Association between mealtimes of first and last meals and food consumption in pregnant women

Eating an early first meal and a tendency towards morningness have been associated with healthy eating habits. The objective of the study was to investigate the association between mealtimes of first and last meals and food consumption of pregnant women. Methods: A cross-sectional study with 111 pregnant women who use a public health service. Sociodemographic, nutritional and health data were collected from medical records. Food consumption was assessed by habitual dietary intake. Nutritional value was determined with the DietPro® program (version 6.1) and diet quality was assessed through Diet Quality Index Adapted for Brazilian Pregnant Women (IQDAG).. The study was approved by the Research Ethics Committee of Universidade Federal de Viçosa (No. 4.098.560). Results: The mean age was 34.3 (±5.5) years. Pregnant women who had a late first meal and an early last meal ( PR :2.55; 95% CI 1.41-4.63) presented a higher prevalence of vitamin B12 deficiency. On the other hand, pregnant women who had a late first meal and an early last meal ( PR :4.74; 95%CI 1.50-15.04), and those who had late first and last meals ( PR :4.31; 95%CI 1.37; 13.58), presented a higher prevalence of having an inadequate number of meals. Conclusion: Pregnant women who eat late have a higher prevalence of vitamin B12 deficiency and eating ≤3 meals during the day compared to those who eat early. The result reinforces the need for approaches to prenatal care based on mealtimes and nutrition aimed at improving the dietary profile of this population.


Introduction
The food consumption of pregnant women can be affected by cultural factors, beliefs, taboos and physiological changes (Africa & Chakona, 2019). Recently, mealtime has been shown to interfere with food consumption and gestational parameters. Eating an early first meal and a trend of morningness have been associated with healthier eating habits (Sato-mito et al., 2011;Gontijo et al., 2019).
A balanced breakfast can be important for the improvement of general diet quality (Murakami et al., 2018), (Hill et al., 2019). A study showed that skipping breakfast during pregnancy is associated with low blood levels of eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), β-carotene and low urine levels of urea nitrogen and potassium (Shiraishi et al., 2019). A cohort study of pregnant women found that those who had their first meal early consumed a higher percentage of energy and carbohydrates during breakfast, whereas this level was lower level during dinner, in addition, they had a better diet quality in terms of consumption of whole fruit and full components of fruit (Gontijo et al., 2020).
Food consumption during inappropriate circadian timing can result in adverse health effects while eating too late can result in weight gain (Loy et al., 2020;McHill et al., 2017). Also, a lower number of meals has been related to premature rupture of membranes and increased risk of preterm birth (Englund-Ögge et al., 2017), (Hernández-Díaz et al., 2014;Siega-Riz et al., 2001). Thus, the assessment of food consumption throughout pregnancy allows us to determine whether it is a protective or risk factor for adequate pregnancy development, as well as identify factors that interfere with its quality (Lisboa et al., 2017).
In this context, the present study aims to investigate the association between food consumption and mealtimes of first and last meals of pregnant women monitored through the nutritional care of mother and infant project (PROAMI), Viçosa, Minas Gerais.

Design and sampling
This study is an analytical cross-sectional study whose sample comprised pregnant women monitored through the nutritional care of mother and infant project (PROAMI), Viçosa, Minas Gerais. The data consist of consultations carried out between December 2015 and March 2020. Data was extracted from medical records by a nutritionist and a trained nutrition student. The exclusion criteria are the following: no information about pregnant women's diet as regards quantity, preparation method and measures, and energy intake below 500 kcal/day or above 3500 kcal/day (Loy et al., 2017). From a total of 116 medical records, 4 pregnant women were excluded for not having information on amounts of food or measures and 1 for having a daily energy intake above 3500 kcal. Thus, the final sample was 111 pregnant women. The study was approved by the Ethics Committee for Research with Human Beings of Universidade Federal de Viçosa (No. 4.098.560).

