Int. J. Vitam. Nutr. Res., 80 (3), 2010, 159 – 167 159

Original Communication Serum Retinol and β-carotene Levels and Risk Factors for in Morbid Gabriela Villaça Chaves, Gisele Gonçalves de Souza, Andréa Cardoso de Matos, Dra. Wilza Abrantes Peres, Silvia Elaine Pereira, Carlos José Saboya, Cristiane Aline D’Almeida, Dra. Andréa Ramalho

Departamento de Nutrição Social e Aplicada, Instituto de Nutrição, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, (Department of Social and Applied Nutrition, Nutrition Institute, Federal University of Rio de Janeiro)

Received: October 13, 2008, Accepted: April 1, 2009

Abstract: Objective: To evaluate retinol and β-carotene serum levels and their relationship with risk factors for cardiovascular disease in individuals with morbid obesity, resident in Rio de Janeiro. Me- thodology: Blood serum concentrations of retinol and β-carotene of 189 morbidly obese individuals were assessed. The was identifi ed according to the criteria of the National Cho- lesterol Education Program (NCEP) and World Health Organization (WHO). Lipid profi le, insulin resistance, basal insulin, glycemia, blood pressure, and anthropometry and their correlation with retinol and β-carotene serum levels were evaluated. Results: Metabolic syndrome diagnosis was observed in 49.0% of the sample. Within this percentage the levels of β-carotene were signifi cantly lower when body mass index increased. Serum retinol didn’t show this behavior. Serum retinol inadequacy in patients with metabolic syndrome (61.3%), according to WHO criterion, was higher (15.8%) than when the whole sample was considered (12.7%). When metabolic syndrome was diagnosed by NCEP criterion, β-carotene inadequacy was higher (42.8%) when compared to the total sample (37.5%). There was a signifi cant difference between average β-carotene values of patients with and without metabolic syn- drome (p=0.048) according to the classifi cation of the NCEP. Lower values were found in patients with metabolic syndrome. Conclusion: Considering the vitamin A contribution in antioxidant protection, especially when risk factors for cardiovascular disease are present, it is suggested that great attention be given to morbidly obese. This could aid in prevention and treatment of cardiovascular disease, which affects a signifi cant part of the population.

Key words: cardiovascular diseases, morbid obesity, risk factors, vitamin A.

DOI 10.1024/0300–9831/a000018 Int. J. Vitam. Nutr. Res., 80 (3), 2010, © Hogrefe & Huber Publishers 160 G.V. Chaves et al.: Serum Retinol and β-carotene Levels and Risk Factors for Cardiovascular Disease

