Decreased arterial stiffness associated with antioxidant supplementation
August 15 2014. The results of a meta-analysis published online on August 6, 2014 in the Journal of Nutrition indicate that supplementing with antioxidant nutrients could help protect against arterial stiffening that occurs with aging. The condition is associated with atherosclerosis, diabetes and other conditions.
Ammar W. Ashor and colleagues at England’s Newcastle University selected 20 randomized trials that included a total of 1,909 participants aged 22 to 63 for their analysis. Studies involved vitamin C and/or E alone, or a combination of antioxidant vitamins and/or mineral supplementation. Arterial stiffness was evaluated via pulse-wave velocity measurement or other methods.
Pooled analysis of the data revealed a significant reduction in arterial stiffness associated with antioxidant supplementation in comparison with a placebo or no treatment. The benefit was more pronounced in studies in which arterial stiffness was experimentally induced or in primary prevention trials, and was stronger among those with lower plasma vitamin C and E prior to supplementation. Antioxidant vitamins were associated with improvement in arterial stiffness regardless of the participants’ age or length of treatment.
“The beneficial effects of antioxidant vitamins on vascular stiffness may be explained by the reduction of the damaging effects of free radicals on structural and functional components of the vessel walls,” the authors explain. “Antioxidant vitamins inactivate free radicals, reduce inflammation, and therefore protect the integrity of the vascular wall. Furthermore, antioxidant vitamins increase the bioavailability of the vasodilator and anti-inflammatory molecule nitric oxide.”
They add that the arterial response to supplementation is different for each vitamin, which suggests that each one has specific effects on the vascular wall.
“The potential public health importance of these findings remains to be tested in suitably designed personalized (or stratified) intervention studies,” they conclude.
Hip fracture predicted by increased oxidative stress
August 13 2014. The Journal of Bone and Mineral Research published an article online on June 23, 2014 that describes how oxidative stress levels predicted hip fracture in a prospective study of postmenopausal women.
Tianying Wu, MD, PhD, of the University of Cincinnati and her colleagues evaluated data from 996 participants aged 60 years or older upon enrollment in the Nurses’ Health Study between 1989 and 1990. Blood samples obtained at enrollment were analyzed for plasma fluorescent oxidation products (FlOP, an indicator of global oxidative burden) at three excitation/emission wavelengths.
Over a follow-up period of up to 23 years, 44 hip fractures occurred. Women whose FlOP levels were among the middle two-thirds of the group had more than double the risk of hip fracture in comparison with those whose levels were among the lowest third, and for women whose levels were highest, the risk was over two and a half times greater. Among the three wavelengths measured, FlOP_320, which is formed when oxidation products react with DNA in the presence of metals, was significantly associated with hip fracture risk.
“To our knowledge, this is the first prospective study among postmenopausal women demonstrating that oxidative stress was a significant predictor for hip fracture,” announced Dr Wu, who is an assistant professor at the UC College of Medicine Department of Environmental Health. “Because FlOP_320 is generated in the presence of metals, its strong association with hip fractures may reflect the co-existing effect of reactive oxygen species and heavy metal.”
“If our findings are confirmed in other studies, adding this marker into the existing fracture assessment model could improve the prediction of hip fracture in postmenopausal women,” she added.
Diabetics gain longevity edge with drug therapy
August 11 2014. Type 2 diabetes is known to shorten life span, but recent research has revealed that a medication commonly used to treat it might enable diabetics to live longer on average than those without the disease.
Writing in the journal Diabetes, Obesity and Metabolism, Professor Craig Currie of Cardiff University and his colleagues report that treatment with metformin improved survival over follow-up in diabetics in comparison with those treated with sulphonylurea drugs, as well as in comparison with untreated nondiabetics.
“What we found was illuminating,” Dr Currie stated. “Patients treated with metformin had a small but statistically significant improvement in survival compared with the cohort of nondiabetics, whereas those treated with sulphonylureas had a consistently reduced survival compared with nondiabetic patients. This was true even without any clever statistical manipulation.”
