In the most recent study, researchers from the Harvard School of Public Health have determined that eating at least three servings of strawberries and blueberries a week can reduce the chance of a heart attack by 33%.
The researchers utilized data from 93,600 adult women between 25 and 42 years old who participated in the Nurses’ Health Study II. The women were all considered healthy at the beginning of the study.
The women were followed for 18 years, and given food questionnaires every four years. The food questionnaires were subsequently validated. During the 18-year period, 405 heart attacks were reported.
Those women who ate the berries three or more servings per week were compared with those who ate a serving of berries once a month or less.
Those who ate at least three servings a week of the berries experienced 33% less incidence of heart attack than those who ate the two berries once per month or less.
Lead researcher Dr. Aedín Cassidy commented on the study. “We have shown that even at an early age, eating more of these fruits may reduce risk of a heart attack later in life.”
The researchers attributed the lower heart attack incidence to the anthocyanin content of the berries. Anthocyanin is a plant flavonoid that has been found in other studies to reduce the risk of heart attacks.
In a 2012 study sponsored by the American Cancer Society, 38,180 men and 60,289 women with average ages of about 70 years old were followed for seven years. Their diets and medical history were monitored.
This study found that those subjects who ate more anthocyanidins and other flavonoids had an 18% lower risk of deaths related to heart disease.
“Flavonoid consumption was associated with lower risk of death from CVD. Most inverse associations appeared with intermediate intakes, suggesting that even relatively small amounts of flavonoid-rich foods may be beneficial,” concluded the researchers.
In a 2011 study from the UK’s University of East Anglia Medical School studied 87,242 men and women with fourteen years of follow up. During the period, 29,018 of the women and 5,629 of the men were diagnosed with high blood pressure (hypertension).
However, those who had the highest consumption of anthocyanins – mostly from eating blueberries and strawberries – were 8% less likely to have high blood pressure when compared to those with the least anthocyanin intake. Those who were less than 60 years old had a 12% reduced risk of hypertension.
The researchers also found that those who ate foods with higher levels of flavan-3-ol catechin – present in apples, teas, onions, beans and other foods – had a 6% reduced incidence of high blood pressure.
Even consuming anthocyanins for a short period can produce cardiovascular benefits. Researchers from China’s Sun Yat-Sen University gave 320 milligrams of anthocyanins (extracts from berries) or a placebo to 150 human subjects with high cholesterol for six months. They found that the anthocyanin supplemented-group experienced a 21.6% reduction in C-reactive protein and a 12% reduction in an artery cell adhesion molecule associated with atherosclerosis, called sVCAM-1.
In a related study from Sun Yat-Sen University, 320 milligrams of anthocyanins for twelve weeks resulted in about 25% higher brachial artery flow among high cholesterol human subjects.
Fresh food consumption is the best way to guarantee anthocyanin content in the diet. In a recent study published in the Journal of Agricultural Food Chemistry, heat and vitamin C degraded anthocyanin content during the processing of grape juice and purple sweet potato juice extract.
Plants produce anthocyanins to help preserve their own tissues under stress. Research has found that plants enduring greater environmental stress will also have higher anthocyanin content.
Written by Case Adams, Naturopath
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