Use of Stable Carbon And Nitrogen Isotopes to Improve Dietary Assessment for Cardiovascular Disease (I-CAN)

In this research study, the investigators will use a novel approach to measure what people eat. The goal is to find out whether stable isotopes that can be measured in blood, hair, and fingernails are better at measuring what people eat than the surveys that are currently used. To meet the goal, the investigators will do three things. First, the investigators will feed study participants known amounts of foods and nutrients. Second, after study participants have eaten the food, the investigators will measure stable isotopes in samples of study participants' blood, hair, and fingernails. Third, the investigators will determine how well these samples reflect what was eaten. The investigators will also give surveys to study participants to determine how well the surveys reflect what was eaten. This will allow the investigators to do a relative comparison of the measurements from isotopes and surveys.

Study Overview

• Status: Withdrawn
• Conditions: Healthy Adults
• Intervention / Treatment: Dietary supplement: one 24 hr cycle of meals at a 2000 kcal level; Dietary supplement: one 24 hr cycle of meals at a 2000 kcal level + one serving sugar sweetened beverage; Dietary supplement: one 24 hr cycle of meals at a 2000 kcal level + two servings sugar sweetened beverage; Dietary supplement: one 24 hr cycle of meals at a 2000 kcal level + three serving sugar sweetened beverage

Detailed Description

This is a controlled feeding study in which the relative validity of stable carbon and nitrogen isotope ratio analysis as a biomarker of dietary intake is compared to controlled feedings and multiple 24-hour recalls. Participants will be randomly assigned to a sequence of diets to be fed on four occasions. Participants will undergo 24 hours of controlled feeding on four non-consecutive days over a month-long period. On the day after feeding, participants will complete 24-hour dietary recalls, and provide blood, hair, and fingernail samples for isotope ratio analyses. The investigators will use a crossover design and the diets will be either high or low in C4 plants (i.e., corn and cane products). A 24-hour urine collection will be done at home during each 24-hour feeding period. Participants will have height and weight measured at the screening visit. Weight will also be measured at each study visit. Additionally, data will be collected via questionnaires administered at each study visit.

• Study Type: Interventional
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • California
    • San Diego, California, United States, 92093
      • University of California, San Diego

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 21 years to 74 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• men and women;
• aged 21 and 74 years;
• no history of chronic disease and in general good health;
• able to provide primary study outcome; and
• willing to tolerate study diets designed for controlled feeding.

Exclusion Criteria:

• recent dietary changes, restrictions, allergies or preferences;
• health conditions that require management beyond the scope of the study (e.g. heart failure, kidney disease, liver disease, gastrointestinal disorder);
• history of drug or alcohol abuse;
• plans to leave the San Diego area before study completion; and
• lack of suitability per investigators' discretion.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Double

Number of Arms

4

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: 50g added sugar; Crossover design and each participant receives all 4 experimental arms/doses in random order	Dietary supplement: one 24 hr cycle of meals at a 2000 kcal level; 50g added sugar
Experimental: 90g added sugar; Crossover design and each participant receives all 4 experimental arms/doses in random order	Dietary supplement: one 24 hr cycle of meals at a 2000 kcal level + one serving sugar sweetened beverage; 90 grams added sugar
Experimental: 130g added sugar; Crossover design and each participant receives all 4 experimental arms/doses in random order	Dietary supplement: one 24 hr cycle of meals at a 2000 kcal level + two servings sugar sweetened beverage; 130 grams added sugar
Experimental: 170g added sugar; Crossover design and each participant receives all 4 experimental arms/doses in random order	Dietary supplement: one 24 hr cycle of meals at a 2000 kcal level + three serving sugar sweetened beverage; 170 grams added sugar

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Carbon isotope values from blood	The ratio of carbon 13 to carbon 12 in human blood will be determined.	30 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Carbon isotope values from hair	The ratio of carbon 13 to carbon 12 in human hair samples will be determined.	30 days
Carbon isotope values from fingernails	The ratio of carbon 13 to carbon 12 in human fingernail samples will be determined.	30 days
Nitrogen isotope values from blood	The ratio of nitrogen-15 to nitrogen 14 in human blood will be determined.	30 days
Nitrogen isotope values from hair	The ratio of nitrogen-15 to nitrogen 14 in human hair will be determined.	30 days
Nitrogen isotope values from fingernails	The ratio of nitrogen-15 to nitrogen 14 in human fingernails will be determined.	30 days

Collaborators and Investigators

• Sponsor: University of California, San Diego
• Investigators: Principal Investigator: Cheryl A. Anderson, PhD, University of California, San Diego

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2021
• Primary Completion (Estimated): February 1, 2022
• Study Completion (Estimated): February 1, 2022

Study Registration Dates

• First Submitted: February 21, 2020
• First Submitted That Met QC Criteria: June 18, 2021
• First Posted (Actual): June 22, 2021

Study Record Updates

• Last Update Posted (Actual): January 26, 2026
• Last Update Submitted That Met QC Criteria: January 22, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: Diet; Health; Sugar; Isotopes
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Technology, Industry, and Agriculture; Facility Design and Construction; Architecture; Floors and Floorcoverings
• Other Study ID Numbers: 16IRG27770080

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No