obese women

Nutrition Research 27 (2007) 313 – 320 www.elsevier.com/locate/nutres

Restricted-energy diets rich in vegetables or cereals improve cardiovascular risk factors in overweight/obese women☆ Elena Rodríguez-Rodríguez a,⁎, Rosa M. Ortega a , Ana M. López-Sobaler a , Pedro Andrés b , Aránzazu Aparicio a , Laura M. Bermejo a , Luisa García-González a b

a Departamento de Nutrición, Facultad de Farmacia, Universidad Complutense, Madrid, Spain Laboratorio de Técnicas Instrumentales, Facultad de Farmacia, Universidad Complutense, Madrid, Spain Received 24 October 2006; revised 2 April 2007; accepted 23 April 2007

Abstract This study was conducted to determine how the follow-up of 2 different energy-restricted (hypocaloric) diets, based on approximating the diet to its theoretical ideal, influences cardiovascular risk factors such as obesity, blood pressure, serum cholesterol, serum low-density lipoprotein and very low density lipoprotein, serum triacylglycerol and homocysteine, and serum high-density lipoprotein. Fifty-seven young overweight or obese women were randomly assigned to one of 2 different weight-control programs designed to approximate the diet to the theoretical ideal. Twentyeight women were assigned to the vegetable (V) group; this group was characterized by a relatively increased consumption of vegetables. Twenty-nine women were assigned to the cereal (C) group, which was characterized by a relatively increased consumption of cereals. Dietetic, anthropometric, and biochemical data were collected at the outset of the study and again 2 and 6 weeks into the program in both groups. Both interventions resulted in a significant improvement in warning parameters of obesity (weight, body mass index, and waist/hip ratio), total serum cholesterol, and homocysteine at the end of the study. Plasma homocysteine levels fell by 14.9 ± 13.6% in the group C subjects and by 8.8 ± 14.0% in the group V subjects after 6 weeks. This may have been due to an increase in the intake and serum levels of vitamin B6 and folate in both groups. At the end of the intervention, the V group exhibited a significant reduction in low-density lipoprotein cholesterol and in non–high-density lipoprotein cholesterol. Group C subjects showed a reduction in diastolic blood pressure at this time. The results suggest that both hypocaloric diets with a relative increase in the consumption of vegetables or cereals were effective in improving cardiovascular risk factors in overweight and obese women. © 2007 Elsevier Inc. All rights reserved. Keywords:

Human; Overweight; Cardiovascular diseases; Dietary intervention; Cereals; Vegetables

1. Introduction Cardiovascular diseases represent one of the main causes of death in developed nations [1]. For this reason, the control of cardiovascular risk factors (CRF) is a major pubic health ☆ This work was supported by a grant from Kellogg España, The Universidad-Empresa project 362/2003. ⁎ Corresponding author. Tel.: +34 91 394 18 37; fax: +34 91 394 18 10. E-mail address: [email protected] (E. Rodríguez-Rodríguez).

0271-5317/$ – see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.nutres.2007.04.014

goal. Some of this CRF are obesity [2,3], elevated serum total cholesterol, low-density lipoprotein cholesterol (LDLC) and triacylglycerols, low serum high-density lipoprotein cholesterol (HDL-C) [3,4], and elevated blood pressure [5] and homocysteine level [6-9]. Although weight-loss diets can be beneficial in the prevention of cardiovascular diseases [4,5], they can be harmful and may increase CRF if the diets are unbalanced. Poorly controlled diets, skipping meals, and fasting

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(practices that are very common in young women) favor the appearance of deficiencies [10]. Some of these deficiencies are associated with an increase in serum cholesterol levels and blood pressure [11-13]. Other deficiencies such as vitamin B6, B12, or folic acid deficiency are associated with increased homocysteine levels [6-8]. For this reason, it is important to plan diets that, besides producing a loss of weight, contribute the necessary nutrients in order that deficiencies do not take place and that the next result is to improve CRF. The average Spanish diet is characterized by its low content of cereals (C) and vegetables (V), with regard to the ideal theoretical [14], but specially persons worried by their weight usually restrict the consumption of cereals and this can lead to an unbalanced diet [15]. The aim of the present investigation was to analyze the changes in some CRF in a group of young overweight/obese women who followed a weight-control program based on approximating the diet to the theoretical ideal by following a slightly hypocaloric diet that provided a relative increase in their consumption of either vegetables or breakfast cereals. This study will evaluate the efficiency of both types of diets on weight control and on changing CRF.

