The effect of the menstrual cycle
on the body composition of
weight-stable woman through BIA
J.A.C. Gaarthuis, S.M. Gerdes
2011105, januari 2011
Bachelor opleiding Voeding en Diëtetiek
Titel scriptie
The effect of the menstrual cycle on the body composition of weight-stable woman
through BIA
Auteurs
Jamie Gaarthuis
Bijlacker 1
1902 AL Castricum
[email protected]
Sofie Gerdes
Hasselaarsweg 32
1704 DX Heerhugowaard
[email protected]
Afstudeerproject
2011105
Opdrachtgever
P.J.M. Weijs
Hogeschool van Amsterdam
Dr. Meurerlaan 8
1067 SM Amsterdam
[email protected]
Docent begeleider
A. Verreijen
Hogeschool van Amsterdam
Dr. Meurerlaan 8
1067 SM Amsterdam
[email protected]
Copyright ©2010, J.A.C. Gaarthuis en S.M. Gerdes
© Niets uit deze scriptie mag worden verveelvoudigd of openbaar gemaakt, in enige vorm of op enige wijze, hetzij
elektronisch, mechanisch, door fotokopieën of op enige manier, zonder voorafgaande toestemming van de auteurs.
2
Voorwoord
Wat voor u ligt is onze scriptie die wij hebben geschreven ter afronding van onze Bacheropleiding Voeding en
Diëtetiek aan de Hogeschool van Amsterdam.
Gedurende 20 weken hebben wij een onderzoek uitgevoerd naar het effect van de menstruele cyclus op de
lichaamssamenstelling van gewichtstabiele vrouwen. Deze opdracht hebben wij uitgevoerd in het Voedingslab
van de opleiding Voeding en Diëtetiek ter Amsterdam. Voor het tot stand komen van deze scriptie willen we
graag een aantal mensen bedanken. Allereerst bedanken wij onze opdrachtgever Peter Weijs voor het mogelijk
maken van het onderzoek. Tevens willen wij alle deelneemsters bedanken die hebben deelgenomen aan ons
onderzoek. Ook gaat onze dank uit naar onze praktijkbegeleidster Amely Verreijen voor alle hulp, ideeën en
nieuwe inzichten die zij ons gegeven heeft gedurende dit onderzoek en tijdens het schrijven van onze scriptie.
Tot slot bedanken wij Suzanne van der Plas voor het beschikbaar stellen van haar werkruimte.
Jamie Gaarthuis en Sofie Gerdes
Januari 2011
3
Index
1.
2.
3.
4.
5.
Titel pagina
Voorwoord
Index
Abstract
Introduction
5.1 Motivation of this study
5.2 Factors that influence the measurements
5.3 The menstrual cycle
5.4 Hypotheses
2
3
4
5
5-7
6. Methods
6.1 Subjects
6.2 Study design
6.3 Measurements
6.4 Statistics
8-10
7. Results
7.1 Response
7.2 The comparison in body composition between the follicular
and luteal phase
7.3 Energy intake in follicular phase vs. luteal phase
11-13
8. Discussion
8.1 Discussion
8.2 Conclusion
14-15
9. References
16-17
Appendix:
I.
Flyer
II.
Information brochure
III.
General questionnaire
IV.
24 hour recall of the participants
4
The effect of the menstrual cycle on the body composition of weight-stable
woman through BIA
Jamie A.C. Gaarthuis and Sophia M. Gerdes
Abstract
Background & Aims: Women complain of weight gain for their menstruation. Therefore we hypothesized that
women have a higher weight in the luteal phase compared to the follicular phase caused by a higher Total Body
Water. It is expected that there will be a higher dietary intake during the luteal phase compared with the
follicular phase.
Methods: The data were collected from 20 healthy, weight stable women between the age of 16-45 years who
reported a regular menstrual cycle. Four measurements were done, two in the follicular phase and two in the
luteal phase by Bodpod, BIS and Tanita. 24 hour recalls were reported on every measurement day. The results
were analyzed with SPSS 18.0 and MS Excel for Windows.
