Study of the Reversibility of Glucose Intolerance Caused by Chronic Aspartame Consumption

Not Applicable

Completed

• Conditions: Glucose Metabolism Disorder
• Interventions: Other: Oral glucose tolerance test (OGTT); Other: Diet soda containing aspartame only

• Registration Number: NCT02520258
• Lead Sponsor: Rockefeller University

Brief Summary

Experiments have shown that some artificial sweeteners like those in diet soda can cause changes in how the body responds to and uses sugar. These changes increase the chance of obesity, type 2 diabetes, and other metabolic diseases. In this study, the investigators plan to see if the most common artificial sweetener, aspartame (brand name Equal, NutraSweet), causes these changes. The investigators believe that if metabolic changes are observed in a person who consumes aspartame, then removing all aspartame from the diet might lead to a reversal of the changes and a normalization of test results.This would impact sweetener additives in our foods and thus decrease the incidence of obesity, diabetes, and the metabolic syndrome.

Detailed Description

Experiments have shown that some artificial sweeteners like those in diet soda can cause changes in how the body responds to and uses sugar. These changes increase the chance of obesity, type 2 diabetes mellitus, and other metabolic diseases. In this study, the investigators plan to see if the most commonly used artificial sweetener, aspartame, affects the body's response to sugar. The investigators believe that if metabolic changes are observed in a person who consumes aspartame, then removing all aspartame from the diet might lead to a reversal of the changes and a normalization of test results.

The investigators plan to study two (2) cohorts of healthy volunteers: 1) Those who regularly drink at least three cans per day of diet soda that contains aspartame (Cohort 1, Aspartame Consumers) and 2) participants who consume less than or equal to two (2) cans of diet soda per week (Cohort 2, Aspartame Naïve Participants).

Phase I of the study, the investigators will ask participants questions about their usual diet, including how much diet soda they usually drink. Participants will be screened by a test called the oral glucose tolerance test, or OGTT. This test involves coming to the hospital to drink sugary syrup, then have blood sugar checked every thirty (30) minutes for five (5) hours. Before the test, participants must refrain from eating or drinking anything for ten (10) hours. If the OGTT shows a high value, then the participant in cohort 1 (Aspartame Consumers) who regularly drink 3 or more cans per day of diet soda will be approached about continuing into the second phase of the study. For the participants in cohort 2 (consume less than or equal to two (2) cans of diet soda per week; Aspartame Naïve Participants), this will be the end of their participation in the study.

Phase II of the study, blood tests, OGTT, stool samples, and weight and body fat measurements a few times a week will track any changes in the participants during the study. During the phase II five (5) week study, participants will receive all of their meals from the Rockefeller University Hospital and should not have any outside food or drinks. The diet used throughout this study phase (II) is the Prudent Metabolic Diet. Participants can leave the hospital and continue to work, but must come for all tests and to receive meals. During Week One, participants will eat only food provided by the hospital but will continue to drink three (3) cans of diet soda per day. In Weeks Two through Four, participants will continue to eat food given to them by the hospital and will not be allowed to consume any foods or drinks that contain aspartame. In Week Five, participants will continue on the hospital diet, but will again start drinking three (3) cans of diet soda per day.

Study Timeline

• Study First Submitted: 2015-07-30
• Study Start: 2015-08
• Study First Submitted QC: 2015-08-06
• Study First Posted: 2015-08-11
• Primary Completion: 2019-06-25
• Study Completion: 2019-06-25
• Status Verified: 2020-06
• Last Update Submitted: 2020-06-03
• Last Update Posted: 2020-06-04

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 75

Inclusion Criteria

1. Male or female aged 18 - 45

2. Weight stable for at least 3 months prior to screening (< 5% weight change)

3. BMI of 21 - 29

4. Cohort 1 - Aspartame Consumers: Primary dietary sweetener is aspartame; consumes at least 36 ounces of diet soda in which aspartame is a primary ingredient (Diet Coke or Diet Dr Pepper) a day for at least 6 months duration prior to study enrollment (Primary dietary sweetener is aspartame" should be defined as: "840g per week sucrose equivalent from aspartame and less than 280 grams per week sucrose equivalent from all other sweeteners (non-caloric and caloric sweeteners). For reference, one 12oz soda is 40g sucrose equivalent, and one teaspoon (one packet) of artificial sweetener is 4g sucrose equivalent.)"

   Cohort 2 - Aspartame Naïve Participants: Consumes less than or equal to 2 cans of diet soda per week

5. Screening Visit #2 OGTT Outcome:

   • 0-h plasma glucose < 110 mg/dl AND
   • 2-h plasma glucose < 140 mg/dl

6. Abnormal OGTT during the screening phase of the study (area under curve on the high end of distribution)

7. Must be able to comply with a metabolic Prudent diet

8. Willing to fast 10 hours before each OGTT and BodPod

9. Current level of exercise (aerobic and/or resistance training) must be able to be sustained while an in-patient

Exclusion Criteria

1. Any evidence of US National Cholesterol Education Program Adult Treatment Panel III

   Clinical Identification of the Metabolic Syndrome (must have 3 or more of the following risk factors):

   Abdominal Obesity, given as a waist circumference:

   • Men >102 cm (>40 in)
   • Women > 88 cm (>35 in)

   Triglycerides >150 mg/dl

   HDL Cholesterol:

   • Men < 40 mg/dl
   • Women <50 mg/dl

   Blood Pressure >130/ >85 mm Hg

   Fasting Glucose > 110 mg/dl

2. Average systolic blood pressure (SBP) > 150 mmHg and / or diastolic blood pressure (DBP) > 90 mmHG (based on 3 BPs taken at screening visit #1),

