Validity of reported energy expenditure and energy and protein intakes in Swedish adolescent vegans and omnivores.
BACKGROUND
It is difficult to obtain accurate reports of dietary intake; therefore, reported dietary intakes must be validated. Researchers need low-cost methods of estimating energy expenditure to validate reports of energy intake in groups with different lifestyles and eating habits.


OBJECTIVE
We sought to validate the reported energy expenditure and energy and protein intakes of Swedish adolescent vegans and omnivores.


METHODS
We compared 16 vegans (7 females and 9 males; mean age: 17.4 +/- 0.8 y) with 16 omnivores matched for sex, age, and height. Energy expenditure as reported in a physical activity interview and energy and protein intakes as reported by diet history were validated by using the doubly labeled water method and by measuring urinary nitrogen excretion.


RESULTS
The validity of reported energy expenditure and energy and protein intakes was not significantly different between vegans and omnivores. The physical activity interview had a bias toward underestimating energy expenditure by 1.4 +/- 2.6 MJ/d (95% CI: 2.4, 0.5 MJ/d). The diet-history interview had a bias toward underestimating energy intake by 1.9 +/- 2.7 MJ/d (95% CI: 2.9, 1.0 MJ/d) but showed good agreement with the validation method for nitrogen (protein) intake (underestimate of 0.40 +/- 1.90 g N/d; 95% CI: 1.10, 0.29 g N/d).


CONCLUSIONS
The physical activity and diet-history interviews underestimated energy expenditure and energy intake, respectively. Energy intake and expenditure were underestimated to the same extent, and the degree of underestimation was not significantly different between vegans and omnivores. Valid protein intakes were obtained with the diet-history method for both vegans and omnivores.
Larsson
Christel L
CL
Department of Food and Nutrition, Umeå University, Umeå, Sweden. christel.larsson@kost.umu.se
Westerterp
Klaas R
KR
Johansson
Gunnar K
GK
D010129:4-Aminobenzoic Acid / Q000652:urine; D000293:Adolescent; D000704:Analysis of Variance; D015415:Biomarkers; D016022:Case-Control Studies; D017666:Deuterium Oxide / Q000378:metabolism; D004034:Diet Surveys; D014676:Diet, Vegetarian; D004044:Dietary Proteins / Q000008:administration & dosage*; D002149:Energy Intake; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D013548:Sweden
D015415:Biomarkers; D004044:Dietary Proteins; D017666:Deuterium Oxide; D010129:4-Aminobenzoic Acid