Results: Significant differences were found in weight [p < 0.001] measured by the three devices. Similarly, there
is a significant decrease from the follicular phase to the luteal phase in FFM (kg) [p=0.025] and TBW (l) [p=0.023] measured by Tanita. Furthermore we found a higher dietary intake during the luteal phase compared
with the follicular phase (85 kCal) but no significance differences.
Conclusions: It is suggested that there are differences in Weight, Total Body Water and Fat Free Mass between
the two phases of the menstrual cycle as especially for Tanita. Therefore it’s important for dieticians to take
into account the moment of measurement in the menstrual cycle from their female clients.
KEYWORDS: menstrual cycle, BIA, menstrual phases, body composition, food intake
Introduction
Motivation of this study
In the Netherlands 42 percent of the women over 15 years is overweight. This increasing problem leads to a
higher prevalence of chronic diseases and so it is important to address this problem. (1,2)
People who are overweight or with chronic illnesses are often referred to a dietitian. In addition to weight,
dieticians may use body fat percentage to evaluate course of treatment. In practice this is often done by bio
impedance analysis (BIA). BIA measures the impedance of the body to a frequency dependent current. This
impedance reflects amount of total body water; the current flows better through water with dissolved
electrolytes than fat. Since fat mass doesn’t contain water, and approximately 73% of fat free mass exists of
water, the amount of fat free mass can be estimated. Therefore fat-free tissues are good conductors of the
electrical current because they are rich in body water and dissolved electrolytes, whereas fat mass is
nonconductive. (3)
The Impedance describes a measure of opposition to alternating current and can be done by several devices,
for example the Bodyscout (bio-impedance spectrometer, BIS), Tanita (which has a lot of different models) and
the Inventum (a cheap ‘variant of the BIA’). BIA is often used in practice because it’s not expensive, portable,
safe, battery chargeable and it gives quick results. (4,3)
Factors that influence the measurement
Factors like, eating or drinking, excessive alcohol consumption, exercise, smoking, not having been to the toilet
and menstruation may be of influence by the BIA measurements.
5
This last factor, menstruation, can affect measurements because during the menstrual cycle many hormonal
and mental changes take place in the body such as: fluctuations in hormone and change in hydration status
resulting in variation in weight (Figure 1). (4)
The changes in hydration status are due to a difference in level of anti-diuretic hormone (ADH) between the
follicular (day 1-13) and the luteal phase (day 15-28) of the menstrual cycle. ADH blocks the water excretion in
the urine. In the luteal phase is the quantify of ADH in the body higher compared to the follicular phase. This
result in more water is retention and therefore the weight is higher in the phase before menstruation
compared with the phase after the menstruation. (5)
The menstrual cycle
As described above, the menstrual cycle can be broadly divided in two different phases, the follicular phase and
luteal phase. The follicular phase takes place from the first day of the menstruation until the ovulation. The
luteal phase is from the ovulation until the beginning of the next menstruation. Several studies have shown
that there are quite some differences between those two phases. (4)
The endometrium changes during the monthly cycle. It gets thicker during the follicular phase, change in the
luteal phase and is rejected during the menstruation. Estradiol, a female sex hormone, is responsible for the
thickening and
changing of the
endometrium during
the follicular phase.
The thickness and
volume of the
endometrium
increases during the
follicular phase with a
peak before the
ovulation. Thereafter
it increases during the
middle and late luteal
phase en is rejected
during the
menstruation. (6)
Figure 1 Hormonal and mental changes during the menstrual cycle
6
Estradiol and progesterone may affect the nutritional intake of women in the various phases of the menstrual
cycle. Receptors of these hormones are located in the hypothalamus where they affect the brain. Estradiol, of
which the concentration in the blood is higher during the follicular phase, provides an anorexigenic affect
during the late follicular phase. It provides further for an increase in the heat production of the body. In
contrast, progesterone, which is higher during the luteal phase, causes an increase in food intake during the
luteal phase of the menstrual cycle. (4,7,8)
Other studies have shown that a higher fat free mass during the luteal phase is probably partly caused by fluid
retention. They pose that the weight gain in the luteal phase is caused by a rise in total body water (TBW) (4).
