Purpose– Use biomarkers of energy and protein intake to validate the AMPM
Sample– 524 healthy volunteers from the Washington DC area:
- 30-69 years of age, equal numbers of males and females
- BMI range of 18-44 kg/m
- Weight stable
- No medications known to affect food intake or water balance
Data Collection Period– July 2002 to September 2003
Study Design– Each volunteer entered the study for a 14-day period, and data were
collected during 4 visits to the Beltsville Human Nutrition Research Center
plus 3 telephone contacts. During the study period, participants were interviewed
three times using the AMPM, and asked to report all foods and beverages
eaten the previous day. These food recalls were conducted four to five
days apart. The first interview was conducted in-person and subsequent
recalls were conducted by telephone. Over the 15 months of the study, interviews
were conducted on every day of the week and during all seasons of the year.
Because the AMPM is the instrument used to collect dietary data in What
We Eat in America, the dietary intake interview component of the National
Health and Nutrition Examination Survey (NHANES), the environment in which
participants were interviewed replicated that used for the NHANES dietary
interview to the extent possible.
- Total energy expenditure by the doubly labeled water method
- 24-hour urinary nitrogen excretion as a biomarker for protein intake
- Resting energy expenditure
- Physical activity measured with the MTI Actigraph worn for 14 days
- Height, weight, waist and hip circumference
- Body composition and bone density measured by dual energy x-ray absorptiometry
- Blood pressure
- Fasting blood and adipose tissue samples
- Questionnaires on physical activity, dietary supplement use, and psychosocial
factors associated with eating behavior
- Physical fitness measured on a stationary bicycle
Doubly Labeled Water Method– The doubly labeled water method was used to validate energy intake.
It provides an accurate measure of total daily energy expenditure. When
individuals are weight stable (not gaining or losing weight), energy expenditure
and energy intake are equal. Thus, the energy expenditure estimates that
the method provides serve as an excellent biomarker for energy intake.
On their first visit to the study center, participants drank a dose of
doubly labeled water and then collected urine samples daily over the 14-day
study period. Doubly labeled water contains a higher concentration than
usual of deuterium and oxygen-18, which are naturally-occurring stable
isotopes of hydrogen and oxygen. The rates at which these isotopes are
excreted in urine can be measured and used to calculate total daily energy
- Biological samples will continue to be analyzed through 2005.
- Data from the study will be used to:
- Identify the magnitude of reporting error in dietary
with the AMPM.
- Define socio-demographic and psychosocial characteristics
with misreporting of energy and
- Identify differences in food and nutrient intakes
of acceptable versus
- See how AMPM memory cues and portion size estimation
- Preliminary results based on the first 100 subjects have been presented
in poster presentations and reports as follows:
- Rhodes DG, Moshfegh A, Cleveland L, Murayi T, Baer
D, Sebastian R,
and Perloff B. (2004). Accuracy
of 24 hour dietary recalls: Preliminary
results from USDA AMPM Validation
Study. FASEB J 18(4): A111.
- Moshfegh AJ, Cleveland LE, Baer DJ, Sebastian RS,
and Perloff BP. (2003). Accuracy of
Americans reporting dietary intakes:
Results from cohort 1 of the USDA Doubly
Labeled Water Study.
J Am Diet Assoc 103(9):A-23.
- Bliss, R.M. (2004).
Researchers produce innovation in dietary recall.
Agric Res 52(6):10-12.