Introduction β-carotene alone is an important element in defend- ing against the oxidative attack of low-density lipo- Obesity is a growing problem, with alarming rates protein cholesterol (LDL-C), and has been associated worldwide; the World Health Organization (WHO) with high-density lipoprotein cholesterol (HDL-C) estimates that there are currently over 300 million cas- increase, both in vitro and in vivo. On the other hand, es, occurring in both developed or developing nations, retinol inhibits transcription of the inducible nitric affecting adults and children and possibly co-existing oxide synthase gene (iNOS), an enzyme that enables in patients suffering from malnutrition. Obesity can oxygen to stimulate the production of other free radi- be described as a “New World Syndrome”, causing cals, especially the nitric oxide variety. Carotenoids a signifi cant burden to health care services, and is also act as suppressors of iNOS expression, reducing thus considered by developed nations to be the most production of reactive oxygen species [9]. important nutritional disorder [1]. In recent times, the relationship between low serum In Brazil, data published by the Brazilian Institute retinol and/or carotenoid concentrations and some of Geography and Statistics (the second stage of the cardiovascular disease (CVD) risk factors has been Household Budget Survey, from 2002 to 2003, in part- demonstrated, which is extremely relevant due to the nership with the Ministry of Health), reveals how the importance of antioxidants in maintaining cardiovas- incidence of excess weight is suffered by 38.8 million cular health [10]. Brazilians, accounting for 40.6% of the adult popula- In relation to metabolic syndrome (MS), there tion. Excessive weight tends to increase in men as they have been few studies designed for assessment of the age and become wealthier. It appears that the frequen- vitamin A nutritional status in individuals with the cy of being overweight greatly exceeds that of being syndrome and, in the case of morbidly obese individu- underweight by eight times in the case of the female als with MS, no work has been done to investigate population, and fi fteen times in the male population [2]. defi ciency in this vitamin. Ford et al. [11] found re- An increase in obesity could be found in the popu- duced vitamin C, E, and carotenoid levels, as well as lation’s wealthiest social classes as well as the poorest lower dietary intake of fruits and vegetables, among since, in addition to being conducive to a sedentary individuals suffering from MS. Moreover, carotenoid life-style, the process of industrialization has reduced levels decreased according to the increase in the num- the cost of food production, making foods with low ber of components of MS. vitamin and mineral content more accessible. These The purpose of this study was to investigate retinol foods generally contain large amounts of energy and and β-carotene serum levels and their relationship to fat, especially saturated fats [2, 3]. As a consequence, CVD risk factors in morbid obesity. Among these the incidence of defi ciencies in micronutrients, even factors we highlight: lipid profi le, blood pressure, gly- if subclinical, can be noted, characterizing a “hidden cemia, baseline insulin, insulin resistance, body mass hunger” co-existing with an increase in obesity [4]. index (BMI), waist circumference (WC), waist/hip Vitamin A defi ciency (VAD) is one of the most ratio (WHR), and the association of these factors, prevalent public health problems in the world, harm- characterized by MS. ing the health of those affl icted in several ways, even causing death. In Brazil, this disorder affects a large proportion of pregnant women and children of pre- school age [5], with a trend toward the situation wors- Material and methods ening due to the nutritional transition that Brazil and several other Latin American countries have been The study investigated 189 individuals with BMI going through over the past twenty years [6], and with ≥ 40 kg/m 2, of both sexes without color or class dis- studies investigating this nutritional defi ciency in other tinction, being treated at the private Carlos Saboya segments of the population being rare. Surgical Clinic in Rio de Janeiro, between February Vitamin A plays a role in several primary func- and September of 2006. The clinic performs on aver- tions of the human body, acting on visual acuity, cell age 250 Roux-en-Y gastric bypass (RYGB) operations differentiation and proliferation, and immunological each year. Around 76% of the patients indicated for activity [7]. Nowadays, more attention is being paid surgery were enrolled in this study. to retinol and carotenoids for their action against free Patients were included in the project by way of radicals, protecting the body against oxidative stress, formal authorization by signing a consent form after thus preventing tissue damage and injuries related to the researcher explained the project’s objectives and various non-transmissible chronic diseases [8]. procedures. Excluded from the study were individu-

Int. J. Vitam. Nutr. Res., 80 (3), 2010, © Hogrefe & Huber Publishers G.V. Chaves et al.: Serum Retinol and β-carotene Levels and Risk Factors for Cardiovascular Disease 161