A lot of studies have shown a higher energy intake during the luteal phase by women. The difference between
the two phases varies between ≈ 90 to 500 kcal/d. (7,9,10,12-16) Significant higher intakes of energy, protein,
carbohydrate and fat in the luteal phase were found in similar studies. (10,11,12)
The previous studies have examined the effect of the menstrual cycle on body composition, they focused more
on the course of the menstrual cycle. They measured the participants during one cycle and then studied at the
changes in body composition. This study aims to investigate the differences in body composition between the
two phases in the menstrual cycle using BIA and investigates whether BIA is giving valid results in body
composition compared to the Bodpod which is used as reference in this study. The Bodpod is used as
reference, because it is less influenced by hydration status compared to BIA. (17) By BIA the TBW is estimated
and based on, FFM is derived. This is not the case with the Bodpod. By Bodpod the body composition is
estimated by the density of the body, making it probably less influenced by TBW. The study aims to investigate
whether the menstrual cycles has to be taken into account while measuring body composition with BIA.
A secondary aim of this study is to examine the difference in food intake between the two phases of the
menstrual cycle.
Hypotheses
It is expected that a higher amount of TBW during the luteal phase, results in a lower fat mass, compared to
the follicular phase. This causes in a higher weight during the luteal phase. BIA is more influenced by the
menstrual cycle than Bodpod because it works with an electrical current which is influenced by the amount of
TBW. During the two phases of the menstrual cycle there are fluctuations in TBW. These fluctuations affect the
result of the BIA. Additionally it is expected that there will be a higher dietary intake during the luteal phase
compared with the follicular phase.
7
Methods
Subjects
The data were collected from 20 healthy, weight stable women between the age of 16-45 years who reported a
regular menstrual cycle. The subjects were recruited from the University of Applied Science, Amsterdam,
School of Sports and Nutrition. Subjects were given a clear written description of the project (appendix 1)
before their general questionnaire was obtained and they gave written informed consent. This study was
conducted according to ethical standards of the institution.
To screen whether subjects were eligible to participate in this study, a questionnaire was filled-out by
interested women. This questionnaire asked a variety of questions including the following: At what age did
your first menstruation occur? Do you use contraceptives? What kind of symptoms do you have before and
during your period? What, on average, is the duration of your menstrual cycle in days? What is the date of the
first and the last day of your current/following period?’
The protocol of the study including a description of preparation for the body composition measurements has
been given before the general questionnaires were obtained. Before the measurements days, subjects were
asked to screen the protocol to be fully prepared for the measurements.
Study design
Overall, body composition of the participants was measured on four days, two days in follicular phase and two
in the luteal phase. All subjects had their Bodpod, bio impedance (Tanita BC 418; and BodyScout, FreseniusKabi) and weight measurements taken two days (day 27,28) before their menses in the luteal phase and two
days (day 8,9) after their menses in the follicular phase by two investigators shown in Figure 2.
During the measurement of the Bodpod the participant was wearing tight clothes and a cap. At each
measurement the participant was wearing the comparable clothes. (4)
Figure 2 Study design
8
On the first day of measurements the subject received a full explanation about the measurements itself. On
each day of the measurement, the investigator conducted a 24-hour recall to get an indication of her food
intake. The investigator also conducted a registration form to obtain several dependent factors like: physical
activity, time of last meal, toilet use and time of last cigarettes.
Measurements
The protocol for the measurements consisted of a number of criteria which were important for the reliability of
the measurements. The following instructions were given to the participants:
-
The subject is not allowed to consume any food 5h before the measurements and to use drinks that are
high in calorie or caffeine.
-
The subjects drink their last glass of water 1h before the measurement.
-
Overeating the day before the measurement is not allowed.
-
Use of alcohol or cigarettes on the measurement day is not allowed.
-
Physical activity or going to the sauna in the 14h before the measurement is not allowed.
-
Taking a shower at least 1h before the measurements is not allowed.
-
Subject wears tight clothes during the measurement and on each measurement day the same clothes.
-
Subject is asked to empty the bladder before measuring.
-
Jewelry, glasses anything like that is not allowed to wear during the measurements.
-
To avoid errors, measurements take place on the same time of the day.
