Effect
of interventions with ingestion of legumes and/or supervised exercise
on the lipid profile of young, healthy sedentary women*
Luis F. Fajardo, MD, MSc1, Dora G. Castellanos Fisiot, MgBiol1, Myriam Chinchilla (qpd) Nutr, MgBiol1,
Luz N. Vargas, Nutr, MgBiol1, Martha Guerra, Bacteriol, MgBiol1, Leonardo Quintana, PhD2, Johnson Niño, MD3
* Research funded by the
Office of Research Promotion of the Academic Vice Rectory at Pontificia
Universidad Javeriana, Bogotá, DC, Colombia.
1. Analysis of Food Security
Research Group, Nutrition and Biochemical Department, Science
Faculty, Pontificia Universidad Javeriana, Bogotá,
DC, Colombia. e-mail: lfajardo@javeriana.edu.co doraginneth@gmail.com
nvargas@javeriana.edu.co mguerra@javeriana.edu.co
2. Director Biomechanics Laboratory, Engineer Faculty, Pontifica Universidad Javeriana, Bogotá, DC, Colombia.
e-mail: lquin@javeriana.edu.co
3. Sport Medicine Specialist. e-mail: johnson.nino@javeriana.edu.co
Received for publication Marach 23, 2009 Accepted for publication April 19, 2010
SUMMARY
Objective: To
contribute to the knowledge of some aspects of the Healthy Life Style
by studying the effects of including legumes in the diet and exercise
at two intensity levels, along with the lipid profile of young
sedentary women living at 2640 meters above sea level.
Materials and methods: The study included a non-randomized clinical trial with four intervention groups: exercise at 45% VO2 peak plus legumes in diet, exercise at 65% VO2 peak plus legumes in diet, only exercise at 65% VO2
peak, and only inclusion of legumes in diet. In each group, 20 to 23
sedentary women were included. The intervention was carried out for
four weeks, three days a week. Exercise prescription was based on
measurement of VO2
peak by ergospirometry; and the current intervention was monitored with
heart-rate monitors. The outcome variables were total serum
cholesterol, LDL cholesterol, HDL cholesterol, and triacylglycerols
measured at baseline and after two and four weeks of intervention.
Results: The measurements taken of participants in the group of exercise at 65% VO2
peak plus legumes in diet showed a reduction of 19.8 mg/dl in total
cholesterol, of 21.8 mg/dl of LDL cholesterol, of 20.7 mg/dl of
tracylglycerol, and an increase of 6.2 mg/dl of HDL cholesterol. The
serum levels of HDL also increased in the group of only exercise at
65% VO2 peak. No significant changes in serum levels were documented for participants in the group with only dietary modifications.
Conclusions: The
results suggest that different interventions that meet some of the
criteria for healthy eating and life style show different effects with
regards to the level of change in the lipid profile components.
Keywords: Healthy eating; Lipid profile; Exercise level; Legume intake.
Efecto de
las intervenciones con ingesta de leguminosas y/o ejercicio supervisado
sobre el perfil lipídico de mujeres jóvenes, sanas y
sedentarias
RESUMEN
Objetivo:
Contribuir al conocimiento de algunos aspectos prácticos para
llevar a cabo una alimentación y estilo de vida saludable,
mediante el estudio de los efectos en el perfil lipídico de la
inclusión de leguminosas (fríjol, lenteja y garbanzos) en
la dieta de mujeres sanas pero sedentarias, acompañada de
ejercicio con dos niveles de intensidad, moderada y alta, efectuados a
una altura de 2,640 metros sobre el nivel del mar (msnm)
Material y métodos: Estudio de intervención clínica no aleatorizada con cuatro grupos de intervención: ejercicio a 45% VO2 pico + leguminosas, ejercicio a 65% VO2 pico + leguminosas, sólo ejercicio a 45% VO2
pico y sólo inclusión de leguminosas en la dieta. En cada
grupo se incluyeron de 20 a 23 mujeres jóvenes sedentarias
evaluadas mediante el International Physical Activity Questionnaire
(IPAQ), y la intervención se llevó a cabo durante 4
semanas. La prescripción del ejercicio se hizo previa
determinación del VO2
pico por ergo espirometría, y su realización se
monitoreó con sensores de frecuencia cardíaca. El
efecto de la intervención se evaluó mediante los cambios
en los niveles séricos de colesterol total (CT), colesterol LDL
(cLDL), colesterol HDL (cHDL) y triacilgliceroles (TAG), tomados a las
semanas cero, dos y cuatro.