Sociodemographic and health variables
Sociodemographic and health data were obtained through a structured questionnaire containing the following variables: age, gestational age, number of children, parity, marital status, level of education, occupation and health profile (low weight gain, excessive weight gain, gestational diabetes, arterial hypertension, pre-eclampsia, nausea, vomiting and information regarding supplement use, the practice of exercise, alcohol consumption and smoking).

Anthropometric variables
Pre-pregnancy weight was self-reported. The pregnant women in the first trimester who did not remember their prepregnancy weight were assessed with their current weight. The current weight was measured on a digital platform weighing scale (Marte), with an accuracy of 0.2g to 100g. Height was measured using a stadiometer (Stanley) with an accuracy of 0.1 cm. Pre-gestational BMI was classified according to WHO cutoff points  Editora do Ministério da Saúde, 2013).Gestational nutritional status was calculated according to gestational age based on the date of last menstruation (LMP) to be exact and/or date of delivery predicted by ultrasound examination. The classification of underweight, normal weight, overweight and obese was done according to the cutoff points proposed by Atalah, which assesses body mass index per gestational week (World Health Organization, 1995;Atalah et al., 1997).

Dietary intake
Food consumption was assessed using habitual dietary intake collected at first nutrition consultation, regardless of gestational age. To calculate the nutritional value of food consumed, the DietPro® program (version 6.1) was used. The  , 2005),. To control the effect of energy consumption on the evaluated nutrients, the residual method was used (Willett & Stampfer, 2009). The inadequacy of macronutrients was assessed using the Acceptable Macronutrient Distribution Range (AMDR). The micronutrients were evaluated by Estimated Average Requirement (EAR) or Adequate Intake (AI) when EAR values were not available. To assess the consumption of fruits, the servings recommended by the food pyramid for well-nourished pregnant women aged between 19 and 30 years were used (Demétrio, 2010). The number of meals was considered inadequate for ≤ 3 meals a day (De Almeida et al., 2004;Pinho-Pompeu et al., 2020).

Diet quality
Diet quality was assessed using the Diet Quality Index Adapted for Brazilian Pregnant Women (IQDAG), which was developed based on the recommendations of the Ministry of Health (2012). The IQDAG has 9 components: vegetables, legumes, fresh fruits (servings/1,000 kcal), fiber, omega 3, calcium, folate, iron and the percentage of total calories from ultraprocessed foods (Crivellenti et al., 2018). The final score index was obtained by the sum of all components and has a maximum value of 100 points. The IQDAG score was categorized into tertiles, adopting the first tertile as reference (Crivellenti et al., 2018).

Statistical analyses
Statistical analyses were performed using STATA for Windows, version 13.0. Descriptive analysis was conducted using the mean, standard deviation, median and interquartile range, n (%). The normality of the variables was tested by the Shapiro Wilk test. ANOVA and Kruskal-Wallis tests were used for continuous variables with and without normal distribution, respectively, followed by Dunn's post-hoc test for the comparison of food consumption among the four mealtime groups.
Besides the chi-square test, the Fisher's exact test and chi-square test for trends were applied to the categorical variable. To investigate the association between the mealtimes of first and last meals (explanatory variable) and food consumption (outcome variable), Poisson regression was conducted. For the bivariate analysis, the model utilized the variables with p<0.20 obtained by the Backward strategy. The final model was adjusted for age, education, pre-pregnancy BMI, and physical activity and nausea in the past 30 days. The statistical significance adopted in all analyses was 0.05.
The consumption of fresh fruit was higher for the group of pregnant women who had their first and last meals early compared to the early-late and late-early groups. The rest of the components and the total score of the IQDAG did not differ among the four groups (Table 3).