meeting the inclusion requirements were informed of the aim of the study, the clinical tests that they would undergo, and the number and type of interviews and testing to which they would be subjected. According to the requirements of the Ethics Committee of the Faculty of Pharmacy, all subjects signed a witnessed form of consent. The number of registrants was 193; only 67 fulfilled the criteria and began the study. Fifty-seven completed the 6-week dietary intervention period. 2.2. Interventions The experimental diets to which the subjects were randomly assigned were designed to provide, on average, approximately 20% less than their theoretical energy requirements. Theoretical energy expenditure was established by taking into account the body weight, age, and physical activity of all subjects using equations proposed by the World Health Organization (WHO) [16]. Both diets were structured with the idea of approximating the theoretical ideal by increasing the relative consumption of either vegetables or cereals in the diets. Previous studies have shown that these foods make the greatest difference between the observed and recommended intakes [17-19]. 2.3. Diet with cereals

2. Methods and materials 2.1. Study subjects The study subjects were 57 women aged 20 to 35 years (average, 27.8 ± 4.7 years). Most were university students. The subjects were enrolled through a public offer to take part in a study on “The Assessment of Nutritional Status and Improvement of Weight Control.” Enrolment was open to young women. The study was advertised using posters, radio announcements, and publications directed at young female university students. Initially, all interested candidates were interviewed by telephone to ensure that they met the inclusion criteria, which were female sex, aged 20 to 35 years, body mass index (BMI) of 24 to 35 kg/m2, cessation of smoking did not occur in the last 2 months, free of disease that might interfere with the study aims (such as diabetes, hyperthyroidism, metabolic diseases, hypertriglyceridemia, lactose or gluten intolerance [celiac disease], and food allergies), not currently involved in a weight-loss program, no loss of more than 4.5 kg in the 2 months before the study, no gain of more than 3 kg between the first interview and the beginning of the study, have a regular menstrual cycle, not consuming more than 2 alcoholic drinks per day, and not pregnant or lactating. Those interested in taking part were declared to meet all inclusion criteria and were invited to the Department of Nutrition at the University Complutense de Madrid. At the institution, body weights and heights were recorded, and questionnaires were completed to collect personal, health, and dietary information. All candidates who were approved as

In this diet, the weight control measures were based on restricting the consumption of energy-rich foods and increasing the consumption of cereals. Breakfast cereals and cereal bars were recommended (a minimum of 3 times per day) as, apart from carbohydrates, they also provide fiber, minerals, and vitamins. The cereal chosen was Special K (Kellogg's España, Madrid, Spain) because of its particularly high mineral and vitamin content per unit weight. Subjects had to eat for breakfast 30 g and for dinner 40 to 60 g of cereal, and they had to include a cereal bar as a mid-morning snack. For the mid-afternoon snack, they could eat a cereal bar, skimmed yogurt, or skimmed milk, although the cereal bars were generally recommended. In addition, the subjects were also advised to eat other cereals. At lunch, they had to eat 30 to 40 g of bread, and they could choose rice or pasta in the trimming. 2.4. Diet with vegetables In this case, the weight control measures were based on restricting the consumption of energy-rich foods and increasing the intake of vegetables (minimum of 3 times per day). Specifically, subjects had to eat salad at lunch and at dinner as well as vegetables as a main course in one of the meals. Details of the 2 experimental diets have been previously described [20] and are summarized in Fig. 1. 2.5. Compliance to diet rules Over the intervention period (a total of 6 weeks), the subjects attended a weekly appointment to record anthropometric data and to discuss (and if necessary solve) any difficulties in following the assigned diet.

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315

Fig. 1. Consumption of different food groups (servings per day).