als with malabsorption syndromes, acute and chronic LDL-C. The National Cholesterol Education Program infections, pregnant and nursing mothers, bearers of (NCEP) criteria [15] for classifying risk of developing associated endocrinopathies, as well as individuals CVD accordingly were adopted. For the purpose of who had undergone bariatric surgery or who were statistical analysis, low-risk/normal-risk values were using vitamin A supplements at the time the study considered appropriate while border high-risk/very- was carried out. high-risk values were considered inadequate. Weight was determined using a platform scale Insulin resistance (IR) was determined by the Ho- (Welmy) with a maximum capacity of 150 kg. Height meostasis Model Assessment Index method (HOMA) was measured using a portable stadiometer (Seca®), [16]. Formula removed. graduated in tenths of a centimeter, attached to a fl at MS was identifi ed by way of diagnostic criteria rec- surface. BMI was calculated from weight and height ommended by the NCEP [15] and the WHO [17], the [12]. most commonly used criteria as they cover several The cut-off points used were those recommended different variables for diagnosis. The NCEP criteria by the WHO (1998) for classifying healthy, over- are the easiest to apply in clinical practice while the weight, and obese individuals. Moreover, the sample WHO criteria identify more serious illnesses. group was classifi ed into BMI interval classes of 5 kg/ According to the NCEP [15], MS diagnosis is per- m2 , resulting in fi ve groups: formed when three or more of the following risk fac- group 1: individuals between 40 and 44.9 kg/m2 ; tors are present: abdominal circumference > 102 cm group 2: those between 45 and 49.9 kg/m2 ; in men or > 88 cm in women; triglycerides ≥ 150 mg/ group 3: those between 50 and 54.9 kg/m2 ; dL, and HDL-C < 40 mg/dL in men or < 50 mg/dL in group 4: those between 55 and 59.9 kg/m2 ; and women; blood pressure ≥ 130/85 mmHg; and fasting group 5: those between 60 to 64.9 kg/m2 . glucose ≥ 110 mg/dL. According to recommendations from the American Waist (WC) and hip (HC) circumference were ob- Association [18], the cut-off point proposed tained using an inextensible measuring tape. Waist/ for impaired fasting glucose diagnosis was altered from hip ratio (WHR) was calculated. The WHR cut-off 110 mg/dL to 100 mg/dL. point used was greater than 1.0 for men and 0.85 for For MS diagnosis, the WHO [17] has proposed that women [12]. individuals with type 2 diabetes (DM II) or glucose Blood pressure was taken according to the Brazil- intolerance should present at least two of the following ian Guidelines for Systemic Arterial components: blood pressure > 140/90 mmHg; hypertri- (SAH) V [13]. Three measurements were taken with glyceridemia > 150 mg/dL or HDL-C levels < 35 mg/dL a minimum interval of one minute between them, for men and < 40 mg/dL for women; central obesity as with the average of the last two measurements consid- measured by waist-hip ratio > 0.90 for men and > 0.85 ered to be the individual’s blood pressure. Individuals for women or BMI > 30 kg/m²; and microalbuminuria with systolic blood pressure greater than or equal to > 20 μg/minute or albumin/creatine relation > 30 mg/g. 140 mmHg and diastolic blood pressure greater than Individuals who did not show any change in glucose or equal to 90 mmHg were considered to have SAH. tolerance must have IR documented by way of a eug- To assess the nutritional state of vitamin A, a 5-mL lycemic clamp, HOMA-IR [16] or by high basal insu- blood sample was collected for laboratory analysis of linemia, in addition to the two criteria aforementioned. serum retinol, after an overnight fast of no less than Statistical analysis was performed using the SPSS 8 hours. Retinol and carotenoid serum levels were statistical package for Windows version 8.0. The level evaluated using high-performance liquid chromatog- of signifi cance adopted was 5%. raphy (HPLC) at the UFRJ Biochemistry Institute laboratory. In this study, serum retinol levels > 1.05 μmol/L were considered to be suffi cient and a cut-off point of ≤ 1.05 μmol/L was used to indicate VAD. Results The cut-off point used to indicate insuffi cient serum β-carotene was ≤ 40 μg/dL, as suggested by Sauberlich The sample group was made up of 189 individuals, et al. [14]. of which 101 (53.4%) were female and 88 (46.6%) The following laboratory tests were performed were male. The mean age was 36.5 ± 11.7 years, with using the esterase/oxidase colorimetric method at a 38.92 ± 2.05 for men and 35.5 ± 1.14 for women. There private laboratory in Rio de Janeiro, Brazil, to assess was no signifi cant difference between the male and lipid profi le: cholesterol, triglycerides, HDL-C, and female average age (p = 0.141).

Int. J. Vitam. Nutr. Res., 80 (3), 2010, © Hogrefe & Huber Publishers 162 G.V. Chaves et al.: Serum Retinol and β-carotene Levels and Risk Factors for Cardiovascular Disease

