Blackberries are a healthy, tasty fruit with extremely high antioxidant levels. The antioxidants in blackberries come in many different forms, including familiar vitamins and minerals as well as multiple classes of phytochemicals that have only recently been identified. These small, dark berries also have a wide range of nutrients that benefit overall health, including fiber provided by their seeds.
Antioxidants neutralize compounds called free radicals in the body. Free radicals form when molecules lose an electron and become unstable. These highly charged molecules then travel through cells in search of other molecules with loosely attached electrons that they can steal. Cellular components can be irrevocably damaged by rampaging free radicals if these particles are left unchecked. Antioxidants work by donating an electron to free radicals, rendering them harmless.
Blackberries score high on the Oxygen Radical Absorbance Capacity, or ORAC, scale, which is used to measure total antioxidant levels in foods. The antioxidant content of blackberries from the U.S. Northwest is between 24 and 77 micromoles per gram, according to Oregon State University. These levels are higher than other high-antioxidant berries, such as blueberries. The high antioxidant levels of blackberries may help in cancer prevention, cardiovascular health and the prevention of neurodegenerative disease when these berries are consumed as part of a nutritious, balanced diet.
Many of the micronutrients present in blackberries have antioxidant activity. One cup of blackberries contains 30.2 milligrams of vitamin C, or almost half of the recommended daily intake of 75 milligrams for women, and more than 1/3 of the recommended 85 milligrams for men. Blackberries also contain 1.68 milligrams of vitamin E, or 10 percent of the recommended daily intake of 15 milligrams for adults, and 308 International Units of vitamin A. Other antioxidant micronutrients in blackberries include selenium, vitamin K and niacin.
The dark purple-black color of blackberries comes from polyphenol antioxidants called anthocyanins. The anthocyanin content of blackberries is 83 milligrams to 326 milligrams per 100 grams of berries. A 100 gram serving of Evergreen blackberries contain 1.4 milligrams of catechins, another type of polyphenolic antioxidant also found in green tea. Other polyphenol antioxidants in blackberries include the flavonols quercetin and kaempferol.
Another category of antioxidant phytochemicals is the carotenoids. Blackberries contain a few different carotenoids, including beta-carotene, lutein, zeaxanthin, beta cryptoxanthin and alpha-cryptoxanthin. A 2007 analysis in the "Journal of Food Composition and Analysis" found that blackberries had a higher carotenoid content than raspberries, blueberries, strawberries, black currants and red currants. Blackberries were particularly high in beta-carotene, with 101.4 micrograms per 100 grams of berries, and lutein, at 270.1 micrograms per 100 grams. Beta-carotene and lutein both boost eye health in addition to their antioxidant properties.