What are antioxidants?
Antioxidants are present in foods as vitamins, or as groups of substances called polyphenols such as flavanoids and carotenoids. Many antioxidants give food their characteristic colours, for example the deep red of cranberries, cherries and tomatoes, the orange of carrots, the yellow of corn, mangos, and saffron, the dark greens of vegetables such as kale, broccoli, sprouts and spinach, the purple of blueberries, blackberries, and grapes.
Some antioxidants are well known components of food such as vitamins A, C, and E and beta-carotene from carrots. Lycopene from tomatoes and apricots, and proanthocyanidins from cranberries are less well known.
Are there high levels of antioxidants in Cranberries? How are they unique?
The antioxidant capacity of cranberries has been demonstrated in a series of scientific publications that deal with levels of flavonoids in cranberries, showing cranberries to have the highest, or among the highest polyphenol content of fruits and berries.
The latest Agricultural Research Service Report from the United States Department of Agriculture (www.ars.usda.gov/Services/docs.htm?docid=15866) that was published in November 2007 shows the results for one of the most comprehensive analysis of antioxidants in food. Cranberries score among the highest of all common fruits on the antioxidant scale. The report gives antioxidant values for a wide variety of foods measured by their Oxygen Radical Absorbance Capacity (ORAC) value. With 9584 ORAC units per 100 grams of fresh fruit, cranberries have the highest antioxidant capacity when compared to 19 common fruits.
The proanthocyanidins (or PAC's) found in Cranberries have a unique molecular structure that is referred to as an A-type linkage. The combination of antioxidants and PAC's with this unique structure is only found in Cranberries.
The scientific consensus
Health organizations have recognized the beneficial roles fruits and vegetables play in the reduced risk of disease and have developed strategies to encourage consumers to eat more antioxidant rich fruits and vegetables.
- In the UK '5-a-day' initiative that recommends "you should eat a variety of fruit and vegetables to get the maximum nutritional benefits" (www.5aday.nhs.uk)
- The American Heart Association recommends healthy adults "Eat a variety of fruits and vegetables. Choose 5 or more servings per day."
- The American Cancer Society recommends to "Eat 5 or more servings of fruits and vegetables each day."
- The World Cancer Research Fund and the American Institute for Cancer Research 1997 Report Food, Nutrition and the Prevention of Cancer: A Global Perspective states, "Evidence of dietary protection against cancer is strongest and most consistent for diets high in vegetables and fruits."
- The potential for antioxidant-rich fruits and vegetables to help improve the health of Americans led the National Cancer Institute (NCI) to start the, "5-A-Day for Better Health" campaign to promote consumption of these foods.
