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

Seasonal Variation in the Intake of Food Groups and Nutrients in Japan: A Systematic Review and Meta-analysis

BACKGROUND

Seasonal variations could systematically bias dietary intakes. This systematic review aimed to determine seasonal variations in dietary intake among Japanese adults.

METHODS

PubMed and Ichushi-Web databases were searched for studies reporting seasonal intakes of nutrients or food groups assessed using dietary records or 24-hour recalls. The protocol was registered with PROSPERO (CRD42022356084).

RESULTS

Ten studies (eight studies on 1-31 nutrients and four on 2-15 food groups) met the inclusion criteria. Six studies included both sexes, whereas four investigated only females. The number of participants ranged from 25 to 459, and the number of dietary survey days in each season ranged from 1 to 14. For most nutrient and food groups, the reported seasonal variations were inconsistent across studies. The meta-analyses comparing differences in mean intakes between two seasons showed no significant differences in all comparisons or differences in only one comparison for most nutrients and food groups. Significant seasonal differences were observed for vegetables, fruits, and potatoes in five out of six comparisons, though the heterogeneity was high. Their biggest differences were as follows: 101 g/day more vegetable intake in summer than spring, 60 g/day more fruit intake in fall than spring, and 20.1 g/day more potato intake in fall than spring.

CONCLUSION

Reported seasonal variations were inconsistent across studies for most food groups and nutrients. Relatively distinct seasonal differences in mean intakes were observed for vegetables, fruits, and potatoes in meta-analyses. However, these results must be interpreted cautiously because of the high heterogeneity and limited representativeness.

The seasonal occurrence of periodontitis - a retrospective cohort study from a practice-based research network

OBJECTIVE

Many diseases are characterised by their seasonal appearance due to circannual changes in immune defence and a lifestyle that changes over the seasons. However, there is a lack of studies regarding the influence of seasonality on periodontitis. Therefore, the aim of this non-interventional, retrospective, observational study was to investigate the influence of seasonality on periodontitis.

MATERIALS AND METHODS

Periodontal parameters of 5,908 patients of a practice-based research network (PBRN) were analysed. Probing pocket depth (PPD), Bleeding on Probing (BOP) and tooth mobility were assessed for seasonal fluctuations.

RESULTS

Within the PBRN patient data, seasonality was significantly associated with PPD of the individual months in patients with periodontitis. Pairwise comparison between the months showed significantly higher PPD in July compared to several months. PPD appeared significantly lower in December compared to June and November. Regarding season, the proportion of deep PPDs ([Formula: see text]6 mm) was significantly higher in summer compared to autumn (p = 0.024). Concerning BOP, a significant difference between winter and autumn could be observed (p = 0.016). No seasonal influence was found for tooth mobility.

CONCLUSION

This practice-network based study indicated a tendency for seasonal variations in periodontal parameters among periodontal patients. However, the differences did not achieve clinical relevance.

CLINICAL RELEVANCE

Regarding the seasonality of several diseases there might also be an influence of seasons on the periodontium, which would have a potential influence on periodontal studies and daily periodontal examination.

Annual and Seasonal Patterns of Dietary Intake in Australian Adults: A Prospective Cohort Study

Poor diet is a major risk factor for non-communicable disease. The aims of this study were to describe temporal patterns and seasonal changes in diet across the year in Australian adults. A total of 375 adults from a prospective cohort study conducted between 1 December 2019 and 31 December 2021 in Adelaide, Australia, were asked to complete the Dietary Questionnaire for Epidemiological Studies at eight timepoints over a year. Average intakes over the previous month of total energy, macronutrients, healthy food groups, and discretionary foods and beverages were derived. Temporal patterns in diet were analysed descriptively. Multilevel linear regression modelling was used to assess seasonal differences in diet. Of the 375 participants recruited, 358 provided sufficient data for analysis. Intake of total energy, all macronutrients, and most discretionary foods and beverages peaked in December. Total energy intake was higher in summer than in autumn, winter, and spring. Fruit intake was higher in summer than in winter. Consumption of alcoholic beverages was higher in summer than in autumn, winter, and spring. Consumption of non-alcoholic beverages was higher in summer than in autumn and winter. This study identified temporal differences in dietary intake among Australian adults. Seasonal effects appear to be driven largely by increases in consumption of foods and beverages over the December (summer) holiday period. These findings can inform the design and timing of dietary interventions.

