Unraveling the complex interplay between obesity and vitamin D metabolism.

Vitamin D deficiency and obesity are a worldwide health issue. Obesity refers to the accumulation of excessive fats in the body which could lead to the development of diseases. Obese people have low vitamin D levels for several reasons including larger volume of distribution, vitamin D tightly bound in fatty tissues, reduced absorption, and diets with low vitamin D. Accurately measuring vitamin D metabolites is challenging. The Ultra-High-Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS) method was developed and validated for the analysis of vitamin D metabolites in the serum. Blood samples were collected from 452 subjects which consisted of baseline (vitamin D deficient obese subjects), follow-up (supplemented obese subjects), and healthy volunteers. The vitamin D metabolites were separated adequately by the developed UHPLC-MS/MS method. Moreover, the validation criteria for the method were within an acceptable range. The baseline, follow-up and even healthy volunteers were deficient in 25OHD3 and 25OHD2. The baseline and healthy subjects had comparable concentration of vitamin D2 and D3. However, healthy subjects had a higher concentration of 25OHD and its epimer compared to the baseline subjects. The vitamin D3 was increased significantly in the follow- up subjects; therefore, the 25OHD3 was increased significantly compared to the baseline as well; however, the increase was insufficient to achieve the optimal range. The UHPLC-MS/MS method test was applied successfully on estimation of vitamin D metabolites in subjects. This study indicates the significance of taking into account the metabolic and storage effects when evaluating the vitamin D status in obese subjects.

A randomized, double-blind, placebo-controlled trial of vitamin D supplementation with or without calcium in community-dwelling vitamin D deficient subjects.

BACKGROUND: Although vitamin D deficiency is highly prevalent in the Middle East, very few studies have attempted to measure its health impact. AIMS: We aimed to assess whether vitamin D3 and calcium, either alone or in combination, have health benefit. METHODS: In a 2 × 2 factorial design double-blind, placebo-controlled trial, Community free living adults living in the city of Al Ain, UAE were randomly assigned to receive daily 2000 IU oral vitamin D3 alone, 600 mg calcium alone, oral vitamin D3 (2000 IU per day) combined with 600 mg calcium, or a placebo for 6 months. Primary outcomes were self-rated health and bone turnover markers. RESULTS: Of the 545 randomized, 277 subjects completed 6 months follow up. 25(OH)D levels marginally increased in the two groups received vitamin D3 alone or combined with calcium compared to the decline seen in those who received calcium supplement alone or a placebo. Sub-group analysis revealed that parathyroid hormone (PTH) concentration decreased and Calcium/creatinine ratio increased significantly in the combined vitamin D and Calcium group compared to the vitamin D alone or Calcium alone in contrast to the increase seen in the placebo group [p < 0.05 for between group difference at 6 months]. There were no statistically significant differences between the supplement and placebo groups at the 6 months follow-up in body weight, body mass index (BMI), blood pressure, body pains and general health. CONCLUSION: PTH concentration decreased and calcium/creatinine ratio increased in subjects who received vitamin D and Calcium together compared to those who received vitamin D alone. TRIAL REGISTRATION: NCT02662491 , First registered on 25 January 2016 ( https://register. CLINICALTRIALS: gov/prs/app/action/SelectProtocol?sid=S00060CE&selectaction=Edit&uid=U0001M6P&ts=3&cx=scu4cb , Last update: 05 August 2019.

Thymoquinone Protects against Myocardial Ischemic Injury by Mitigating Oxidative Stress and Inflammation.

The present study was aimed at investigating the cardioprotective activity of thymoquinone (TMQ), an active principle of the herb, Nigella sativa, which is used for the management of various diseases. The present study examined the cardioprotective effect of TMQ in isoproterenol- (ISP-) induced myocardial infarction in rats. Myocardial infarction was induced by two subcutaneous injections of ISP (85 mg/kg) at an interval of 24 hr. TMQ (20 mg/kg) was administered orally for 21 days. ISP-treated rats showed depletion of antioxidants and marker enzymes from myocardium along with lipid peroxidation and enhanced levels of proinflammatory cytokines. ISP also induced histopathological alterations in myocardium. Treatment with TMQ prevented the depletion of endogenous antioxidants and myocyte injury marker enzymes and inhibited lipid peroxidation as well as reducing the levels of proinflammatory cytokines. TMQ pretreatment also reduced myonecrosis, edema, and infiltration of inflammatory cells and showed preservation of cardiomyocytes histoarchitecture. The present study results demonstrate that TMQ exerts cardioprotective effect by mitigating oxidative stress, augmenting endogenous antioxidants, and maintaining structural integrity. The results of the present study indicate that TMQ may serve as an excellent agent alone or as adjuvant to prevent the onset and progression of myocardial injury.