Resultados: En el grupo «ejercicio a 65% del VO2 pico, más inclusión de leguminosas en la dieta» se obtuvieron los siguientes resultados significantes: una
reducción promedio del colesterol total de 19.8 mg/dl
(p=0.0015), del colesterol LDL de 21.8 mg/dl (p=0.0001), un aumento de
colesterol HDL de 6.2 mg/dl (p=0.0001) y una disminución de los
triacilgliceroles de 20.7 mg/dl (p=0.0001). En el grupo de sólo
ejercicio a 65% del VO2
pico se obtuvo un aumento del HDL. No hubo modificaciones al
perfil lipídico en el grupo correspondiente a sólo
inclusión de leguminosas en la alimentación.
Conclusiones: Los
resultados sugieren que en mujeres jóvenes sedentarias que viven
a 2,640 metros sobre el nivel del mar, la combinación de
ejercicio de intensidad alta e inclusión de leguminosas
(fríjol, lenteja o garbanzos) producen un mayor cambio
benéfico en el perfil lipídico que una
intervención con sólo ejercicio de intensidad alta o
sólo inclusión de leguminosas en la alimentación.
Los cambios benéficos significantes se obtuvieron luego de 4
semanas de intervención en el colesterol total, colesterol LDL,
colesterol HDL y triacilgliceroles, lo que pone de presente la bondad
de esta intervención, así como la utilidad del perfil
lipídico como indicador temprano de cambios en los estilos de
vida. Las intervenciones estudiadas, compatibles con
alimentación y estilo de vida saludables, producen efectos
diferentes en los niveles del perfil lipídico estudiados, y al
poner de presente las debilidades de un diseño no
aleatorizado, se puede recomendar que se insista en las
intervenciones de salud pública que contemplen cambios en la
dieta y cambios en la actividad física.
Palabras clave: Alimentación saludable; Dieta; Perfil lipídico; Intensidad de ejercicio; Consumo de leguminosas.
The World Health
Organization (WHO) holds that a healthy diet and adequate physical
activity are main factors in the promotion and maintenance of good
health throughout the whole life cycle1. In Colombia, this
recommendation is adopted by the National Plan for Public Health, which
among its central issues includes improving the health status of the
population and avoiding the progress and occurrence of adverse outcomes
in the population on the risk of becoming ill2. The National
Policy on Food Safety, specifically announces as one of its objectives
«To promote healthy habits and life styles that permit improving
the population’s state of health and nutrition, and preventing
the appearance of diet-associated illnesses»3.
In spite of the
urgency expressed by the organizations mentioned, the operational
definitions that may lead to the quick adoption of a healthy diet and
adequate physical exercise practiced regularly are scarce. In this
sense, WHO recommendations can be classified as restrictive
recommendations (those that begin by «limiting») like
limiting the energy intake from fats, limiting sugar and salt intake,
etc., and promotional recommendations like increasing intake of fruits
and vegetables, legumes, grains, and dry fruits.
With respect to
physical activity, it is recommended that people keep physically active
during their whole lives with at least 30 minutes of moderate intensity
regular activity on an almost daily basis4.
There are many
combinations of dietary intervention, different from the restrictive
ones, related to achieving healthy eating. The recommendation of
increasing the intake of fruits and vegetables, legumes, grains, and
dry fruit is very general and does not specify value of the increase,
5%, 10%, or 20%, or if all have to be increased at the same time, or if
it suffices with only increasing any or some of these. The publication
of the «Steps to Better Health» food pyramid in the United
States offers indications on the minimum amounts, according to eating
habits of North Americans, for whom legumes are recommended in portions
much lower than those usually consumed in Colombia5.
