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

Abstract

Background Current literature provides conflicting data regarding seasonal variability in dietary intake. Objective 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 18–75 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 (12–15 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 BMI. Results Subjects had an average BMI of 25 ± 3.9 kg/m2 (mean ± SD) and average 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 2214.6 ± 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.

Seasonality of nutrient intake – An analysis including over 44,000 participants in 4 countries

“…Seasonality of total energy and macronutrient intake varied between countries and even between sexes. These results are in agreement with the literature, where discordant findings regarding seasonality of total energy intake and fat have been reported [1,2,4,8,9,23,24]. A study conducted in China showed no seasonality for the main nutrients and only for a selected number of micronutrients such as retinol, ascorbic acid, potassium and calcium [24].…”

“…However, the findings will probably not apply to more developing countries, where dietary intake depends on available crops. Our results thus support the conclusion of a previous US study [8] and suggest that adjusting for season might no longer be necessary when assessing dietary intake in specific settings.…”

“…Further, modern housing facilities in developed countries decrease the need of nutritional adaptation to high or low temperatures, making dietary intake relatively constant throughout the year. Thus, the previous paradigm of seasonality in dietary intake has been challenged [8], but whether seasonality is still important in nutritional epidemiology remains an open debate. For instance, a survey reported a seasonality in food pattern but not in dietary intake [9] and it has been suggested that the effect of seasonality does not impact the interpretation of most epidemiologic studies [10].…”

Does the Dietary Pattern of Shanghai Residents Change across Seasons and Area of Residence: Assessing Dietary Quality Using the Chinese Diet Balance Index (DBI)

“…Most fruits ripen in summer and the actual availability and accessibility of fruit in summer might be much higher than that of other seasons. Other studies have also found increases in vegetable and fruit consumption in summer compared to winter [16,17,33,34,35]. …”

Gluttony and guilt: monthly trends in internet search query data are comparable with national-level energy intake and dieting behavior

“…For example, Bernstein et al (2016) found that intake of energy, macronutrients, and food groups by healthy adults in metropolitan Washington D.C. did not vary between seasons. Yet, seasonal differences in protein (Mori et al, 1981), lipid (Mori et al, 1981;Owaki et al, 1996), and dietary fiber (Owaki et al, 1996;Tokudome et al, 2002) intake were observed in Japanese studies.…”