If your blood pressure is too high, a diet rich in apples can almost halve your risk of premature death, Chinese epidemiologists report in Frontiers in Nutrition.

Study
Researchers at Dalian Medical University analyzed data from 2,368 Americans with high blood pressure who participated in the National Health and Nutrition Examination Survey (NHANES). The researchers were able to follow the study participants for at least 10 years and knew which of them died.

The participants completed questionnaires that gave the researchers an idea of their apple intake. The researchers were also able to filter out the influence of factors such as age, sex, education and income, smoking, diabetes, and cardiovascular disease.

Results
Study participants who ate fresh apples 3-6 times a week had a 48 percent lower risk of death than study participants who never ate apples.

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The researchers also looked for effects from apple juice and applesauce. They found none.

Bioactive phytochemicals
The researchers suspect that apples are, first and foremost, a source of vitamin C. Vitamin C is an antioxidant that, partly because vitamin C increases NO production, also lowers blood pressure. Other epidemiological research has shown that relatively high vitamin C serum levels reduce mortality.

Secondly, apples provide pectins and other dietary fibers, which help improve cholesterol levels and protect against atherosclerosis.

Finally, apples contain polyphenols. These are mainly found in the skin of red and purple apples. According to in vitro studies, polyphenols inhibit the oxidation of cell membranes and genetic material and improve vascular function and immune response. They also slow the growth of tumor cells and trigger the suicide of derailed cells.