Likewise, aerobic exercise is one of the therapeutic focuses related to
life style and it is recommended to improve lipid and lipoprotein
levels in all individuals, including those with cardiovascular
problems. However, except for the general recommendation of almost
daily engaging in moderate intensity exercise lasting at least 30
minutes, there is no specification of what is the desirable level of
intervention in public health.
There is information
available on the positive effect of the intake of legumes and dry whole
grains on the lipid profile and glycemia levels, both in healthy and
ill individuals6-10. There is also evidence of the
beneficial effect of exercise, although random tests have yielded
conflictive results, perhaps due to differences at the base line,
characteristics of the exercise program, and duration of the
intervention11,12.
With the purpose of
contributing to the knowledge of some practical aspects to engaging in
healthy eating and life style, we present the results of the effects on
the lipid profile by including legumes (beans, lentils, and chick peas)
in the diet of healthy but sedentary women at the beginning of the
study, accompanied by exercise at two intensity levels: moderate and
high. The participants live at 2640 meters above sea level (masl).
MATERIALS AND METHODS
Design.
The research was conducted in Bogotá (2640 masl) and it was a
Clinical Intervention Study with four phases each lasting four weeks,
which meant the participation of 4 groups of ~20 young sedentary women,
who were subjected to exercise and food intake intervention, which
consisted in including legumes for lunch three times per week.
Assignment of participants to a particular group was not done randomly.
The groups were the following: Group 1: Food intake and exercise
intervention with a training workload equivalent to 45% of the peak
oxygen consumption – maximum oxygen update – (VO2 peak) by the subject. Group 2: Food intake and exercise intervention with a training workload equivalent to 65% of (VO2
peak) by the subject. Group 3: No food intake intervention, exercise
intervention with a training workload equivalent to 65% of (VO2 peak) by the subject. Group 4: Food intervention for 4 weeks, but without exercise intervention.
Subjects.
Through announcements on the Universidad Javeriana web page, female
students were summoned to express their interest in participating in a
clinical research related with food intake and physical activity. Four
calls were made during four different weeks, corresponding to each
phase of the research. Between 30 and 40 students expressed interest
during each invitation. Assignment of the subjects to each intervention
group was not random and it was done sequentially.
The following
inclusion criteria were considered: a) the subjects identified
themselves as sedentary (without regular physical activity during the
three months prior to the project, especially without physical activity
lasting half an hour or more), b) during a physical activity evaluation
prior to the intervention, the subjects were catalogued as sedentary by
using the abbreviated version of the «International Physical
Activity Questionnaire» (International Consensus Group for the
Development of an International Physical Activity Questionnaire, WHO
1996), c) age 18 to 29 years, d) Body mass index <28, e) fitness to
practice physical exercise and consume legumes evaluated through
physical exam and history carried out by a physician. The exclusion
criteria considered: Abnormal base line lipid profile, missing two or
more exercise sessions or legume intakes.
Of the students expressing
interest, we selected the first 25 students who completed an interview
with a nutritionist, a medical exam, and the international physical
activity questionnaire (IPAQ). Of these, 23 were included in the study
and 2 remained on standby.
In total, 89 young
women were included ranging from 18 to 30 years of age, university
students at Pontifica Universidad Javeriana in Bogotá according
to calculation of the sample: n [n =2S2/D2 F(a-b)] of 23 individuals
per group to detect a difference of 2.2 mg/dl HDL, after 4 weeks of
intervention, assuming a standard deviation of 2.7 mg/dl, and a 0.05%
significance level one tail and power of 80%. one tail and power of.
The participants
were informed on the nature of the study and accepted to participate,
signing an informed consent according to guidelines by the Research
Committee at Pontificia Universidad Javeriana. All the subjects were in
good health and presented no contraindication for exercise and
ingestion of prescribed foods according to the medical exam performed
on each subject.
