It has long been claimed that blueberries have highly beneficial health effects, but there is a slight confusion about their naming. Let’s clarify that first. When the Americans talk about blueberries they most often refer to a species called Vaccinium corymbosum L. in Latin. It is a shrub native to North America that can reach 4 m in height and are also called northern highbush blueberries (they do also have lowbush varieties to further complicate things).
But for Europeans it is more typically a species called Vaccinium myrtillus L. in Latin and more correctly named bilberries, although naming in several local languages translates directly to “blueberry” in English.
Bilberries are distinct from blueberries but closely related to them. The bilberry plant is a low-growing shrub native to northern Europe producing single or paired berries on the bush instead of clusters, as the blueberry does. The fruit is smaller than that of the blueberry but with a fuller taste. Bilberries are darker in colour, and usually appear near black with a slight shade of purple. While blueberry fruit pulp is light green in colour, bilberry is red or purple.
To best distinguish the two use the colour test. If you get a heavily blue-stained tongue after eating the berries, you have just consumed bilberries.
High in antioxidants
With that out of the way, let’s focus on the high content of a range of antioxidants found in both species. Anthocyanins belong to the flavonoid family and are water soluble pigments involved in a wide range of biological activities that may be beneficial to health. Many of the biological properties of the berries are closely associated with the antioxidant activity of the anthocyanin pigments. The bilberry and blueberry fruits, besides anthocyanins, are also rich in other flavonoids (catechin, epicatechin, myrcetin, quercetin, and kempferol), phenolic acids, chlorogenic acid and ascorbic acid, which all possess antioxidant properties as well.
These compounds help to neutralise free radicals which are unstable molecules linked to the development of a number of degenerative diseases and conditions. Antioxidants may reduce the risk of coronary heart disease, inhibit platelet aggregation and protect arterial endothelial cells. In addition, these compounds could decrease the risk of cancer, reduce inflammatory damage and modulate immune response.
Quite an impressive range of beneficial effects, don’t you agree?
The magic of one daily cup of blueberries
Now, a new scientific report claims that just one cup of blueberries per day could be the key to reducing blood pressure and arterial stiffness, both associated with cardiovascular disease. Cardiovascular disease is a leading cause of death, with the risk increasing in menopausal women. Thus, over an eight-week period, 48 postmenopausal women with pre- and stage-1 hypertension were randomly assigned to receive either 22 g of freeze-dried blueberry powder (the equivalent to one cup of fresh blueberries) or 22 g of a placebo powder daily, while continuing their normal diet and exercise routines.
At the beginning of the study, the team measured blood pressure, arterial stiffness and select blood biomarkers. At the end of the eight weeks, participants receiving the blueberry powder on average had a 7 mmHg (5.1%) decrease in systolic blood pressure, a 5 mmHg (6.3%) reduction in diastolic blood pressure, and an average reduction of 97 cm/s (6.5%) in arterial stiffness. Nitric oxide, a blood biomarker known to be involved in the widening of blood vessels, increased by 68.5%. The rise in nitric oxide helps explain the reductions in blood pressure.
Although the results are not surprising, previous studies on blueberries included much larger amounts of blueberry powder consumption, anywhere from 50 to 250 g (equivalent to 2 to an unrealistic 11 daily cups).
So what about bilberries?
I am happy to inform you that the highest content of anthocyanins was found in bilberries compared to several blueberry varieties. However, when measuring total activity of all antioxidant compounds, some blueberry varieties beat bilberries, while others fell below the bilberry activity. So there seems to be a dead heat between the Americans and the Europeans.
One daily cup of either variety should do the deed.
And finally the superfood caveat. Angst and debate about the merits of what we eat is at an all-time high and separating fact from fiction can be difficult. In case you didn’t know, “superfoods” are so called because they supposedly have health-promoting benefits and may even help with certain medical conditions, or so the superfoods advocates claim.
Nutrition scientists are quick to dispute such claims, saying that the word “superfoods” is simply a marketing tool used by their advocates. To rely solely on superfoods would be dangerous as they cannot substitute for a generally healthy and balanced diet.