FEED-Cystic Fibrosis (FEED-CF)

Emory University

Status: Enrolling

Conditions: Cystic Fibrosis-related Diabetes; Cystic Fibrosis

Treatments: Other: Low-added sugar, high-fat diet; Other: High-added sugar, high-fat CF diet

Study type: Interventional

Funder types: Other; NIH

Identifiers

NCT05766774

1R01DK133523-01 (U.S. NIH Grant/Contract)

STUDY00004517

Details and patient eligibility

About

The goal of this study is to determine the extent to which excess dietary sugars serve as a precipitating factor in glucose intolerance in adults with cystic fibrosis (CF), a population at especially high risk for a unique form of diabetes (CF-related diabetes, CFRD) and with standard-of-care dietary recommendations (high-calorie, high-fat) that conflict with recommendations for other forms of diabetes.

This trial will investigate if the typical high-sugar, high-fat CF diet plays a role in diabetes risk and visceral fat accumulation in people with CF. A total of 30 participants will get a low-added sugar, high-fat diet and the other 30 will get a standard CF diet with no sugar restrictions. Participants will be randomized to the diet group they are assigned. All foods will be provided for 8 weeks.

Full description

Approximately half of adults with cystic fibrosis (CF), a genetic disease, will develop diabetes. Dietary strategies shown to be successful in preventing or treating other forms of diabetes in people without CF contradict current nutritional recommendations for people with CF. The nutrition standard-of-care in CF is prescription of an unrestricted high-calorie, high-fat diet because of malnutrition. However, the standard CF diet translates to low-quality diets, with excess added sugars well-above general population recommendations. Also the investigators have shown that people with CF have more fat around their abdominal organs (called visceral fat) compared to healthy controls. The hypothesis is that the typical high-sugar, high-fat CF diet plays a role in diabetes risk and visceral fat accumulation in people with CF. In this study, the investigators will test if a low-added sugar diet improves risk markers for diabetes and decreases visceral fat over 8 weeks. The study will recruit 60 participants with CF. A total of 30 participants will get a low-added sugar, high-fat diet and the other 30 will get a standard CF diet with no sugar restrictions. Participants will be randomized to the diet group they are assigned. All foods will be provided for 8 weeks. There will be a total of 4 study visits at the Emory Hospital clinical research unit. These will include: 1) a screening visit with an oral glucose tolerance test with blood draws to determine if they already have diabetes, 2) a baseline visit for an insulin secretion test (called glucose-potentiated arginine (GPA) stimulation test) to assess risk for diabetes, as well as magnetic resonance imaging (MRI) testing to measure visceral fat, 3) a 4-week visit for another oral glucose tolerance test and in-person check-in, and 4) an 8-week visit for another GPA and MRI. Blood samples will be collected and banked. In addition to all meals provided for 8 weeks, participants will be compensated for their time and effort. Participants will be recruited from patients seen at the Emory CF Clinic. Informed consent will be performed prior to any study testing. The investigators hope this study will contribute to the development of new standardized nutrition guidelines for people living with CF.

Enrollment: 60 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

1. Confirmed CF diagnosis
2. Ages 18 years and older
3. Baseline estimated daily total added sugar intake >16 tsp, as estimated from the Dietary Screener Questionnaire (DSQ).

Exclusion criteria

1. Nocturnal tube feeds
2. BMI <18.5 kg/m2
3. Life expectancy < 12 months
4. Confirmed diagnosis of CFRD
5. Screening OGTT showing fasting hyperglycemia (≥126 mg/dL)
6. Chronic steroid use
7. Current pregnancy or lactation
8. Inability/unwillingness to consume the majority of foods on the menu during the study period
9. MRI-incompatible metal that cannot be removed for testing
10. Uncontrolled exocrine pancreatic insufficiency/malabsorption
11. Clinically instability, defined as no changes in medical regimen (including medications and pulmonary exacerbations) for at least 21 days prior to study visit
12. Initiation of CFTR modulator within previous 8 weeks OR unstable changes in weight and lung function due to CFTR modulator use
13. Actively trying to gain or lose weight
14. Any food allergies or intolerances that cannot be accommodated
15. Any medical condition deemed by the a study physician or PI that may preclude completion of the study or interfere with primary end points.

Trial design

Primary purpose: Prevention

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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60 participants in 2 patient groups

Low-added sugar, high-fat diet Arm

Experimental group

Description:

Patients will receive a low-added sugar, high-fat diet for 8 weeks. Study menus will be designed by registered dietitians using the Nutrient Database System for Research (NDSR) software program with a 2-wk rotation.Total kcal provided will be individually tailored to maintain body weight and adjusted throughout as needed. All foods (including snacks and drinks) for 8 wks will be delivered to participants' homes. Menus will be designed so that food will be delivered to subjects' homes every 3-4 days. It will be expected that participants consume only the foods provided by the study.

Treatment:

Other: Low-added sugar, high-fat diet

Typical CF diet Arm

Active Comparator group

Description:

Patients will receive a high-added sugar, high-fat CF diet for 8 weeks. Study menus will be designed by registered dietitians using the Nutrient Database System for Research (NDSR) software program with a 2-wk rotation. Total kcal provided will be individually tailored to maintain body weight and adjusted throughout as needed. All foods (including snacks and drinks) for 8 wks will be delivered to participants' homes. Menus will be designed so that food will be delivered to subjects' homes every 3-4 days. It will be expected that participants consume only the foods provided by the study.

Treatment:

Other: High-added sugar, high-fat CF diet