Considering the sample as a whole, regardless of dL) in β-carotene serum. Distribution of the sample MS diagnosis, the main risk factor observed in the group, according to serum retinol levels, showed that group was excessive LDL-C, with 69.8% of the sample 12.7% of the patients were below the < 1.05 μmol/L presenting high LDL-C levels. Moreover, 39.3% had cut-off point, presenting insuffi cient levels of vitamin hypertriglyceridemia, 33.6% had insuffi cient HDL-c A. Among patients with insuffi cient serum retinol lev- levels, and 46.9% had hypercholesterolemia. Insulin els, 10.4% were in the ≥ 0.70 μmol/L and < 1.05 μmol/L resistance and elevated blood glucose were diagnosed categories, suggesting marginal defi ciency, and 2.3% in 58.5% and 29.7% of the sample group, respectively. were in the > 0.35 μmol/L and < 0.70 μmol/L catego- SAH occurrence was 48.6%. ries, suggesting moderate defi ciency. Thirty-seven- In classifying dyslipidemia according to risk of point-fi ve% of the patients had insuffi cient levels of CVD, 11.7%, 17.9%, 12.2%, and 33.6% of the indi- serum β-carotene (≤ 40 g/dL). viduals showed, respectively, cholesterol, triglycer- There was a positive correlation in serum retinol ides, LDL-C, and HDL-C levels in the high-risk range and β-carotene levels (r = 0.272, p = 0.001). Compar- for developing the disease. ing the β-carotene averages, according to the degree According to the age range classifi cation proposed of serum retinol insuffi ciency, a gradual decline could by the Institute of Medicine (IOM) [7], dividing the be noted as the severity of VAD increased (Table II). age into 3 groups, 19 – 30 years (group 1), 31 – 50 years The serum retinol and β-carotene averages in (group 2), and 51 – 70 years (group 3), signifi cantly patients without MS were 1.61 ± 0.71 μmol/L and higher weight, BMI, and WC averages were observed 49.9 ± 31.7 μg/dL, respectively, while the averages of in the younger age groups, compared with the me- patients with MS diagnosed by the WHO [17] were dian age. There was no signifi cant difference between 1.68 ± 0.62 μmol/L and 56.1 ± 31.1 μg/dL. There was groups 1 and 3, and 2 and 3 (Table I). no signifi cant difference between the serum retinol MS diagnosis was observed in 62.1% female and and β-carotene averages in patients with and without 37.9% male, according to WHO criteria [17]. The MS MS diagnosed using WHO [17] criteria (p = 0.520, diagnosis, according to NCEP [15], was positive in p = 0.184). 61.4% female and 38.6% male. Considering the NCEP [15] MS diagnosis criteria, The three most frequent CVD risk factors in the the serum retinol and β-carotene averages of patients group classifi ed, according to WHO criteria, were without MS were 1.66 ± 0.65 μmol/L and 59.8 ± 34.0 hypertriglyceridemia, low HDL-C levels, and SAH, μg/dL, respectively, while the averages of patients observed in 37.9%, 37.2%, and 54% of the individuals, with MS were 1.68 ± 0.65 μmol/L and 48.7 ± 29.5 μg/ respectively. Table II shows the prevalence of these dL. A signifi cant difference was found in average three main factors, by sex and age. β-carotene levels between patients with and without Risk factors were more prevalent in males: 78%, MS (p=0.048), but no signifi cant difference was noted 48.5%, and 54.5% of these individuals had SAH, in average serum retinol levels (p = 0.820). hypertriglyceridemia, and insuffi cient HDL, respec- Patients diagnosed with MS by the WHO criteria tively. In females, the prevalence of these risk factors [17] had greater percentages of retinol insuffi ciency, was 38.9%, 31.5%, and 26.4%, respectively. Greater while those diagnosed by the NCEP criteria [15] prevalence of these factors was noted as age increased, had a greater percentage of β-carotene insuffi ciency especially in terms of SAH, which was present in 92.9% (Table III). of the individuals in the 51- to 70-year-old age range. A positive correlation was found between levels of As for vitamin A nutritional status, the individu- serum retinol and triglycerides in patients with MS, als studied presented average values of 1.66 μmol/L diagnosed using both WHO (r = 0.205, p = 0.05) and (± 0.65 μmol/L) in serum retinol and 53.8 g/dL (± 32.7 g/ NCEP (r = 0.280, p = 0.022) criteria. A negative cor-

Table I: Mean and standard deviation of the anthropometric variables, according to age. Anthropometric Variables 19 – 30 age 31 – 50 age 51 – 70 age p-value Weight 130.0 ± 16.9a 115.0 ± 15.7b 118.9 ± 16.3b 0.008 BMI 46.0 ± 5.0a 42.6 ± 2.7b 43.2 ± 2.8b 0.035 WC 125.1 ± 8.4a 118.6 ± 10.9b 118.1 ± 8.9b 0.041 BMI = Body mass index; WC= Waist-circumference; Statistical Test: Kruskal-Wallis (post hoc Tukey) * Different letters indicate signifi cant difference (p < 0.05)

Int. J. Vitam. Nutr. Res., 80 (3), 2010, © Hogrefe & Huber Publishers G.V. Chaves et al.: Serum Retinol and β-carotene Levels and Risk Factors for Cardiovascular Disease 163

