Research is showing that blueberries
contain a number of compounds that have medicinally beneficial properties. The earliest recorded use of blueberry for medicinal purposes dates from the Middle Ages, and it has been used in European folk medicine since the 16th century. Some of its reported medicinal benefits include preventing urinary tract infections, antioxidant (anti-cancer) activity, reducing heart disease risk, strengthening collagen, regulating blood sugar, improving
night vision, reducing replication of the HIV virus, and treating diarrhea.
Research has been done by Rutgers Lab in New Jersey, and by scientists in Israel on the ability of blueberries to prevent urinary tract infections. The compounds inhibit the binding E. coli bacteria to the urinary tract wall, thus preventing the bacteria from invading the tissues and causing an infection. Treatment with blueberry compounds offers an alternative to the use of antibiotics.
Recent work indicates that blueberries contain compounds having anti-cancer properties. They act to induce enzymes
that protect against cancer and reduce rapid tumor growth. A survey of the antioxidant capacity of a number of fruits and vegetables conducted by Dr. Ron Pryor of the USDA placed blueberry at the top of the list.
Work is now underway in a collaborative effort between Rutgers and researchers at the University of Wisconsin to determine the blueberry compounds responsible for anti-platelet aggregation (protecting against heart disease). The compounds act in two ways: They reduce the oxidation of LDLs, which can result in lowering of arterial plaque
build-up, and they reduce the stickiness of blood platelets, which can lower the tendency to form blood clots. Some reports exist on the favorable effects
of blueberries on eyesight. One study showed that when Israeli fighter pilots were given regular doses of blueberry, their night vision significantly
improved. The effects result from the ability of the blueberry compounds to enhance capillary elasticity and permeability of the eye.
The molecules in blueberry that are responsible for these medicinal effects are called bioactive compounds. A bioactive compound is found in plants and elicits a positive (or negative) effect on animal or plant tissues. Examples of some compounds that exist in plants that have bioactive properties are proteins (enzymes), lipids (steroids), sugars (glycosidic linkages), acids (antioxidants), vitamins (fat and water-soluble), and polyphenolics. The focus of the reasearch lab at Rutgers is on certain polyphenolics of blueberry, including anthocyanins,
flavonols, and tannins. Functions of anthocyanins in plants include acting as plant colorants, attracting animals for pollination and seed dispersal, and playing roles in light filtration and general metabolism. Functions of flavonols in plants include intensifying flower petal color, attracting pollinator insects, and acting as anti-microbial agents. The role of tannins
in plants is mainly one of defense, acting to deter insects and animals from feeding and to protect the plant from fungal and bacterial attack.
These polyphenolic compounds are responsible for a number of the medicinally beneficial properties attributed to blueberries. However, when these compounds are isolated from the plants, they can be toxic when ingested at high dosages. Therefore, it is unwise to ingest these
isolated compounds in capsule or pill-form until further studies are undertaken to determine dosages and toxicity levels. It is often better to eat the whole blueberry, fresh from the field, to obtain the maximum healthful benefits.
Information for this article was from a research update on beneficial medicinal compounds in blueberries by Amy Howell, Rutgers Research Center