2.6. Methods The following data were collected from all subjects during the preintervention stage and again after 2 and 6 weeks. 2.6.1. Physical activity The subjects completed a questionnaire on their normal physical activity and the information was used to calculate their energy expenditure [21]. Subjects indicated the length of time spent sleeping, eating, and playing sport during weekdays and on weekends. An activity coefficient was established for each subject [16,22]. 2.6.2. Anthropometric information All subjects were weighed, their height measured, and their waist and hip circumferences recorded. All data were collected at the Department of Nutrition by trained personnel following procedures described by the WHO [23]. Weight and height were determined using a Seca Alpha digital electronic balance (Seca Alpha, Igmy, France; range, 0.1-150 kg) and a Harpenden digital stadiometer (Harpender Pfifter, Carlstadt, NJ; range, 70205 cm), respectively. In both cases, the subjects were barefoot and wore only undergarments. Waist and hip circumferences were recorded using a nonextendable measuring tape. The following indicators were then calculated for each subject: • Body mass index (BMI): weight (kg)/height2 (m2) • Waist/hip ratio: waist circumference (cm)/hip circumference (cm)

2.6.3. Health variables Information was collected on any medical issues, the use of medications or supplements, and the consumption of manufactured diet foods. Systolic and diastolic blood pressures were also recorded [24]. 2.6.4. Dietetic study A “3-day food and drink record” was used to register all intakes (both at home and away) for 3 consecutive days, including 2 weekdays and 1 weekend day (Sunday if possible) [25]. Subjects were instructed to record the weights of food consumed if possible or to use household measurements (spoonfuls, cups, etc). The aim was to collect information as accurately as possible, and the subjects were asked to record all intakes even if they broke the “rules” of their diet. The energy and nutrient contents of foods were then calculated using food composition tables [26]. The values obtained were compared to those recommended [27] to determine the adequacy of the diets. Special attention was paid to vitamins B6, B12, and folic acid, given their role in homocysteine metabolism [6-8]. DIAL software (Alce Ingeniería, Madrid, Spain) was used to analyze all data [28]. Energy needs (theoretical energy expenditure [TEE]) were established using equations proposed by the WHO [16] for the calculation of basal metabolic rate, multiplying the answer by the activity coefficient [16]. As a measure of the discrepancy between energy intake and expenditure, the following was calculated: (TEE − energy intake) × 100/TEE.

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For the preintervention phase of the study, during which the subjects maintained a stable weight, the discrepancy between TEE and the theoretical intake provided a measure of the possible underestimation of energy intake. Once the intervention phase had begun, a positive discrepancy was expected (expenditure always greater than intake); the larger the difference, the greater the chance of losing weight. 2.6.5. Blood analyses Cholesterol levels were determined by an enzyme colorimetry method [29] (enzyme hydrolysis followed by reaction with cholesterol oxidase [coefficient of variation (CV) = 3.1%]). High-density lipoprotein cholesterol was determined by the same method after precipitating the chylomicrons and the very low density lipoprotein cholesterol (VLDL-C) and LDL-C (achieved via the addition of phosphotungsten and magnesium ions [28]) (CV = 3.3%) [30]. Very low density lipoprotein cholesterol was determined mathematically from the triacylglycerol levels (dividing the latter by 5), and LDL-C using the formula of Friedewald et al [31]. Serum folic acid was measured by radioimmunoassay [32] (CV = 4.5%) and pyridoxine was determined by radiochemical assay [33] (CV = 8.5%). Plasma homocysteine levels were determined by polarized fluorescence immunoanalysis using an Imx analyzer (Comodoro, Ontario, Canada) [34] (CV = 6.3%). Low serum folic acid concentrations were defined as concentrations of less than 6.80 nmol/L [35,36]; moderate deficiency serum folic acid concentrations were considered to be within the range of 6.80 to 14.90 nmol/L [35]. The cut-