Before the measurements of body composition height of the subjects was measured. The subjects stood
against a wall with bare feet while the investigator held the stadiometer on the head and reads the given
height.
The first measurement was the Tanita, the investigator enables the Tanita for measurement. The following
data were entered in the device: 1 kg weight allowance (for the clothes that the subject is wearing during the
measurement), standard women (the device has two options, standard women or athletic women) height, and
age. After the data is entered the subject stepped on the scale. After 4 seconds the subject has to grasp the
handles and hold them along her body. The measurement starts from this point. After measuring with the
Tanita, the following data is measured: weight, fat%, fat mass, FFM and TBW. (19)
The second measurement was the Bodpod measurement, the Bodpod also named a Body Composition
Tracking System that uses patented Air Displacement Plethysmography for determining percent fat and fat-free
mass in adult. Before the subject entered the Bodpod she had to put on a lycra cap. The subject entered the
Bodpod and the measurement started, one measurement contained two or three measurement moments each
one took about 50 sec. After the first measurement the subject stepped out off the Bodpod and waited for
three minutes. In these three minutes the Bodpod is recalibrated.
9
Then the subject re-entered the Bodpod for the second time and the measurements started again. Volume and
weight was measured by a very accurate electronic scale and by using the Bodpod device. Weight divided by
volume is density. Predicted long volume was used. From these two measurements, the subject's average
density is calculated. The formula used to convert density into fat percentage is the Siri formula. (18)
Siri formula: Percent Fat = [495/Density] - 450 (18)
The third measurement was the Bodyscout. While the subject is lying relaxed on the bed for two minutes, the
investigator cleans the left hand and feet with alcohol. After cleaning, detector electrodes were placed on the
left pulse and on the top of the left foot. After placing the electrodes the measurement was started. The
following data were measured: FFM, Fat, Intracellular water (ICW), Extracellular water (ECW) and TBW and
BMI.
Statistics
The statistical analysis programs SPSS, version 18.0 for Windows and MS Excel 2007 was used for statistical
analysis. All data were expressed as mean ± SD values. To measure differences within the two phases of the
menstrual cycle for weight, FM, FFM and TBW the paired sample t-test was used. To analyze the differences
and to look if there were any significance between the results of the body composition measured by the
Bodpod, BIS and Tanita, we also used the paired sample t-test. For analyzing the food intake between the two
phases of the menstrual cycle the paired sample t-test was used. P-values of <0.05 were considered statistically
significant.
10
Results
Response
Twenty women were selected after completed
the general questionnaire about their
menstrual cycle pattern. The measurements
were classified according to their menstrual
cycle. The selection process of the participants
for this study is shown in Figure 3.
Figure 3 Selection process
A detailed description of the general characteristics of the women; age, height, weight, BMI, age of menarche,
length of menses and Oral Contraceptives use are given in Table 1. All of the participants have a normal weight
and BMI.
Table 1 General characteristics and biological parameters at baseline
Number of subjects
N = 20
Age (y)
22.2 ± 4.2
Height (cm)
167.4 ± 7.3
Weight (kg)
60.5 ± 8.9
BMI (kg/m²)
21.5 ± 2.2
Age of menarche (y)
12.9 ± 1.3
Length of menses (d)
5.2 ± 1.2
Oral Contraceptives use (%)
60 %
** Values are shown in mean ± SD.
The comparison in body composition between the follicular and luteal phase
Table 2 shows the comparison between the follicular and the luteal phase in the measurements of body
composition with the Bodpod, BIS and Tania. Analysis of the data indicated that the weight varied with the
phases of the menstrual cycle. There is a significant difference in weight between the follicular and the luteal
phase of the menstrual cycle [p < 0.001]. The weight increase from the follicular to the luteal phase is 0,4 kg
measured by Bodpod. Similarly, there is a significant decrease from the follicular phase to the luteal phase in
FFM (kg) [p=0.025] and TBW (l) [p=-0.023] measured by Tanita. The Bodpod and BIS didn’t show any other
significance. Table 2 shows a column with the difference between the averages for Bodpod, BIS and Tanita.
No significant differences were found between the Bodpod and the other two devices in change in body
composition between the two phases of the menstrual cycle.
