New data suggests that blueberries may support brain and cardiovascular health.
Eating a handful of wild blueberries daily may boost cognitive and cardiovascular health, according to a new study. The study reveals that the anthocyanins in blueberries are responsible for improving vascular and cerebral blood circulation, which are some of the likely mechanisms behind healthy cognitive function.
Anthocyanins are polyphenols, a family of plant-derived compounds increasingly associated with health benefits. A cup of wild blueberries is more than a tasty snack, according to new research from the Faculty of Life Sciences and Medicine at King’s College London, UK. It can also stimulate the brain, lower blood pressure and contribute to better cardiovascular health.
The randomized, double-blind, placebo-controlled study found that blueberry eaters had better executive function, strengthened short-term memory, and had faster reaction times. Study participants who took a daily drink of 26 grams (g) of freeze-dried wild blueberry powder for 12 weeks saw a 3.59 millimeters of mercury (mmHG) reduction in systolic blood pressure and an improvement of blood vessel function compared to people who consumed a placebo powder.
Participants who consumed blueberries were more successful in immediately recalling word lists and demonstrated better switching accuracy. The researchers, however, did not observe any improvement in delayed recall. The study is published in the American Journal of Clinical Nutrition.
178 grams of blueberries per day
The study involved 61 participants from London, men and women, aged 65 to 80 and in good health. For 12 weeks, half of them drank a drink containing 26 g of freeze-dried wild blueberry powder every day, while the other half consumed a matching placebo in terms of taste, appearance, macronutrients, fiber and vitamin C. It is common for food studies to use powdered substances to obtain accurate measurements. The 26 g of blueberry powder that the participants consumed each day was equivalent to 178 g of whole blueberries. This represents between 75 and 80 blueberries, which vary in size. The blueberries didn’t have to be wild, because “other studies have been done with other types of blueberries and have shown benefits for cognitive and vascular health.”
Anthocyanins: healthy natural pigments
Researchers believe that the beneficial effects of blueberries are due to their blue pigments called anthocyanins. Each daily dose of wild blueberry powder in the study contained 302 milligrams (mg) of anthocyanins. The placebo drink did not contain any. Anthocyanins are a class of polyphenols. There are approximately 8,000 different types of polyphenols that have health benefits. Other types of foods containing beneficial polyphenols include green tea, broccoli, pears, and spices like turmeric and cinnamon. Anthocyanins are also present in strawberries, raspberries, red grapes and purple vegetables.
There is already evidence of the health benefits of other anthocyanin-rich foods. There is no reason to think that they will not be as effective as blueberries, provided that the amount of anthocyanins provided by these foods is sufficient and that the anthocyanins are bioaccessible and bioavailable.
How the study came about
The authors of the study, had separately studied the cognitive and cardiovascular benefits of blueberries and obtained similar results. They therefore decided to study the effects on vascular and cognitive functions simultaneously in a single clinical study. They decided to measure cerebral blood flow because other research suggested that this might be a mechanism behind the beneficial effects of polyphenols, alongside increasing vascular blood flow. Furthermore, recent insights into the gut microbiota and the gut-brain axis prompted them to explore this relationship as well.
What polyphenols can do
The mechanism behind the beneficial effects of polyphenols is not yet fully understood. One theory is that “metabolites of polyphenols may act as signaling molecules, through several cellular signaling pathways, modulating the bioavailability of nitric oxide and different enzymes. Researchers found an increase in anthocyanin metabolites in participants’ urine after the 12-week study period. While the study showed that blueberries improved cerebral and vascular blood flow, it did not show any difference in arterial stiffness and blood lipids between people consuming the fruit and the placebo group. However, when blood flow is improved, heart and brain health benefits. Regarding the role of the gut microbiota, one hypothesis would be that polyphenols may act by increasing the abundance of beneficial butyrate-producing bacteria, and therefore the production of butyrate.
Other foods good for heart and brain health
Better cardiovascular and cognitive health are promoted by eating a diet rich in vegetables, fruits, whole grains, healthy proteins, minimally processed foods, and moderate oil and salt intake.
Recent research has indicated that the Mediterranean diet may be the optimal diet for heart health.
On the other hand, there are also the benefits of green vegetables, especially spinach, Swiss chard and kale, which are rich in nitrates, which can help dilate the arteries. This helps to improve blood circulation and vascular, cardiac and cognitive functions. There are many other foods linked to cognitive health. Omega-3 fats like wild salmon and sardines are linked to better cognition due to their rich DHA content and powerful anti-inflammatory properties. Additionally, some studies suggest that unsaturated fats, such as omega-3 fats, may also help reduce levels of beta-amyloid, a component in the development and progression of Alzheimer’s disease.