Discussion
In this study, it was observed that having a late first meal and early last meal was positively associated with vitamin B12 deficiency. Likewise, having a late first meal and an early last meal, and eating the first and last meals late were positively associated with eating 3 or fewer meals a day.
In the present study, it was also observed that the frequency of illnesses was higher in the early-late and late-early groups, probably because these groups have a higher concern about food and health, as they must take medications, which mostly starts early.
Vitamin B12 is essential for hematological and neurological functions (Bae et al., 2015). Maternal deficiency in vitamin B12 has been associated with an increased risk of adverse pregnancy outcomes such as neural tube defects, premature birth and intrauterine growth retardation (Molloy et al., 2008), as well as an increased risk of diabetes mellitus compared to those with vitamin B12 sufficiency (Kouroglou et al., 2019). This shows the importance of adequate vitamin B12 intake and nutritional status during pregnancy for good fetal growth and development.
In this study, food intake less than or equal to 3 meals was observed for pregnant women who had late first meal and early last meal, as well as for those who ate their first and last meals late. Other studies found that pregnant women who ate less than three main meals during the day had a higher risk of premature rupture of membranes followed by preterm delivery (Englund-Ögge et al., 2017;Paoli et al., 2019). Evidence shows that having several meals in small portions a day is associated with lower BMI, possibly due to the consumption of a lower density diet and an improvement in nutritional quality.
Furthermore, eating fewer meals may be associated with eating out and at late hours, which can be characterized by energyrich foods with low nutrient density such as fried foods, alcohol consumption and lower amounts of foods with high nutrient density such as fruits and vegetables (Misan et al., 2019;Aljuraiban et al., 2014). Therefore, positive results have been observed when foods eaten late are small in amount, rich in nutrients and low in energy and/or macronutrients (Kinsey & Ormsbee, 2015). In addition, changes in meal frequency and timing have the potential to influence energy and macronutrient intake (Englund-Ögge et al., 2017;Paoli et al., 2019).
Eating an early first meal has been associated with eating more calmly, and probably eating more adequately in terms of quantity and quality of essential nutrients, thus favoring pregnancy (Gibney et al., 2018)., as breakfast contributes around 20% of total energy intake and increases the intake of various nutrients (Gaal et al., 2018;Shiraishi et al., 2019).
A study suggests that carbohydrate intake at late hours may be associated with metabolic risk during pregnancy, especially among women who were obese before pregnancy (Henriksen, 2008;Chandler-Laney et al., 2016). Therefore, it has often been pointed out that pressure associated with time, long working hours and lifestyle habits can be the main factors that contribute to unhealthy eating, including having a late last meal (Englund-Ögge et al., 2017).
A study recommends that prenatal nutritional assessment should consider and explain the fact that the mealtime of the first meal may be related to a more adequate diet, patterns with greater food intake in the morning and less intake in the evening, thus improving diet quality (Gontijo et al., 2019). In this sense, prenatal nutritional monitoring becomes essential, as the assessment of food consumption during pregnancy allows the early detection of nutritional problems that can be corrected, avoiding losses during pregnancy (Lisboa et al., 2017).
The strength of the study lies in the coverage of a recent and less explored topic, which can help in the development of prenatal nutritional monitoring strategies. There is a lack of evidence on the relationship between food consumption and mealtimes, therefore, this work seeks to help fill this knowledge gap. The study had as limitations the use of secondary data, which only allowed the attainment of existing information in medical records. The pre-pregnancy weight was self-reported, which may be subject to underestimation. In addition, the sample size can be a limiting factor to identify differences among the groups. Another limitation is the cross-sectional design that does not allow the establishment of a causal relationship between exposure and outcome.

Conclusion
The results show that pregnant women who eat late have a higher prevalence of inadequacy in vitamin B12 and having 3 meals or less during the day compared to those that have early meals. Thus, it reinforces the need to explore mealtimes and nutrition during prenatal care, aimed at improving the profile of food intake and consequently, the health of this population. More articles that relate meal times and diet quality and pregnancy outcomes are important to clarify these relationships, in addition to helping to propose effective strategies for pregnancy success.