11
Table 2 Bodpod, BIS and Tanita compared in the luteal and the follicular phase of the menstrual cycle
Bodpod
BIS
Follicular phase Luteal phase Differences
Bodpod
Tanita
Follicular phase Luteal phase Differences Follicular phase Luteal phase Differences
BIS
Tanita
Weight (kg) 60.2 ± 8.7
60.6 ± 8.8
0.4 ± 0.6†
60.2 ± 8.7
60.6 ± 8.8
0.4 ± 0.6†
60.2 ± 8.8
60.6 ± 8.8
0.3 ± 0.6†
FM (kg)
16.7 ± 5.6
16.8 ± 5.8
0.1 ± 1.0
15.2 ± 6.5
15.4 ± 6.4
0.3 ± 2.4
15.2 ± 5.9
15.2 ± 5.6
-0.0 ± 0.8
FM (%)
27.1 ± 6.0
27.1 ± 6.0
- 0.0 ± 1.6
24.6 ± 7.9
24.8 ± 7.3
0.2 ± 4.4
24.6 ± 6.0
24.5 ± 5.5
- 0.1 ± 1.4
FFM (kg)
43.6 ± 4.5
43.8 ± 4.3
0.2 ± 1.2
45.2 ± 4.7
45.1 ± 4.6
- 0.0 ± 2.4
45.0 ± 3.6
45.3 ± 4.0
0.4 ± 1.0†
FFM (%)
72.9 ± 6.0
72.9 ± 6.0
0.0 ± 1.6
75.8 ± 8.2
75.2 ± 7.3
- 0.6 ± 4.2
75.4 ± 6.0
75.5 ± 5.5
0.1 ± 1.4
TBW (L)
-
-
-
32.6 ± 3.4
32.4 ± 3.3
- 0.2 ± 2.1
32.9 ± 2.7
33.2 ± 2.9
0.3 ± 0.7†
Values are shown in mean ± SD.
F = Follicular phase, L = Luteal phase
†Significantly different from follicular phase, p < 0.05 (paired sample t test).
12
Energy intake in Luteal phase versus Follicular phase
24 Hour recalls were reported on each measurement by the investigator to get an indication of the differences
in food intake between the two phases of the menstrual cycle. Table 3 shows a 6% increase in the energy
intake between the two phases. The intake of carbohydrates increases with 15% from the follicular to the
luteal phase. This study found differences between the two phases, however no significances were found.
From the results of this study and other studies it can be assumed there is a preference of carbohydrates
during the luteal phase. Figure 4 shows the food intake in en% between the two phases. This bar chart also
shows clearly a difference in carbohydrates.
Table 3 Average energy and macronutrient intake during the follicular and luteal phase of the menstrual cycle
Follicular phase
Luteal phase
Energy (kCal/day) 1471 ± 314
Protein (g/day)
56 ± 13
Carbohydrates (g/day)194 ± 40
Fat (g/day)
51 ± 19
Alcohol (g/day)
5±9
1558 ± 375
58 ± 13
227 ± 91
50 ± 18
8 ± 13
Values for consumption represented by the mean ± SD
*p-value<0.05: significant difference between follicular and luteal phase.
Figure 4 Food intake in en% in the follicular and luteal phase
13
Discussion
This study aims to investigate the differences in body composition between the two phases in the menstrual
cycle using BIA. Also this study investigates whether BIA gives valid results in body composition compared to
the Bodpod which is used as reference in this study. The expectation was that a higher Total Body Water in the
luteal phase, results in a lower Fat Mass in the follicular phase. The three devices show a significant difference
in weight between the two phases. The data indicate an increase in weight and Total Body Water during the
luteal phase of the menstrual cycle. The increase in weight is probably the result of the increase in Total Body
Water measured by Tanita. Furthermore there are no significant changes in Fat Mass and Fat Free Mass
measured by Bodpod and BIS. There is a little reduction of Fat Mass during the luteal phase which is
accompanied by a significant increase of FFM at the same time measured by Tanita. It is striking to see that
there are high differences between the measurements of the BIS and Tanita. The results of the Tanita show an
increase of Total Body Water and Fat Free Mass from the follicular to the luteal phase, as expected. On the
other hand the same results measured by BIS are exactly the opposite. After investigating the results measured
by BIS, there were no outliers to be excluded. The differences are probably due to measurements errors like;
wearing a bracket bra during the measurement, wearing jewelry or a belt, wearing a wallet in the pocket, other
metals in clothes and misjudgment of menstrual cycle.
