All Posts tagged vascular

Antioxidants lower stroke risk

Eating a diet high in antioxidants may protect against ischemic stroke, an Italian cohort study showed.

People who had a diet high in total antioxidant capacity — an index that takes into account several different antioxidants and their interactions — had a 59% reduced relative risk of ischemic stroke (HR 0.41, 95% CI 0.23 to 0.74), according to Nicoletta Pellegrini, PhD, of the University of Parma in Italy, and colleagues. But there was no such relationship with hemorrhagic stroke, they reported in the January issue of the Journal of Nutrition. In fact, the highest intake of the antioxidant vitamin E was associated with a greater risk of hemorrhagic stroke (HR 2.94, 95% CI 1.13 to 7.62).
Considering evidence suggesting that oxidative stress and systemic inflammation are involved in the pathogenesis of ischemic stroke, the researchers noted that “a high-total antioxidant capacity diet could be protective as a consequence of its ability to deliver compounds with antioxidant activity and with a demonstrated anti-inflammatory effect.” But, they acknowledged that the mechanism for such activity was unclear may “go beyond the antioxidant activity of the numerous total antioxidant capacity contributors present in foods and beverages.”

Pellegrini and her colleagues set out to explore the relationship between dietary total antioxidant capacity and the risk of stroke among 41,620 people participating in EPICOR, the Italian segment of the European Prospective Investigation into Cancer and Nutrition (EPIC). None had a history of stroke or MI at baseline. Dietary intake was assessed with a food frequency questionnaire. In the study population, more than half of the total antioxidants consumed came from coffee, wine, and fruit. Through a mean follow-up of 7.9 years, there were 112 ischemic strokes, 48 hemorrhagic strokes, and 34 other types of strokes. After adjustment for energy intake, hypertension, smoking status, education, nonalcoholic energy intake at recruitment, alcohol intake, waist circumference, body mass index, and total physical activity, individuals eating a diet in the highest tertile of total antioxidant capacity had a reduced risk of ischemic — but not hemorrhagic — stroke.

Looking at individual antioxidants, the researchers found that participants consuming the highest amounts of vitamin C had a reduced risk of ischemic stroke (HR 0.58, 95% CI 0.34 to 0.99). Controlling for vitamin C intake did not negate the overall association between antioxidants and ischemic stroke, which ruled out the nutrient as the sole driver of the relationship. High intake of vitamin E, on the other hand, was associated with nearly triple the relative risk of hemorrhagic stroke. However, “it must be stressed that the small number of cases observed in this population strongly limits the validity of statistical observations on hemorrhagic stroke,” noted the researchers, who called for further studies.

Aside from anti-inflammatory effects, it is possible that the association between antioxidants and ischemic stroke risk can be explained by the interaction between polyphenols — the major contributors to total antioxidant capacity — and the generation of nitric oxide from the vascular endothelium. That interaction leads to the vasodilation and expression of genes that may be protective for the vascular system, according to the researchers. In addition, coffee — the main source of antioxidants in the study population — reduces blood pressure, which is a recognized risk factor for ischemic stroke, the researchers wrote.

They noted some limitations of the study, including the low numbers of cases when different types of stroke were analyzed, the measurement of total antioxidant capacity at baseline only, and the inability to rule out confounding effects of other dietary components, like sodium and potassium.

Source: Del Rio D, et al “Total antioxidant capacity of the diet is associated with lower risk of ischemic stroke in a large Italian cohort” J Nutr 2011; 141: 118-123.

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Tomatoes Fight Cholesterol

If you want to wage battle against cholesterol and other lipids (fat) that can contribute to vascular disease, then make tomatoes a big part of your diet. Scientists say this popular fruit contains a nutrient that can fight vascular disease such as stroke and arteriosclerosis.

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Tomatoes fight more than cholesterol and fat

Excessive levels of lipids, such as cholesterol and triglycerides in the bloodstream, a condition known as dyslipidemia, can lead to potentially deadly diseases such as arteriosclerosis, cirrhosis, and stroke. Scientists from Kyoto University and New Bio-industry Initiatives, Japan, report that a compound called 9-oxo-octadecadienoic extracted from tomatoes can boost oxidation of fatty acids and contribute to the regulation of lipid metabolism by the liver. These qualities indicate that 9-oxo-octadecadienoic acid can fight cholesterol and other lipids and therefore help prevent vascular diseases.