Oxidative damage and inflammation in obese diabetic Emirati subjects.

Visceral obesity is more common in the Arab population and more closely related to morbidity, including diabetes and related cardiovascular diseases (CVD). Possible mechanisms that link visceral fat/obesity to diabetes and CVD complications include inflammation and increased oxidative stress; however, few data are available from the Arab population. Our aim was to determine whether increased adiposity in obese diabetic United Arab Emirates citizens is associated with sub-clinical inflammation and/or increased oxidative stress. A hundred diabetic patients who were part of a randomized controlled trial of nutritional supplements had their baseline characteristics assessed from anthropometric and clinical data following informed written consent. We used WHO figures to classify general and central obesity. Fasting blood samples were collected for the measurement of antioxidants and markers of oxidative damage and inflammation. We found that increased adiposity measured by both body mass index and waist circumference was associated with increased C-reactive protein (CRP) and decreased vitamin C after adjusting for age, duration and treatment of diabetes (p < 0.05). Although there is a clear trend of increased inflammatory markers, notably CRP, and decreased antioxidants with increased BMI and waist circumference in both men and women, the results are statistically significant for women only. CRP were also inversely associated with HDL. Overall, we found that BMI underestimates the rates of obesity compared to waist circumference and that increased adiposity is associated with increased inflammation and decreased HDL and antioxidant status.

Effect of traditional Arabic coffee consumption on the glycemic index of Khalas dates tested in healthy and diabetic subjects.

The consumption of dates with coffee is common among Arabs and may affect postprandial hyperglycemia ex-cursion. The study aimed to determine the effect of coffee on the glycemic index of a common variety of dates (Khalas) tested in healthy and type 2 diabetes mellitus individuals. Study subjects were thirteen healthy volunteers (mean age: 40.2±6.7 years) and ten diabetic participants with a mean HbA1c of 6.6±(0.7%) and a mean age of 40.8±5.7 years. Each subject participated in five days of tests with 50 g of glucose and 50 g equivalent of available carbohydrates from the dates (with/without coffee). Capillary glucose was measured in the healthy subjects at 0, 15, 30, 45, 60, 90 and 120 min, and for the diabetics at 0, 30, 60, 90, 120, 150 and 180 min. Glycemic indices were determined as ratios of the incremental areas under the response curves for the interventions. Statistical analyses were performed using the independent samples and paired t-tests. Mean±SE glycemic indices of the Khalas dates for the healthy individuals were 55.1±7.7 and 52.7±6.2 without and with coffee consumption, respectively. Similar values were observed for those with diabetes (53.0±6.0 and 41.5±5.4). Differences between glycemic indices of Khalas with or without coffee were not significant (p=0.124). There were no significant differences in glycemic index between the diabetic and healthy subjects (p=0.834 and p=0.202 without and with coffee respectively). In conclusion, at least in the short term, coffee does not adversely affect capillary glucose levels following Khalas dates consumption in healthy and diabetic volunteers.

Serum 25-hydroxyvitamin D is not related to cardiac natriuretic peptide in nulliparous and lactating women.

BACKGROUND: Vitamin D deficiency is associated with heightened risk of cardiovascular disease. Potential mechanisms include involvement of vitamin D in regulation of renin-angiotensin system and manufacture and secretion of cardiac natriuretic peptides. Our aim was to document relationships between 25 hydroxyvitamin [25(OH)D] and N-terminal pro B-type natriuretic peptide (NT-proBNP) and plasma renin activity (PRA) levels and to document the effect of vitamin D administration on NT-proBNP and PRA levels in vitamin D deficient subjects. METHODS: Serum 25(OH)D, parathyroid hormone (PTH), plasma or serum NT-proBNP and PRA levels were measured at baseline in nulliparous and lactating women and after 2 months of oral vitamin D2 (2,000 IU/day or 60,000 IU/month) supplementation to lactating women. RESULTS: Baseline levels of 25(OH)D were low (<50 nmol/L) in most women whereas PRA and NT-proBNP levels were within the normal range. There were no significant correlations between baseline 25(OH)D or PTH with NT-proBNP and PRA. Vitamin D administration over a 2-month period in lactating women was associated with a decline in NT-proBNP (by 9.1 +/- 2.0 pmol/L; p < 0.001) and PRA (by 0.32 +/- 0.17 nmol/L/hr; p = 0.064). However, there were no significant correlations between the changes from baseline in 25(OH)D and either NT-proBNP (r = -0.04, p = 0.8) or PRA (r = -0.04, p = 0.8). CONCLUSION: We found no significant correlations between 25(OH)D or PTH with NT-proBNP and PRA in vitamin D deficient women. Further information is required to clarify the effects of vitamin D administration on cardiac structure and function.