Eman M. Alissa

Heavy Metal Poisoning and Cardiovascular Disease

Cardiovascular disease (CVD) is an increasing world health problem. Traditional risk factors fail to account for all deaths from CVD. It is mainly the environmental, dietary and lifestyle behavioral factors that are the control keys in the progress of this disease. The potential association between chronic heavy metal exposure, like arsenic, lead, cadmium, mercury, and CVD has been less well defined. The mechanism through which heavy metals act to increase cardiovascular risk factors may act still remains unknown, although impaired antioxidants metabolism and oxidative stress may play a role. However, the exact mechanism of CVD induced by heavy metals deserves further investigation either through animal experiments or through molecular and cellular studies. Furthermore, large-scale prospective studies with follow up on general populations using appropriate biomarkers and cardiovascular endpoints might be recommended to identify the factors that predispose to heavy metals toxicity in CVD. In this review, we will give a brief summary of heavy metals homeostasis, followed by a description of the available evidence for their link with CVD and the proposed mechanisms of action by which their toxic effects might be explained. Finally, suspected interactions between genetic, nutritional and environmental factors are discussed.

Functional Foods and Nutraceuticals in the Primary Prevention of Cardiovascular Diseases

Cardiovascular disease (CVD) is now the leading cause of death globally and is a growing health concern. Dietary factors are important in the pathogenesis of CVD and may to a large degree determine CVD risk, but have been less extensively investigated. Functional foods are those that are thought to have physiological benefits and/or reduce the risk of chronic disease beyond their basic nutritional functions. The food industry has started to market products labelled as “functional foods.” Although many review articles have focused on individual dietary variables as determinants of CVD that can be modified to reduce the risk of CVD, the aim of this current paper was to examine the impact of functional foods in relation to the development and progression of CVD. Epidemiologic studies have demonstrated the association between certain dietary patterns and cardiovascular health. Research into the cardio-protective potential of their dietary components might support the development of functional foods and nutraceuticals. This paper will also compare the effect of individual bioactive dietary compounds with the effect of some dietary patterns in terms of their cardiovascular protection.

The effects of coadministration of dietary copper and zinc supplements on atherosclerosis, antioxidant enzymes and indices of lipid peroxidation in the cholesterol-fed rabbit

It has previously been shown that dietary copper can modulate the extent of atherosclerosis in the thoracic aorta of cholesterol‐fed rabbits. The metabolism of copper and zinc are closely related, and it has been hypothesized that the balance of dietary copper to zinc may be important in determining coronary risk. Hence, we have investigated the interaction between dietary copper and zinc in atherogenesis in the New Zealand White rabbit. Juvenile male rabbits were randomly allocated to eight groups. Four groups were fed a normal chow diet with zinc (0.5%, w/w), copper (0.2%, w/w), copper plus zinc or neither in their drinking water for 12 weeks. Four other groups were fed a diet containing 0.25–1% (w/w) cholesterol plus zinc, copper, both or neither. Serum cholesterol of individual animals was maintained at approximately 20 mmol/l.

Dietary Fruits and Vegetables and Cardiovascular Diseases Risk.

ABSTRACT Diet is likely to be an important determinant of cardiovascular disease (CVD) risk. In this article, we will review the evidence linking the consumption of fruit and vegetables and CVD risk. The initial evidence that fruit and vegetable consumption has a protective effect against CVD came from observational studies. However, uncertainty remains about the magnitude of the benefit of fruit and vegetable intake on the occurrence of CVD and whether the optimal intake is five portions or greater. Results from randomized controlled trials do not show conclusively that fruit and vegetable intake protects against CVD, in part because the dietary interventions have been of limited intensity to enable optimal analysis of their putative effects. The protective mechanisms of fruit and vegetables may not only include some of the known bioactive nutrient effects dependent on their antioxidant, anti-inflammatory, and electrolyte properties, but also include their functional properties, such as low glycemic load and energy density. Taken together, the totality of the evidence accumulated so far does appear to support the notion that increased intake of fruits and vegetables may reduce cardiovascular risk. It is clear that fruit and vegetables should be eaten as part of a balanced diet, as a source of vitamins, fiber, minerals, and phytochemicals. The evidence now suggests that a complicated set of several nutrients may interact with genetic factors to influence CVD risk. Therefore, it may be more important to focus on whole foods and dietary patterns rather than individual nutrients to successfully impact on CVD risk reduction. A clearer understanding of the relationship between fruit and vegetable intake and cardiovascular risk would provide health professionals with significant information in terms of public health and clinical practice.