Secular trends and determinants of ad libitum energy intake measured in a research setting from 1999-2020

Introduction

Historically, secular and seasonal trend analyses have been examined using self-report measures of intake. Rarely are objective measures and known determinants of dietary intake used in these analyses. Our objective was to quantify the seasonal and secular differences in an objective ad libitum intake paradigm while considering the contribution of determinants, such as fat-free mass (FFM) index and spontaneous physical activity (SPA) limited to the restricted space of a whole-room calorimeter.

Methods

For this study, recruitment of N = 292 healthy, diabetes free, adults occurred from 1999 to 2020. Assessment during their 10-day stay included body composition (by DXA), SPA (by an approximately 24-h stay in whole-room calorimetry), and ad libitum intake (by a vending machine for 3 days). This secondary analysis used general linear models (GLM) to investigate secular and seasonal differences while adjusting for sex, age, FFM index, FM (fat mass) index, SPA, and race/ethnicity.

Results

FFM index and SPA were positively associated with all intake measures (p < 0.05). In all adjusted seasonal models, season did not affect intake. Adjusted secular trends models (kcals/year) demonstrated a decrease in total kcals (β = -55), intake as percent weight maintaining energy needs (β = -2), protein kcals (β = -10), fat kcals (β = -27), and carbohydrates kcals (β = -22) (all p < 0.05). After further adjustment for SPA, significance remained in all intake measures (p < 0.05). Secular trends in body composition revealed no changes in weight, BMI, and percent body fat (all p > 0.20).

Discussion

Our results indicate that over time, ad libitum intake decreased in this controlled research setting and remained significant even after accounting for positive determinants of intake. A significant ad libitum decrease, coupled with no change in body composition, may highlight a participant bias toward calorie restriction in a controlled setting over time and deserves further investigation.

Seasonal and Regional Differences in Eating Times in a Representative Sample of the Brazilian Population

Human food intake and its timing are a complex behavior that can be influenced by a variety of factors, some of which may vary from season to season or from region to region. In this study, our aim was to investigate the seasonal variation in food intake times, with a particular focus on how these may vary across different regions of a country. We conducted an analysis of data from 20,622 adults from the National Household Budget Survey (POF-IBGE), encompassing complete food diaries collected from individuals residing in Brazil, and thereby ensuring representation across different latitudes. Each participant's daily food intake was reported for two non-consecutive days at different times in the same week using food diaries. An ANOVA revealed a later food intake time in the evening in high-latitude regions compared to low-latitude regions. The Sidak post-hoc test showed a significant interaction effect between region and season, demonstrating a pattern of early First Intake Time and Eating Midpoint in the Northeast region during spring/summer. Additionally, we observed an independent effect of the region, as early food intake times were found in low-latitude regions. These findings offer a basis for discussing food intake times among individuals living in different regions located on distinct latitudes.

Factors explaining seasonal variation in energy intake: a review

Maintaining a balance between energy intake and expenditure is crucial for overall health. There are seasonal variations in energy intake, with an increase during spring and winter as well as a decrease during summer. These variations are related to a combination of environmental factors, including changes in temperature and daylight hours; social factors, including events and holidays; and physiological factors, including changes in physical activity and emotions. Accordingly, this review aimed to summarize the environmental, social, and physiological factors that contribute to seasonal variations in energy intake. A review of the current literature revealed that changes in temperature and daylight hours may affect eating behavior by altering homeostatic responses and appetite-related hormones. Additionally, increased participation in events and frequency of eating out, especially during winter vacations, may contribute to increased energy intake. Notably, these findings may not be generalisable to all populations since environmental and social factors can vary significantly depending on the local climatic zones and cultural backgrounds. The findings of the present review indicate that seasonal climate, events, and associated hormonal changes should be taken into account in order to maintain adequate energy intake throughout the year.

