by Dr. Gordon Chang, PhD
There are currently many products being marketed as antioxidants with their biggest claim to fame being that their particular ingredient or product has the highest ORAC values. It’s suggested that product X is better than product Z because the ORAC value of an ingredient is higher, creating a competition for the product with the highest ORAC value which is almost akin to the situation of “mine is bigger than yours”. Let us examine what exactly is meant by the ORAC value of an antioxidant and what meaning the ORAC value has to the human body.
ORAC is an acronym for Oxygen Radical Absorbance Capacity. The ORAC value of a product or compound is a number which is supposed to represent the potential of the compound to react with an oxygen free radical. The test for ORAC values is (or should be) done in a test tube under laboratory conditions but there are several problems with ORAC values. Firstly, ORAC values only represent the ability of a particular product to quench (stop) an oxygen free radical reaction. In real life the body encounters many different types of free radicals which have no resemblance to an oxygen free radical or any related oxygen free radicals such as a peroxide free radical. This means that even if a product has a high ORAC value it may be useless if it encounters a chlorine free radical for example. Oxygen free radicals are only a fraction of the total number of different types of free radicals normally encountered by the cells of the body on a daily basis.
Secondly, the chemical assay to determine the ORAC value is usually performed in a water environment. However, in the human body there are structures (cell membranes) which are constantly under free radical attack where there is no water present. Therefore the ORAC values cannot predict if the product is going to be effective in an environment free of water.
Thirdly, since ORAC values are determined in a test tube an ORAC value does not indicate whether the antioxidant will even be absorbed by the body. If the antioxidant is absorbed, the ORAC value gives no indication of how much of the antioxidant is actually absorbed, which is a fairly important consideration. The implication here is that an item with a lower ORAC value (e.g. – *tomatoes at 342/100g ORAC value) but which is highly absorbable is more effective than another item which has a higher ORAC value (e.g. – *cloves at 314,446/100g ORAC value) but with low absorption. Absorption of the antioxidant by the body is of major importance but just as important is where does the absorbed antioxidant go to inthe body? E.g. – does it go to the eyes in the case of lutein or does it go to the ovaries and testes in the case of lycopene? Realistically, supplementing with a variety of antioxidants is best to help build a synergistic defence network of antioxidants in the body. In other words, an ORAC value is not a reliable measure of the antioxidant’s ability to stop the free radical damage at the cellular level.
In conclusion, while the ORAC value of an antioxidant gives a rough guide as to the potential active antioxidant capacity of a product it should not be considered to be the final word on the value of the antioxidant to preserve our health. Touting high ORAC values as the reason one should consume a certain antioxidant over another is not really good science. To be sure one is going to win the fight against free radicals, it is better to consume as many different types of antioxidants as possible byeating a variety of antioxidant rich foods such as fruits and vegetables. Since many people do not eat enough of these important food groups, the next best choice is to supplement with a high quality multi-antioxidant supplement so that the variety of antioxidants can protect from the many different types of free radicals one would encounter on a daily basis.
* USDA http://www.ars.usda.gov/SP2UserFiles/Place/12354500/Articles/AICR07_ORAC.pdf