Wednesday, September 22, 2010

Superfruit: Blueberry

Blueberries are flowering plants of the genus Vaccinium (a genus which also includes cranberries and bilberries) with dark-blue berries and is a perennial. Species in the section Cyanococcus are the most common fruits sold as "blueberries" and are mainly native to North America. They are usually erect but sometimes prostrate shrubs varying in size from 10 centimetres (3.9 in) to 4 metres (160 in) tall. In commercial blueberry production, smaller species are known as "lowbush blueberries" (synonymous with "wild") and the larger species, are known as "highbush blueberries". The leaves can be either deciduous or evergreen, ovate to lanceolate, and 1–8 centimetres (0.39–3.1 in) long and 0.5–3.5 centimetres (0.20–1.4 in) broad. The flowers are bell-shaped, white, pale pink or red, sometimes tinged greenish.
The fruit is a berry 5–16 millimetres (0.20–0.63 in) diameter with a flared crown at the end; they are pale greenish at first, then reddish-purple, and finally indigo when ripe. 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 height of the crop can vary from May to August depending upon these conditions.
The genus Vaccinium has a circumpolar distribution with species in North America, Europe and Asia. Many commercially sold species whose English common names include "blueberry" are currently classified in section Cyanococcus of the genus Vaccinium and come predominantly from North America. Many North American native species of blueberries are now also commercially grown in the Southern Hemisphere in Australia, New Zealand and South American countries.
Several other plants of the genus Vaccinium also produce commonly eaten blue berries such as the predominantly European bilberry (Vaccinium myrtillus), which in many languages has a name that means "blueberry" in English.
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, blueberry pies, muffins, snack foods and cereals.
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.
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. One serving provides a relatively low glycemic load score of 4 out of 100 per day.
Nutrients and phytochemicals
Blueberries, raw : Nutritional value per 100 g (3.5 oz)
Energy 239 kJ (57 kcal) | Carbohydrates 14.5 g
Dietary fiber 2.4 g | Fat 0.3 g | Protein 0.7 g
Vitamin A 54 IU | Lutein and Zeaxanthin 80 μg
Thiamine (Vit. B1) 0.04 mg (3%)
Riboflavin (Vit. B2) 0.04 mg (3%)
Niacin (Vit. B3) 0.42 mg (3%)
Pantothenic acid (B5) 0.1 mg (2%)
Vitamin B6 0.1 mg (8%) | Folate (Vit. B9) 6 μg (2%)
Vitamin C 10 mg (17%) | Vitamin E 0.6 mg (4%)
Calcium  6 mg (1%) | Iron  0.3 mg (2%)
Magnesium 6 mg (2%) | Phosphorus 12 mg (2%)
Potassium 77 mg (2%) | Zinc 0.2 mg (2%)
Manganese 0.3 mg (20%) | Vitamin K 19 mcg (24%)
Percentages are relative to US recommendations for adults.
Source: USDA Nutrient database
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 certain cancers.

Research on the potential anti-disease effects of blueberries

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.
A chemical isolated from blueberry leaves can block replication of the hepatitis C virus and might help to delay disease spread in infected individuals.
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.
A study soon to be published in the Journal of Agricultural and Food Chemistry found that supplementation with wild blueberry juice enhanced memory and learning in older adults, while reducing blood sugar and symptoms of depression.
Marketing of Blueberries as a Superfood (Antioxidant Properties)
Based on the promising research discussed above, magazines and newspapers have recently begun to hail blueberries as a superfood. Example: an article in the July 2010 issue of Chatelaine magazine mentions the blueberry as a food that can increase the body's natural ability to heal.

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