Antioxidants are compounds that protect cellular health by neutralizing the damage that is caused by free radicals. But, what do antioxidants do? In short, they prevent cell and tissue damage. Free radicals are unstable molecules that are a normal byproduct of the body’s metabolic processes and can also be found in the environment as well as our diet. They are made unstable by the fact that they are missing electrons. Their search for electrons leads them to damage cells and tissues. The body, however, has developed a defense system to handle free radicals and stabilize them so they can no longer perpetrate their damaging effects. This is through a network of compounds and molecules that have excess electrons they are willing to donate, called antioxidants. Antioxidants can range from vitamins and minerals such as vitamin C and zinc, to other molecules found in fruits and vegetables, in particular the polyphenols. These are compounds that impart the bright colors to plants at the same time as participating in their self defense and protecting them from illness and predators. It just so happens those polyphenols serve the purpose of conferring antioxidants benefits in humans.
Polyphenols vary in chemical structure with the defining factor of these molecules being the presence of a phenol ring. This sets them apart from other plant compounds. While polyphenols are not always absorbed intact by humans though the digestive tract, they often serve as food for the microbiome, the plethora of bacteria and other organisms that make up or digestive flora. These organisms metabolize polyphenols from the diet and the metabolic byproducts are absorbed through the intestinal tract where they buttress the body’s own antioxidant defenses.
How is Antioxidant Activity Measured?
There are numerous ways that scientists have developed to measure the antioxidant capacity or potential of various foods and supplements. One method that was developed by US Department of Agriculture (USDA) scientists more than a decade ago is called the ORAC score, or Oxygen Radical Absorbance Capacity. As the name suggests, the ORAC score is simply a measure of how well antioxidant foods or nutrients absorb various types of oxygen free radicals. While this measure does not always indicate how well a food or nutrient works in the body at absorbing free radicals for some of the reasons mentioned above (including the fact that polyphenols are first often metabolized by our gut bacteria before being absorbed), the ORAC value does give an indication of how powerful a food or nutrient is at quenching free radicals. So, what foods are high in antioxidants? Let’s look at what the USDA data says.
What Fruits are High in Antioxidants?
Fruits that contain high levels of polyphenols tend to make the list of foods high in antioxidants, based on the ORAC score. Naturally, this would include berries, including blueberries, blackberries, strawberries and raspberries. Per 100-gram serving (about 3.5 ounces of whole fruit), blueberries came in at 2,400 ORAC units, followed by blackberries at 2,036, strawberries at 1,540 and raspberries at 1,220 units.
Some of the other top-scoring fruits on the USDA list include plums, oranges, red grapes, cherries, and kiwi. What about superfoods? Depending on the list being referenced, fruits that are considered superfoods are off the chart from an ORAC perspective. As an example, elderberries came in at a whopping 14,697 ORAC units per 100-gram serving! That’s powerful support! What is elderberry good for? Well, elderberry is known for its potent ability to support immune health. It does this in a few different ways, including its ability to counteract the effects of viruses and reduce inflammation; but a key to elderberry’s ability to support immune health is its antioxidant potential. Given the high ORAC score elderberries tested out at, it makes sense that these berries would be efficient antioxidants and contribute to promoting immunity.
What About Vegetables?
The top-rated veggies on the USDA ORAC list include leafy greens such as kale, spinach, and brussels sprouts. Kale has an ORAC score of 1,770 units per 100 grams, while spinach and brussels sprouts came in at 1,260 and 980 units per 100-gram serving, respectively. Other top-ranked veggies including beets, red bell peppers, onions, corn, and eggplant.
So, from a dietary point of view, no matter how you cut it, fruits and veggies are a must and focusing on those antioxidant rich foods that have a high ORAC value is critical for health.
When diet falls short, supplementing with antioxidants in the form of dietary supplements is a good fallback plan to fill the gaps. A good multivitamin with a broad range of antioxidant vitamins and minerals such as vitamins A, C, and E and the minerals zinc and selenium is a strong bet to reinforce the body’s antioxidant defenses. More targeted antioxidant supplements, such as those for immune health containing vitamins C and D, along with zinc and elderberry, or more specialized antioxidants including glutathione and N-acetylcysteine may also be helpful for those needing added support.
Whether you consume foods high in antioxidants or fill in the dietary gaps with antioxidant supplements, ensuring an adequate intake of external antioxidants can go a long way in supporting your body’s innate antioxidant defenses so it can keep your cells and tissues healthy for years to come.
- High-ORAC Foods May Slow Aging. https://www.ars.usda.gov/news-events/news/research-news/1999/high-orac-foods-may-slow-aging/