Keywords
menstrual cycle - food intake - nutrition assessment - feeding behavior - luteal phase
- follicular phase
Palavras-chave
ciclo menstrual - consumo alimentar - avaliação nutricional - comportamento alimentar
- fase lútea - fase folicular
Introduction
Thousands of women of childbearing age experience some degree of premenstrual syndrome
(PMS), which includes emotional, physical, cognitive and behavioral symptoms related
to the menstrual cycle, such as irritability, depressive mood, changes in appetite,
pain, and anxiety. These symptoms are recurrent during the luteal phase (LP) and usually
remit within a few days after the onset of menstruation.[1] Nutrition, stress, and emotion are environmental factors that can interfere with
the menstrual cycle.[2]
According to the hormonal fluctuations, the menstrual cycle is divided into phases.
In a simplified division, there are two phases, the follicular phase (FP) and the
LP. The FP begins in the 1st day of menstrual bleeding (1st day of the cycle) and ends with the ovulation. The FP is characterized by increased
secretion of estrogen, of follicle-stimulating hormone (FSH), and of luteinizing hormone
(LH) just before ovulation. The LP follows the ovulation and is characterized by rising
progesterone and estrogen levels. It is the only time during the cycle in which progesterone
is unopposed by estrogen.[3] The normal alteration in estrogen and progesterone hormone levels in the menstrual
cycle appear to act on the serotonergic function, leading to manifestations of the
symptoms of the syndrome.[1]
According to Reid (2017),[4] during the reproductive years, up to between 80 and 90% of the women who menstruate
feel some change during the premenstrual period, such as breast pain, bloating, acne
and constipation. The incidence of severe symptoms ranges between 3 and 5% of the
women of childbearing age, who are severely incapable of carrying out their lives
during this phase of the cycle. Severe symptoms are also responsible for causing changes
in their family, social and professional life for approximately two weeks at the beginning
of each month. Epidemiological surveys have shown that between 75 and 80% of the women
have symptoms in the premenstrual period.[5] Among the main symptoms described in the period of PMS, there are changes in mood,
depression, low self-esteem, irritation, anxiety, nervousness, aggression, sensitivity
to emotions, impulsive behavior, body aches, fatigue, insomnia, changes in appetite,
and binge eating of sweet or salty foods as the main symptoms described during the
PMS period.[1]
Many women change their eating habits during the phases of the menstrual cycle, especially
in relation to the consumption of chocolates, sweets in general, and salty foods.[6] The increased intake of carbohydrates in the LP can be justified by the reduction
of serotonin mediators in this period. The increased production of serotonin relieves
symptoms, so craving for sweet foods like chocolate would be an unconscious way of
improving such symptoms, since by increasing serotonin levels, a balance would be
achieved as a form of relief,[7] so eating usually reduces irritability or promotes positive affect.[8]
Estrogens and progestogens have been linked to disordered eating during the LP. Klump
et al (2013)[9] discovered that in a community sample, there were day-to-day associations between
ratings of emotional eating and estradiol and progesterone levels.
Although data from the literature[6]
[10] demonstrate the existence of changes in the eating behavior of women during the
menstrual cycle, there are few studies that address these changes in Brazilian women.
Therefore, the present study aims to evaluate the alteration of dietary intake, food
cravings, and nutritional status in the stages of the menstrual cycle of nutrition
students from a public university in Campo Grande, state of Mato Grosso do Sul, Brazil.
Methods
This cross-sectional study was conducted between March and June of 2017 in a public
university, with students enrolled in the nutrition undergraduate course.
The participants were regularly menstruating (25–35 days, as self-reported) premenopausal
women recruited from the undergraduate course in nutrition. All the female students
regularly enrolled were invited to participate through electronic mail and visits
to classrooms. Other inclusion criteria were being in childbearing age and > 18 years
old. Students were excluded if they were pregnant or lactating, taking oral contraceptives,
hormone supplements, or any weight- or hydration status-modifying drugs (cortisone,
antidepressants and others), or if they were on any calorie-restricted diet.