off for low pyridoxal phosphate status was 25 nmol/L [37]. A homocysteine concentration of greater than 10.4 μmol/L was defined as hyperhomocysteinemia [38,39]. 2.7. Statistical analyses Results are expressed as mean ± SD. For statistical analysis, the RSIGMA BABEL software was used [40]. The Student t test (when distributions in the 2 groups were homogeneous) or Mann-Whitney U nonparametric test (when distributions in the 2 groups were nonhomogeneous) was used to compare differences between groups C and V for each variable in the same period. Analysis of variance (ANOVA) was used to compare changes in dietary intakes and biomarkers that occurred between baseline, 2 weeks, and at the end of the study period. The Pearson test was used to quantify any association between the 2 variables. Comparisons between proportions were made using an approximation of the binomial distribution to the normal distribution using continuity correction. A P value lower than .05 was considered as statistically significant. 3. Results Fig. 1 shows the consumption of foods throughout the study period. The initial data showed the consumption of cereals, fruits, and vegetables to be noticeably lower than that recommended [17,18,20,41]. During the intervention period, the consumption of cereals increased in group C subjects and the consumption of vegetables increased in group V subjects (both at 2 and 6 weeks).

Table 1 Cardiovascular disease risk factors in adult women at baseline and during weight loss consuming hypocaloric diets based on increased consumption of vegetables (diet V) or cereals (diet C) Preintervention data

Results at 2 weeks

Diet V (n = 28) Diet C (n = 29) Diet V (n = 28) Weight (kg) 72.15 ± 7.22 Height (cm) 161.74 ± 5.31 27.59 ± 2.54 BMI (kg/m2) Waist/hip ratio 0.78 ± 0.07 Systolic blood pressure (mm Hg) 116.21 ± 8.10 Diastolic blood pressure (mm Hg) 73.46 ± 5.32 Total cholesterol (mmol/L) 4.89 ± 1.01 HDL-cholesterol (mmol/L) 1.64 ± 0.30 Triacylglycerol (mmol/L) 1.86 ± 0.75 VLDL-cholesterol (mmol/L) 0.37 ± 0.15 LDL-cholesterol (mmol/L) 2.89 ± 1.03 Non–HDL- cholesterol (mmol/L) 3.26 ± 1.10 LDL-cholesterol/HDL-cholesterol 1.87 ± 0.84 Cholesterol/HDL-cholesterol 3.11 ± 0.92 Homocysteine (μmol/L) 7.51 ± 2.49 N10.4 μmol/L (%) 7.41

a⁎⁎

Results at 6 weeks

Diet C (n = 29)

Diet V (n = 28) a⁎⁎

75.24 ± 10.54 76.80 ± 10.57 71.13 ± 7.24 164.56 ± 5.82 161.74 ± 5.31 164.56 ± 5.82 28.33 ± 3.40 27.20 ± 2.56 a⁎⁎ 27.40 ± 3.56 a⁎⁎ 0.79 ± 0.07 0.77 ± 0.06 0.78 ± 0.07 115.90 ± 11.4 115.29 ± 9.41 115.00 ± 10.23 74.86 ± 8.18 73.07 ± 7.61 70.89 ± 6.96 4.49 ± 0.57 4.51 ± 1.24 a⁎⁎ 4.20 ± 0.64 a⁎⁎ 1.61 ± 0.40 1.45 ± 0.30 a⁎⁎ 1.39 ± 0.28 a⁎⁎ 1.85 ± 0.55 1.89 ± 0.96 1.83 ± 0.53 0.37 ± 0.11 0.38 ± 0.19 0.37 ± 0.11 2.50 ± 0.52 2.68 ± 1.10 a⁎ 2.45 ± 0.52 2.87 ± 0.56 3.06 ± 1.23 2.82 ± 0.55 1.65 ± 0.55 1.92 ± 0.78 1.82 ± 0.47 2.90 ± 0.61 3.19 ± 0.89 3.10 ± 0.53 a⁎ 7.27 ± 1.72 7.19 ± 1.66 6.56 ± 1.46 a⁎⁎ 3.45 0 0

Values are mean ± SD except for percentages. a Difference between preintervention and 2-week data. b Difference between preintervention and 6-week data. c Difference between 2- and 6-week data (ANOVA). ⁎ P b .05. ⁎⁎ P b .01.

