By Toby Amidor, R.D., Contributing Editor
As one of the few fruits native to the United States, blueberries are a healthy part of the country’s history. Native Americans gathered fresh blueberries from forests and bogs and used them for food and medicinal purposes. Once the settlers arrived, the Wampanoag Indians taught them how to gather, dry and store blueberries for the long winter months to supplement their cultivated food supply. Civil War soldiers drank blueberry juice in order to prevent scurvy. Today, blueberries have gained a reputation as being a superfruit because of their nutritional benefits.
All about blueberries
The blueberry genus Vaccinium includes over 450 plants, but three varieties are most abundant. The northern highbush (V. corymbosum) grows wild in North American forests, and the bush can reach a height of 15 ft. The lowbush (V. angustifolium), known as “wild blueberries,” grow on 1- to 2-ft. dwarf bushes and survive in the wild as far north as Arctic North America. Unlike cultivated highbush berries, lowbush blueberries are harvested from wild clones. The southern rabbiteye (V. ashei) thrives in the southern United States.
The North American blueberry season is from April through October; in South America it runs from November through March. This makes blueberries available year-round. About half of the blueberry crop is sold as fresh; the rest are processed into various forms, including frozen, dried, and liquid juices and purees.
Superfruit nutrient stats
Cultivated blueberries contain approximately 57 calories per 100 grams, no fat, only 1 mg sodium, and provide 2.4 grams fiber. They are an excellent source of vitamin C (9.7 mg per 100 grams). Wild blueberries are smaller than the cultivated highbush varieties―approximately 1,600 wild blueberries in a pound, compared with around 500 cultivated―so they tend to be more nutrient-dense. One of the most notable differences is that wild blueberries contain more than eight times more manganese per 100 grams than cultivated blueberries. Wild varieties also have 25% fewer calories.
Blueberries rank among the highest in ORAC (oxygen radical absorption capacity) value at 2,400 per 100 grams and, in addition to vitamin C, contain a number of phytochemicals, such as phenolic acid, anthocyanins, proanthocyanidins and ellagic acid; the latter is linked to inhibiting tumor growth (Nutrition and Cancer, 2008; 60(2):227-234). According to the "USDA Database for the Flavonoid Content of Selected Foods," they contain the following average flavonoid amounts: the anthocyanins cyanidin (15 mg per 100 grams), delphinidin (30 mg per 100 grams), malvidin (49 mg per 100 grams), peonidin (7 mg per 100 grams), petunidin (12 mg per 100 grams); the flavan-3-ol epicatechin (1.11 mg per 100 grams); and the flavonols myricetin (0.82 mg per 100 grams) and quercetin (3.11 mg per 100 grams). Anthocyanins give blueberries their deep-blue color and are a major contributor to their antioxidant activity. Procyanidins (catechin and epicatechin, and a series of oligomers) make up to 32% of blueberries’ total ORAC. Fresh and frozen blueberries contain the highest amounts of anthocyanins; little is found in the dried form. A study published in the Journal of Agriculture and Food Chemistry in 2006 (54(11):4,069-4,075) found anthocyanins were highest in fresh and frozen berries, but were almost undetectable in processed foods. The fresh highbush (cultivated) contain 125 mg anthocyanins per 100 grams. Proanthocyanidins, or condensed tannins, are polymers of flavan-3-ols, and contribute an astringent flavor.