Increasingly, we are becoming interested in the antioxidant activity of the foods in our diet. Antioxidants are believed to play a vital role in the defence against harmful free radicals, a by-product of cell aerobic respiration. Unlike many other nutrients, antioxidants are chemically diverse and can come from a variety of sources. The antioxidants present in vegetables for example can be present as Vitamin C, Vitamin E, carotenoids and flavonoid compounds. One way to measure the total antioxidant capacity of the foods we eat is a method called Oxygen Radical Absorbance Capacity or ORAC.
It’s a lab test that attempts to quantify the “total antioxidant capacity” (TAC) of a food by placing a sample of the food in a test tube, along with certain molecules that generate free radical activity and certain other molecules that are vulnerable to oxidation.
One of the benefits of using the ORAC method to evaluate substances antioxidant capacities is that it takes into account samples with and without lag phases of their antioxidant capacities. This is especially beneficial when measuring foods and supplements that contain complex ingredients with various slow – and fast -acting antioxidants, as well as ingredients with combined effects that cannot be pre-calculated.
ORAC measures the degree and the length of time it takes to destroy oxygen radicals.
In addition to ORAC analysis, NMI (the National Measuring Institute) also has the capability of analysing a range of other compounds known to have antioxidant properties. These include Vitamins, such as Vitamin E, Vitamin C and Carotenes
The measure is expressed (generally in Vitamin E equivalents but can be Vitamin C equivalents) in uMol Trolox equivalents (TE) per litre/kg. An example is the Edenvale Shiraz has 46,500uMole/litre, which is very high. Generally above 50,000uMole/litre is high, above 15,000uMole /litre is medium and below 15,000uMole/litre is considered low. Reference: National Measurement Institute – South Melbourne Laboratories .
Extensive studies indicate that diets high in antioxidant rich foods, such as fruit and vegetables, offer significant protection against other age-related degenerative diseases.