People with high blood pressure have higher levels of vitamins A and E but lower levels of vitamin C and beta carotene than those without blood pressure problems, according to a new study by US researchers.
The results raise questions about the use of vitamins - it seems that vitamin E does not help to reduce the risk of blood pressure or heart disease. In fact blood pressure rose as blood levels of vitamins A and E increased.
Writing in the December issue of Hypertension: Journal of the American Heart Association, the authors noted that serum vitamin C has been inversely associated with blood pressure in several epidemiologic studies, but little is known about the effect of other antioxidant vitamins.
The researchers at Tulane University in New Orleans examined the relation between serum vitamins A, C, and E, alpha-carotene, and beta-carotene levels and blood pressure among more than 15,000 men and women, aged 20, who participated in the Third National Health and Nutrition Examination Survey.
While findings confirmed previous research on the benefits of vitamin C on blood pressure, alpha carotene and beta carotene, (converted to vitamin A by the body) were also associated with a lower risk of high blood pressure for the first time.
This could be due to the impact of antioxidants on free radicals, which are thought to lead to heart disease and cancer. However there is a need for further research to confirm the findings and explain further if antioxidants do indeed have a role in blood pressure regulation.
The authors conclude: "These findings indicate that antioxidant vitamins may be important in the underlying cause and prevention of hypertension. Further studies in this important area are warranted."