Blueberry

Blueberries are flowering plants in the genus Vaccinium, sect. Cyanococcus. The species are native only to North America. They are shrubs varying in size from 10 cm tall to 4 m tall; the smaller species are known as "lowbush blueberries" (synonymous with "wild"), and the larger species as "highbush blueberries". The leaves can be either deciduous or evergreen, ovate to lanceolate, and from 1–8 cm long and 0.5–3.5 cm broad. The flowers are bell-shaped, white, pale pink or red, sometimes tinged greenish.

The fruit is a false berry 5–16 mm diameter with a flared crown at the end; they are pale greenish at first, then reddish-purple, and finally blue on ripening. They have a sweet taste when mature, with variable acidity. Blueberry bushes typically bear fruit from May through June in the Western Hemisphere; blueberry season peaks in July, which is National Blueberry Month in the United States and Germany.

Beginning in 2005, blueberries have been discussed among a category of functional foods called superfruits having the favorable combination of nutrient richness, antioxidant strength, emerging research evidence for health benefits and versatility for manufacturing popular consumer products.

Blueberries are sold fresh or processed as individually quick frozen (IQF) fruit, purée, juice, or dried or infused berries which in turn may be used in a variety of consumer goods such as jellies, jams, pies, muffins, snack foods, and cereals.

To freeze freshly picked blueberries, place in a single layer on a cookie sheet in the freezer. When frozen, put in freezer containers. It is best to rinse before using, but not before freezing.

Blueberry jam is made from blueberries, sugar, water, and fruit pectin. Premium blueberry jam, usually made from wild blueberries, is common in Maine, Ontario, Quebec, and British Columbia.

Nutrients and phytochemicals

Blueberries have a diverse range of micronutrients, with notably high levels (relative to respective Dietary Reference Intakes) of the essential dietary mineral manganese, vitamin B6, vitamin C, vitamin K and dietary fiber (table). One serving provides a relatively low glycemic load score of 4 out of 100 per day.

Especially in wild species, blueberries contain anthocyanins, other antioxidant pigments and various phytochemicals possibly having a role in reducing risks of some diseases, including inflammation and different cancers.

Potential anti-disease effects

Researchers have shown that blueberry anthocyanins, proanthocyanidins, resveratrol, flavonols, and tannins inhibit mechanisms of cancer cell development and inflammation in vitro. Similar to red grape, some blueberry species contain in their skins significant levels of resveratrol, a phytochemical.

Although most studies below were conducted using the highbush cultivar of blueberries (V. corymbosum), content of polyphenol antioxidants and anthocyanins in lowbush (wild) blueberries (V. angustifolium) exceeds values found in highbush species.

At a 2007 symposium on berry health benefits were reports showing consumption of blueberries (and similar berry fruits including cranberries) may alleviate the cognitive decline occurring in Alzheimer's disease and other conditions of aging.

Feeding blueberries to animals lowers brain damage in experimental stroke. Research at Rutgers has also shown that blueberries may help prevent urinary tract infections.

Other animal studies found that blueberry consumption lowered cholesterol and total blood lipid levels, possibly affecting symptoms of heart disease. Additional research showed that blueberry consumption in rats altered glycosaminoglycans which are vascular cell components affecting control of blood pressure.