Dietary Intake Patterns Are Consistent Across Seasons in a Cohort of Healthy Adults in a Metropolitan Population.

Background: Current literature provides conflicting data regarding seasonal variability in dietary intake.

Objective: Our aim was to examine seasonal variation in dietary intake in healthy adults from the metropolitan Washington, DC, area.

Design: This study utilized an observational cohort design.

Participants/setting: Male and female healthy volunteers (n=103) between the ages of 18 and 75 years were recruited from the metropolitan Washington, DC, area to participate in a clinical study at the National Institutes of Health Clinical Center from February 2011 to June 2014.

Main Outcome Measures: Three- to seven-day food records were collected from subjects (n=76) at three time points (12 to 15 weeks apart). Subjects were excluded from analysis (n=27) if they completed less than three time points. Food records were reviewed by nutrition staff, assigned to a season, and coded in Nutrient Data System for Research for energy, macronutrient, micronutrient, and food-group serving analysis.

Statistical Analyses: Multivariate general linear models were run on energy, macronutrient, micronutrient, and food-group intakes, while being adjusted for age, sex, race, and body mass index (calculated as kg/m(2)).

Results: Subjects had a mean±standard deviation body mass index of 25±3.9 and age of 34±12.4 years. Subject demographics were 71.1% white, 9.2% black/African American, 13.2% Asian, and 6.6% unknown race, with 44.7% males and 55.3% females. Mean intake of energy across seasons was 2,214.6±623.4 kcal with 17.3%±4.1%, 33.6%±5.5%, 46.6%±8.0%, and 2.7%±3.2% of calories from protein, fat, carbohydrate, and alcohol, respectively. Intakes of energy, macronutrients, micronutrients, and food groups did not differ between seasons.

Conclusions: People living in the metropolitan Washington, DC, area did not exhibit seasonal variation in dietary intake. Therefore, when designing studies of nutrient intake in a metropolitan population, these findings suggest that investigators do not need to consider the season during which diet is examined.