Antioxidants - Can You Get Too Many?
As a result of an increased awareness of the damaging effects of free radicals, everywhere you turn someone has a high antioxidant supplement they want you to buy. They range from supplements containing vitamins C and E and the trace mineral selenium (give or take a few nutrients) to supercharged juices made from exotic berries, like acai berries. The prices are anywhere from about $10.00 all the way up to $70.00 for a bottle of juice; or $2.00 for one small square of acai-added chocolate.
One of the features used to market these products is their high ORAC value, and the manufacturers are now trying to outdo one another by getting higher and higher on their ORAC values. So what is ORAC and are these products really worth the high prices?
ORAC stands for oxygen radical absorbance capacity. Researchers at the National Institute of Aging developed ORAC testing as a way to measure the level of antioxidant protection capacity of a product or food. If a product has a high ORAC value, it has the ability to neutralize many free radicals.
Diets that are plentiful in high ORAC foods are associated with decreased disease risks,2 and more recent studies are trying to clarify which compounds are responsible for those benefits. For example a study of several high antioxidant legumes (black bean, kidney beans, lentils and more) found that these foods have the potential for preventing the development of atherosclerosis (plaque formation) by inhibiting LDL cholesterol oxidation. The study found that the foods' phenolic compounds seemed to be most responsible for that effect, and that the foods' ORAC values correlated well with those effects.
When most people think about antioxidant protection they tend to think about the well-marketed super fruits such as gogi berries (from China) and acai berries (from Brazil). Freeze-dried acai berry is indeed very high in antioxidants with an ORAC value of 161,400 units. Gogi berries have an ORAC score of 25,300, but there are many common foods that also have high ORAC scores that can be found at your supermarket right now.
Spices, for example. The ORAC value of ground cloves is very impressive at 314,416 units. Cinnamon and oregano are also right up there on the list of high ORAC foods. Unsweetened dry cocoa powder weighs in at 80,933 units. Pecans have a score of 17,940, and English walnuts which are known for their healthy omega-3 fats, have an ORAC value of 13,541. Kidney and black beans both have ORAC scores greater than 8,000.
A good website to visit for easy ORAC searches is http://oracvalues.com/sort/orac-value/. The values reported are for 100 grams of the food.
As Jim described, we find that the best way to lower oxidative stress is to address all the factors causing the increased oxidative stress to begin with, but for the dietary component we follow at LMI, we don't send patients out with acai drinks or pills. These products can be quite expensive and they only address one thing -- ORAC value. And believe it or not, we are still learning about all the effects of an excessively high intake of antioxidants, even those from substances like plant flavonoids. Some studies are showing they may have negative effects, like inhibiting key enzymes in the body.
Researchers will continue to try to identify if there is a level of antioxidant intake that is too high. In the meantime, many people eat diets that are almost devoid of antioxidants, and in this polluted world, that is not good. So, I want to emphasize that the preponderance of the evidence does show dietary antioxidants are beneficial to our health, and even the researchers who are concerned, say that antioxidants are safe and beneficial even at amounts that would be consumed from a typical vegetarian diet, which is much higher than a typical low fruit and vegetable intake diet.
We try to put our patients' dollars to better use by choosing supplements for them that address their specific health needs. We find that a low carbohydrate, organic foods diet that includes plenty of high antioxidant foods like spices, beans, nuts, plentiful vegetables and 1-2 servings of fruit or berries each day can go a long way to reducing oxidative stress -- without the expensive super-high ORAC supplements that still need more research.
What Is ORAC? Found online at: http://www.oracwatch.org/what_orac.php.
Leighton F, et al. Drugs Exp Clin Res. 25:133-141
Xu BJ, et al. Journal of Food Science. Found online at:http://www3.interscience.wiley.com/journal/118510071/abstract.
Skibola CF, et al. Free Radic Biol Med. 200 Aug; 29(3-4):375-83.