Márcia Regina Simas Torres Klein

Vitamin D deficiency is associated with insulin resistance independent of intracellular calcium, dietary calcium and serum levels of parathormone, calcitriol and calcium in premenopausal women

BACKGROUND There is evidence that vitamin D deficiency is associated with increased risk of cardiovascular disease. However, it is not known if this association is independent of dietary calcium, intracellular calcium and serum levels of parathormone, calcitriol and calcium. OBJECTIVES To investigate the independent relationship of vitamin D deficiency with insulin resistance, lipid profile, inflammatory status, blood pressure and endothelial function. METHOD Cross-sectional study conducted with 73 healthy Brazilian premenopausal women aged 18 - 50 years. All participants were evaluated for: 25 hydroxyvitamin D serum levels, anthropometric parameters, body composition, calcium metabolism, insulin resistance, lipoprotein profile, inflammatory status, blood pressure and endothelial function. Endothelial function was assessed by reactive hyperemia index using Endo-PAT 2000®. Women were stratified in two groups: with vitamin D deficiency (25 hydroxyvitamin D < 20 ng/ml; n=12) and without vitamin D deficiency (25 hydroxyvitamin D ≥ 20 ng/ml; n=61). RESULTS AND DISCUSSION Participants with vitamin D deficiency compared with those without deficiency of this vitamin had significantly higher levels of glucose (88.25 ± 3.24 vs. 80.15 ± 1.13 mg/dl), greater HOMA-IR (6.43 ± 0.73 vs. 4.42 ± 0.25) and lower reactive hyperemia index (1.68 ± 0.1 vs. 2.17 ± 0.1). After adjustments for confounding factors including age, body mass index, waist circumference, dietary calcium, intracellular calcium and serum levels of parathormone, calcitriol and calcium differences between groups remained significant, regarding glucose and HOMA-IR. CONCLUSIONS The findings of the present study suggest that vitamin D deficiency is associated with insulin resistance independent of dietary calcium, intracellular calcium and serum levels of parathormone, calcitriol and calcium in healthy premenopausal women.

Short-term Effects of Green Tea on Blood Pressure, Endothelial Function, and Metabolic Profile in Obese Prehypertensive Women: A Crossover Randomized Clinical Trial

Background: Green tea consumption has been inversely associated with cardiovascular disease (CVD) in epidemiological studies. Although some interventional trials suggest that green tea has beneficial effects on CVD risk factors, such as hypertension and obesity, others have failed to show such benefits. Aims: To evaluate the short-term effects of green tea on blood pressure, endothelial function, metabolic profile, and inflammatory activity in obese prehypertensive women. Methods: This study was a crossover, randomized, double-blind, placebo-controlled clinical trial. Participants were randomly allocated to receive daily 3 capsules containing either 500 mg of green tea extract (GTE) or a matching placebo for 4 weeks, with a washout period of 2 weeks between treatments. Each GTE capsule contained 260 mg of polyphenols. At the beginning and at the end of each treatment, participants were submitted to evaluation of blood pressure (ambulatory blood pressure monitoring, ABPM), endothelial function (Endo-PAT 2000 and cellular adhesion molecules), nutritional parameters, metabolic profile, and biomarkers of inflammation. Results: Twenty women age 41.1 ± 8.4 years completed the study. After 4 weeks of GTE supplementation in comparison with placebo, there was a significant decrease (p < 0.05) in systolic blood pressure at 24 hours (−3.61 ± 1.23 vs 1.05 ± 1.34 mmHg), daytime (−3.61 ± 1.26 vs 0.80 ± 1.57 mmHg), and nighttime (−3.94 ± 1.70 vs 1.90 ± 1.66 mmHg). Changes in diastolic blood pressure and in all other parameters did not present a significant difference between GTE and placebo. Conclusion: The findings of this study suggest that in obese prehypertensive women, short-term daily intake of GTE may decrease blood pressure.

The effects of moderate energy restriction on apnoea severity and CVD risk factors in obese patients with obstructive sleep apnoea.

