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Vitamin C May Ward Off Stroke

Study finds added benefit for smokers

TUESDAY, Nov. 11, 2003 (HealthDayNews) -- People who eat a diet rich in vitamin C may be at lower risk of suffering strokes, and smokers who do so may benefit the most.

A new Dutch study finds people with the lowest amount of vitamin C in their diets were 30 percent more likely to have a stroke than people with the highest amount of it.

People with the highest amount of vitamin C in their diets consumed more than 133 milligrams of vitamin C per day. People with the lowest amount in their diets got less than 95 milligrams per day. The recommended daily amount is 60 milligrams a day.

Smokers with diets high in vitamin C were more than 70 percent less likely to have a stroke than smokers with diets low in vitamin C.

Antioxidants such as vitamin C may protect cells from oxidative stress, which plays a role in stroke, the researchers say.

"The lower third will have a higher risk of stroke and those with higher intake will be at lower risk," says study author Dr. Monique Breteler of Erasmus Medical Center in Rotterdam. "Vitamins don't react so differently within populations -- so this fits for general populations."

The research "confirms that the healthy diet is good for you, one that is rich in antioxidants and vegetables, as we have seen over the last several years," she adds.

Researchers studied 5,197 people aged 55 and older living in Rotterdam, all of the whom had no cognitive problems, were living independently, and had never had a stroke.

Participants were then tracked for an average of 6.4 years, and during that time, 253 of them suffered strokes.

The study also found smokers benefited from high levels of vitamin E in their diets. They were more than 20 percent less likely to have a stroke than those with diets low in vitamin E. Ironically, nonsmokers with high vitamin E levels didn't enjoy similar protection.

"This is not an excuse to continue smoking. There is more than enough medical evidence to show that smoking is extremely bad for you," Breteler cautions. "The effects of anti-oxidation are more than outweighed by other factors."

"But we looked at that because smoking causes damage due to increased oxidative stress. Then vitamin C has anti-oxidative properties, so we looked at [that] connection and saw that it was indeed the case," she says.

However, the use of dietary supplements containing vitamins C and E and other antioxidants didn't seem lower the risk of stroke more, but Breteler says this finding doesn't mean supplements have no potential benefit.

"I think it's important for the public to keep hearing the message about our diet and reducing stroke risk, and this study shows this quite very nicely," says Dr. Philip B. Gorelick, head of the cerebrovascular disease and neurological critical care department at Rush University Medical Center in Chicago.

The results appear in the Nov. 11 issue of Neurology.

This seems to confirm similar findings from a 2002 Finnish study, which showed a relationship between low vitamin C levels and an increased risk of stroke. The study of 2,419 men between the ages of 42 and 60 also showed a relationship between high levels of vitamin C and reduced stroke risk, especially in overweight and hypertensive men.

One possible explanation is that vitamin C enhances endothelial function, which inhibits artery clogging and lowers blood pressure. But the link could also simply be that people who take vitamin supplements or eat vitamin-rich fruits and vegetables may be more health-conscious than those who don't.

So the study cautions that vitamin C alone may not be responsible for the results of the study.

Rich sources of vitamin C include oranges and other citrus fruits, strawberries, red and green peppers, broccoli, and brussels sprouts. Good sources of vitamin E are vegetable oils such as sunflower seed, cottonseed, safflower, palm and wheat germ oils, margarine and nuts.

Vitamin C has had a much heralded history, ever since the 18th century British explorer James Cook was credited with being the first captain to use diet as a cure for scurvy, the disease caused by lack of ascorbic acids. After making his crew eat cress, sauerkraut and an orange extract, he lost no men to the ailment on several months-long voyages.

It has, it also seems, even reached a sort of cult status. One such example is the efforts of the former Nobel-prize winner Linus Pauling, who advocated, against medical evidence some say, megadoses of vitamin C to protect against cancer and many other ailments. Pauling died in 1994 at age 93.

But studies have shown that, since vitamin C passes out of the body via urine, amounts in excess of what the body can use are simply eliminated.

More information

Learn more about stroke prevention from the National Institute of Neurological Disorders and Stroke, while MedlinePlus has more on vitamin C.

SOURCES: Philip B. Gorelick, M.D., M.P.H., head, cerebrovascular disease and neurological critical care, Rush University Medical Center, Chicago; Monique Breteler, M.D., Ph.D., Erasmus Medical Center, Rotterdam, The Netherlands; Nov. 11, 2003, Neurology
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