Food High in Antioxidants Doesn’t Have to Taste Bad or Be Eaten Raw
(HealthDayNews) -- Sometimes, the best preventative medicine is right before your eyes -- or in your mouth, as is the case with vegetables containing antioxidants.
Research continues to turn up new information on why certain foods with high antioxidant content will prevent cancer or heart disease and will possibly even prolong your life or keep your memory sharp. Antioxidants are substances in the body -- often enzymes -- believed to reduce the risk of chronic disease by limiting cell oxidation in the human body. They attack and kill other substances called free radicals that can cause chemical changes in the body that contribute to a number of serious diseases.
During the past few years it’s become more apparent that eating certain foods would indeed help prevent serious diseases and decline in later life.
For example, two animal studies have found that antioxidants in fruits and vegetables can improve learning and memory, and they minimize the effect of aging on the brain. Certain foods do a better job of this, the studies show, because they have higher levels of antioxidant activity.
Antioxidants can undo cell damage caused by renegade free radical molecules, and previous studies have shown they can prevent disease and improve mental functioning, among other things.
"What we have done is focus on the fruits and vegetables high on the U.S. Department of Agriculture (USDA) list of antioxidants," says Paula Bickford, professor in the Department of Neurosurgery, Center for Aging & Brain Repair at the Veterans Administration Medical Center, at the University of South Florida in Tampa. She was the lead author of both studies, just published in the Journal of Neuroscience. The USDA ranks foods by their antioxidant content. Spinach, spirulina (an algae often sold in capsule form in health food stores) and apples were particularly beneficial for learning and memory in the rat study, Bickford says.
"We think that what we are experiencing [in the rats] is an improvement in neuron functioning. Because we improve the ability of the neurons to communicate, it is easier for the animals [on the spinach-enriched diets] to learn," she adds.
In the second study, the researchers compared three types of diets, again fed to rats: one group got a diet enriched with spirulina (high in antioxidants), another group got apples (moderate in antioxidant activity), and a third got cucumber, which is low in antioxidants.
"Initially, I was amazed," Bickford says. "We were seeing effects within two weeks with the apple and spirulina diets."
When the rats' brain functioning was evaluated, the researchers found the accumulation of inflammatory substances in the brain that typically occurs with age had been reversed in those on the apple and spirulina diets, and that they had better neuron functioning.
"I've always eaten a lot of fruits and vegetables," she says. Since the study results, she's boosted her intake even more, she adds.
And, contrary to popular belief, the vegetables don’t have to be raw. Whether it's sauce on your spaghetti or pizza, tomato soup or even ketchup, research says heated tomatoes have higher levels of lycopene and other antioxidants.
"It's a popular misconception that processed foods have a lower nutritional value," says study author Dr. Rui Hai Liu, an associate professor in the Department of Food Science at Cornell University. "But we found that processed tomatoes have higher antioxidant activity and lycopene than fresh tomatoes."
Lycopene is the substance that gives tomatoes their red color. Tomatoes are the main dietary source of lycopene, although it is also found in watermelon, papaya and pink grapefruit. