Bioactive compounds in berries may reduce high blood pressure

January 19, 2011

A study published in The American Journal of Clinical Nutrition shows that eating blueberries may guard against high blood pressure. High blood pressure—or hypertension—is one of the major cardiovascular diseases worldwide. The new findings show that bioactive compounds in blueberries called anthocyanins may offer protection against hypertension

Anthocyanins belong to the bioactive family of compounds called flavonoids and are found in high amounts in blackcurrants, raspberries, aubergines, blood orange juice, and blueberries. This is the first large study to investigate the effect of different flavonoids on hypertension. The team of scientists from the University of East Anglia (UEA) and Harvard University studied 134,000 women and 47,000 men from the Harvard established cohorts, the Nurses’ Health Study, and the Health Professionals Follow-up Study over a period of 14 years. None of the participants had hypertension at the start of the study. Subjects were asked to complete health questionnaires every two years and their dietary intake was assessed every four years. Incidence of newly diagnosed hypertension during the 14-year period was then related to consumption of various different flavonoids.

During the study, 35,000 participants developed hypertension. Dietary information identified tea as the main contributor of flavonoids, with apples, orange juice, blueberries, red wine, and strawberries also providing important amounts. When the researchers looked at the relation between individual subclasses of flavonoids and hypertension, they found that participants consuming the highest amounts of anthocyanins (found mainly in blueberries and strawberries in this US-based population) were 8% less likely to be diagnosed with hypertension than those consuming the lowest amounts. The effect was even stronger in participants under 60. Compared to people who ate no blueberries, those eating at least one serving of blueberries per week were 10% less likely to become hypertensive.

“Our findings are exciting and suggest that an achievable dietary intake of anthocyanins may contribute to the prevention of hypertension,” said lead author Aedin Cassidy of the Department of Nutrition at UEA’s Medical School.

The next stage of the research will be to conduct randomized controlled trials with different dietary sources of anthocyanins to define the optimal dose and sources for hypertension prevention. This will enable the development of targeted public health recommendations on how to reduce blood pressure.