What is ORAC | Oxidation | Antioxidants | Why ORAC? | References
Lately there have been a host of “nutrition scores” given to a variety of foods. These scores are supposed to make it easier for us to pick “healthy” foods. But do they really? This article will focus on ORAC scores, and provide information about what they really tell you about the food you are eating.
ORAC stands for Oxygen Radical Absorbance Capacity. This measure was created by the National Institute of Health as a way of measuring a food’s antioxidant capacity. (3) Anti-oxidants are promoted as being important for reducing free radicals and therefore decreasing potential for inflammation and preventing a whole host of diseases. For this reason, we’ve been encouraged to increase our consumption whether through supplementing or through eating foods which are anti-oxidant rich.
Before we can really discuss the benefits of antioxidants, we need to understand what oxidation is, and how it affects our bodies. According to Dr. Andrew Weil, “Oxidation is the chemist’s term for the process of removing electrons from an atom or molecule. The result of this change can be destructive – rusting iron is a familiar result of oxidation. Here, oxygen is the responsible agent, but other oxidizing agents, such as chlorine, can be as harsh.
Although we need oxygen to live, high concentrations of it are actually corrosive and toxic. We obtain energy by burning fuel with oxygen – that is, by combining digested food with oxygen from the air we breathe. This is a controlled metabolic process that, unfortunately, also generates dangerous byproducts. These include free radicals – electronically unstable atoms of molecules capable of stripping electrons from any other molecules they meet in an effort to achieve stability. In their wake they create even more unstable molecules that then attack their neighbors in domino-like chain reactions.
By the time a free radical chain fizzles out, it may have ripped through vital components of cells like a tornado, causing extensive damage, similar to that caused by ionizing radiation.
Oxidative stress is the total burden placed on organisms by the constant production of free radicals in the normal course of metabolism plus whatever other pressures the environment brings to bear (natural and artificial radiation, toxins in air, food and water; and miscellaneous sources of oxidizing activity such as tobacco smoke)." (2)
So, oxidative stress can cause damage to cells, which in turn can lead to medical conditions such as cancer, Alzheimer’s disease, and Parkinson’s disease. But, oxidation is a normal physiological process which allows us to break down foods, mix them molecularly with oxygen, and provide the fuel our bodies need to function. According to Dr. Mercola, “It is generally recognized that antioxidants are powerful nutrients that protect your health by fighting against free radicals in your body, preventing damage from oxidation. Free radicals are highly reactive molecules that steal electrons from the first thing they encounter, such as a cell wall, or a strand of DNA. The loss of an electron, in turn, oxidizes these cells, which makes them unstable and easily breakable.
As this free-radical damage continues, cells can no longer perform properly, and hence, tissues begin to degrade and disease sets in.
And yet, you still need a certain level of free radicals, as your body uses the chain reaction of the free radicals to turn air and food into chemical energy. They also play a vital role in your immune response, attacking foreign invaders and bacteria.
Eliminating or dramatically reducing them, might actually lead to more problems than not having them would solve.
Free radicals are a natural byproduct of breathing; antioxidants mop up the excess, and leave the rest to fulfill their other functions. This fine balancing act can be easily tipped to the point of either too much or too little.” (1)
The summary here is that oxidation is a normal process which is required for our physiological functioning. The issue is not to completely eliminate oxidation, the issue is to maintain the correct balance between too much oxidation and too little oxidation. Under normal conditions, our bodies are quite capable of dealing with the oxidative by-products of breathing. But when we are eating mostly processed foods, not sleeping enough, experiencing blood sugar fluctuations, and under too much stress our normal response starts to break down and we may no longer be able to keep on top of oxidative damage.
Are antioxidants good for us? It depends! Generally it is better to obtain antioxidants from a well balanced diet of mostly organic and minimally processed foods than it is to take supplements. And just because you need vitamin A today does not mean that it will be the best antioxidant for you tomorrow or next week. Your body’s need for individual nutrients will vary from day to day based on what you’ve eaten and what types of stressors you have experienced. There are numerous studies which suggest that one anti-oxidant or another is the best thing since sliced bread and will instantly solve all of your health problems. But for every study promoting the benefits of an anti-oxidant substance there is an equally compelling article suggesting that this substance is harmful to your health.
There are several issues I see with use of ORAC scores for making nutrition decisions.
First, it assumes that anti-oxidant foods are good for us, and that the more we eat, the healthier we will be. While this may be true, it is equally possible that it is not true that more is better. And generally speaking we are healthiest when we eat a wide variety of whole, minimally processed, organic foods. We are, after all, omnivores.
Second, the ORAC scale was determined by looking at chemical constituents of foods in a test tube, not in actual human beings. Just because a food is rich in antioxidants does not mean that these nutrients are readily accessible to a human who eats them.
Third, when comparing ORAC data, care must be taken to be certain the units and foods being compared are similar. Some evaluations will compare ORAC units per gram of dry weight, others will evaluate ORAC units in wet weight and still others will look at ORAC units per serving. Under each evaluation, different foods can appear to have higher ORAC values. For example, although a raisin has no more antioxidant potential than the grape from which it was dried, raisins will appear to have a higher ORAC value per gram of wet weight than grapes due to their reduced water content. Likewise, the large water content in watermelon can make it appear as though this fruit is low in ORAC. Similarly, the typical quantity of food used should be considered; herbs and spices may be high in ORAC, but are applied in much smaller quantities than for other foods. (4)
While some food producers are using ORAC scores as a marketing tool for their products, the United States Department of Agriculture, previously a publisher of ORAC data, withdrew its web publication of ORAC values for common American foods in 2012 due to absence of scientific evidence that ORAC has any biological significance. (5)
What is a thinking omnivore who wants to optimize his or health to do? As always, my advice is to pay less attention to a food’s “score”, and more attention to its taste. Eat a wide variety of vegetables, some fruits, moderate amounts of minimally processed grains, lots of good quality organic and sustainably farmed protein, and minimize sugar, processed foods, and alcohol. If you are going through a period of extreme stress, take a broad spectrum antioxidant supplement for a few weeks until the situation eases up, but don’t worry about supplementing all the time unless you have a documented nutrient deficiency.
4) Tapsell, Linda C; Ian Hemphill, Lynne Cobiac, Craig S Patch, David R Sullivan, Michael Fenech, Steven Roodenrys, Jennifer B Keogh, Peter M Clifton, Peter G Williams, Virginia A Fazio, Karen E Inge (2006-08-21). "Health benefits of herbs and spices: the past, the present, the future". The Medical Journal of Australia 185 (4 Suppl): S4–24. ISSN 0025-729X.PMID 17022438. Retrieved 2009-09-23.
5) United States Department of Agriculture, Agricultural Research Service. "Withdrawn: Oxygen Radical Absorbance Capacity (ORAC) of Selected Foods, Release 2 (2010)". 16 May 2012.