Food-Intake Intervention. For
food-intake intervention, the subjects were prescribed lunch including
legumes as low glycemic level food (beans, lentils, or chick peas), in
amounts that would provide 13% of the daily energy intake. The lunch
was calculated to account for 30% of the daily energy intake. This
lunch was offered between 12 noon and 1 pm, 3 days per week during the
4 weeks of the intervention for groups 1, 2, and 4. For the dietary
prescription, we kept in mind the usual values of energy ingestion and
other nutrients, along with the feeding characteristics of each
individual, obtained through a detailed dietary assessment. The lunch
offered included the following foods: red beans, lentils, or chick peas
(130-140 g), cooked white rice (70 g), fruit (80 g), raw or cooked
vegetable (75 g) and an unsweetened beverage or natural lemonade (250
ml). The subjects were instructed to always consume the amount of
legumes offered and the other foods making up the lunch ad libitum.
During each of the
days of intervention (three days per week for 4 weeks) each subject
recorded the weight of the food portions consumed during the day. To
comply with this activity, they were furnished a weighing scale and a
measuring cup.
Exercise intervention. The exercise prescription for the intervention was done by first determining the VO2
peak for each individual through ergospirometry with a Metapeak
III® ergospirometer and an exercise protocol with increasing load
on an Ergoline® cycloergometer, according to parameters established by Astrand and Wasserman13.
Rest for 3 minutes on the bike to stabilize the parameters measured
before starting the ergospirometry; Warm up by pedaling for 3 minutes
at minimum power (15 watts); during this stage, each subject had to
pedal at a constant rhythm between 60 and 70 revolutions per minute
(rpm); the test included power increases of 15 watts every 3 minutes
until reaching a respiratory coefficient of 1.15 or more, or
• VO2 Plateau, in spite of the increased exercise load or • not being able to keep pedaling at the same rate of frequency.
Group 1 was prescribed 30 minutes of exercise, 3 days per week with cardiac frequency equivalent to 45% of VO2 peak. Groups 2 and 3 were prescribed 30 minutes of exercise 3 days per week with cardiac frequency equivalent to 65% of VO2
peak. The participants in the study were instructed to do the exercise
on the athletic field at Universidad Javeriana or at the same
university’s Sports Center. In both situations, the participants
were accompanied by a trained physical therapist. The subjects were
free to do the exercise at their convenience between 9 am and 3 pm.
During each programmed exercise session, each participant wore a
cardiac frequency monitor (Timex Iron Man® or Polar S810®)
capable of storing the time at which the subject reached and maintained
the target cardiac frequency; this time was denominated time in zone.
The study also stored the average cardiac frequency obtained over the
time each exercise session was developed. Ideally, the time in zone and
the average cardiac frequency during the activity should coincide with
the time prescribed and the target cardiac frequency prescribed. During
the programmed exercise sessions, the subjects were also asked for
their perception of effort by using the Borg scale.
Determination of lipoproteins.
Blood samples were taken from the antecubital vein during the early
morning hours after 12-hour fasting. Total cholesterol and triglyceride
concentrations were analyzed via colorimetric enzyme assays
(Serapak-Bayer). HDL cholesterol (HDL) was determine don the
supernatant by centrifugation, post precipitation (chylomicrons, VLDL
cholesterol (VLDL) and LDL cholesterol) with phosphotungstic acid and
magnesium ions (Serapak-Bayer). LDL cholesterol and VLDL cholesterol
levels were calculated by using the Friedwald formula when the samples
did not have triglycerides greater than 400 mg/dl14. The
assessments were made on an RA 50 (Bayer) instrument at the Clinical
Biochemistry Specialization Laboratory at Pontificia Universidad
Javeriana in Bogotá DC, and to control instrument efficiency, we
used known-concentration calibrators (SERA CHEK from BAYER Labs SA).
Statistical analysis. The
statistical analysis was aimed at determining the differences in serum
biochemical parameter measurements prior to intervention and after two
and four weeks of intervention for the 4 groups intervened. One-way and
contrast variance analysis tests were run via the Bonferroni method to
study the differences in biochemical parameter changes among the four
intervention groups, and Student t tests were run and confidence
interval at 95% (CI 95%) to determine the significance of the
differences in the biochemical parameters measured at the base line and
after four weeks of intervention. The Stata IC version 10 statistical
package was used.
RESULTS
The study included 81 women
(Table 1), ranging in age between 18 and 29 years; with an average age
of 20.89 years (CI 95% 20.45-21.33) average weight of 54.52 kg. (CI 95%
53.19-55.84), average height of 1.58 m (CI 95% 1.56-1.59) and average
Body Mass Index (BMI) of 21.78 (95% CI 21.33-22.23).