Risk of dietary intake of organochlorine pesticides among the childbearing-age women: A multiple follow-up study in North China

Exposure to organochlorine pesticides (OCPs) can cause adverse health effects in the female population. We investigated the dietary OCP intake of childbearing-age women living in large agricultural areas of Northern China, as well as their associated health risks. Ten childbearing-age women were recruited during 2015-2016. Their weekly dietary intake diaries and food samples were collected over the course of five visits. The OCP residues of 322 food samples from seven categories (i.e., cereal, vegetable, fruit, fish, meat, egg, and milk) were analyzed by gas chromatography-mass spectrometry. The average concentrations of the total hexachlorocyclohexanes (ΣHCH), dichlorodiphenyltrichloroethanes and their metabolites (ΣDDX), endosulfans (ΣES), and dieldrin and endrin (ΣDrin) in all food categories were, overall, much lower than the maximum residue limits. Relative high mean residues of ΣDrin and ΣES were found in fruits (ΣDrin: 0.687 ng g-1 wet weight (w.w.), ΣES: 2.24 ng g-1 w.w.) and vegetables (ΣDrin: 0.690 ng g-1 w.w., ΣES: 2.11 ng g-1 w.w.). The estimated daily dietary intake (EDI) of these compounds was calculated, with mean levels of 10.6 (ΣES) > 4.37 (ΣDrin) > 1.51 (ΣHCH) > 0.850 (ΣDDX) ng kg-1 day-1. Women during the heating period (from January to March) tended to ingest more ΣHCH, ΣDDX, ΣDrin, and ΣES. Overall, women had no obvious non-carcinogenic and carcinogenic risks due to intake of OCPs, but 83.9% of them has potential carcinogenic risk, with estimated life carcinogenic risk (LCR) exceeding 10-6. Furthermore, women had a higher potential carcinogenic risk during the heating period (mean LCR: 1.33 × 10-5) than during the non-heating period (mean LCR: 8.50 × 10-6). ΣDrin was the dominant OCP responsible for health risks, followed by ΣHCH. We concluded that women in North China still have some dietary OCP intake, especially during the heating period.

Administering a combination of online dietary assessment tools, the Automated Self-Administered 24-Hour Dietary Assessment Tool, and Diet History Questionnaire II, in a cohort of adults in Alberta's Tomorrow Project

BACKGROUND

Evidence suggests that combining tools that gather short- and long-term dietary data may be the optimal approach for the assessment of diet-disease associations in epidemiologic studies. Online technology can reduce the associated burdens for researchers and participants, but feasibility must be demonstrated in real-world settings before wide-scale implementation.

OBJECTIVE

The objective of this study was to determine the feasibility and acceptability of combining web-based tools (the Automated Self-Administered 24-hour Dietary Assessment Tool [ASA24-2016] and the past-year Diet History Questionnaire II [DHQ-II]) in a subset of participants in Alberta's Tomorrow Project, a prospective cohort.

DESIGN

For this feasibility study, invitations were mailed to 550 randomly selected individuals enrolled in Alberta's Tomorrow Project. Consented participants (n = 331) were asked to complete a brief sociodemographic and health questionnaire, four ASA24-2016 recalls, the DHQ-II, and an evaluation survey.

PARTICIPANTS/SETTING

The study was conducted from March 2016 to December 2016 in Alberta, Canada. The majority of participants, mean age (SD) = 57.4 (9.8) years, were women (70.7%), urban residents (85.5%), and nonsmokers (95.7%).

MAIN OUTCOME MEASURES

Primary outcomes were number of ASA24-2016 recalls completed, response rate of DHQ-II completion, and time to complete each assessment.

STATISTICAL ANALYSES

The Wilcoxon signed rank sum test was used to assess differences in completion time.

RESULTS

One-third (n = 102) of consenting participants did not complete any ASA24-2016 recalls. The primary reason to withdraw from the feasibility study was a lack of time. Among consenting participants, 51.9% (n = 172), 41.1% (n = 136), and 36.5% (n = 121) completed at least two ASA24-2016 recalls, the DHQ-II, and at least two ASA24-2016 recalls plus the DHQ-II, respectively. Median (25th to 75th percentile) completion times for participants who completed all recalls were 39 minutes (25 to 53 minutes) for the first ASA24-2016 recall and 60 minutes (40 to 90 minutes) for the DHQ-II.

CONCLUSIONS

Findings indicate combining multiple ASA24-2016 recalls and the DHQ-II is feasible in this subset of Alberta's Tomorrow Project participants. However, optimal response rates may be contingent on providing participant support. Completion may also be sensitive to timing and frequency of recall administration.

Effects of Health Risk Assessment and Counselling on Fruit and Vegetable Intake in Older People: A Pragmatic Randomised Controlled Trial

OBJECTIVES

Interventions to increase fruit and vegetable intake among community-dwelling older people have shown mixed effects. We investigated whether an intervention based on an initial multidimensional health risk assessment and subsequent physician-lead nutrition counselling has favourable effects on dietary intake among community-dwelling older people.