In other studies there are also increases in weight and TBW during the luteal phase. (21-24) The subjects were
tested six different times, during the early follicular (twice) and midluteal (twice) menstrual phases. The
increase in weight can be compared with this study. They found an increase of weight of 0,4 kg from the
follicular to the luteal phase. Assumed is that these increases are caused by the raise of estradiol during the
luteal phase. (23) In this study the hormonal status is not measured so it can’t be determined as the cause of
this increase. For an better explanation the hormonal status should be included in follow-up studies.
A secondary hypotheses was that there would be a higher dietary intake during the luteal phase compared
with the follicular phase. Although we found a little increase of energy intake (87 kCal) and carbohydrates
(33g/day) between the two phases of the menstrual cycle, it was not enough to be significant. Other studies
with larger populations show clear differences in food intake (154 kCal) in contrast with this study. (25) This is
probably due to the power of this study. There would be more significant differences, if the population of this
study was larger.
Other factors could be underreporting, errors in processing 24 hour recalls and report of 24 hour recall after
the weekend. This last factor is investigated in other studies, they found a higher energy intake in the weekend
compared to the other days of the week. (14) Twenty two of the eighty measurements were carried out on
Monday, so it can be assumed that this had an impact on the food intake reported in this study. The results of
this study showed that the intake of carbohydrates is higher during the luteal phase. However, this increase is
not significant in contrast with other studies that show significant differences in the increase of carbohydrates
between the two phases.
They suggest that the increase of carbohydrates is due to the preferences of sweet food during the luteal
phase. (26,27) To conclude if the higher intake of carbohydrates in this study is due to the preferences of sweet
food, it is necessary to investigate the different product groups. (28)
14
This study did not explore other non nutritional factors that might influence BIA measurements, including skin
temperature, hydration status. The Oral Contraceptive use is investigated but not included in the results,
because the statics didn’t show any differences compared to the non Oral Contraceptives users. This is also
attributed to the low population of this study.
Previous studies show that the use of Oral Contraceptives affects the body fluid regulation. The amount of
estradiol in Oral Contraceptives affects fluid retention. Estradiol leads to a lower osmolarity resulting in a
higher fluid retention during the luteal phase of menstrual cycle. (21,23) The results show a higher Total Body
Water during the luteal phase. (24) Therefore it would be better if future studies take the influence of the use
Oral Contraceptive during the menstrual cycle into account.
Probably there were women who were not satisfied with the results of their body composition on the first
measuring day, resulting in weight loss. Trough this weight loss the woman were no longer weight-stable, this
may cause measurement errors.
The aim of this study is to investigate whether the menstrual cycles has to be taken into account while
measuring body composition with BIA. Overweight is a growing problem, therefore dieticians get more and
more overweight clients. This study shows that the weight of women depends on the period of their menstrual
cycle because of the fluctuation of Total Body Water measured by Tanita. The majority of the dieticians use
Tanita to measure the weight gradient of their clients. (19) This study shows an increase of weight of 0.4 kg in
the luteal phase of the menstruation. Therefore it’s important for dieticians to take into account the moment
of measurement in the menstrual cycle from their female clients.
2
The average BMI of the women is 21,5 (kg/m ) but it would be better if the participants of this study had a BMI
2
above the 25 (kg/m ). Whether the results of this study will be different in overweight women is unknown,
there is no literature found for this target group.
In conclusion this study shows an increase in weight (for all devices), Total Body Water and Fat Free Mass (kg)
from the follicular to the luteal phase of the menstrual cycle for Tanita, contrast to a reduction of the FM (kg).
Most of the significant differences are measured by the Tanita. It concludes that measuring during the luteal
phase is affected by Total Body Water which results in a higher weight in this period.
15
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