When an interested student accepted to attend the project and followed the criteria
for inclusion and exclusion, the investigator scheduled an initial assessment. During
that assessment, the women received instructions regarding the study procedures, signed
a written consent form and completed questionnaires about demographic information
such as age, marital status, and in which period they were enrolled in the course.
Information regarding food intake, food cravings, and the anthropometric evaluation
were scheduled according to the onset of menstruation of each participant: one in
the FP (from the 5th to the 9th day of the menstrual cycle) and another in the LP (from the 20th to the 25th day of the menstrual cycle). They were classified in phases according to the onset
of menstruation.
To measure the dietary intake, participants completed two 24-hour recalls (R24H):
one in the LP and another in the FP. DietPro Clinico software version 5.8 (DietPro,
Viçosa, MG, Brazil) was used to analyze the dietary intake and to obtain the caloric
value of the diet, as well as the percentages of energy derived from carbohydrates,
proteins and lipids. Food was classified according to the food group, considering
the Food Guide for the Brazilian Population.[11]
Food cravings were also assessed in both phases by the Food Desire Questionnaire.[12] The questionnaire was minimally adapted with local foods and comprised a list of
38 foods and beverages, as in the original version. The participants were asked to
rate how much they would like to eat each of the items in the questionnaire, on a
5-point scale, ranging from 0 (no desire) to 4 (very high desire).
For the anthropometric evaluation, body weight (kg), height (m) and waist circumference
(WC) (cm) were measured in both phases of the cycle. All of the measurements were
performed according to the standards of the Food and Nutrition Surveillance System
(SISVAN, in the Portuguese acronym).[13] The data collection procedures were performed at the nutrition evaluation laboratory
of the faculty of pharmaceutical sciences, food and nutrition of the Universidade
Federal do Mato Grosso do Sul.
The results were presented through descriptive statistics, as arithmetic mean and
standard deviation (SD). For food consumption variables, as the data presented a normal
curve (Kolmogorov-Smirnov), a parametric statistic was done, using the analysis of
variance (ANOVA) test, followed by the Tukey test. For the food cravings analysis,
non-parametric analyses were performed (non-normal curve), using the Mann-Whitney
test. In all tests, a significance level of 5% or corresponding p-value and 95% confidence interval (CI) were used. Stata Statistical Software release
14 (StataCorp, College Station, TX, USA) was used to perform the statistical analyses.
The study started after receiving the approval of the study protocol by the Research
Ethics Committee of the Universidade Federal do Mato Grosso do Sul, under the protocol
no. 1.936.178/2017. All of the volunteers freely consented to participate by signing
an informed consent form after the clarification of the purpose of the study and authorized
the use of the data under the guarantee of anonymity and confidentiality, following
the Resolution 466 of 12/12/2012.
Results
Considering the 116 female students enrolled in the nutrition undergraduate course
who were invited by e-mail to participate, only 27 were eligible and concluded the
full protocol of evaluation. Subjects withdrew from the study due to non-compliance
with the study protocol, personal reasons, and time conflict. The mean age of the
participants was 21.85 years old (standard deviation [SD] = 0.54). The majority of
the students reported being single (81.48%).
Among the participants, 33.33% (n = 9) were in the first year of the course, 29.63% (n = 8) were in the third year, 25.93% (n = 7) were in the fourth year, and 11% (n = 3) were in the fifth year. There were no participants in the second year of the
course. The minimum duration of the course is 5 years.
Anthropometric Data
The anthropometric data of the 27 participants are presented in [Table 1]. The mean height of the participants was 1.61 m (SD = 0.13).