DESIGN

Randomised controlled trial comparing the intervention versus usual care.

SETTING AND PARTICIPANTS

Non-disabled persons aged 65 years or older at an ambulatory geriatric clinic in Bucharest, Romania, allocated to intervention (n=100) and control (n=100) groups.

INTERVENTION

Participants received a computer-generated health profile report based on answers to a health risk assessment questionnaire, followed by monthly individual counselling sessions with a geriatrician on topics related to health promotion and disease prevention, with a special focus on adequate fruit and vegetable consumption.

MEASUREMENTS

Fruit and vegetable intake at baseline and at 6-month follow-up.

RESULTS

At baseline, fruit and vegetable intake was below the recommended five portions per day in most study participants (85% in the intervention group, and 86% among controls, respectively). At six months, intake increased in the intervention group from a median of 3.8 to 4.6 portions per day, and decreased in the control group due to a seasonal effect from a median of 3.8 to 3.1 portions per day. At six months, fruit and vegetable consumption was significantly higher among persons in the intervention group as compared to controls (median difference 1.4 portions per day, 95% confidence interval 1.1-1.7, p<0.001).

CONCLUSION

Personalised food-based dietary guidance, delivered as part of multidimensional preventive health counselling during geriatric clinic visits, results in relevant improvement of fruit and vegetable intake in community-dwelling older adults.

Best Practices for Conducting and Interpreting Studies to Validate Self-Report Dietary Assessment Methods

Careful consideration of the validity and reliability of methods intended to assess dietary intake is central to the robustness of nutrition research. A dietary assessment method with high validity is capable of providing useful measurement for a given purpose and context. More specifically, a method with high validity is well grounded in theory; its performance is consistent with that theory; and it is precise, dependable, and accurate within specified performance standards. Assessing the extent to which dietary assessment methods possess these characteristics can be difficult due to the complexity of dietary intake, as well as difficulties capturing true intake. We identified challenges and best practices related to the validation of self-report dietary assessment methods. The term validation is used to encompass various dimensions that must be assessed and considered to determine whether a given method is suitable for a specific purpose. Evidence on the varied concepts of validity and reliability should be interpreted in combination to inform judgments about the suitability of a method for a specified purpose. Self-report methods are the focus because they are used in most studies seeking to measure dietary intake. Biomarkers are important reference measures to validate self-report methods and are also discussed. A checklist is proposed to contribute to strengthening the literature on the validation of dietary assessment methods and ultimately, the nutrition literature more broadly.

Variety, Price, and Consumer Desirability of Fresh Fruits and Vegetables in 7 Cities around the World

Few studies have attempted to quantify the variety, price, and consumer desirability of fruits and vegetables (F&Vs) across a diversity of cities. We implemented a market basket survey of F&Vs from December 2018 to February 2019 in middle-income neighborhoods of the following cities: Visakhapatnam, India; Kathmandu, Nepal; Addis Ababa, Ethiopia; Dar es Salaam, Tanzania; Mexico City, Mexico; Bangkok, Thailand; and Brookline, United States. The total variety of fruits ranged from 4.1 in Visakhapatnam to 17.3 in Brookline, and of vegetables from 6.1 in Dar es Salaam to 20.3 in Brookline. Of the 3 fruits for which price data were collected, apples tended to be the most expensive, and bananas the least expensive. For vegetables, capsicum tended to be the most expensive and eggplants the least expensive. Tablet-based market basket surveys are a useful tool for evaluating food environments. These pilot data provide further evidence of the homogenization of global diets.

Does Season of Reported Dietary Intake Influence Diet Quality? Analysis From the Women's Health Initiative

We evaluated the role of seasonality in self-reported diet quality among postmenopausal women participating in the Women's Health Initiative (WHI). A total of 156,911 women completed a food frequency questionnaire (FFQ) at enrollment (1993-1998). FFQ responses reflected intake over the prior 3-month period, and seasons were defined as spring (March-May), summer (June-August), fall (September-November), and winter (December-February). FFQ data were used to calculate the Alternate Healthy Eating Index (AHEI), a measure of diet quality that has a score range of 2.5-87.5, with higher scores representing better diet quality. In multivariable linear regression models using winter as the reference season, AHEI scores were higher in spring, summer, and fall (all P values < 0.05); although significant, the variance was minimal (mean AHEI score: winter, 41.7 (standard deviation, 11.3); summer, 42.2 (standard deviation, 11.3)). Applying these findings to hypothesis-driven association analysis of diet quality and its relationship with chronic disease risk (cardiovascular disease) showed that controlling for season had no effect on the estimated hazard ratios. Although significant differences in diet quality across seasons can be detected in this population of US postmenopausal women, these differences are not substantial enough to warrant consideration in association studies of diet quality.

