Dr. Vinson’s study measured the total number of polyphenols in about 70 whole grain ready-to-eat breakfast cereals, hot cereals and other grain-based foods and snacks, such as crackers, chips and popcorn—one of his personal favorites—and found that many popular breakfast cereals and snacks foods have “surprisingly large” amounts of antioxidants.
“Epidemiological studies have shown that consumption of whole grain foods reduce the risk for certain cancers, coronary heart disease and obesity,” he said. “Whole grains contain vitamins, minerals and fiber along with phenolic compounds, predominately the class known as phenolic acids. Phenolic acids are excellent antioxidants.”
The professor’s research found that products from whole grains have comparable antioxidants per gram as fruits and vegetables. Whole grain flours are also very high in antioxidants, whereas processed grain foods are low. In general, cold cereals performed better than hot cereals. Whole grains fared much better than processed grains.
Cereals formulated with whole-grain corn or oats contained the most polyphenols, about 0.2% by weight per box. Wheat-based cereals contained an average of 0.07% polyphenols. Rice-based cereals contained the lowest amount, at 0.05%.
Raisin Bran was found to contain the highest amount of polyphenols per serving (524 mg), about 3% by weight, but that is primarily due to the raisins, which like other dried fruits, are an excellent source of antioxidants. The study also found cinnamon flavored cereals to be much higher in antioxidants due mainly to the spices.
As for snack foods, popcorn ranked as the snack with the highest amount of polyphenols, about 2.6%, followed by whole-grain crackers, which contained about 0.45% polyphenols.
“We have been measuring total phenolic antioxidants in the U.S. diet for about 10 years and had snack foods still to be done,” said Dr. Vinson. “I knew whole grain flours were high [in antioxidants] from previously published data but little was known about breakfast cereals and almost nothing about snacks. We found that, in fact, whole-grain products have comparable antioxidants per gram to fruits and vegetables.
“Be aware that no one has done total phenols (i.e., not just extracting but clipping off the sugars hiding the phenolic groups) except for flours,” he added. “I was certainly surprised by the popcorn but in fact among the cereal grain products consumed it is the one that is almost entirely whole grain (i.e., not processed).”
In a press conference discussing his research presentation, Dr. Vinson noted that overall Americans do consume the right amount of grains, however, only 15% of the consumption is of whole grains, far below the 50% level recommended by the U.S. government.
“Americans are eating enough grains, but not the right kinds,” said Dr. Vinson. “We need to eat more whole grains, not more grains. Too much of our intake is from refined grains containing less antioxidants. Consumers need to pay attention to labels to make sure that the first ingredient listed is whole grain.”
In an interview with Nutraceuticals World, Dr. Vinson said it was important to note that levels of polyphenols in foods do not necessarily correlate with biological activity or health. “We need to determine if the phenolic compounds get into the body from consuming whole grain cereal products,” he said. “This needs to be done along with determining if the fiber alone from the grains is the bioactive component. Epidemiology seems to indicate both fiber and polyphenols are needed for bioactivity from cereal grains.”