Table II: Mean β-carotene means in different Vitamin A nutritional statuses Vitamin A Nutritional status β-carotene (μg/dL) Insuffi cient Retinol (≤ 1.05 μmol/L ) 56.2 ± 32.3 Marginal VAD (< 1.05 ≥ 0.7 μmol/L) 48.0 ± 40.6 Moderate VAD (< 0.7 ≥ 0.35 μmol/L) 42.7 ± 46.3 VAD = Vitamin A defi ciency

Table III: Suffi cient serum retinol and β-carotene levels according to MS diagnosis Vitamin A MS – WHO, 1998 MS – NCEP, 2002 Retinol Suffi cient (> 1.05 μmol/L) 84.2% 88.9% Insuffi cient (≤ 1.05 μmol/L) 15.8% 11. % β-carotene Suffi cient (> 40 μg/dL) 67.5% 57.2% Insuffi cient (≤ 40 μg/dL) 32.5% 42.8% MS – WHO= Metabolic syndrome according to WHO, 1998 MS – NCEP= Metabolic syndrome according to NCEP, 2002

relation was found between HC (WC?) extent and as BMI subclasses increased, with a signifi cant differ- β-carotene levels in patients with MS, according to ence between averages from the subclass 40 – 44.9 kg/ NCEP criteria (r = – 0.265, p = 0.029). There was a m² (60.4 ± 31.1 μg/dL), and 60 – 64.9 kg/m² (17.6 ± 7.0 signifi cant negative correlation between WC and μg/dL; p = 0.006). β-carotene levels in patients considered to have MS There was no signifi cant difference between serum according to WHO criteria (r = – 0.211, p = 0.05). retinol (p = 0.649) and β-carotene (p = 0.445) averages In patients without MS, negative correlations as the number of factors involved in diagnosing MS between glycemia and retinol levels (r = – 0.259, increased. p = 0.028) and between triglycerides and β-carotene levels (r = – 0.252, p = 0.031) were found. The other CVD risk factors and other components used for di- agnosing MS showed no correlation with retinol and Discussion β-carotene levels. When comparing average values of anthropometric Morbid obesity is the disease with the highest mor- and biochemical variables for groups with suffi cient tality rate in the world. In Latin America, it is likely and insuffi cient serum retinol and β-carotene levels, that 200,000 people die annually due to associations it was noted that in individuals without MS, the aver- between comorbidities [19]. In the 1990 s, cardiovas- age LDL-C was signifi cantly greater in those present- cular disease was responsible for 26% of deaths in ing insuffi cient serum retinol (133.6 ± 41.4 mg/dL) this region [20]. than in those with suffi cient retinol (111.8 ± 26.9 mg/ In this study, the average age of individuals evalu- dL; p < 0.03). In individuals with MS, according to ated as morbidly obese was 36.5 ± 11.7 years of age, WHO criteria, signifi cantly greater average LDL-C with no statistically signifi cant difference between men (29.4 ± 13.1 mg/dL) was noted in patients with insuf- and women, showing greater prevalence of morbid fi cient serum retinol, when compared with (non-MS?) obesity in the population’s younger age groups. Bray individuals with insuffi cient retinol (19.7 ± 5.1 mg/dL; et al. [21] report that the rate of mortality from morbid p = 0.009). In individuals with MS, according to NCEP obesity is 12 times greater among men from 25 to 40 criteria, no difference was found between the groups years of age compared to normal weight individuals. studied. This makes morbid obesity the second leading cause In individuals with MS, according to WHO guide- of preventable death in the world, second only to au- lines, a reduction was observed in β-carotene levels tomobile accidents.

Int. J. Vitam. Nutr. Res., 80 (3), 2010, © Hogrefe & Huber Publishers 164 G.V. Chaves et al.: Serum Retinol and β-carotene Levels and Risk Factors for Cardiovascular Disease

