Bringing ORAC to a New Level
It’s time to see if a high ORAC number translates into meaningful health benefits.
By Douglas Kalman
PhD, MS, RD, CCRC, FACN
The results of clinical research can be misleading when presented to the mass market in a “snippet” or via an overly simplified take home message. Unfortunately, that is often the case with nutrition studies, where marketing has a tendency to obscure the truth.
I have spent many years on the clinical side of the nutraceuticals business (research, development, publishing, etc.), and have come across some “truths” that need to be amended, particularly in the case of antioxidants. I think it’s high time that someone reviewed some of the realities concerning antioxidant food or beverages, and how these are portrayed to the general population.
High on ORAC?
ORAC, also known as oxygen radical absorbance capacity, is a method used in food science research to quantify the ability of a food or beverage to quench free radicals and stave off oxidative damage. Some consumers are under the impression that an ORAC value of a particular food must correspond with strong antioxidant properties inside the body—but that’s not entirely true.
Does a high ORAC value mean that an antioxidant ingredient or fruit or vegetable will have a positive impact on health? Or, does a high ORAC number translate into reduced disease risk? Or, is ORAC testing the best or most complete test for antioxidant capacity? These are some of the questions being asked by consumers, researchers and companies today.
Putting Study Results in Context
While there are many tests that can be conducted to determine the antioxidant capacity of a food or food stuff (i.e., FRAP testing), it may be more appropriate to start asking dietary supplement, beverage and food companies that tout the ORAC value of their product if their particular product actually does anything in the human body. In other words, does it matter if a fruit tests very high for antioxidant capacity if that same fruit and its ORAC do not reduce your risk of disease or significantly alter physiologic function in such a way that health is improved?
Early findings suggest that eating plenty of high-ORAC fruits and vegetables—such as spinach and blueberries—may help slow the processes associated with aging in the body and brain. This research, in its infancy, indicates that a diet rich in fruits and vegetables may reduce in vivo markers of oxidative damage and thus slow down the aging process (via quenching free radicals plus perhaps upregulating translational activity). If the early research pans out in larger trials, then might we one day see young and middle-aged people attempting to reduce the risk of diseases of aging—including senility—simply by adding high-ORAC foods to their diets?
In recent studies, eating plenty of high-ORAC foods:
• Raised the antioxidant power of human blood 10-25%;
• Prevented some loss of long-term memory and learning ability in middle-aged rats;
• Maintained the ability of brain cells in middle-aged rats to respond to a chemical stimulus—a function that normally decreases with age; and
• Protected rats’ tiny blood vessels—capillaries—against oxidative damage.
Dr. Ronald Prior of the USDA contends, “If we can show some relationship between ORAC intake and health outcome in people, I think we may reach a point where the ORAC value will become a new standard for good antioxidant protection.”
Dr. Guohua Cao, a physician and chemist who developed the ORAC assay, believes that combinations of nutrients found in foods may have greater protective effects than each nutrient taken alone.
But connecting an ORAC value to disease risk reduction is a long way off. Fortunately, Dr. Prior and his colleagues at the USDA have a passion for learning about the antioxidant effects of fruits and vegetables. Their research has showed that high-ORAC foods (spinach, strawberries), as compared to vitamin C alone (in a 1250 mg dose), may have differential effects in humans.
In fact, one of the studies found that a large serving of fresh spinach produced the biggest rise in the women’s blood antioxidant scores—up to 25%—followed by vitamin C, strawberries and red wine. In another study, men and women experienced a 13-15% increase in the antioxidant power of their blood after doubling their daily fruit and vegetable intake compared to what they consumed before the study. Just doubling intake more than doubled the number of ORAC units the volunteers consumed, according to Dr. Prior.
We seem to be on the cusp of knowing which dietary strategies might reduce risks of diseases while enhancing overall quality of life. However, the preponderance of evidence from published studies on fruits, vegetables, beverages and dietary supplements, particularly as they relate to ORAC value, should be classified as “unknown” for the moment. While testing for an ORAC value may be appealing because it can be used in subsequent product advertising, the clinical trial route is probably the better path to travel. The feeling within the research community and perhaps within the regulatory arena as well is that it is high time for ORAC to provide human proof of its impact on health.NW
References furnished upon request.