Study detects much higher levels than suspected; Findings put whole grain cereals and snacks on a par with pure whole grains, and with colorful fruits and veggies
by Craig Weatherby
Antioxidant compounds called polyphenols abound in colorful fruits and vegetables such as berries and spinach, and in raw cocoa, nuts, coffee, olives, tea, spices, and herbs.
And when it found equivalent or higher amounts in whole grains, a 2002 study turned the scientific consensus onto its ear… ear of corn, that is.
Antioxidants such as polyphenols tend to “turn off” genetic switches that promote the low-level, chronic inflammation believed to promote cancer, heart disease, Alzheimer’s and most other non-infectious diseases.
Chronic inflammation results from stress and America’s sugary, starchy, nutrient-poor diets.
Cornell University research reported at a 2002 cancer conference showed that, compared with fruits and vegetables, whole grains contain as much or more of the powerful, anti-inflammatory polyphenol antioxidants that routinely make preventive-health headlines.
And in line with many other studies, a 2007 analysis of data from the large Iowa Women’s Health Study found that women who rarely ate whole grain foods were much more likely to die from diseases linked to inflammation.
(To read about both studies, see “Whole Grains: Under-Sung Antioxidant Aces." The Cornell study is described in a green-hued sidebar.)
While polyphenols have been primarily perceived as antioxidants that can neutralize damaging free radicals in the body, they also deactivate genetic switches that are known to promote inflammation.
This fact positions food-borne antioxidants—including the bright-orange carotene pigment in wild salmon (astaxanthin)—as “nutrigenomic” substances that, by definition, influence genes that affect myriad metabolic functions, almost always in beneficial ways.
Now, a team led by renowned antioxidant researcher Joe Vinson, Ph.D., has found that—like whole grains—cereals and snacks made from whole grains also contain polyphenol antioxidants in amounts that rival those found in colorful fruits and vegetables.
As he said in a press release, “Early researchers thought that fiber was the active ingredient for these benefits in whole grains, [and were] the reason why they may reduce the risk of cancer and coronary heart disease. But recently, polyphenols emerged as potentially more important.”
What the new study showed
Vinson, a chemist at the University of Scranton, led a team that confirmed the earlier Cornell finding, and extended them to whole grain cereals and snacks.
Theirs was the first study to quantify the total amount of phenol antioxidants in whole grain breakfast cereals and snacks - including the amounts bound up in fiber and freed up only during digestion.
In descending order, Vinson’s team found the highest antioxidant levels in cereals and snacks made with whole wheat, whole corn, whole oats and whole (brown) rice.
Raisin bran cereal had the highest levels of antioxidants per serving, primarily due to the raisins.
(Plain wheat bran cereals had less antioxidants than whole wheat cereals, but more fiber.)
In addition, Vinson’s group found that whole grain flours were also high in antioxidants, while whole grain snacks had slightly lower levels of antioxidants than cereals.
Surprisingly—except to those familiar with the 2002 Cornell study—whole corn kernels in the form of popcorn had the highest level of antioxidants among whole grain snacks.
Professor Vinson made a key point: “Breakfast cereals, pasta, crackers, and salty snacks constitute over 66 percent of whole grain intake in the U.S. diet.”
It’s important to stress that these findings do not apply to the cereals and snacks made from refined grains, which constitute the great majority of cereals and grain-based snacks.
And, it makes sense to seek out whole grain foods with minimal amounts of added sugar, fat, or salt.
- Vinson J et al. Total polyphenol antioxidants in whole grain cereals and snacks: Surprising sources of antioxidants in the US diet. Aug. 18, 2009, presentation, American Chemical Society annual meeting, Washington, D.C. Accessed at http://oasys2.confex.com/acs/238nm/techprogram/
- Flint AJ, Hu FB, Glynn RJ, Jensen MK, Franz M, Sampson L, Rimm EB. Whole grains and incident hypertension in men. Am J Clin Nutr. 2009 Jul 1. [Epub ahead of print]
- de Munter JS, Hu FB, Spiegelman D, Franz M, van Dam RM. Whole grain, bran, and germ intake and risk of type 2 diabetes: a prospective cohort study and systematic review. PLoS Med. 2007 Aug;4(8):e261.