Measuring Antioxidant Activity
If you read about health topics, you have heard about the importance of antioxidants squelching free radicals to help prevent chronic disease and aging. Maybe you’ve also heard the term “ORAC” as a score to prove that certain fruits are high in antioxidants.
Marketers trumpet ORAC scores, which is a type of measurement for antioxidant activity in vitro, (meaning in a laboratory dish, not in a human body) with each one trying to claim their product has more antioxidant activity than any other.
Unfortunately, not nearly enough is known about how antioxidants behave in the human body as opposed to how they behave in the lab dish. The ORAC test may be an invalid means of making antioxidant claims for this reason.
Direct Antioxidants and Indirect Antioxidants
Vitamin C and E are well known “direct antioxidants” found in foods, meaning that they squelch free radicals but then they are inactivated. They basically have one shot and after that, they are over and out. However, now there is research showing that there is a class of “indirect antioxidants” that can reactivate the direct antioxidants and also stimulate the body to produce its own antioxidants over a much longer period of time. These are the types of antioxidants found in herbs, cruciferous vegetables, wine, cocoa and tea.
Researchers now understand that all antioxidants work best in synergy with each other so it is essential to consume a wide variety of herbs and foods to get a diversity of antioxidants. Indirect antioxidants, which are prevalent in herbs and spices, aid the body in fighting the millions of free radicals produced daily in our cells.
Herbs Supply Antioxidants, known As Polyphenols
Herbs such as rooibos have unique antioxidants known as polyphenols that only occur in that particular plant. For instance, Rooibos studies, which have been funded in South Africa where rooibos tea is indigenous, show that its unique antioxidant, aspalathin, is active in the human body to prevent free radical damage.
The antioxidants in most herbs, however, haven’t yet been studied in humans due to lack of funding. Nevertheless, we know they have antioxidant capabilities because beyond their unique polyphenols, they also share the same types of polyphenols that have been studied in other plants. The USDA has identified some herbs that contain flavonoids, anthocyanins and proanthocyanidins, compounds known to be active in humans after consumption.
The quick and easy ORAC test shows that many herbs have very high antioxidant activity in the laboratory. Hopefully, funding will become available in the future to perform studies showing their antioxidant activity in the human body. Even though it is not an accurate measurement for antioxidant activity in humans, ORAC scores can be read as an indication for the presence of certain types of antioxidant action. Here are some ORAC scores for herbs with a comparison to commonly eaten foods to show how high herbs score on ORAC tests:
|Apples, Granny Smith with skin||3,898||Cocoa, dry powder||80,933|
|Blueberries, fresh||6,552||Dates, deglet noor||3,895|
|Broccoli, boiled||2,386||Figs, fresh||3,383|
|Cranberries, raw||9,584||Ginger root, ground||28,811|
|Grapes, red||1,260||Cinnamon, ground||267,536|
|Potatoes, Russet with skin, baked||1,680||Almonds||4,454|
|Whole Grain Bread||1,421||Chili Flakes||23,636|
|Green tea, brewed||1,253|
Date from Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, 2007, Nutrient Data Laboratory, November 2007