- A new study found people who consume blueberries may be able to lower their blood pressure.
- Wild blueberry powder drinkers also saw improvements in their blood vessel function.
- Other studies have also found that eating blueberries — or blueberry compounds known as anthocyanins — improves vascular function.
A cup of wild blueberries is not only a tasty, low-calorie snack, but it also lowers blood pressure, improves blood vessel function and provides a small brain boost, a new study suggests.
People who consumed a drink made out of freeze-dried wild blueberry powder once a day for 12 weeks saw a reduction in their systolic blood pressure of 3.59 millimeters of mercury (mmHg), compared to people who consumed a drink made from a placebo powder.
Wild blueberry powder drinkers also saw improvements in their blood vessel function, as measured by flow-mediated dilation.
The study was published March 25 in The American Journal of Clinical Nutrition.
Heart-related benefits of blueberries
An earlier study by the same researchers at King’s College London in the United Kingdom found similar changes in middle-aged healthy males who consumed a drink made from wild blueberry powder.
Other studies have also found that eating blueberries — or blueberry compounds known as anthocyanins — improves vascular function.
These kinds of changes are good for the entire cardiovascular system.
“Any reduction in blood pressure reduces the incidence of stroke, heart attack and other end-organ damage,” Dr. Robert Pilchik, a cardiologist with Manhattan Cardiology in New York City, who was not involved in the new study, told Healthline.
He pointed to a recent study which found that for each 5 mmHg decrease in systolic blood pressure, a person’s risk of cardiovascular events such as heart attack or stroke fell by 10%.
In addition, Pilchik said the new study showed that the decrease in systolic blood pressure was due to improvements in the ability of the blood vessels to dilate (widen) and endothelial function. The endothelium is a thin membrane that lines the inside of the blood vessels and heart.
“This improvement of endothelial function in and of itself is a protective factor against atherosclerosis,” he said.
Atherosclerosis, the build-up of fats, cholesterol and other substances on the inner artery walls, can increase the risk of heart attack, stroke, vascular dementia and other conditions.
The new study, though, found no significant differences between the two groups for arterial stiffness, diastolic blood pressure or blood lipids — risk factors for cardiovascular disease — or cerebral blood flow.
Lower cerebral blood flow — blood flow the brain — is linked to an increased risk of dementia.
Randomized controlled trial
This randomized, double-blind, placebo-controlled trial included 61 healthy older adults aged 65 to 80 years.
Around half of the participants consumed a beverage each day containing 26 grams of freeze-dried wild blueberry powder rich in anthocyanins — the equivalent of just under one cup of fresh blueberries.
The rest consumed a similar-tasting powder with no anthocyanins, but the same level of vitamin C.
Food studies sometimes use powdered foods to ensure more precise measurements.
The study was funded by the Wild Blueberry Association of North America.
Blueberries provide brain boost
In the new study, researchers also found that people who consumed a drink made from wild blueberry powder saw improvements on two cognitive function tests — immediate word recall and a test of task switching.
However, there was no improvement in delayed word recall, in contrast to an earlier study using wild blueberry juice.
Dr. James E. Galvin, professor at the University of Miami and director of the Comprehensive Center for Brain Health at UHealth — University of Miami Health System, cautioned that this is a small study. However, “the results suggest that powdered blueberries provided a significant benefit in memory recall,” he said.
“While future studies are needed to replicate these findings,” he said, “this work is exciting because trials such as this one provide experimental confirmation of observational studies of dietary patterns.”
So what kind of impact would eating a handful of blueberries every day have on a person’s risk of developing dementia?
Galvin said by itself, this single change would have only a small effect.
However, “in combination with other lifestyle changes such as physical exercise, cognitive activity, social engagement, mindfulness, green space exposure and other such activities, it is likely to have a more powerful effect,” he said.
Together, diet and these other modifiable lifestyle factors make up a “Resilience Index” developed by Galvin and his colleagues. This measure provides an estimate of a person’s dementia risk, and also suggests ways they can lower that risk through lifestyle changes.
Similarly, a 2020 report by the Lancet commission on dementia identified 12 modifiable risk factors for dementia, including diet. Making changes to these risk factors could prevent or delay up to 40% of dementias, the report found.
Eat a variety of nutrient-dense foods
The dietary worksheet that Galvin uses for his resilience studies includes a category for berries and nuts, which “contain rich polyphenols that may offer neuro-protective benefits,” he said.
Polyphenols are naturally occurring plant compounds found in fruits, vegetables, tea, chocolate and other foods. These have been linked to a number of health benefits.
The authors of the new study believe that the vascular and brain-related benefits of wild blueberries are due to a specific type of polyphenol called anthocyanins.
Pilchik said in addition to the benefits seen in this study, blueberries have other heart-related benefits.
Blueberries are a good source of soluble fiber, which binds cholesterol and removes it from the body, he said, and they are also high in antioxidants, which can reduce inflammation in the body.
Both of these can reduce the risk of cardiovascular disease and events, said Pilchik.
And, of course: “blueberries are delicious,” he added.
While blueberries are certain to provide a health boost, many foods are equally rich in polyphenols or other healthful compounds. Regularly eating a wide variety of foods ensures that you gain the most health benefits.
The Mediterranean diet, which emphasizes the consumption of fruits, vegetables, lean protein and healthy fats such as olive oil, is a good example of a varied diet rich in nutrients.
This diet has been shown to improve heart health and reduce the risk of dementia.
“In studies of people living with dementia, individuals following a Mediterranean style diet had a slower progression than people who ate a more typical American diet,” said Galvin.
“So, I believe there is ample convergence of evidence supporting the importance of diet in dementia prevention,” he said.
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