use of medications or supplements known to affect lipid metabolism.

• Established cardiovascular disease (myocardial infarction, stroke, heart failure, coronary artery. bypass graft, stenosis > 50%, peripheral arterial disease).

• Unwillingness to adhere to study protocol.

• Weight gain or loss of more than 15 lbs within 6 months prior to enrollment.

Related Conditions & MeSH terms

• Cardiovascular Disease
• Cardiovascular Diseases
• Diabetes
• Metabolic Syndrome
• Metabolic Syndrome X
• Obesity

Intervention

Other:
• Carbohydrate + Protein
Light Tuna Packed in water.
• Carbohydrate + Fat
Butter
• Fiber
Unrefined Carbohydrate
• Carbohydrate load
Carbohydrate

Locations

Country	Name	City	State
United States	Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University	Boston	Massachusetts

Sponsors (2)

Lead Sponsor	Collaborator
Tufts University	National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

Country where clinical trial is conducted

United States, 

References & Publications (13)

Amano Y, Kawakubo K, Lee JS, Tang AC, Sugiyama M, Mori K. Correlation between dietary glycemic index and cardiovascular disease risk factors among Japanese women. Eur J Clin Nutr. 2004 Nov;58(11):1472-8. — View Citation

Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults.. Executive Summary of The Third Report of The National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, And Treatment of High Blood Cholesterol In Adults (Adult Treatment Panel III). JAMA. 2001 May 16;285(19):2486-97. — View Citation

Foster-Powell K, Holt SH, Brand-Miller JC. International table of glycemic index and glycemic load values: 2002. Am J Clin Nutr. 2002 Jul;76(1):5-56. — View Citation

Jenkins DJ, Wolever TM, Taylor RH, Barker H, Fielden H, Baldwin JM, Bowling AC, Newman HC, Jenkins AL, Goff DV. Glycemic index of foods: a physiological basis for carbohydrate exchange. Am J Clin Nutr. 1981 Mar;34(3):362-6. — View Citation

Jenkins DJ, Wolever TM, Wong GS, Kenshole A, Josse RG, Thompson LU, Lam KY. Glycemic responses to foods: possible differences between insulin-dependent and noninsulin-dependent diabetics. Am J Clin Nutr. 1984 Nov;40(5):971-81. — View Citation

Salmerón J, Ascherio A, Rimm EB, Colditz GA, Spiegelman D, Jenkins DJ, Stampfer MJ, Wing AL, Willett WC. Dietary fiber, glycemic load, and risk of NIDDM in men. Diabetes Care. 1997 Apr;20(4):545-50. — View Citation

Salmerón J, Manson JE, Stampfer MJ, Colditz GA, Wing AL, Willett WC. Dietary fiber, glycemic load, and risk of non-insulin-dependent diabetes mellitus in women. JAMA. 1997 Feb 12;277(6):472-7. — View Citation

Schulze MB, Liu S, Rimm EB, Manson JE, Willett WC, Hu FB. Glycemic index, glycemic load, and dietary fiber intake and incidence of type 2 diabetes in younger and middle-aged women. Am J Clin Nutr. 2004 Aug;80(2):348-56. — View Citation

Vega-López S, Ausman LM, Griffith JL, Lichtenstein AH. Interindividual variability and intra-individual reproducibility of glycemic index values for commercial white bread. Diabetes Care. 2007 Jun;30(6):1412-7. Epub 2007 Mar 23. — View Citation

Wolever TM, Csima A, Jenkins DJ, Wong GS, Josse RG. The glycemic index: variation between subjects and predictive difference. J Am Coll Nutr. 1989 Jun;8(3):235-47. — View Citation

Wolever TM, Jenkins DJ, Josse RG, Wong GS, Lee R. The glycemic index: similarity of values derived in insulin-dependent and non-insulin-dependent diabetic patients. J Am Coll Nutr. 1987 Aug;6(4):295-305. — View Citation

Wolever TM, Jenkins DJ. The use of the glycemic index in predicting the blood glucose response to mixed meals. Am J Clin Nutr. 1986 Jan;43(1):167-72. — View Citation

Wolever TM, Vorster HH, Björck 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. — View Citation

* Note: There are 13 references in all — Click here to view all references

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Glucose, Insulin, Free Fatty Acids.		5 hours
Secondary	Fasting and non-fasting plasma lipids and lipoproteins, C reactive protein (CRP), HbAIc.		5 hours