Diet C (n = 29)

b⁎⁎, c⁎⁎

70.14 ± 7.27 74.02 ± 10.87 b⁎⁎, c⁎⁎ 161.74 ± 5.31 164.56 ± 5.82 26.83 ± 2.61 b⁎⁎, c⁎⁎ 27.31 ± 3.56 b⁎⁎ 0.76 ± 0.07 b⁎⁎, c⁎ 0.77 ± 0.07 b⁎ 113.68 ± 9.29 113.66 ± 10.66 72.86 ± 9.34 70.17 ± 8.52 4.40 ± 1.12 b⁎⁎ 4.13 ± 0.65 b⁎⁎ 1.40 ± 0.33 b⁎⁎ 1.39 ± 0.30 b⁎⁎ 1.90 ± 0.99 0.38 ± 0.20 2.61 ± 0.94 b⁎ 2.99 ± 1.09 b⁎ 1.97 ± 0.83 3.25 ± 0.95 6.64 ± 1.50 b⁎, c⁎ 0

1.93 ± 0.73 0.39 ± 0.15 2.35 ± 0.59 2.74 ± 0.62 1.78 ± 0.57 3.07 ± 0.63 6.12 ± 1.19 b⁎⁎, c⁎ 0

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Table 2 Daily energy and vitamin intake and percentage of subjects with vitamin intake below recommended intake (%) in adult women at baseline and during weight loss consuming hypocaloric diets based on increased consumption of vegetables (diet V) or cereals (diet C) Preintervention data Diet V (n = 28) Energy (kJ) Vitamin B6 (mg) Folate (μg) Vitamin B12 (μg) Intake b RI (%) Vitamin B6 Folate Vitamin B12

Results at 2 weeks

Diet C (n = 29) d⁎

Diet V (n = 28)

b⁎⁎

Diet C (n = 29)

10049 ± 212 2.16 ± 0.49 273.4 ± 78.2 6.05 ± 3.10

6546 ± 984 2.45 ± 0.59 a⁎⁎ 344.0 ± 108.7 a⁎⁎ 4.06 ± 2.44 a⁎⁎

6604 ± 1185 4.22 ± 0.78 a⁎⁎, d⁎⁎⁎ 544.9 ± 120.8 a⁎⁎, d⁎⁎⁎ 4.84 ± 1.42 a⁎, d⁎⁎

6639 ± 1144 2.74 ± 0.83 b⁎⁎ 418.4 ± 115.9 b⁎⁎, c⁎⁎ 3.70 ± 1.76 b⁎⁎

6727.89 ± 1173.61 b⁎⁎ 4.13 ± 0.73 b⁎⁎, d⁎⁎⁎ 533.6 ± 103.1 b⁎⁎, d⁎⁎⁎ 4.76 ± 1.29 b⁎, d⁎

10.7 96.4 7.1

0

0 75.0 x⁎ 7.1

0 6.9 x⁎⁎⁎, d⁎⁎⁎ 3.4

0 46.4 y⁎⁎⁎ 14.3

0 13.8 y⁎⁎⁎, d⁎⁎ 0 d⁎

0

a⁎⁎

Diet V (n = 28)

8755 ± 2417 1.90 ± 0.53 232.8 ± 74.6 6.48 ± 4.82

93.1

a⁎⁎

Results at 6 weeks

Diet C (n = 29)

Values are mean ± SD except percentages of intake. RI indicates recommended intake [16]. a Difference between preintervention and 2-week data. b Difference between preintervention and 6-week data. c Difference between 2- and 6-week data (ANOVA). d Difference between diets C and V (Student t test). x Difference between preintervention and 2-week data. y Difference between preintervention and 6-week data (comparisons between proportions). ⁎ P b .05. ⁎⁎ P b .01. ⁎⁎⁎ P b .001.

