Blueberries are perennial flowering plants with indigo-colored berries from the section Cyanococcus within the genus Vaccinium (a genus that also includes cranberries, bilberries and grouseberries). Species in the section Cyanococcus are the most common fruits sold as "blueberries" and are native to North America (commercially cultivated highbush blueberries were not introduced into Europe until the 1930s).
Blueberries are usually erect, prostrate shrubs that can vary in size from 10 centimeters (3.9 in) to 4 meters (13 ft) in height. In the commercial production of blueberries, the smaller species are known as "lowbush blueberries" (synonymous with "wild"), while the larger species are known as "highbush blueberries".
The leaves can be either deciduous or evergreen, ovate to lanceolate, and 1–8 cm (0.39–3.15 in) long and 0.5–3.5 cm (0.20–1.38 in) broad. The flowers are bell-shaped, white, pale pink or red, sometimes tinged greenish. The fruit is a berry 5–16 millimeters (0.20–0.63 in) in diameter with a flared crown at the end; they are pale greenish at first, then reddish-purple, and finally dark purple when ripe. They are covered in a protective coating of powdery epicuticular wax, colloquially known as the "bloom". They have a sweet taste when mature, with variable acidity. Blueberry bushes typically bear fruit in the middle of the growing season: fruiting times are affected by local conditions such as altitude and latitude, so the peak of the crop can vary from May to August (in the northern hemisphere) depending upon these conditions.
Fresh blueberries are one of the most popular summer treats of all time. They are sweet, succulent, full of nutrients, and can be eaten freshly picked as well as incorporated into a variety of recipes.
Blueberries contain a type of flavonoid known as anthocyanins, which are responsible for giving foods like blueberries, cranberries, red cabbage and eggplants their iconic deep red, purple and blue hues. Anthocyanins are responsible for more than just the blueberry's pretty blue color - they also contribute to the popular fruit's numerous health benefits.
This MNT Knowledge Center feature is part of a collection of articles on the health benefits of popular foods. It provides a nutritional breakdown of the blueberry and an in-depth look at its possible health benefits, how to incorporate more blueberries into your diet and any potential health risks of consuming blueberries.Possible health benefits of blueberriesblueberries
Anthocyanins that are responsible for the blueberry's color, contributes to the numerous health benefits of consuming the fruit.
Consuming fruits and vegetables of all kinds has long been associated with a reduced risk of many lifestyle-related health conditions.
Many studies have suggested that increasing consumption of plant foods like blueberries decreases the risk of obesity, diabetes, heart disease and overall mortality while promoting a healthy complexion and hair, increased energy, and overall lower weight.
Although more research is needed before any of these health links can be said to be conclusive, blueberries have been associated with the following health benefits:
Maintaining healthy bones
The iron, phosphorous, calcium, magnesium, manganese, zinc and vitamin K in blueberries all contribute to building and maintaining bone structure and strength.
Iron and zinc play crucial roles in maintaining the strength and elasticity of bones and joints.2 Low intakes of vitamin K have been associated with a higher risk for bone fracture, while adequate vitamin K intakes improve calcium absorption and may reduce calcium loss.
Lowering blood pressure
Maintaining a low sodium intake is essential to lowering blood pressure. Blueberries are naturally free of sodium and contain potassium, calcium, and magnesium, all of which have been found to decrease blood pressure naturally.
Studies have shown that type 1 diabetics who consume high-fiber diets have lower blood glucose levels and type 2 diabetics may have improved blood sugar, lipids and insulin levels. One cup of blueberries contributes 3.6 grams of fiber.
The Dietary Guidelines for Americans recommends 21-25 grams of fiber per day for women and 30-38 grams per day for men.
A large cohort study published in the BMJ in 2013 suggested that certain fruits - but not juices - may reduce the risk of type 2 diabetes in adults. Over the course of the study, 6.5% of the participants developed diabetes, but the researchers found that consuming three servings per week of blueberries, grapes, raisins, apples or pears reduced the risk of type 2 diabetes by 7%.
Warding off heart disease
The blueberry's fiber, potassium, folate, vitamin C, vitamin B6 and phytonutrient content, coupled with its lack of cholesterol, all support heart health. The fiber in blueberries helps lower the total amount of cholesterol in the blood and decrease the risk of heart disease.
Vitamin B6 and folate prevent the buildup of a compound known as homocysteine. When excessive amounts of homocysteine accumulate in the body, it can damage blood vessels and lead to heart problems.
According to a recent study from the Harvard School of Public Health and the University of East Anglia, regular consumption of anthocyanins can reduce the risk of heart attack by 32% in young and middle-aged women. The study, which was led by nutrition professor Aedin Cassidy, PhD, MSc, BSc, found that women who consumed at least three servings of blueberries or strawberries, showed the best results.
Vitamin C, vitamin A, and various phytonutrients in blueberries function as powerful antioxidants that help protect cells against free radical damage. They inhibit tumor growth, decrease inflammation in the body and help ward off or slow several types of cancer, including esophageal, lung, mouth, pharynx, endometrial, pancreatic, prostate and colon.
Blueberries also contain folate, which plays a role in DNA synthesis and repair, thus preventing the formation of cancer cells from mutations in the DNA.
Improving mental health
Population-based studies have shown that consumption of blueberries can reduce the risk of cognitive decline as well as Parkinson's disease - a neurodegenerative disorder resulting from cell death in parts of the brain.
Studies have also revealed that in addition to reducing the risk of cognitive damage, blueberries can also improve short-term memory loss and motor coordination.
Because of their fiber content, blueberries help to prevent constipation and promote regularity for a healthy digestive tract.
Weight loss and satiety
Dietary fiber is commonly recognized as an important factor in weight loss and weight management by functioning as a "bulking agent" in the digestive system. High fiber foods increase satiety and reduce appetite, making you feel fuller for longer and thereby lowering your overall calorie intake.
Collagen, the skin's support system, relies on vitamin C as an essential nutrient that works in our bodies as an antioxidant to help prevent damage caused by the sun, pollution and smoke. Vitamin C also promotes collagen's ability to smooth wrinkles and improve overall skin texture. Just one cup of blueberries provides 24% of your daily need for vitamin C.
Recent developments on the health benefits of blueberries:
Blueberries could be used to fight Alzheimer's, researchers suggest
Blueberries are a popular fruit, easily added to cereals, salads and desserts or eaten as a sweet treat in their own right. They are also known by some as a "superfood," containing a wide variety of nutrients that offer protection against conditions such as cancer and heart disease. Now, researchers believe that they may have a part to play in the fight against Alzheimer's disease.