Anthocyanins are bioactive flavonoid compounds that are extensively studied for their benefits to human health. One of their most important health benefits is the ability to scavenge free radicals. Free radicals are rogue atoms or atomic groups that have lost at least one electron, forcing them to steal electrons from neighbouring molecules in the hope of stabilising themselves. Unsurprisingly, this can cause havoc in the body, leading to a whole host of health problems. Anthocyanins seek out these groups and donate electrons, stabilising the atoms, protecting cells from damage (oxidative stress) and neutralising free radicals.
Blueberries have the highest concentration of anthocyanins of almost any fruit. As well as providing protection from free radical damage, these powerful antioxidants are also anti-inflammatory, immune boosting, brain boosting, heart healthy and promote healthy vision. Furthermore, blueberries have been shown to increase antioxidant levels within the body.12
Research shows that the anthocyanins in blueberries can prevent cognitive decline in older people. In a study published in the “Annals of Neurology”, Harvard researchers measured the cognitive function of 16,010 participants from the “Nurses Study”. They concluded that blueberries can slow brain aging by an average of 2.5 years.6
In younger people, blueberries may also boost cognitive function. In a small crossover study, 14 children consumed either a blueberry drink or a placebo. The blueberry drink group produced significant improvements in the delayed recall of a previously learned list of words. Researchers concluded, "the improvements in delayed recall found in this pilot study suggest that, following acute flavonoid-rich blueberry interventions, school-aged children encode memory items more effectively."7
In May 2019, The University of East Anglia conducted a ground-breaking study whose findings were published in the “American Journal of Clinical Nutrition”. They found that eating 150g of blueberries daily reduces the risk of cardiovascular disease by 15 percent.
The team set out to determine whether eating blueberries had any effect on Metabolic Syndrome - a condition, affecting 1/3 of westernised adults, which comprises at least three of the following risk factors: high blood pressure, high blood sugar, excess body fat around the waist, low levels of "good cholesterol" and high levels of triglycerides.
Lead researcher Prof Aedin Cassidy, from UEA’s Norwich Medical School, said: “Having Metabolic syndrome significantly increases the risk of heart disease, stroke and diabetes. We wanted to find out whether eating blueberries could help people who have already been identified as being at risk of developing these sort of conditions.”
The team investigated the effects of eating blueberries daily in 138 overweight and obese people, aged between 50 and 75, with Metabolic Syndrome. The six-month study was the longest trial of its kind.
Co-lead, Dr Peter Curtis, also from UEA's Norwich Medical School, said: “We found that eating one cup of blueberries per day resulted in sustained improvements in vascular function and arterial stiffness – making enough of a difference to reduce the risk of cardiovascular disease by between 12 and 15 per cent.”34
In a study published in the Journal of the Academy of Nutrition and Dietetics, researchers conducted a double-blind, placebo-controlled clinical trial on 48 post-menopausal women with pre-hypertension or stage one hypertension. Postmenopausal women have a high prevalence of hypertension and often develop arterial stiffness thereby increasing cardiovascular disease risk.
Every day, half the women were given 22g of freeze-dried blueberry powder equivalent to one cup of fresh blueberries. The other half received a placebo. After just 8 weeks, the women who took the blueberry powder had significantly lowered their systolic (5.1 percent) and diastolic (6.3 percent) blood pressure. Those on the placebo had no change.
Additionally, the blueberry powder reduced arterial stiffness on average by 6.5 percent. No change was seen in the placebo group. Arterial stiffness is a symptom of atherosclerosis and predicts cardiovascular risk. It indicates that the heart has to work harder to circulate blood to the peripheral blood vessels.
The researchers attributed the beneficial effects to an amazing 68.5 percent increase in blood levels of nitric oxide in the women who took the blueberry powder. Nitric oxide is known to widen blood vessels, increase blood flow and lower blood pressure. Those on the placebo had no changes in nitric oxide levels.5
Folklore and history
Native to North America, blueberries were well known to the Native Americans who ate the berries fresh and dried them for the winter. They were added to meat to make pemmican, and mixed with cornmeal, honey and water to make a pudding called “sautauthig”. Dried berries were used in soups and stews and used as a rub for meat.
Medicinally, the juice of the fruit was used to make cough syrup while the leaves were made into a tea that was drunk to fortify the blood.
Blueberries have hit the world’s headlines over recent years due to their many health benefits. Their glorious deep blue/indigo colour comes from the powerful compounds that impart many of these benefits – anthocyanins, earning this humble berry the title “King of the Antioxidants”.
Blueberries can be eaten straight as a delicious, healthy snack or used to brighten up breakfast dishes, such as cereal, porridge and yoghurt. These versatile berries can also be included in baked goods, raw desserts and smoothies.
Blueberries contain vitamins C and K and the trace mineral manganese. Polyphenols present in blueberries include: flavonoids, procyanidins (monomeric and oligomeric form) , flavonols (kaempferol, quercetin, myricetin) and phenolic acids. Different types of anthocyanins include: malvidin, delphinidin, petunidin, cyanidin and peonidin.
If you are taking blood thinning medication, please consult your healthcare provider before consuming large amounts of blueberries.