Table 1 shows the changes in anthropometric variables and the CRF examined over the study period. Weight and BMI declined in group C and V subjects at both 2- and 6-week intervals, and a reduction in the waist/hip ratio was noticed at 6 weeks. No significant changes in blood pressure were found by ANOVA test (Table 1), but when the Student t test for paired samples was used, a significant reduction in the diastolic blood pressure of group C subjects at 6 weeks was found (from 74.9 ± 8.2 to 70.2 ± 8.5 mm Hg; P b .01). Blood analyses showed a reduction in total cholesterol and HDL-C levels in both groups of subjects and at both time intervals. Low-density lipoprotein cholesterol and non– HDL-C levels decreased only in diet group V after 2 and

6 weeks. Plasma homocysteine levels were significantly reduced by week 2 in group C subjects and in both groups after 6 weeks (Table 1). We found correlations between the decrease in homocysteine levels and other CRF. At the beginning of the study, homocysteine levels were inversely related to folate intake (r = −0.343) and serum levels (r = −0.400). At week 2, these correlations were maintained (r = −0.529 and r = −0.353, respectively). No such relations were observed with either pyridoxine or vitamin B12. Table 2 shows daily energy and vitamin B6, folate, and B12 intake, and percentage of subjects with vitamin intakes below recommended levels in groups C and V. In both groups, subjects showed a significant reduction in energy

Table 3 Serum vitamin concentrations and percentage of subjects with vitamin values below selected cutoffs in adult women at baseline and during weight loss consuming hypocaloric diets based on increased consumption of vegetables (diet V) or cereals (diet C) Preintervention data

Results at 2 weeks

Diet V (n = 27) Diet C (n = 29) Diet V (n = 26) Diet C (n = 29) Folic acid (nmol/L) Folic acid b6.8 nmol/L (%) Folic acid b14.9 nmol/L (%) Pyridoxal phosphate (nmol/L) Piridoxal phosphate b25 nmol/L (%)

17.2 ± 8.5 0 44.4 50.9 ± 45.2 14.8

18.4 ± 15.6 3.5 41.4 68.8 ± 67.3 10.3

21.2 ± 10.6 a⁎ 0 30.8 62.7 ± 80.7 11.5

30.4 ± 15.8 a⁎⁎, d⁎⁎ 0 13.8 x⁎ 142.7 ± 102.1 a⁎⁎, d⁎⁎ 0

Values are mean ± SD except percentages. a Difference between preintervention and 2-week data. b Difference between preintervention and 6-week data. c Difference between 2- and 6-week data (ANOVA). d Difference between diets C and V (Student t test). x Difference between preintervention and 2-week data. y Difference between preintervention and 6-week data (comparisons between proportions). ⁎ P b .05. ⁎⁎ P b .01. ⁎⁎⁎ P b .001.

Results at 6 weeks Diet V (n = 26) Diet C (n = 27) 21.3 ± 7.9 0 11.5 y⁎⁎ 54.7 ± 31.7 7.7

32.9 ± 15.1 b⁎⁎, d⁎⁎ 0 11.1 y⁎⁎ 110.0 ± 54.4 b⁎⁎, c⁎, d⁎⁎⁎ 0

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and vitamin B12 intake, whereas the intake of vitamin B6 and folate increased after 2 and 6 weeks. Table 3 presents serum vitamin B6, folic acid, and B12 concentrations, and percentage of women with vitamin values below the selected cutoffs. Group C subjects showed an increase in serum folic acid and pyridoxine at 2 and 6 weeks; only group V showed an increase in serum folic acid at 2 weeks. In addition, the intake of these nutrients, their serum concentrations, and the amount by which these variables increased were greater in group C subjects after 2 and 6 weeks. The influence of folate on homocysteine levels was further reflected in those subjects who increased their folate intake by 50 μg/d or less and showed significantly smaller reductions in their homocysteine levels than those who increased their intake by 350 μg/d or more (0.13 ± 1.35 μmol/L compared to 1.62 ± 1.1 μmol/L) (P b .05). Folate status was thus determined to be the most important factor influencing plasma homocysteine levels. 4. Discussion The initial dietetic and anthropomorphic data obtained were similar to that reported by other groups of overweight women [17,20,22,42]. The initial consumption of meat/fish/ eggs was somewhat higher than that recommended, whereas that of cereals/pulses, vegetables/greens, and fruit was lower. The same situation has been reported in other studies [17,20,42]. This justifies the use of diets C and V during the intervention period, which was the aim of this study to approximate the diet to the theoretical ideal [17,18,20,41] while providing a slightly restricted (hypocaloric) energy intake. The results obtained over the study period indicate that the goals set by the study were attained and that food intake was brought closer to that recommended. As a consequence of this dietary intervention, a reduction in energy intake was achieved. Reductions in body weight, BMI (at 2 and 6 weeks into the study period), and waist/hip ratio (at 6 weeks) were achieved with both diets C and V. Energy restriction with an increase in vegetables or cereals could bring about favorable changes in anthropometric and cardiovascular risks in women [43,44]. Several authors have reported a strong correlation between reduction in body weight and blood pressure values [5,43]. In our study, we found a correlation in group C of reduced diastolic blood pressure at 6 weeks. This might be due to the greater weight loss noticed in these subjects or to the nutritional improvement they experienced with respect to certain nutrients. The initial blood analysis results were similar to those recorded in other studies [7-9,45-47]. As reported by other authors for groups following weight loss diets, HDL-C [3,44], total-cholesterol, and LDL-C levels [48] decreased in our study (LDL-C only in group V). Some studies have observed that low-fat and high-carbohydrate diets increase triacylglycerol levels, but this was not observed in the