Table 1
Anthropometric data of nutrition undergraduate students (n = 27) during the luteal and follicular phases of the menstrual cycle
|
Variable
|
Mean (SD) LP
|
Mean (SD) FP
|
p-value
|
|
Weight (kg)
|
60.91(2,68)
|
60.67 (2,61)
|
0.4781
|
|
BMI (kg/m2)
|
23.47 (0,89)
|
23.38 (0,86)
|
0.3462
|
|
WC (cm)
|
75.89 (1,94)
|
75.26 (1,95)
|
0.1183
|
Abbreviation: BMI, body mass index; FP, follicular phase; LP, luteal phase; WC, waist
circumference.
Effect of the Menstrual Cycle on Food Intake
The average intake of calories, macronutrients, fibers, calcium, and iron are presented
in [Table 2]. A higher intake of calories (kcal/day), proteins (g/day), carbohydrates (g/day),
fibers (g/day), and calcium (mg/day) during the LP can be observed. However, this
difference was not significant for any of the variables analyzed during the phases
of the menstrual cycle.
Table 2
Energy, macronutrients, fibers, calcium and iron intake during the luteal and follicular
phases of the menstrual cycle of nutrition undergraduate students (n = 27)
|
Variable
|
Mean (SD)
LP
|
Mean (SD)
FP
|
p-value
|
|
Kcal/day
|
1,737.96 (413.66)
|
1,693.60 (436.51)
|
0.3832
|
|
Carbohydrates (g)/day
|
226.46 (67.27)
|
219.23 (69.51)
|
0.3881
|
|
Protein (g)/day
|
70.22 (24.73)
|
67.14 (20.70)
|
0.4973
|
|
Lipids (g)/day
|
61.27 (18.73)
|
62.37 (19.69)
|
0.2112
|
|
Fiber (g)/day
|
16.72 (9.51)
|
14.93 (9.10)
|
0.7056
|
|
Calcium (mg)/day
|
537.75 (292.14)
|
514.34 (249.74)
|
0.3164
|
|
Iron (mg)/day
|
10.44 (3.94)
|
10.52 (3.46)
|
0.0793
|
Abbreviations: FP, follicular phase; LP, luteal phase; SD, standard deviation.
Considering the percentage of energy from the macronutrients, the results can be observed
in [Fig. 1]. There was no statistically significant difference between the percentages of energy
from the macronutrients during the menstrual cycle phases of the nutrition students.
Fig. 1 Mean percentage of energy from carbohydrates (% cho), protein (% prot) and lipids
(% lip) during the phases of the menstrual cycle of nutrition students (n = 27). Abbreviations: cho, carbohydrates; FP, follicular phase; lip, lipids; LP,
luteal phase; prot, protein.
In relation to the portions of food consumed, classified according to the Food Guide
for the Brazilian Population, [Fig. 2] shows the comparison between the number of portions consumed in the LP and in the
FP. No significant difference was found in the consumption of any of the food groups
during the phases of the menstrual cycle (p > 0.05).
Fig. 2 Comparison between the number of portions consumed in the luteal and follicular phases
of nutrition students (n = 27). Abbreviations: FP, follicular phase; LP, luteal phase.
Food Desire Questionnaire
The findings referring to the food cravings during the phases of the menstrual cycle
are represented in [Fig. 3]. The foods presented in [Fig. 3] are those with a statistically significant change in the desire to be eaten. The
food craving for pastries (p = 0.002), fried snacks (p = 0.01), desserts and sweets (p = 0.0002), sandwiches and hot dogs (p = 0.001), chocolate and “brigadeiro” (a typical Brazilian dessert, made of chocolate
and condensed milk) (p = 0.0001), and sausages (p = 0.04) was higher during the LP when compared with the FP of the menstrual cycle.
A tendency for higher intake of ice cream (p = 0.06) and of foods like French bread, soda, and alcoholic beverages (p = 0.07) was observed.
Fig. 3 Foods that have changed the desire to be consumed during the phases of the menstrual
cycle in nutrition students. *“brigadeiro”: a typical Brazilian dessert, made of chocolate
and condensed milk. Abbreviations: FP, follicular phase; LP, luteal phase.
