Review: What Makes a Superfood?

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superfoodMost age-related disease, and even aging itself, are at least in part a result of free radical or oxidative damage to tissues. The good news is – your body has an anti-free radical system, called the antioxidants, that prevents oxidants from damaging cells.  The trick is to maintain an antioxidant arsenal equal to or better than the daily oxidant onslaught.

Stockpiling antioxidants is essential throughout life, especially during stress and as a person ages. Stress is a death sentence for cells. Feeling tense and anxious sets off a cascade of events, releasing chemicals and hormones, including cortisol, that generate a free-radical flood toxic to all cells, including brain cells. No wonder people with high blood levels of cortisol score lower on memory tests compared to people who are relatively stress-free. With age, oxidative damage to tissues, including the brain, intensifies. Hence, a 60-year-old needs more antioxidant-rich foods than a 30-year-old woman, who needs more than a 12-year-old.

All colorful fruits and vegetables, 100% whole grains, legumes, tea, cocoa powder, and red wine, in short, just about any real, unprocessed food, has antioxidants. So, what makes one a superfood and one not? It’s the amount of antioxidants. Some foods are super stars when it comes to their boatloads of antioxidants, while others are merely supporting cast members. You can’t only check for the vitamin C or vitamin E content or for one or two phytonutrients, since it is the whole array of antioxidants that counts. For example, an apple is a vitamin C wimp compared to an orange, but it’s entire antioxidant content, which includes all of the phytonutrients, is equivalent to 1,000 milligrams of vitamin C!

To measure a food’s antioxidant content, researchers use the ORAC assay, which stands for Oxygen Radical Absorbance Capacity. This is a measure of the total antioxidant content in a given food. ORAC is a way to measure how many free radicals a specific food can absorb and destroy. The more oxygen radicals a food absorbs, the higher its ORAC score. Theoretically, the higher its ORAC score, the better it is at  preventing memory loss, coping with stress, and staying disease-free. Granted, there is a downside to this measurement, since an ORAC score in a laboratory might not equate to how potent that antioxidant level is once in the body or even if it is absorbed from the GI tract. However, we do know that the more colorful produce a person eats, the higher the antioxidant arsenal to combat disease and aging.

Nutrition experts estimate each one of us needs a minimum of 3,000 ORAC points a day to protect the mind and body (most Americans average less than half that amount). A daily ORAC intake of 10,000 or more is even better. An upper limit has not been identified. The body has a limited ability to store antioxidants, so ORAC points must be replenished every day.

A word of caution: Many tests promise to evaluate antioxidant status. They might take urine, skin, or blood samples to measure by-products of free radical metabolism. However, assessing antioxidant status is not that simple. For example, one test uses a scanner to shine a laser through your finger. It only measures a handful of carotenoids, not the tens of thousands of antioxidants in real foods. The only way to guarantee a super antioxidant arsenal is to load every plate with produce.

Food Chemistry 2014;164:81-88/BMC Complement Alternative Medicine 2014;14:161.

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