Vascular disease is a general term used to describe diseases that affect the blood vessels. The Vascular Disease Foundation offers information on nearly two dozen different conditions that fit this category, including abdominal aortic aneurysm, carotid artery disease, deep vein thrombosis, lymphedema, peripheral artery disease, and stroke.

Tomatoes are also valued for other health benefits. Much research has been dedicated to a potent antioxidant in tomatoes, lycopene, and its potential in the fight against various types of cancer, and especially prostate cancer. Tomatoes also contain excellent levels of other nutrients, including niacin, which helps lower cholesterol; and potassium, which reduces blood pressure and the risk of heart disease.

Dr. Teruo Kawada, who is from Kyoto University and who led the study, noted that “Finding a compound which helps the prevention of obesity-related chronic diseases in foodstuffs is a great advantage to tackling these diseases. It means that the tomato allows people to easily manage the onset of dyslipidemia through their daily diet.” To help the fight against cholesterol and other fats that contribute to vascular disease, enjoy more tomatoes.

SOURCES:
Kim YI et al. Molecular Nutrition & Food Research doi:10.1002/mnfr.201000264

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Diabetes may be linked to air pollution

Cardiovascular and lung researchers at The Ohio State University Medical Center are the first to report a direct link between air pollution and diabetes. If the ongoing research continues to confirm this association, scientists fear human health in both industrialized and developing countries could be impacted.

“We now have even more compelling evidence of the strong relationship between air pollution and obesity and type II diabetes,” said Dr. Sanjay Rajagopalan, section director of vascular medicine at Ohio State's medical center and principal investigator of the study. The latest study builds upon previous research from Rajagopalan's team implicating air pollution as a major adverse risk factor for cardiovascular effects, high blood pressure and acute coronary syndromes.

Researchers found that exposure to air pollution, over a period of 24 weeks, exaggerates insulin resistance and fat inflammation. The results of the study are available online in the current issue of Circulation. “The prevalence of obesity has reached epidemic proportions with 34 percent of adults in the U.S., ages 20 and over, meeting the criteria for obesity,” said Rajagopalan. “Obesity and diabetes are very prevalent in urban areas and there have been no studies evaluating the impact of poor air quality on these related conditions until now.”

Type II diabetes, a consequence of obesity, has soared worldwide with a projected 221 million people expected to suffer from this disease in 2010, a 46 percent increase compared to 1995.

In the Ohio State research, scientists fed male mice a diet high in fat over a 10-week period to induce obesity and then exposed them to either filtered air or air with particulate matter for six hours a day, five days a week, over a 24-week period. Researchers monitored measures of obesity, fat content, vascular responses and diabetic state. The air pollution level inside the chamber containing particulate matter was comparable to levels a commuter may be exposed to in urban including many metropolitan areas in the U.S.

According to the U.S. Environmental Protection Agency, the four most common pollutants emitted into the air are particulate matter, ozone, nitrogen dioxide and sulfur dioxide. Air pollution is commonly the result of industrial emissions, power plants and automobile exhaust.

“This study provides additional guidance for the EPA to review air pollution standards,” says Rajagopalan. “Our study also confirmed a need for a broader based approach, from the entire world, to influence policy development.”

Dr. Qinghua Sun, first author of the study, is leading an international effort to understand the effects of urban air pollution in Beijing, where the impact of recent stringent measures on air quality during the Olympics is being monitored in another controlled experiment. Researchers at the University of Michigan and the New York University School of Medicine participated in the study. Along with Rajagopalan and Sun, other Ohio State researchers involved in the study were Peibin Yue, Jeffrey A. Deiuliis, Thomas Kampfrath, Michael B. Mikolaj, Ying Cai, Michael C. Ostrowski, Bo Lu, Sampath Parthasarathy and Susan D. Moffatt-Bruce.

Funding from the National Institutes of Health supported this research.

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