3. LDL-C > 240mg/dl

4. Triglycerides > 400 mg/dl

5. Evidence of a liver disorder (ALT > three fold of the ULN)

6. Evidence of any renal disease

7. Currently on a weight-loss diet

8. Diabetes

9. Self-reported history of thyroid dysfunction

10. Sugar sweetened beverage consumption (> 84 ounces per week)

11. Hemoglobin <13.0 g/dl for males and 12.0 g/dl for females

12. Current, prior (within 2 months), or anticipated use of any of the following medications:

    antihyperlipidemic, hyperglycemic medications, Antineoplastics, Antiretrovirals, Selective Serotonin Reuptake Inhibitors, Diuretics, Antihypertensives, Anticonvulsants, Hormone therapy, Birth control

13. Self-reported antibiotic use within the previous 3 months

14. Currently pregnant or lactating

15. History of cardiac disease

16. Active illegal drug user (self-reported)

17. History of GI surgery (gastric bypass, bariatric, Roux-en-Y, colon resection, etc.)

18. Habitual ingestion of > 2 alcoholic beverages/day

19. Ever diagnosed with an eating disorder (self-reported)

20. Use of steroids or beta agonists (orally, intranasal or inhaled) within a week of any OGTT

21. Positive Hepatitis Serology (Hep. B surface Antibody; Hep. B surface antigen; Hep. C surface antibody)

22. HIV Positive

23. Tobacco use within the past 3 months

24. Any medical or social condition that, in the opinion of the Investigator, might pose additional risk to the participant or confound the results of the study

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SEQUENTIAL

Arm && Interventions

Group	Intervention	Description
Aspartame Consumers - Cohort 1	Oral glucose tolerance test (OGTT)	Experimental Group/Arm Phase I - Questionnaires and fasting oral glucose tolerance test (OGTT). Phase II - (If OGTT results are abnormal, participants will be invited to participate in Phase II) Five (5) week study phase with Prudent Metabolic Diet and Intervention of diet soda containing aspartame only; Week 1: Prudent Metabolic Diet and 36oz diet soda po daily, Week 2-4: Prudent Metabolic Diet and no diet soda, Week 5: Prudent Metabolic Diet and 36 oz diet soda po daily.
Aspartame Consumers - Cohort 1	Diet soda containing aspartame only	Experimental Group/Arm Phase I - Questionnaires and fasting oral glucose tolerance test (OGTT). Phase II - (If OGTT results are abnormal, participants will be invited to participate in Phase II) Five (5) week study phase with Prudent Metabolic Diet and Intervention of diet soda containing aspartame only; Week 1: Prudent Metabolic Diet and 36oz diet soda po daily, Week 2-4: Prudent Metabolic Diet and no diet soda, Week 5: Prudent Metabolic Diet and 36 oz diet soda po daily.
Aspartame Naive Participants - Cohort 2	Oral glucose tolerance test (OGTT)	Control Group/Arm Phase I - Questionnaires and fasting oral glucose tolerance test (OGTT). Phase II - Not applicable for this cohort.

Primary Outcome Measures

Name	Time	Method
Interval changes in blood glucose	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in blood glucose will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
Blood glucose	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): Blood glucose will be quantified from incremental area under the curve calculated from averaged oral glucose tolerance tests (OGTT)

Secondary Outcome Measures

Name	Time	Method
Interval changes in Ghrelin	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in Ghrelin will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
Interval changes in Glucagon	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in glucagon will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
Peptide Tyrosine Tyrosine (PYY)	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): PYY will be quantified from area under the curve calculated from averaged oral glucose tolerance tests (OGTT)
Glucagon	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): glucagon will be quantified from area under the curve calculated from averaged oral glucose tolerance tests (OGTT)
Interval changes in Peptide Tyrosine Tyrosine (PYY)	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in PYY will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
Interval changes in Leptin	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in Leptin will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
Leptin	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): Leptin will be quantified from area under the curve calculated from averaged oral glucose tolerance tests (OGTT)
Interval changes in Insulin	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in Insulin will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
Insulin	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): Insulin will be quantified from area under the curve calculated from averaged oral glucose tolerance tests (OGTT)
Ghrelin	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): Ghrelin will be quantified from area under the curve calculated from averaged oral glucose tolerance tests (OGTT)
Glucagon-like peptide-1 (GLP-1)	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): GLP-1 will be quantified from area under the curve calculated from averaged oral glucose tolerance tests (OGTT)
Glucose-dependent insulin-releasing peptide (GIP)	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): GIP will be quantified from area under the curve calculated from averaged oral glucose tolerance tests (OGTT)
Interval Changes in C-peptide	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in C-peptide will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
Interval changes in Glucagon-like peptide-1 (GLP-1)	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in GLP-1 will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
Interval changes in Glucose-dependent insulin-releasing peptide (GIP)	Interval 1: days 1 to 7; interval 2: days 8 to 28; interval 3: days 29 to 35	Phase II (cohort 1): Interval changes in GIP will be quantified from area under the curve calculated from oral glucose tolerance tests (OGTT)
C-peptide	Screening Visit 2: conducted between day -42 up to Day 1.	Phase I (both cohorts): C-peptide will be quantified from area under the curve calculated from averaged oral glucose tolerance tests (OGTT)

Trial Locations

Locations (1)

The Rockefeller University; 🇺🇸 New York, New York, United States