The study included 78,241 diabetics treated with metformin and 12,222 prescribed sulphonylureas, matched with 90,463 nondiabetic control subjects. Nondiabetics experienced a 15% lower adjusted median survival time in comparison with diabetics treated with metformin. For those receiving sulphonylurea monotherapy, median survival time was 38% lower than metformin-treated patients.
“Surprisingly, the findings indicate that this cheap and widely prescribed diabetic drug may have beneficial effects not only on patients with diabetes but also for people without, and interestingly, people with type 1 diabetes,” Dr Currie observed. “Metformin has been shown to have anticancer and anti-cardiovascular disease benefits. It can also reduce prediabetics’ chances of developing the disease by a third.”
“This does not mean that people with type 2 diabetes get off Scott free,” he cautioned. “People lose on average around eight years from their life expectancy after developing diabetes. The best way to avoid the condition altogether is by keeping moderately lean and taking some regular light exercise.”
Calcium supplementation associated with reduced all-cause mortality over 9.4 year follow-up
August 8 2014. Findings from a study examining the association between calcium intake and subclinical cardiovascular disease in diabetics not only failed to find an adverse effect for calcium on any measure of calcified plaque, but also uncovered a modest reduction in all-cause mortality over a 9.4 year average period in women who supplemented with the mineral.
The study, described online on August 6, 2014 in the American Journal of Clinical Nutrition included 720 participants in the Diabetes Heart Study recruited between 1998 and 2005. Questionnaires administered upon enrollment provided information concerning calcium and vitamin D intake from diet and supplements. Calcified atherosclerotic plaque in the coronary and carotid arteries, and abdominal aorta was measured via computed tomography (CT).
No association between any measure of calcified plaque and calcium intake from diet or supplements was observed, nor was increased calcium intake associated with a greater risk of all-cause mortality over follow-up. On the contrary, among women who supplemented with calcium there was a 38% lower adjusted risk of death from all causes over follow-up in association with each 500 milligram increase in calcium evaluated in this study.
“Studies have raised concerns that calcium supplementation may have the unintended negative consequence of increasing cardiovascular disease risk,” authors Laura M. Raffield and her associates observe. “In this study, we did not observe any negative cardiovascular impacts of differing calcium intakes from diet and supplements in contrast to some previous reports. Instead, calcium supplement use was associated with lower all-cause mortality risk in women.”
Study adds evidence to protective effect of vitamin D against dementia
August 6 2014. A report published online on August 6, 2014 in the journal Neurology® provides more evidence for a link between higher serum vitamin D levels and a lower risk of dementia, including Alzheimer’s disease.
“We expected to find an association between low vitamin D levels and the risk of dementia and Alzheimer’s disease, but the results were surprising—we actually found that the association was twice as strong as we anticipated,” reported study coauthor David J. Llewellyn, PhD, of the University of Exeter Medical School.
The analysis included 1,658 participants in the Cardiovascular Health Study, who did not have dementia, cardiovascular disease or stroke upon enrollment. After six years, 171 subjects were diagnosed with dementia, which included 102 cases of Alzheimer’s disease.
The researchers found a 53% greater risk of dementia and a 69% higher risk of Alzheimer’s disease among subjects with moderate vitamin D deficiency, and more than double the risk of dementia or Alzheimer’s disease among those with severe deficiency. A serum 25-hydroxyvitamin D level of 20 nanograms/milliliter (ng/mL) was determined to be the threshold at which the vitamin became protective.
The study is the first involving vitamin D to utilize a multidisciplinary team and neuroimaging to confirm dementia diagnoses.
“Clinical trials are now needed to establish whether eating foods such as oily fish or taking vitamin D supplements can delay or even prevent the onset of Alzheimer’s disease and dementia,” Dr Llewellyn stated. “We need to be cautious at this early stage and our latest results do not demonstrate that low vitamin D levels cause dementia. That said, our findings are very encouraging, and even if a small number of people could benefit, this would have enormous public health implications given the devastating and costly nature of dementia.”