Discussion
According to the classification of body mass index (BMI), the majority of the participants
was classified as eutrophic (59.26%), 18.52% were classified as overweight, 14.81%
were classified with obesity, and 7.41% with leanness, according to the World Health
Organization (WHO).[14] The results of the present study showed that there was no statistically significant
difference between food intake and the anthropometric evaluation during the LP and
the FP of the menstrual cycle of the nutrition students. However, the food cravings
differed significantly between the two phases. Measurements of weight and of BMI were
not altered during the menstrual cycle phases, differently from those described in
the literature.[15]
Weight variation during the menstrual cycle is commonly reported, and one of the causes
for such an outcome would be an increase in energy intake due to the increased appetite
caused by hormonal oscillation.[16]
[17] In the present study, there was no change in energy intake, which may explain the
absence of alterations in the anthropometric measures analyzed.
The food intake did not present change between the LP and the FP. Although the intake
of calories (kcal/day), proteins (g/day), carbohydrates (g/day), fibers (g/day), and
calcium (mg/day) during the LF was higher, it was not statistically different. There
was also no significant difference in the intake of any of the food groups during
the phases of the menstrual cycle (p > 0.05).
In the literature, there is no consensus on the impact of the menstrual cycle on food
intake. The general consensus is an increase in energy intake during the premenstrual
period compared with the postmenstrual period, although reports on macronutrients
are less consistent. In studies with similar methodologies, authors[15]
[18]
[19] reported a higher caloric intake in the LP, although these increases have not always
been statistically significant. There are also some studies that found no differences
in caloric intake or even an alteration in the intake of food groups.[20]
[21] In Brazil, there is a lack of information on these modifications during the menstrual
cycle of healthy women.
Data from the literature describe results similar to those found in the present study,[15]
[20] in which there was no statistically significant difference in the caloric intake
before and after the menstrual period. The mean difference observed in the present
study is 44 kcal between the phases.
In the present study, there is a difference of 7 g of carbohydrate intake between
the LP and the FP, which is very close to that found in a study that evaluated Arab
women.[15] According to the author of this study, a difference of 9g of carbohydrate intake
was observed between the phases of menstrual cicle was observed, despite different
eating habits. Moreover, this increase in carbohydrate intake would subjectively justify
the greater sense of the need to consume their food source, like the foods identify
as the greater food craving, like chocolate, desserts, pastries among others. Regarding
the type of carbohydrate consumed in the premenstrual period, a previous study reported
that sources of simple carbohydrates present a higher intake than the sources of complex
carbohydrates.[20]
[21]
One of the hypotheses to be considered for the increase in carbohydrate intake in
this period would be the relationship between simple carbohydrates (high glycemic
index) and a higher production of cerebral serotonin,[22] thus reducing the negative mood effects.[23] The second hypothesis to be considered is the relationship between carbohydrate
intake and the menstrual cycle, since there is a variation in the concentration of
steroids, and it is observed that estrogen suppression may influence the intake of
carbohydrates.[15]
However, in a study comparing food intake, nutrients, and serum levels of estrogen,
progesterone and leptin during the phases of the menstrual cycle in 39 Thai women
aged between 20 and 40 years old, the authors reported that, although consuming more
total calories (+ 160 kcal/day, p < 0.05) and more grams of proteins (+ 6–8 g/day, p = 0.01) during the LP when compared with the FP, no correlations were observed between
the serum levels of sex hormones, serum leptin levels, food intake, or body weight.[24]
Regarding the food groups, there was no change in the intake of any of the analyzed
groups. In a study performed with 45 university students from the faculty of nutrition
of the Universidade Federal Fluminense,[21] it was observed that there was no statistically significant difference in the intake
of the food groups in the menstrual cycle, similar to the results described here,
except for the group considered complementary and beverages (with high fat, sugar
and salt content), whose intake increased (p = 0.04) during the LP.