Chromium status and glucose tolerance in Saudi men with and without coronary artery disease.

Chromium deficiency is associated with impaired glucose tolerance (IGT) and dyslipidemia. Hence, the objective of the current study was to investigate chromium status among Saudi men with and without established cardiovascular disease (CVD) and its relationship to glucose tolerance, lipid profile and other established CVD risk factors. We measured serum and urine chromium concentrations, fasted lipid profile, plasma glucose, and serum lipid peroxide in 130 Saudi men with an established history of myocardial infarction and 130 age-matched controls without established CVD. Patients with established CVD had higher serum triglycerides (p < 0.05) and plasma glucose (p < 0.0001) and lower serum and urinary chromium concentrations (p < 0.0001) than controls. Serum chromium was inversely correlated with plasma glucose among cases and controls (r = −0.189, p < 0.05 and r = −0.354, p < 0.00001, respectively). Plasma glucose (OR 1.127, CI 1.0–1.269, p < 0.05), serum chromium (OR 0.99, CI 0.985–0.995, p < 0.0001), and urinary chromium (OR 0.988, CI 0.981–0.995, p < 0.001) were independently associated with the presence of established coronary disease applying this model. While chromium metabolism appears to be altered in individuals with CVD, it is unclear whether chromium supplementation would be effective in CVD prevention among patients with IGT. This would need to be tested in long-term outcome trials.

Increased insulin resistance is associated with increased urinary excretion of chromium in non-diabetic, normotensive Saudi adults

The role of trivalent chromium in improving glucose tolerance is well documented. Increased urinary chromium has been reported in type 2 diabetes mellitus, but it was not clear whether this had preceded diabetes mellitus, or was caused by it. Aim was to investigate the relationship between urinary chromium and the degree of insulin resistance in non-diabetic normotensive Saudi adults. 357 healthy adults aged 18–50 years were recruited randomly in a cross-sectional study design. Anthropometric and demographic information were taken. Insulin, glucose and free fatty acids were measured in fasting blood samples. Fasting urinary chromium and creatinine were also determined. Using modified QUICKI, subjects were labeled as high insulin resistant, or low insulin resistant. High insulin resistant subjects were matched for age and sex to low insulin resistant subjects. High insulin resistant subjects had higher mean BMI (p<0.001), mean waist circumference (p<0.01), and median urinary chromium (p<0.001) compared to low insulin resistant subgroup. Higher urinary chromium in high insulin resistant subgroup indicates a renal lesion leading to chromium deficiency and possibly diabetes mellitus eventually. Chromium supplementation might help to protect against the development of diabetes mellitus in this group of high insulin resistant non-diabetic Saudi individuals.

Selenium Status and Cardiovascular Risk Profile in Healthy Adult Saudi Males

The purpose of this research was to investigate the relationship between selenium levels, thyroid function and other coronary risk factors in 140 Saudi subjects without overt coronary heart disease stratified by age. Demographic data and serum fasting lipid profile, glucose, thyroid function tests, selenium status and dietary intake was assessed. The relationships between selenium status, thyroid function and cardiovascular risk factors were assessed by univariate and multivariate analysis. The results showed that thyroid hormone levels did not differ with age. Erythrocyte glutathione peroxidase (GPx) levels were significantly higher in the youngest vs. oldest tertile (p<0.0001). Selenium and iodine intake did not differ significantly with age tertile, but the average intake for the population sample was below the estimated average requirements for both elements. Serum lipoprotein (a) concentrations correlated with selenium (r = 0.417, p<0.0001) and TSH (r = 0.172, p<0.05). After adjustment for confounding variables; serum fT4 and erythrocytes GPx remained significant determinants of serum TSH levels, whilst serum selenium and TSH were determinants of serum fT4 levels. Serum Lp(a), a coronary risk factor, was strongly related to measures of selenium status. A significant relationship between measures of selenium status and thyroid function was found. Serum Lp(a) a known risk factor for cardiovascular disease was also related to selenium status in our population.

Estimation of insulin resistance in non-diabetic normotensive Saudi adults by QUICKI, HOMA-IR and modified QUICKI: a comparative study.