Higher weight, BMI, and WC averages were found 70% of morbidly obese individuals, using the NCEP in younger age groups. Crerand et al. [22], compared criteria for evaluation. On the other hand, Mendez et historical data regarding the weight of women with al. [29] showed MS to be prevalent in 44% of seriously class III obesity with the weights of women with class obese individuals by using the WHO criteria. I and II obesity. The authors found that women with This study found 12.7% of the sample group to morbid obesity had a longer history of obesity, start- have insuffi cient serum retinol levels, while 37.5% of ing at adolescence, and presented greater body weight the sample group presented insuffi cient β-carotene. throughout life than those with class I and II obesity. Literature shows [10] that in adults, individuals with According to Syme et al. [23], among adolescent lower serum β-carotene levels are at signifi cantly subjects with high levels of intra-abdominal fat (IAF), greater risk of CVD. MS was found in 13.8% of males and 8.3% of females. In Brazil, there are no population studies showing In both males and females, subjects with high vs. low the prevalence of VAD in individuals with diseases IAF had higher levels of fasting insulin, triglycerides, similar to this study profi le (morbidly obese). Howev- and HOMA indices, and lower levels of HDL cho- er, one can conclude that the VAD found in this study, lesterol. The values for insulin, HOMA index, and although lower than those described for traditional triglycerides were higher by 20% to 30% and those risk groups in Brazil [30], is high enough to justify of HDL cholesterol were lower by 7%. greater attention to this segment of the population. So, metabolic alterations can be observed at an Insuffi cient vitamin A nutritional status reduces early age. Therefore, longer periods of obesity can carotenoid conversion in retinol, demonstrating that lead to greater risk of developing chronic diseases, there is a relationship between retinol and carotenoid among them CVD, due to prolonged exposure to nutritional status [31]. In this study, it was found that risk factors. individuals with suffi cient serum retinol levels had The main CVD risk factors found in this study higher serum β-carotene levels, suggesting that a were high levels of LDL-C and glycemia, presence smaller portion of β-carotene had been converted of SAH, and hypercholesterolemia. Lanas et al. [20] into retinol, corroborating the fi ndings of Mecocci et found that abdominal obesity is the most prevalent al. [31]. These fi ndings emphasize the importance of risk factor for acute myocardial infarction in Latin maintaining serum carotenoid levels, given the various America. Obesity is among the ten main risk factors functions they perform in the fi ght against oxidative in the development of the most prevalent and fatal stress. diseases, associated with 40% of all deaths. The other Although no difference between retinol and ten subsequent factors relate to more than 10% of β-carotene levels and components of MS was found, deaths. It is important to note that the risk factors patients with MS displayed signifi cantly lower levels of reported in 3 rd, 7 th, and 14 th place (hypertension, high β-carotene (according to NCEP criteria). In patients cholesterol, and ) have strong as- with MS, according to WHO criteria, as the individu- sociations with obesity [24]. als’ BMI increased, signifi cantly lower β-carotene The proportion of MS cases was greater when using levels were found. Moreover, insuffi ciency of serum the WHO criteria [17]. Women presented a higher retinol in these patients (15.8%) was higher than when prevalence of MS than men in both criteria. Other the sample was considered as a whole (12.7%). studies have compared the use of two criteria for MS Few studies have been designed to assess vitamin diagnosis, some of them showing a higher percentage A nutritional status in individuals with MS. Ford et of MS cases when WHO criteria [25, 26] were applied. al. [11] found reduced levels of vitamin C, E and ca- There are substantial differences between the two rotenoids, as well as lower dietary intake of fruits and criteria. The WHO’s main focus is to detect cases of in- vegetables among individuals with MS. Furthermore, sulin resistance and its association with co-morbidities, the authors noted that carotenoid levels decreased while the NCEP’s defi nition prioritizes abdominal with as the number of components of MS increased, obesity and does not take insulin resistance into con- which was not observed in this study. sideration. Moreover, the WHO uses microalbumin- According to Bozbaş et al. [32] patients with meta- uria, based on its ability to predict CVD, while the bolic syndrome (MS) aggregate atherosclerotic risk NCEP does not include this marker because of the factors. It is general consensus in the literature that diffi culty of using it in practice [27]. all components of MS lead mainly to increased car- As there are many defi nitions of MS in use, it is hard diovascular risk [33], and many studies show the to compare MS prevalence and impact in different relationship between serum retinol and carotenoid populations. Mattar et al. [28] found MS prevalent in levels, due to the role of free radicals in disease patho-