Despite the fact that no change in the intake of energy, of nutrients and of food
groups was observed, food cravings had a significant alteration. When the pre-and
postmenstrual food craving was analyzed, there was a significant variation in the
desire to eat caloric foods rich in simple carbohydrates, salt, and sugar, such as
pastries, snacks, sausages, chocolate, sweets, and desserts in general. Other studies
that evaluated the impact of the menstrual cycle on food cravings found results similar
to those of the present study.[6]
[21]
The mechanism underlying the selective effect of these symptoms of the LP on the desire
to eat highly sweet foods is unclear. According to Gibson (2006),[8] sweet foods may improve emotion and mitigate the effects of stress through brain
opioidergic and dopaminergic neurotransmission. Repeated short-term positive experiences
after the ingestion of sweet foods might create positive emotional expectations for
the ingestion of sweets. If so, more depressed women might engage in more emotional
eating to alleviate their negative emotion.[25]
Impulsivity and irritability, symptoms that are commonly described as exacerbated
in the LP, are associated with the desire to eat highly sweet foods, because of its
emotional responses, which increase the risk of obesity.[26] On the other hand, during the FP, estrogens could progressively decrease eating
and the preference for sweet foods.[27]
Qualitative results[28] showed that there is preference for the intake of sweets, carbohydrates, and foods
with high fat contents. In the literature,[10]
[20] some researchers found that the desire for food, especially those containing fat,
were significantly higher in the LP when compared with the FP. There was also a higher
intake of foods such as sweets, sugars, and fats in the LP.[21] Corroborating with the current study in relation to food cravings, another author[29] applied a questionnaire to 52 women and found that 49% of them had a higher desire
to eat sweet foods and that 37% reported a higher than usual food intake.
The present study backs up the findings of a study[21] that also evaluated nutrition academics and found similar results of both intake
and anthropometry. However, these results differ from what has been described in the
literature when randomly selected women in the community were evaluated.[15]
[20]
[23]
[29]
Despite the desire for high-calorie, high-fat, and high-sugar foods during the LP,
this desire did not effectively change the intake due to the food control that may
exist in the study group, since the participants in the study are academics of the
nutrition course and, therefore, know the importance and principles of healthy eating.
However, these marked changes in appetite during the LP is described in the literature,
as well as specific food cravings.[30] Therefore, population studies need to be conducted to better clarify the mechanisms
involved in this selected food preference, not only for sweet foods in general, but
also for high-fat and high-calorie foods, thus providing improvements in health care
and in the quality of life of this group.
Nevertheless, it is important for health professionals, especially nutritionists and
gynecologists, to know the possible oscillations that may occur in the premenstrual
period and to consider them for research on food intake and food craving, as well
as to provide differentiated care at this stage.
Several limitations of the present study should be noticed. First, the number of participants
is limited. Despite the number of female students enrolled in the course (n = ∼ 116), only 27 completed the full study protocol, that is, performed the evaluation
at both moments: during the LP and the FP of the menstrual cycle. The need to perform
two evaluations at different times, as well as the exclusion criteria, made it difficult
to perform the follow-up of the participants of the present study. Second, the absence
of a test to confirm in which phase of the cycle the participants were in, which was
classified according to the onset of the menstruation. Third, the Food Desire Questionnaire
was minimally adapted from the original version with local foods, but this adaptation
had not been validated in a previous study.
Conclusion
The menstrual cycle presents itself as a unique model for regulating food intake and
craving. The findings of the present study suggest that, during the menstrual cycle,
the participants presented alterations in food craving, with a higher desire for caloric
foods, as well as for foods rich in fats, sugars and salt during the LP compared with
the FP, thus identifying PMS as a possible determinant of dietary desires in women
of childbearing age. However, despite the changes in food craving, the total intake
of calories and also of macro and micronutrients did not fluctuate across the menstrual
cycle. There was also no fluctuation in body weight, BMI, or WC. This fact may be
a reflection of food control.