The Dietary Intake and Its Features across Four Seasons in the Metropolis of China

Chinese diet pattern known as plant-based is more linked with seasonal supply, but it is lack of study on seasonal difference in dietary intakes in China. Our study was to assess seasonal variation in the absolute dietary intake among general population in a metropolis, Shanghai, China. A representative sample of general population aged 15 and older (n=1,704) were randomly stratified-sampled from communities in Shanghai. Dietary survey included consecutive 3-day-24-hour diet record recall and household condiments weighing. Data was collected across four seasons during 2012-2014. Most of food and condiments consumption differed across seasons in Shanghai. Intakes of grains, legumes and cooking oil were highest in spring; vegetables, fruit and non-alcoholic beverage highest, but cooking oil and cooking salt lowest in summer; red meat, nuts and cooking salt highest in winter. Seasonality existed in the intakes of energy and energy contributed from macronutrients that fat contributed more in winter but less in summer. Seasonal variations were also found in beta-carotene, vitamin E, vitamin K, thiamin, folate and sodium intakes. Seasonal changes of dietary intake were extensively observed in Shanghai, a highly-developed metropolis in China. Given the seasonal differences and their features described in current article, the estimation methods of the average dietary intake across whole year by just conducting dietary survey in one single season warrants further study.

Exploring the Perceived Barriers to Following a Mediterranean Style Diet in Childbearing Age: A Qualitative Study

A considerable amount of research has focused on interventions in pregnancy to promote health in current and future generations. This has yielded inconsistent results and focus has turned towards improving health in the preconception period. Promotion of healthy dietary patterns similar to a Mediterranean diet in the preconception years has been suggested as a dietary strategy to prevent maternal obesity and optimize offspring health. However, it is uncertain whether adoption is acceptable in women of childbearing age. This qualitative study aims to investigate the perceived barriers to following a Mediterranean diet in women of childbearing age. Semi-structured focus groups were used to generate deep insights to be used to guide the development of a future intervention. Nulliparous women aged between 20 and 47 years were recruited (n = 20). Six focus groups were digitally audio recorded and transcribed verbatim by the researcher. Thematic analysis was used to analyze data, which occurred in parallel with data collection to ascertain when data saturation was reached. Five core themes were identified: Mediterranean diet features, perceived benefits, existing dietary behavior and knowledge, practical factors, and information source. The present study highlights that a Mediterranean diet is acceptable to childbearing-aged women, and the insights generated will be helpful in developing an intervention to promote Mediterranean diet adoption.

A time for everything and everything in its time - exploring the mechanisms underlying seasonality of COPD exacerbations

Across Europe, COPD affects 23 million people leading to annual health care costs of ~€25.1 billion. This burden is particularly severe during winter months in association with the peak incidence of exacerbation events. Seasonal variation in the health status of patients with COPD places additional and often critical pressure on already strained health care resources. COPD exacerbations are characterized by worsening day-to-day symptoms of an individual and often triggered by respiratory infections, but the process by which this occurs in a seasonal fashion is likely to be multifactorial. In this review, we discuss recent population studies that highlight the impact of seasonality in COPD and review the proposed biological mechanisms underlying this. An appraisal of the role of the host susceptibility and response, environmental triggers and the biology of respiratory pathogens is detailed. The impact of each aspect is considered, and an integrated model of the context for the whole individual and society in general is explored.

The Seasonal Periodicity of Healthy Contemplations About Exercise and Weight Loss: Ecological Correlational Study

Background

Lack of physical activity and weight gain are two of the biggest drivers of health care costs in the United States. Healthy contemplations are required before any changes in behavior, and a recent study has shown that they have underlying periodicities.

Objective

The aim of this study was to examine seasonal variations in state-by-state interest in both weight loss and increasing physical activity, and how these variations were associated with geographic latitude using Google Trends search data for the United States.

