SATURDAY MARCH 1, 2008 (Foodconsumer.org) — University of Cambridge researchers found those who had the highest level of vitamin C in their blood were much less likely to have a stroke, suggesting that intake of vitamin C ma help reduce the risk.
The study published in the Jan, 2008 issue of American Journal of Clinical Nutrition showed those who had the highest level (greater than 66 micromoles per liter) had a 42 percent reduced risk for stroke compared to those who had the lowest level (less than 41 micromoles per liter).
The study did not mean that increasing vitamin C intake through one’s diet or a supplement would definitely reduce the risk of stroke or increased levels of the vitamin was the cause for the reduced risk although the possibility could not be excluded either.
Phyo Myint and colleagues suggested that vitamin C in the blood may be a good biomarker of lifestyle. A high level of it indicates that one follows a healthy lifestyle, minimizing their risk for stroke.
For the study, the researchers followed 20,649 men and women participating in the European Prospective Investigation into Cancer for 9.5 years to record their health status such as incidence of stroke.
Their dietary habits and other lifestyle parameters were surveyed at the entry of the study using a health and lifestyle questionnaire and vitamin C levels in the blood samples were measured. During the follow-up, 448 stroke cases were identified.
The association between the plasma vitamin C level and the risk of stroke existed after a series of other factors were considered including age, sex, smoking habits, alcohol consumption, blood pressure, cholesterol, BMI, physical activity, and use of supplements.
The researchers said the association was probably not due to the supplemental vitamin C because when those who used vitamin C supplements were excluded, the link still held, suggesting that the possible benefit could come from vitamin C-rich foods such as fruit and vegetables.
The US government recommends in dietary guidelines adults should take at least five servings of fruit and vegetables per day to maintain health. But often vitamin C supplementation is not encouraged.
The researchers said although the study did not mean to say taking vitamin C supplements would render this protective effect and trials of vitamin C supplements in preventing cardiovascular disease unlikely occur, the association was substantial and independent of known major risk factors for stroke.
Sebastian Padayatty and Mark Levine from the National Institutes of Health (NIH) said in their commentary accompanying the study report that “Vitamin C is an attractive marker of fruit and vegetable intake because these foods are the primary sources of dietary vitamin C.” and the take-home message is to use five to nine servings of fruits and vegetables.
Vitamin C has proved controversial. Some experts notably Noble Prize laureate Dr. Linus Pauling had been advocating for years that people should use HIGH doses of vitamin C to prevent a whole spectrum of diseases from colds to cancer. But trials proved that vitamin C at low doses does not help prevent diseases.
Dr. Pauling had worked with a doctor to test how vitamin C affects the survival of cancer patients and they found that cancer patients subject to conventional treatments, but using high doses of vitamin C often lived a few more years than those who received only conventional treatments.
Vitamin C is non-toxic and many people use more than 5 grams per day, according to The Vitamin C Foundation, a not-for-profit organization advocating use of vitamin C.
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