Nutritional intervention for weight loss is one of the treatment options for obstructive sleep apnoea (OSA) in patients with overweight or obesity. However, the effects of moderate energy restriction on OSA severity are not yet known. The present study aimed to evaluate the effects of moderate energy restriction on OSA severity and CVD risk factors in obese patients with OSA. In this 16-week randomised clinical trial, twenty-one obese subjects aged 20-55 years and presenting an apnoea/hypopnoea index (AHI)≥5 events/h were randomised into two groups: the energy restriction group (ERG) and the control group (CG). The ERG was instructed to follow an energy-restricted diet -3347·2 kJ/d (-800 kcal/d) and the CG was advised not to change their food intake. At the beginning and at the end of the study, participants underwent evaluation of the following: OSA (Watch-PAT200®), nutritional parameters, blood pressure, sympathetic activity, inflammatory biomarkers, metabolic profile and endothelial function. The ERG (n 11), compared with the CG (n 10), had a significantly greater reduction in body weight (Cohens d=-1·19; P<0·001), in AHI (Cohens d=-0·95; P=0·04) and in plasma concentrations of adrenaline (Cohens d=-1·02; P=0·04) as well as a significantly greater increase in minimum O2 saturation (Cohens d=1·08; P=0·03). Although energy restriction was not associated with significant improvements in CVD risk factors, medium-to-large effect sizes were observed, suggesting that the statistically non-significant difference between groups may be due to the small sample size. This study suggests that in obese patients with OSA, moderate energy restriction is able to reduce the parameters of OSA severity and sympathetic activity.

Phytosterols in the Treatment of Hypercholesterolemia and Prevention of Cardiovascular Diseases

Phytosterols are bioactive compounds found in foods of plant origin, which can be divided into plant sterols and plant stanols. Clinical studies consistently indicate that the intake of phytosterols (2 g/day) is associated with a significant reduction (8-10%) in levels of low-density lipoprotein cholesterol (LDL-cholesterol). Thus, several guidelines recommend the intake of 2 g/day of plant sterols and/or stanols in order to reduce LDL-cholesterol levels. As the typical western diet contains only about 300 mg/day of phytosterols, foods enriched with phytosterols are usually used to achieve the recommended intake. Although phytosterols decrease LDL-cholesterol levels, there is no evidence that they reduce the risk of cardiovascular diseases; on the contrary, some studies suggest an increased risk of atherosclerosis with increasing serum levels of phytosterols. This review aims to address the evidence available in the literature on the relationship between phytosterols and risk of cardiovascular disease.

No difference in acute effects of supplemental v. dietary calcium on blood pressure and microvascular function in obese women challenged with a high-fat meal: a cross-over randomised study.

Recent studies suggest that supplemental Ca (SC) increases the risk of cardiovascular events, whereas dietary Ca (DC) decreases the risk of cardiovascular events. Although frequently consumed with meals, it remains unclear whether Ca can mitigate or aggravate the deleterious effects of a high-fat meal on cardiovascular risk factors. This study aimed to evaluate the effects of SC or DC on blood pressure (BP) and microvascular function (MVF) in the postprandial period in obese women challenged with a high-fat meal. In this cross-over controlled trial, sixteen obese women aged 20-50 years were randomly assigned to receive three test meals (2908 kJ (695 kcal); 48 % fat): high DC (HDCM; 547 mg DC), high SC (HSCM; 500 mg SC-calcium carbonate) and low Ca (LCM; 42 mg DC). BP was continuously evaluated from 15 min before to 120 min after meals by digital photoplethysmography. Before and 120 min after meals, participants underwent evaluation of serum Ca and microvascular flow after postocclusive reactive hyperaemia (PORH) by laser speckle contrast imaging. Ionised serum Ca rose significantly only after HSCM. Systolic BP increased after the three meals, whereas diastolic BP increased after LCM and HDCM. Hyperaemia peak, hyperaemia amplitude and AUC evaluated after PORH decreased with LCM. After HDCM, there was a reduction in hyperaemia peak and hyperaemia amplitude, whereas HSCM decreased only hyperaemia peak. However, comparative analyses of the effects of three test meals on serum Ca, BP and MVF revealed no significant meal×time interaction. This study suggests that in obese women SC and DC do not interfere with the effects of a high-fat meal on BP and MVF.

Obstructive sleep apnea in non-dialyzed chronic kidney disease patients: Association with body adiposity and sarcopenia