The subjects
programmed for the dietary intervention, groups 1, 2, and 4, during the
days programmed had an intake of 14%, 16%, and 16% of the total daily
energy as legumes, respectively, and energy intake was reduced by 15%
in group 1 and by 22.6% in group 2 (in group 4 this parameter was not
evaluated). Note that the food intake was not stimulated by the
researchers, but was rather spontaneously given (Table 2).
Exercise
intervention was carried out with 61 participants in the following
manner: Group 1 had 12 exercise sessions (sessions 3 days per week for
4 weeks), prescribed at an intensity of 45% of VO2 peak, and done at an average intensity of 47% of VO2 peak. Group 2 had 12 programmed sessions with intensity at 65% and effectively done at an average intensity of 63.3% of VO2 peak, and group 3 also had 12 programmed exercise sessions with an intensity at 65% of VO2 peak that were done at an average intensity of 60.2% of VO2 peak (Table 3).
Lipid profile
measurements were done prior to starting the intervention, at two weeks
of intervention and after four weeks of intervention. Base line
measurements were taken from 88 subjects, at two weeks in 87
individuals and after 4 weeks in 82 individuals.
The result of the
interventions on the lipid profile was evaluated through TC, LDL, HDL,
and TAG serum measurements. For the 4 groups intervened, we calculated,
in the four components of the lipid profile, the average of differences
(d) among the base line values and after four weeks of intervention
(delta (d) = base line value – value after four weeks of
intervention).
In Table 4 we show
the ä changes occurring in the levels of the lipid profile
parameters after 4 weeks of intervention (note that the positive values
indicate diminishing of the serum level profile and the negative values
indicate increased serum level). The statistical significance of the
differences (d) among the intervention groups was evaluated through
one-way variance analysis of the d for the 4 groups and following
contrasts via the Bonferroni test (Table 5). We also studied the
difference of the serum values at the base line and after four weeks of
intervention and were compared through a Student t test. These data are
presented in Table 6.
Total cholesterol. It was observed that in the intervention group of «Exercise at 65% VO2
peak + legumes» the maximum reduction was obtained (greater size
d) for the TC value, and that this d was significantly different to
that observed in the groups «Only exercise at 65% VO2 peak» (Bonferroni p=0.002) and «Only included legumes» (Bonferroni p = 0.001), (Tables 4 and 5).
In the group of «Exercise at 65% VO2
peak + legumes» a decrease of serum TC was observed after four
weeks of intervention, which was statistically significant for the t
test (p=0.0048) (Table 6). To evaluate the possibility of a dosage
response effect an ANOVA was run of the TC including the terms group
and week, revealing a significant effect for the term Group (F=5.04,
p=0.0021), but not for the term Week (F=0.29, p=0.7496), thus
discarding a dosage response effect of the time of intervention.
Upon analyzing group
averages of the TC presented in Table 6, it can be observed that the
base line values for the four intervention groups are within the normal
limits; however, the base line of the intervention group of «Only
exercise at 65% VO2 peak», revealed significantly lower figures than groups of «Exercise at 45% VO2 peak + legumes» and «Exercise at 65% VO2
peak + legumes» (one-way ANOVA F 4.74, p= 0.0042; Bonferroni
contrast p=0.016 and 0.005). We have no definite explanation for these
differences and they could be attributed to bias in the selection of
the participants in this group, which should be kept in mind in the
discussion and conclusions because reductions are more difficult when
starting with low TC values.
LDL cholesterol. The greatest value of d LDL was observed for the group «Exercise at 65% VO2 peak + legumes», followed by the value obtained by the group «Exercise at 45% VO2
peak+ legumes» (Tables 4 and 5). These data reveal that the
maximum reduction in LDL (greatest value of d LDL) was obtained in the
group «Exercise at 65% VO2
peak + legumes», this reduction merely being significantly
greater than that observed in the group «Only inclusion of
legumes».
