Author: Marie Spano, M.S., R.D., Contributing Editor
Nutritionally speaking, good things come in sweet—and tart—little packages. Research is discovering berries pack a nutritional punch due to their vitamin, fiber and antioxidant content.
Botanically speaking, berries are indehiscent fruits (they don’t need to be opened to release their seeds) that ripen through the ovary wall. However, any small, edible fruit with multiple seeds is typically considered a berry.
In addition to lending flavor and brilliant colors to a wide variety of dishes, all berries are packed with an array of antioxidants, nutrients and potential health benefits. Berries that are especially antioxidant-rich include fresh crowberries, bilberries, black currants, wild strawberries, blackberries, blueberries, goji berries, sea buckthorn, blueberries and cranberries. However, the antioxidant content of berries varies based on the geographical growing condition. And, while fresh berries are an excellent source of antioxidants, total phenol content drops during processing. In fact, processed berry jams and syrup contain approximately half the antioxidant capacity of fresh berries, and juices show the greatest loss of anthocyanins and tannins due to the removal of seeds and skin (Nutrition Journal, 2010; 9:3; Journal of Agricultural and Food Chemistry, Jan 13, 2012).
Shiny, scarlet-colored cranberries are rich in vitamin C, loaded with antioxidants, including flavonoids, and score higher in their ORAC score than many other fruits (“Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods—2007”, USDA ARS). Cranberries are perhaps best known for the role their juice plays in the prevention of urinary tract infections (UTI) in women, particularly those with recurrent UTIs (Cochrane Database Systems Review, 2008; 23:CD001321). However, cranberries may also inhibit the growth and proliferation of some types of cancer cells (Journal of Nutrition, 2007; 137:186S-193S), reduce low-density lipoprotein (LDL) oxidation and platelet aggregation, and improve vascular function (Nutrition Reviews, 2010; 68:168-177; Nutrition Reviews, 2007; 65:490-502). In addition, polyphenols isolated from cranberries appear to inhibit the formation of cariogenic bacteria and reduce both inflammation and the production of enzymes that contribute to the destruction of the extracellular matrix in periodontal disease, making them beneficial for oral health (Journal of the Canadian Dental Association, 2010; 76:a130).
Processing and storage affects the phytochemicals found in cranberries. Anthocyanins are present at much higher levels than flavonols in cranberries, but the reverse is true for cranberry juice, due, in part, to the instability of anthocyanins. Some flavonols are also degraded during processing but to a lesser extent than anthocyanins (Critical Reviews in Food Science and Nutrition, 2009; 49:741-781).
Also leading the nutritional way is the tiny blueberry. According to the U.S. Highbush Blueberry Council, Folsom, CA, blueberries are packed with vitamin C, dietary fiber, potassium and antioxidants, with a total of 6,552 ORAC units per 100 grams. Further, many studies have indicated blueberry supplementation can help mitigate age-related neurodegenerative diseases. In one study, for example, rats fed 18.6 grams of dried blueberry extract per kilogram of diet for eight weeks showed a reversal of age-related deficits in brain and behavioral function (The Journal of Neuroscience, 1999; 19:8,114-8,121). The phytochemicals in blueberries also may help protect against some cancers. A study that identified blueberry anthocyanins also determined their ability to inhibit the growth of colon, breast, oral and, especially, prostate cancer cell lines. The same study showed blueberries were effective in inducing cell death of colon-cancer cells (Journal of Agricultural and Food Chemistry, 2006; 54:9,329-9,339).
Other less commonly consumed berries show promising health benefits. Though relatively few health-related studies have been conducted using black, white and red currants, one study using mixed berries, including currants, found that consumption of two portions of berries daily (including black currant purée on alternating days) resulted in favorable changes in high-density lipoprotein (HDL) cholesterol, blood pressure and platelet functioning (American Journal of Clinical Nutrition, 2008; 87:323-331). Red and black currants are an excellent source of vitamin C, and black currants are also an excellent source of fiber and good source of manganese and potassium.
Wolfberries, otherwise known as goji berries, contain several antioxidants, notably zeaxanthin, one of the two antioxidants found in the retina of the eye. One double-blind, placebo-controlled study in healthy elderly subjects found that, compared to placebo, daily supplementation with goji berry (13.7 grams per day) for 90 days increased plasma zeaxanthin and antioxidant levels while protecting from hypopigmentation and soft drusen accumulation (yellow deposits under the retina) in the macula of the eye (Optometry & Vision Science, 2011; 88:257-262). Additional studies have found that goji berry juice improves antioxidant biomarkers in healthy humans (Nutrition Research, 2009; 29:19-25), subjective feelings of well-being, neurologic and psychologic performance and gastrointestinal functioning (Journal of Alternative and Complementary Medicine, 2008; 14:403-412).
More research needs to be done on the health benefits of gooseberries and muscadine grape berries, but they, too, have a great nutrition profile. Gooseberries are an excellent source of vitamins A and C, and a good source of potassium and fiber. Muscadine grape berries are an excellent source of manganese, a good source of fiber and contain reseveratrol (American Journal of Enology and Viticulture, 1996; 47:57-62).
In addition to the nutrition attributes for botanical berries, non-botanical berries, including strawberries, chokeberries, blackberries and raspberries, are also loaded with nutrients and antioxidants.
Strawberries are an excellent source of vitamin C and also contain fiber, vitamins, potassium and phytonutrients. Animal research has shown that strawberries improve indices of memory and cognitive functioning (Current Opinion in Clinical & Metabolic Care, 2009; 12:91-94), while human intervention studies indicate that strawberries (in addition to chokeberries, cranberries and blueberries; fresh, as juice or freeze-dried) lead to significant improvements in LDL oxidation, lipid peroxidation, dyslipidemia and glucose metabolism (Nutrition Reviews, 2010;6 8:168-177).
Chokeberries (Aronia melanocarpa) contain a mix of many antioxidants, including procyanidins, anthocyanins and phenolic acids. A review of studies to date on chokeberries indicate they may be a promising functional food for diseases related to oxidative stress, but more rigorous scientific research is necessary (Phytotherapy Research, 2010; 24:1,107-1,114).
Blackberries are an excellent source of vitamin C and fiber. Studies show anthocyanin-rich fractions of blackberry extracts reduce UV-induced free radical damage to skin cells (Phytotherapy Research, 2012; 26:106-112), and freeze-dried blackberries reduce esophagus and colon cancer development in rodents (Nutrition and Cancer, 2006; 54:69-78).
Raspberries are an excellent source of vitamin C, manganese and dietary fiber, and a good source of vitamin K. However, much of the interest in raspberries stems from their anthocyanin and ellagic acid content. In vitro studies show ellagic acid is protective against cancer (Journal of Nutrition and Biochemistry, 2004; 15:672-678). And this antioxidant, as well as the overall antioxidant capacity of raspberries, is similar in fresh commercial, freshly picked and frozen raspberries (Journal of Agricultural and Food Chemistry, 2002; 50:5,197-5,201).
All berries are full of antioxidants and nutrients. And, the various colors, textures and different forms of berries, including frozen, fresh, dried and pulp, make berries a versatile, nutritious, eye-appealing and tasty addition to a variety of foods and beverages.
About the author:
Marie Spano, M.S., R.D., CSCS, is a nutrition communications expert whose work has appeared in popular press magazines, e-zines and nutrition-industry trade publications. She has been an expert guest on NBC, ABC and CBS affiliates on the East Coast.