Int. J. Vitam. Nutr. Res., 80 (3), 2010, © Hogrefe & Huber Publishers G.V. Chaves et al.: Serum Retinol and β-carotene Levels and Risk Factors for Cardiovascular Disease 165

genesis [34]. The literature suggests risk of CVD de- Conclusion creased with increased consumption of β-carotene, by increasing serum HDL-C levels, or by inhibiting Despite no difference in retinol and ß-carotene having smooth-muscle-cell proliferation in the arteries’ in- been observed in individuals with CVD risk factors timal layer [4]. alone, greater prevalence of VAD was found in indi- Hypertension is associated with oxidative stress in viduals suffering from MS, regardless of the diagnostic that, as individuals’ blood pressure levels increase, criteria used. there is an increase in free radical production and Based on the aspects discussed, one can conjecture a reduction in some important antioxidants, which that the VAD may have great impact on the preva- could have reduced oxidative damage and possibly lence of CVD, as well as in its progression and com- blood pressure [35]. plications. Therefore, fi ghting vitamin A defi ciency Studies on hypertensive individuals have found low may contribute signifi cantly to the prevention and serum retinol levels, and have reported an inverse treatment of these diseases. It is recommended that association between serum levels of this nutrient and greater attention be paid to this segment of the popula- individuals’ blood pressure [10]. This study found no tion in terms of encouraging greater intake of dietary relationship between vitamin A and β-carotene levels carotenoids and retinol, as foods rich in these nutrients and blood pressure. are also sources of other nutrients with antioxidant In patients without MS, a negative correlation be- functions that are key in maintaining cardiovascular tween glycemia and retinol levels was found. In these health. individuals, average LDL-C was signifi cantly higher among those with insuffi cient retinol. Silva et al. [36] found that insuffi cient carotenoid levels remained in individuals with type 2 diabetes, and no association References with serum retinol levels was found. Literature shows [34] that the hyperglycemia tends to reduce levels of 1. WHO. (2004) Global Strategy on , physical serum antioxidants, such as β-carotene, and increase activity and health. Fifty-seventh world health lipid peroxide levels. Additionally, ingestion of anti- assembly. Disponível em: http://www.who.int/ dietphysicalactivity/en/ oxidants reduces lipid peroxidation levels. In this study, a reduction in β-carotene levels as 2. INSTITUTO BRASILEIRO DE GEOGRAFIA E BMI increased was also observed, with signifi cant dif- ESTATÍSTICA (IBGE). Pesquisa de Orçamento ference between the averages of the different interval Familiar – POF 2002 – 2003. Disponível em: http://ftp. classes. Overweight and obese individuals appear to ibge.gov.br/Orcamentos_Familiares/Pesquisa_de_ be at greater risk of presenting reduced serum reti- Orcamentos_Familiares_2002_2003/Precisao_das_ Estimativas. Acesso em 09/07/2008. nol or carotenoid levels. Studies have shown serum carotenoids to be lower in obese individuals when 3. Monteiro, C.A., Mondini, L. and Costa, R.B.L. (2000) compared to healthy ones, with no signifi cant differ- Mudançãs na composição e adequação nutricional ence in intake of dietary sources for these nutrients da dieta familiar nas áreas metropolitanas do Brasil [37]. Literature also shows [38] a negative correlation (1988 – 1996). Rev. Saúde Pública 34 (3), 251 – 58. between retinol and β-carotene, and BMI. 4. Ramalho, A., Accioly, E. and Silva, L.M. (2003) In regard to retinol and β-carotene levels and obe- Doenças cardiovasculares: Efeito antioxidante das sity, a negative correlation was observed between vitaminas A, C e E. Rev. Metab. Nutr. 17 (1), 6 – 9. β-carotene and WC and HC, according to the WHO and NCEP criteria, respectively. Moreover, in patients 5. UNICEF and The Micronutrient Initiative. Vitamin with MS, according to the WHO criteria, a reduction & Mineral defi ciency: a global progress report. March 2004. in β-carotene levels as BMI interval classes increased was found. Neuhouser et al. [10] observed lower ca- 6. Kac, G. and Velásquez-Meléndez, G.A (2003) rotenoids levels in obese subjects in relation to non- Transição nutricional e a epidemiologia da obesidade obese, and studies [38, 39] with adults have reported na América Latina. Cad. Saúde Pública 19 (suppl 1), lower β-carotene levels in individuals with higher BMI 4 – 5. values. This fi nding may be due to greater metabolic 7. Institute of Medicine (IOM). (2001) Vitamin A. In: use of carotenoids in fi ghting oxidative stress, since Dietary reference intakes for vitamin A, vitamin these individuals are more exposed to increased free K, arsenic, boron, chromium, copper, iodine, iron, radical production. manganese, molybdenum, nickel, silicon, vanadium,

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