Background and Objectives :Identification of insulin resistance (IR) in the general population is important for developing strategies to reduce the prevalence of non-insulin-dependent diabetes mellitus (NIDDM). We used the original and a modified version of the Quantitative Insulin Sensitivity Check Index (QUICKI, M-QUICKI), and the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) to divide non-diabetic normotensive adults into high- (HIR) and low-insulin-resistant (LIR) subgroups to investigate similarities and differences in their characteristics. Subjects and Methods : Three hundred fifty-seven healthy adults aged 18-50 years were recruited randomly from health centers in Jeddah in a cross-sectional study design. Anthropometric and demographic information was taken. Insulin, glucose, lipid profile and free fatty acid were determined in fasting blood samples. M-QUICKI, HOMA-IR and QUICKI were calculated. Reported cut-off points were used to identify HIR subjects, who were then matched for age and sex to others in the study population, resulting in 3 HIR and 3 LIR subgroups. Results : Two hundred nine subjects satisfied the selection criteria. M-QUICKI correlated significantly (P=.01) with HOMA-IR and QUICKI values. Increased adiposity was the common characteristic of the three HIR subgroups. HIR subgroups identified using M-QUICKI (97 subjects) and HOMA (25 subjects), but not QUICKI (135 subjects), had statistically different biochemical characteristics compared to corresponding LIR sub-groups. Conclusion : Adiposity, but not sex, is a risk factor for IR in the studied population. Further studies are needed to choose the most appropriate index for detecting IR in community-based surveys.

Bronchial asthma and hypovitaminosis D in Saudi children

Background Asthma, a common lung disease in children, is caused by excessive immune responses to environmental antigens. Objective Given the immuno-modulatory properties of vitamin D, the aim of the current study was to investigate the relationship between vitamin D levels and markers of asthma severity. Methods This was investigated in a 70 Saudi children with and without asthma and were recruited from the King Abdul Aziz University Hospital, Jeddah, Saudi Arabia, over the period of 11 months (May 2011-April 2012). Childhood asthma control test instrument was employed to assess the level of asthma control among asthmatic patients. Anthropometric measurements were taken and interviewer-administrated questionnaire was completed for all study participants. Pulmonary function test was performed by recording changes in the peak expiratory flow. Venous blood samples were withdrawn for measurements of vitamin D, bone profile, cytokines profile (interleukin-10, tumor necrosis factor-alpha, platelets derived growth factor), and atopy markers (IgE and eosinophil count). Results Hypovitaminosis D is highly prevalent among asthmatic children with highly significant increase in several markers of allergy and asthma severity as compared with healthy control children. Significant correlations between several inflammatory and immunological markers and vitamin D levels were also found. Finally, lower 25-hydroxyvitamin D levels were associated with a higher asthma prevalence in multivariable analysis. Conclusion Our study showed that hypovitaminosis D is highly prevalent in the whole population in addition to a highly significant increase in several markers of allergy and asthma severity among asthmatic children as compared with healthy control children.

Serum osteocalcin is associated with dietary vitamin D, body weight and serum magnesium in postmenopausal women with and without significant coronary artery disease

Osteoporosis and atherosclerosis often present atypically in postmenopausal women, making clinical recognition difficult. Prospective studies suggest independent associations between bone mass and vascular calcification through vitamin D deficiency as an established predictor of both conditions. We aimed to examine the relationship between serum osteocalcin and vitamin D status in postmenopausal women with and without angiographic evidence of coronary artery disease (CAD). One hundred and eighty postmenopausal women undergoing coronary angiography were selected sequentially from the Catheterization unit of King Abdulaziz University Hospital. Socio-demographic, anthropometric parameters and dietary habits were measured. Biochemical variables were estimated in blood samples. Half of the postmenopausal women did not have significant CAD, 24% had significant CAD in a single and/or double coronary vessels, 26% had significant CAD in three coronary vessels. Mean serum vitamin D concentrations showed that vitamin D deficiency was a common finding in the whole population. Vitamin D and calcium intakes were uniformly low in the study cohort. Serum osteocalcin was significantly correlated with dietary vitamin D in all subgroups (r=-0.172, p<0.05) and positively correlated among the patients (r=0.269, p=0.01). Serum magnesium, alkaline phosphatase, dietary vitamin D, and body weight were independent variables of serum osteocalcin level. In conclusion, elevated levels of serum C reactive protein and vitamin D were associated with low serum osteocalcin levels. Therefore, osteocalcin may be a potential cardiovascular risk marker. However, further studies are needed to clarify the pathophysiological processes underlying the relationship between serum osteocalcin level and atherosclerosis parameters.