The Impact of Steviol Glycosides on Human Gut Microflora Profile and Function

The Impact of a 28-day Steviol Glycoside Beverage on Human Gut Microflora Profile and Function vs. a Sucrose Beverage in Healthy Adults

Diet and dietary ingredients can have a profound effect on gut microflora, both positive and negative. The reported effects on low and non caloric sweeteners (LNCS) on human gut microflora are contradictory in some of the in vitro and rodent studies. More specifically, the latter studies, using doses above the acceptable daily intake (ADI), suggest that LNCS may have adverse effects on gut microflora whereas recent data from human RCTs, using doses at or below the ADI, show little to no effect. In this study we will compare the effects of a low energy beverage made with steviol glycosides vs. a beverage made with sucrose on human gut microflora profile and function in a double blind, randomized study. A sucrose beverage was chosen as a control as it represents a caloric sugar sweetened beverage which is commonly consumed.

This is a double blind randomized parallel study with 2 treatments to understand the effects of a low energy steviol glycoside beverage vs. a sucrose sweetened beverage on gut microflora profile and function over 28 days.

Participants will have a daily exposure to each test product for 28 days. (1) steviol glycosides (flavored water, steviol glycosides) and (2) sucrose (flavored water, sucrose). Individuals will be supplied with fecal collection kits to collect stool samples. The volunteers will be advised to collect a fecal sample before week 0(baseline), week 4(study end) and week 8(follow up period). Fecal microbial alpha diversity, beta diversity, and abundance of microbial taxa between the steviol glycoside and sucrose beverage consuming groups will be evaluated as well as fecal SCFA concentration, fasting serum insulin, glucose and lipids, weight, BMI, pulse and blood pressure at weeks 0(baseline),4(study end) and 8(follow up).

Inclusion Criteria:

• Generally healthy
• Non-pregnant, non-lactating individuals at least 25 of whom are male and 25 female
• Aged 18-50 years, inclusive
• BMI 18.5 to 24.9, inclusive
• Has access to a phone or tablet and wifi (to complete app based 3DDR)
• Consumption of ≤600ml (20oz) high intensity sweetened beverages per week for 1 month before screening
• Normal bowel frequency (≥3 per week)
• Understanding the study procedures and willing to provide informed consent to participate in the study and authorization to release relevant protected health information to the study Principal investigator
• Willing to not significantly alter their normal diet, physical activity routine, fiber intake or consume prebiotics or probiotics during the 8-week treatment period.
• Subjects must be eligible to receive income in Canada and be covered by a health insurance plan such as OHIP

Exclusion Criteria:

• Failure to meet any one of the inclusion criteria
• Use of prebiotic or probiotic supplement one month prior to the study and during the entire duration of the study
• Smokers (cigarettes, vape or marijuana)
• Habitual consumption of >1.5L sugar sweetened beverages (eg. juice, soft drinks) per day
• High alcohol consumption (>14 drinks per week and >4 drinks per day for males; and >7 drinks per week and >3 drinks per day for females), or history of alcohol abuse. Alcohol intake during the study must stay below these limits listed above
• History of major trauma or major medical or surgical event requiring hospitalization within 3 months of screening
• Individuals with diabetes, bariatric surgery, celiac disease, phenylketonuria, inflammatory bowel disease, moderate or severe renal failure, moderate or severe liver disease or any other medical conditions or medications that increase risk to the subject or others or may affect the results, as judged by the Principal Investigator
• Use of antibiotics within 3 months of screening or with a condition likely to require the use of antibiotics during the study
• Unwillingness or inability to comply with the experimental procedures and to follow INQUIS safety guidelines
• Known intolerance, sensitivity, or allergy to any ingredients in the study test beverages.
• Subject is currently participating or recently (within 30 days of screening) participated in a clinical trial involving long-term exposure (greater than 24 hours) to an investigational drug, nutritional supplement, or lifestyle modification.
• Reported weight change of > 5kg in the preceding 3 months
• Employed by the study sponsor or affiliated organizations