Likewise, the group «Exercise at 65% VO2
peak + legumes» also showed a significant reduction in average
LDL, going from 101.1 mg/dl to 81.1 mg/dl (p=0.0001). The possibility
of a dosage response effect was analyzed via an ANOVA of the LDL
including the terms Group and Week. The ANOVA (LDL-Group-Week) was
significant (F=5.23, p=0.0001), with the term Group also being
significant (p<0.0001), but not so for the term week.
HDL cholesterol. The
most negative values for d HDL in Table 4 (greater increases of HDL)
were seen in the intervention groups «Exercise at 65% VO2 peak + legumes» and «Only exercise at 65% VO2
peak». In the group «Only inclusion of legumes»
favorable HDL level changes were not observed. And in the group
«Exercise at 45% VO2 peak+ legumes» HDL increase was lower than in the groups with greater intensity exercise.
The comparison of
HDL values at the base line and after 4 weeks of intervention
demonstrated a significant increase for the groups «Exercise at
65% VO2 peak + legumes» (51.2 mg/dl to 57.6 mg/dl) and «Only exercise at 65% VO2 peak» (49.8 mg/dl to 55.9 mg/dl) (Table 6). The ANOVA (HDL-Group-Week) was not significant (F=1.12, p=0.3511).
Triacylglycerols. As
in the case of the other lipid profile components, the differences in
TAG serum values on the base line and after intervention (d TAG) in the
intervention groups are shown in Tables 4 and 5.
The three
intervention groups including exercise, revealed the greatest reduction
of serum TAG levels (d TAG), greatest in the groups of exercise with
intensity greater than (65% VO2
peak). In the group of «Only inclusion of legumes» we
observed a d TAG = -8.4 (negative value), which indicates increased TAG
levels post intervention.
The TAG averages for the group «Exercise at 65% VO2
peak + legumes» (Table 6) show significant diminishing of serum
level going from 86.2 mg/dl to 64.9 mg/dl, p=0.0001. The ANOVA analysis
(TAG – Group – Week) showed the existence of an effect on
TAG levels attributable to the Intervention Group (ANOVA F=2.60,
p=0.05), but not an effect attributable to time of intervention in
weeks.
DISCUSSION
The study considered young,
sedentary women with life styles concordant with their condition as
university students, living in Bogotá DC, at an altitude of
2,640 masl. The change in lipid profile was evaluated as an indication
of the beneficial effect of four weeks of intervention with actions
that could become part of a healthy life style.
The four intervention groups in this work were thus: Exercise at 45% of VO2 peak (~ 4 METs – moderate-intensity exercise) plus inclusion of legumes in diet, Exercise at 65% of VO2 peak (~ 6 METs high-intensity exercise) plus inclusion of legumes in diet, Exercise at 65% of VO2
peak (~6 METs high-intensity exercise) without dietary intervention
(time of exercise: 30 minutes three days per week), and finally, diet
intake intervention including legumes without changes physical activity
levels; may be seen as different implementation stadiums to
accomplishing healthy feeding and life styles.
The results shown in
Tables 4 and 5 refer to the differences in the magnitude of change
obtained through the interventions. In the group «Exercise at 65%
of VO2
peak + inclusion of legumes in diet» significant statistical and
physiological results were obtained. We obtained an average reduction
in TC of 19.8 mg/dl, in LDL of 21.8 mg/dl, an increase in HDL of 6.2
mg/dl, and reduction in TAG of 20.7 mg/dl. In the group of exercise at
45% of VO2
peak (moderate intensity) plus inclusion of legumes changes obtained
were in the expected direction, but at a lower magnitude and not
statistically significant. The values were: a reduction of 7.3 mg/dl in
TC, a reduction of 6.8 mg/dl in LDL, and an increase of 0.9 mg/dl in
HDL.
Strategies by the WHO to prevent chronic illnesses1 contemplate efforts to have people consume healthy diets and perform moderate physical activity; however, other authors15
alert on the difficulties of carrying out these interventions. Our
results indicate that the combination legume intake (healthy diet) and
high-intensity exercise is better than any of the other interventions;
furthermore, there is a relationship between exercise intensity and the
resulting changes in lipid profile.