present study despite the fact that in both diets the amount of energy from carbohydrates increased (9.6% in diet V and 14.3% in diet C at 6 weeks). Cui et al [49] suggested that the serum concentration of non–HDL-C may be a better indicator of risk of cardiovascular disease death than LDLC concentration. In the present study, non–HDL-C levels were changed by dietary intervention in group V; this diet might therefore be considered positive in this respect. Some authors [7,50] have reported a correlation between homocysteine levels and other cardiovascular risk factors such as body weight and blood pressure. However, we did not find this correlation. Plasma homocysteine levels are influenced by folate, vitamin B6, and vitamin B12 status [6-8]; the levels of these vitamins were therefore monitored in the present study. Homocysteine levels were reduced to a greater extent in group C subjects at 2 weeks. This might be caused by the greater increase in their intake and serum concentrations of folic acid [51]. This greater intake was probably due to the consumption of the breakfast cereals: the variety used is enriched with this vitamin. Although some vegetables are very rich in folates, cooking may cause their thermal breakdown or their elimination with the cooking water during straining [52]. Group B vitamins, and in particular vitamin B6, are modulators of cardiovascular risk independent of homocysteine levels [53]. In the present population, increases in the intake and serum levels of this vitamin were recorded; however, in agreement with other authors [54], no correlation was observed between intake or serum concentration increase and the reduction in homocysteine levels. Although both dietary interventions (C and V) led to similar reductions in body weight, BMI, waist/hip ratio, and total cholesterol concentration, diet V was more successful in reducing LDL and non–HDL-C than diet C, whereas the latter reduced diastolic blood pressure and plasma homocysteine levels more at 2 weeks than diet V. Increasing the consumption of breakfast cereals and vegetables in the context of a slightly hypocaloric diet may therefore be a good way to lose body weight and reduce some of the cardiovascular risks faced by overweight/obese women. References [1] World Health Organization. Diet, nutrition and the prevention of chronic diseases 2003. Report of a joint WHO/FAO Expert Consultation. Technical Report Series 916. Geneva: World Health Organization; 2003. p. 81-94. [2] McGee DL. Diverse populations collaboration. Body mass index and mortality: a meta-analysis based on person-level data from twenty-six observational studies. Ann Epidemiol 2005;15:87-97. [3] Pelkman CL, Fishell VK, Maddox DH, Pearson TA, Mauger DT, KrisEtherton PM. Effects of moderate-fat (from monounsaturated fat) and low-fat weight-loss diets on the serum lipid profile in overweight and obese men and women. Am J Clin Nutr 2004;79:204-12. [4] Liu L, Ikeda K, Chen M, Yin W, Mizushima S, Miki T, et al. Obesity, emerging risk in China: trend of increasing prevalence of obesity and its association with hypertension and hypercholesterolaemia among the Chinese. Clin Exp Pharmacol Physiol 2004;31(Suppl 2):S8–S10.

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