If you’ve done any research about antioxidants, such as what your daily recommended intake should be or which foods provide the highest level of antioxidants, you may have come across an ORAC rating. Many people are unaware of what ORAC ratings mean or the significance of the rating itself.
ORAC stands for oxygen radical absorbance capacity, which is a way to measure the amount of antioxidants in food components in an isolated environment (in vitro). The antioxidant activity of food can also be measured in vivo, which means the substance is tested as a whole in its natural state. In vitro is often referred to as test tube experiments, and only small portions of a substance are measured. This can cause outcomes to differ greatly, as it has been found that with in vitro testing, many food substances have a high ORAC rating, while the same substances show minimal, if any, antioxidant effect as the result of in vivo testing.
On the ORAC rating tables published online, berries, beans, spices, and some dark green vegetables rate very high with ORAC values of more than 1,000. Before following an ORAC chart, it is important to understand how the rating is displayed. Some charts use a food’s weight, but there is quite a difference between the weight of wet food and dry food. Also, some charts display ORAC values per serving. Understanding these differences can help you make the right decisions in what to eat without being misled about the nutritional effects and contents.
In general, spices rank the highest on ORAC charts, with berries next, and then vegetables. Acai berries are the highest-ranking fruits, while ground cloves score even higher than acai. And although beans and vegetables may fall far below spices in the ratings, they are still very nutritional and good for our bodies.
- Fruits: Some of the fruits that rank high on ORAC ratings include acai berries, blueberries, prunes, raisins, blackberries, raspberries, maqui berries, cranberries, pomegranates, and strawberries. All of these fruits provide excellent nutritional value and should be incorporated into any diet.
- Vegetables: For higher ORAC values, stick to kale, raw spinach, Brussel sprouts, and alfalfa sprouts.
- Spices: Thyme, cloves, oregano, rosehip, rosemary, cinnamon, turmeric, dried vanilla beans, sage, Szechuan pepper, parsley, basil, and nutmeg all rank highly on ORAC charts, so don’t forget the spices next time you cook dinner.
ORAC rating controversy
Many foods and spices have been tested with the results published on a variety of websites, including (for a time) the United States Department of Agriculture. However, through extensive research, the USDA found no scientific basis for the use of the rating system, and in May 2012, the department pulled the rating chart from its website. The European Food Safety Authority and the U.S. Food and Drug Administration have both independently set forth guidelines which prohibit claims of antioxidant benefits on food labels without physiological evidence. The reasoning of these governmental agencies is that there is no proof that foods produce a beneficial antioxidant effect in their natural state (in vivo), and so making similar nutritional claims on food labels is considered misleading. These claims do not include the antioxidants vitamin A, vitamin C, and vitamin E.
In vitro testing has shown that antioxidants, specifically polyphenols and flavonoids, have a high antioxidant efficacy, and the popularity of using the ORAC rating can partly be attributed to food manufacturers and consumers who look to flavonoids for medicinal purposes. Some of these products include wine, tea, fruits, and vegetables, however physiological evidence for these claims is lacking. According to Balz Frei, distinguished professor in the Department of Biochemistry and Biophysics at Oregon State University, the body sees flavonoids as foreign objects and tries to get rid of them.
Of course, departments and agencies of governing bodies must be extremely critical of any claims before promoting new ideas and health benefits to the public for safety reasons. It would be unwise and irresponsible to perpetuate claims without physiological proof, but that does not mean that proof cannot be found. The ORAC rating system of food is still a newer concept, and studies and research will continue to expand our knowledge on the subject. Until we know all the facts, the best course of action is to keep eating our fruits and vegetables in conjunction with a healthy diet, and when needed, taking vitamins and supplements as recommended by a doctor.