Blauwe bessen tegen hoge bloeddruk en aderverkalking*
Uit twee studies blijkt dat het regelmatig eten van blauwe bessen goed is tegen
hoge bloeddruk en de kans op aderverkalking. Uit de eerste studie onder 181.000 mensen die 14 jaar gevolgd werden blijkt dat verschillende fruitsoorten met
anthocyanen zorgen voor minder kans op hoge bloeddruk. Na de aardbei blijken blauwe bessen het beste te zijn. Een kopje blauwe bessen per week doet de kans op hoge bloeddruk al met 10% verlagen. In de tweede studie, weliswaar met muizen, blijkt dat na 20 weken voeding verrijkt met poeder van blauwe bessen de plaquevorming in de slagaderen wel de helft minder was als bij muizen die niet het poeder in hun voedsel gekregen hadden.
Bioactive Compounds in Berries Can Reduce High Blood Pressure
Eating blueberries can guard against high blood pressure, according to new research by the University of East Anglia (UEA) and Harvard University.
High blood pressure -- or hypertension -- is one of the major cardiovascular diseases worldwide. It leads to stroke and heart disease and costs more than $300 billion each year. Around a quarter of the adult population is affected globally -- including 10 million people in the UK and one in three US adults.
Published next month in the American Journal of Clinical Nutrition, the new findings show that bioactive compounds in blueberries called anthocyanins offer protection against hypertension. Compared with those who do not eat blueberries, those eating at least one serving a week reduce their risk of developing the condition by 10 per cent.
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. Other flavonoids are found in many fruits, vegetables, grains and herbs. The flavonoids present in tea, fruit juice, red wine and dark chocolate are already known to reduce the risk of cardiovascular disease.
This is the first large study to investigate the effect of different flavonoids on hypertension.
The team of UEA and Harvard scientists 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 eight per cent less likely to be diagnosed with hypertension than those consuming the lowest amounts. The effect was even stronger in participants under 60.
The effect was stronger for blueberry rather than strawberry consumption. Compared to people who ate no blueberries, those eating at least one serving of blueberries per week were 10 per cent 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 Prof Aedin Cassidy of the Department of Nutrition at UEA's Medical School.
"Anthocyanins are readily incorporated into the diet as they are present in many commonly consumed foods. Blueberries were the richest source in this particular study as they are frequently consumed in the US. Other rich sources of anthocyanins in the UK include blackcurrants, blood oranges, aubergines and raspberries."
The next stage of the research will be to conduct randomised 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.
Blueberries halt hardening of the arteries
Atherosclerosis is a disease marked by plaque in the arteries. Made up of fat, cholesterol, calcium, and other substances found in the blood, plaque hardens overtime not unlike concrete -- and that narrows arteries and limits the flow of oxygen-rich blood throughout the body. The result can be potentially fatal strokes and heart attacks.
But now, for the first time, scientists have direct evidence that a side-effect free natural substance exists that can help prevent these harmful atherosclerotic plaques from increasing in size and narrowing arteries. What is this powerful hardening of the arteries fighter? Blueberries.
Principal investigator Xianli Wu, who works with the U.S. Department of Agriculture (USDA) Agricultural Research Service (ARS) Arkansas Children's Nutrition Center in Little Rock and with the University of Arkansas Center for Medical Sciences, led the new study which was reported in the Journal of Nutrition. Dr. Wu's research team compared the size of atherosclerotic lesions in 30 young laboratory mice with this form of heart disease. These animals were deficient in apolipoprotein-E (which helps regulate fats in the body), making them highly susceptible to forming atherosclerotic
lesions.
Half of the rodents were fed diets supplemented with freeze-dried blueberry powder for 20 weeks. The blueberry-spiked diet contained the equivalent of about a half-cup of fresh blueberries. The mice in the control group did not eat food containing the berry powder. At the end of the study, the plaques measured at two sites on the aorta (arteries leading from the heart) were 39 and 58 percent smaller in the mice who ate the blueberry powder compared to the plaque lesions in the animals whose diet did not contain blueberry powder.
Previous studies have suggested that eating blueberries may help prevent cardiovascular disease but this is the first direct evidence that something in the berries causes plaque in arteries to regress. Next, Dr. Wu's group wants to figure out the mechanism or mechanisms by which blueberries help control lesion size. For example, according to a statement to the media, the scientists want to see if blueberries reduce oxidative stress, a known risk factor for atherosclerosis, by boosting the activity of antioxidant enzymes.
(Januari 2011)
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