Methods

Internet search query data were obtained from Google Trends (2004-2016). Time series analysis (every 2 weeks) was performed to determine search volume (normalized to overall search intensity). Seasonality was determined both by the difference in search volumes between winter (December, January, and February) and summer (June, July, and August) months and by the amplitude of cosinor analysis.

Results

Exercise-related searches were highest during the winter months, whereas weight loss contemplations showed a biphasic pattern (peaking in the summer and winter months). The magnitude of the seasonal difference increased with increasing latitude for both exercise (R²=.45, F_1,49=40.09, beta=−.671, standard deviation [SD]=0.106, P<.001) and weight loss (R²=.24, F_1,49=15.79, beta=−.494, SD=0.124, P<.001) searches.

Conclusions

Healthy contemplations follow specific seasonal patterns, with the highest contemplations surrounding exercise during the winter months, and weight loss contemplations peaking during both winter and summer seasons. Knowledge of seasonal variations in passive contemplations may potentially allow for more efficient use of public health campaign resources.

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

Background: Few studies have applied the Chinese Diet Balance Index (DBI) in evaluating dietary quality across seasons. Method: The Shanghai Diet and Health Survey (SDHS) included 1680 participants from all districts of Shanghai from 2012 to 2013. Dietary data were obtained using three-day 24-h recall in spring, summer, fall, and winter. Higher bound score (HBS), lower bound score (LBS) and diet quality distance (DQD) were calculated according to compliance with the dietary guidelines and based on the recommendations for consumption within the main food groups. HBS, LBS, and DQD represent over-intake, under-intake, and overall imbalance of the diet, respectively. Results: 836 males and 844 females were included. The HBS indicated that 10.08%, 11.84%, 10.31%, and 12.73% people have moderate or high levels of over-intake of food in spring, summer, fall, and winter, respectively; and 74.04%, 37.61%, 53.09%, and 42.72% people have moderate or high levels of deficit food intake for each of the four seasons. The mean HBS and LBS among the four seasons were statistically significant difference (p < 0.001). The mean (SD) DQD was 43.27 (10.21), 35.67 (9.71), 39.19 (9.36), and 36.84 (9.45) in each season. A multivariable model showed statistically significant differences in DQD according to age, gender, occupational status, education, smoking, drinking status, season, and residency (p < 0.001). Conclusion: An unbalanced diet is common among people living in Shanghai. Seasonality and area of residence were found to be two significant predictors. Strengthening the accessibility and the supply of food across seasons and regions should be considered.

Measures of Diet Quality across Calendar and Winter Holiday Seasons among Midlife Women: A 1-Year Longitudinal Study Using the Automated Self-Administered 24-Hour Recall

BACKGROUND

Systematic seasonal bias may confound efforts to estimate usual dietary intake and diet quality. Little is known about dietary quality over the winter holiday season.

OBJECTIVES

The aims of this study were to test for differences in intakes of energy, percentage of energy from macronutrients, fruits and vegetables, and diet quality measured using the Healthy Eating Index 2010 (HEI-2010) by calendar and winter holiday seasons.

DESIGN

Longitudinal cohort design.

PARTICIPANTS/SETTING

Data were derived from the Life in All Seasons study. Two cohorts of women aged 40 to 60 years (N=52) from the greater Grand Forks, ND, area were followed for 1 year each between July 2012 and July 2014. Each woman completed an online diet recall using the Automated Self-Administered 24-Hour Recall every 10 days during the year, with a 92% response rate.

STATISTICAL ANALYSES

Effects of calendar and winter holiday seasons on intakes of energy, percent energy from macronutrients, HEI-2010 total and component scores, and grams per day of individual fruits and vegetables were tested using mixed linear models.

RESULTS

The mean total HEI-2010 score was 60.1±1.4. There were seasonal differences in some HEI-2010 component scores, but not in total scores. More lettuce or mixed lettuce salad was consumed during summer than during winter (P=0.034), and more fresh tomatoes were consumed during summer and fall compared with winter (P=0.001). More corn, berries, peaches and nectarines, and melons (P<0.001) were consumed during summer. There was no seasonal difference in reported intakes of energy (P=0.793). The total HEI-2010 score for dietary intake observed over the winter holiday season was lower than the rest of the year (P<0.001). Reported energy intake was not different (P=0.228).

CONCLUSIONS

In this population, diet quality is significantly lower during the winter holiday period, but mostly consistent by season. Multiple recalls in any season can give a reasonable representation of usual overall diet quality throughout the year.