HEALTH UPDATES

Is Higher Better?

Two testing methods attempt to determine the antioxidant potential of foods

Each day, we hear about the newest food that has an even higher level of antioxidants. But, how is the antioxidant level of a food or supplement determined? More importantly, is higher better? This article offers information on the current methods for measuring antioxidant efficacy so that you can better evaluate the foods and supplements which are good sources of antioxidants.

Bio-photonic scanning of carotenoids. One company attempting to gauge antioxidant quality uses a scanner to measure the concentration of carotenoids in the body’s tissue. The test involves a safe, low-energy blue light laser that scans the palm to obtain a reading or antioxidant score.

The problem with the photonic scan is that it measures only one type of antioxidant – carotenoids. These fat-soluble compounds are commonly found in colored fruits and vegetables. Beta-carotene is one of the most widely recognized carotenoid but lutein and lycopene are also gaining recognition. While carotenoid content of tissue is the most significant factor in determining maximal life span potential of mammals, this test doesn’t measure levels of other antioxidants or other tissues of the body. The presumption is that the antioxidant score is a marker for overall antioxidant health status.

Oxygen Radical Absorbance Capacity. In an attempt to measure the relative efficacy of antioxidants, scientists at the National Institute on Aging (NIA) developed a test called Oxygen Radical Absorbance Capacity or ORAC. The ORAC test measures the antioxidant capacity of different foods.

The test assay measures both water-soluble (e.g., vitamin C) and oil-soluble (e.g., vitamin E) antioxidant levels in foods. ORAC is a measure of the ability of foods or supplements to subdue harmful oxygen free radicals that can damage the body. Foods that rank high in ORAC value include spices (ORAC: 267,536 per 100 grams of cinnamon), berries (ORAC: 13,427 per 1 cup of wild blueberries) and legumes (ORAC: 13,259 per ½ cup dried red kidney beans).

While the ORAC test provides valuable information about the antioxidant potential of a food, it is not without problems. Right now, ORAC does not use a standard measurement unit (by servings or grams; by wet weight or dry weight), making it difficult for consumers to compare products. The ORAC value assigned to an antioxidant can vary, depending on how the test is conducted.

In addition, if testing was done on vitamin C (water-soluble) and tocotrienol (vitamin E fat-soluble), in a water-soluble environment, then vitamin C would have a higher ORAC value because the test was conducted in an environment that favors vitamin C.

Finally, ORAC values are tested in a lab so the test does not measure the metabolic or biological value of antioxidants in animals and humans.

Cellular Antioxidant Activity. A newer method for measuring antioxidant activity – Cellular Antioxidant Activity or CAA – was introduced last year in an attempt to address some of the problems inherent with ORAC.

Instead of looking at just an antioxidant’s value, CAA measures the uptake, metabolism, distribution and activity of an antioxidant compound. High in the CAA ranking is blueberry, cranberry, apple, red grape and green grape.

One of the problems with the CAA test is that the results to do not correlate with those of the ORAC test. The test also uses human liver tumor cell lines which may not be representative of other body tissue.

The CAA test uses quercetin – a plant flavonoid found in high concentrations in onions and apples – as the standard against which antioxidant activity level is measured. Quercetin may not be a good standard from which other antioxidant levels are measured.

Taking a Step in the Right Direction. While the debate will continue regarding how antioxidants are measured, it is known that a link exists between colorful fruits and vegetables and higher levels of antioxidants. These foods are health-promoting in their own right and should be included as part of a regular diet. Consumption of foods such as beans (especially kidney or pinto), prunes, raisins, blueberries, blackberries, kale, spinach and Brussels sprouts, not only promote health but may slow down the aging process too. Now, that’s something everyone can agree upon.