The current study was conducted at an altitude of 2,640 masl, and the effect of altitude on the physiology of exercise16
has been well established. Although with the information available, we
cannot confirm or deny the influence of this parameter on the results,
we do want to wish to direct attention on this fact given the important
number of people living in the Andean high plains. Several studies have
shown the relationship between exercise intensity and the effects on
lipid profile11,17; however, few studies report altitude
over the sea level where the exercise is done. It is possible that at
the altitude in Bogotá, longer-lasting interventions may be
warranted (months instead of weeks). Other studies examining the effect
of exercise on TC or on LDL report diminishing of 4 and 5% with respect
to the initial value and indicate that reductions greater than 2%
already have positive effects with respect to reduction of
cardiovascular risk11.
The group with
moderate-intensity exercise and diet intervention showed a tendency for
diminished TC, LDL, and TAG; rather, the group with only exercise at
65% of VO2
peak did not reveal significant reduction of TC or LDL, instead the
tendency during the four weeks of intervention was to increase-although
not significantly. According to the results of this study, it would
seem that to achieve changes in TC, LDL, and TAG parameters, some
combination form of legume intake and exercise is needed.
In the group of only
dietary intervention, we did not observe the changes associated to the
consumption of legumes as reported by other authors6-10. An
explanation of this result may be the type of legumes used, given that
in our case we used canned beans, lentils, and chick peas and in
several of the articles cited only beans are consumed; however, the WHO
recommends legumes in general. Similarly, it must be kept in mind that
the current study was of short duration and the consumption of whole
grains and legumes associated to fruits and vegetables for longer
periods may be beneficial, as noted with the Mediterranean diet18.
With respect to
increased HDL (Table 6) with the type of intervention, significant
increases were obtained in the three intervention groups that included
exercise; with the greatest increase registered in the groups with
exercise intensity at 65% of VO2
peak. These results agree with the literature, both in the level of
increase as in the association between magnitude of change and exercise
intensity11.
As reported by other
studies, TAG levels diminish with exercise and in our study we obtained
a reduction of 20.7 and 19.6 mg/dl in the groups with exercise
intensity at 65% of VO2
peak, without the existence of significant differences attributable to
the inclusion of legumes in the dietary intake (Table 6).
Bearing in mind the
limitations of a non-random study with only four weeks of observation,
the results suggest that greater benefit is obtained with a combination
of high-intensity exercise (~6 METS) carried out for 30 minutes three
times per week and the inclusion of legumes (beans, lentils, chick
peas) in amounts representing 15% of the daily energy intake, judging
such benefit as desirable changes in the lipid profile (Diminishing of
TC, LDL, TAG and increase of HDL). Hence, it would be the most
desirable combination among those studied. Conversely, by merely
including legumes in the dietary intake at the level used and
monitoring the lipid profile for 4 weeks, it was not possible to
evidence any change in lipid profile, suggesting that the
recommendation of «increasing legume consumption» should be
carried out for more prolonged periods with intake of greater amounts,
i.e., it should be more qualified. The intervention of only
high-intensity exercise (~6 METS) had the effect of increasing HDL, as
shown in other studies and diminished TAG (p = 0.06) was marginally
observed. This study highlights the importance of the dietary
intervention, which as with the group of «Exercise at 65% VO2
peak + legumes» in the current study could be measured by the
dietary fiber provided by the legumes and the low-glycemic index of the
carbohydrates supplied by these legumes. The intervention with
moderate-intensity exercise (~4 METS) and legumes revealed changes in
the expected direction, but these were not statistically significant.
Although the effects of moderate- or low-intensity exercise upon lipid
profile is still a motive for discussion19, the effects of the altitude where the study was conducted are still an issue of study.
In conclusion,
different interventions compatible with healthy dietary intake and life
style behave differently as far as their effect on the change in the
levels of the fractions of the lipid profile studied, and,
consequently, the manner of implementing the recommendation to adopt a
healthy diet and life style can bear implications on the final outcome.
For the altitude in
Bogotá and the age group studied, an intervention with healthy
eating and high-intensity exercise for 30 minutes, three days per week
produces effects on the lipid profile consistent with diminished risk
of cardiovascular disease.
Conflict of interest. None of the authors has conflicts of interest related to this study.
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