OBJECTIVES Obstructive sleep apnea (OSA) is a risk factor for cardiovascular disease (CVD), the main cause of mortality in chronic kidney disease (CKD). Although the prevalence of OSA in patients with CKD has not been established, a few studies suggest that it is higher than in the general population, potentially increasing the risk for CVD. Obesity increases the risk, whereas sarcopenia has been suggested as a consequence of OSA in the general population. To our knowledge, these associations have not been adequately evaluated in patients with CKD. The aim of this study was to evaluate OSA frequency and its association with total and upper body adiposity and sarcopenia in non-dialyzed CKD patients. METHODS This cross-sectional study included 73 patients with stages 3b-4 CKD (42 men, 62.9 ± 1.1 y of age). Glomerular filtration rate was estimated by the CKD-Epidemiology Collaboration equation. Patients were assessed for OSA by Watch-PAT200 (apnea-hypopnea index ≥5 events hourly; Itamar Medical), total body adiposity by dual-energy x-ray absorptiometry (DXA) and body mass index (BMI), upper body adiposity by anthropometric parameters and by trunk and visceral fat by DXA, and sarcopenia. RESULTS OSA frequency was 67% (N = 49). Both total and upper body adiposity were associated with the presence and severity of OSA. In non-obese patients (BMI <30 kg/m2), upper body obesity increased significantly the frequency of OSA. OSA association with sarcopenia was blunted when BMI was included in regression model. CONCLUSIONS Results from the present study suggest that in non-dialyzed CKD patients OSA is very common and associated with total and upper body obesity, but not with sarcopenia.

Serum Uric Acid Levels are Associated with Cardiometabolic Risk Factors in Healthy Young and Middle-Aged Adults

Background Observational studies have highlighted an association between serum uric acid (SUA) levels and cardiovascular risk factors. Despite the growing body of evidences, several studies were conducted in older individuals or in carriers of diseases susceptible to affect SUA levels and cardiometabolic risk markers. Objective To evaluate the relationship of SUA with body adiposity, metabolic profile, oxidative stress, inflammatory biomarkers, blood pressure and endothelial function in healthy young and middle-aged adults. Methods 149 Brazilian adults aged 20-55 years, both sexes, underwent evaluation of body adiposity, SUA, fasting glucose and insulin, lipid profile, malondialdehyde (MDA), high sensitivity C-reactive protein (hs-CRP), adiponectin, blood pressure and endothelial function. Endothelial function was assessed by the reactive hyperemia index (RHI) derived from peripheral arterial tonometry method. Participants were allocated in two groups according to SUA levels: control group (CG; n = 130; men ≤ 7 mg/dL, women ≤ 6 mg/dL) and hyperuricemia group (HG; n = 19; men > 7 mg/dL, women > 6 mg/dL). A P-value < 0.05 was considered statistically significant. Results After adjustment for confounders, participants in HG compared with those in CG displayed higher body mass index (BMI): 34.15(33.36-37.19) vs.31.80 (26.26-34.42) kg/m2,p = 0.008, higher MDA: 4.67(4.03-5.30) vs. 3.53(3.10-4.07) ng/mL, p < 0.0001 and lower RHI: 1.68 ± 0.30 vs. 2.05 ± 0.46, p = 0.03). In correlation analysis adjusted for confounders, SUA was positively associated (p < 0.05) with BMI, waist circumference, LDL-cholesterol, triglycerides and MDA, and negatively associated (p < 0.05) with HDL-cholesterol, adiponectin and RHI. Conclusions This study suggests that in healthy young and middle-aged adults higher SUA levels are associated with higher body adiposity, unfavorable lipid and inflammatory phenotype, higher oxidative stress and impaired endothelial function.

The influence of dietary and supplemental calcium on postprandial effects of a high-fat meal on lipaemia, glycaemia, C-reactive protein and adiponectin in obese women

Non-fasting hypertriacylglycerolaemia is a risk factor for CVD and the amount of fat in a meal seems to be the main factor influencing postprandial lipaemia. Although several studies suggest that Ca can increase faecal fat excretion, it is not known whether Ca can decrease postprandial TAG. This study aimed to evaluate the influence of dietary Ca (DC) and supplemental Ca (SC) on lipaemia, glucose metabolism, C-reactive protein (CRP) and adiponectin during postprandial period in obese women challenged with a high-fat meal. In this cross-over controlled trial, sixteen obese women aged 20-50 years were randomly assigned to receive three test meals (approximately 2900 kJ; 48 % fat): high DC (547 mg DC), high SC (HSCM; 500 mg SC-calcium carbonate) and low Ca (42 mg DC). Blood samples were collected in the fasting period and at minutes 120 and 240 after meals to evaluate total cholesterol and fractions, TAG, glucose, insulin, high-sensitivity CRP and adiponectin. Serum levels of TAG and insulin increased significantly after all test meals. Only after HSCM total cholesterol did not present a significant increase and LDL-cholesterol had a significant decrease. Postprandial glucose, HDL-cholesterol, CRP and adiponectin did not present significant changes after the three test meals. The comparative analysis of the effects of the three test meals on serum lipids, glucose, insulin, CRP and adiponectin revealed no significant meal-by-time interaction. These results suggest that in obese women challenged with a high-fat meal DC and SC do not interfere with postprandial lipaemia, glucose metabolism, CRP and adiponectin.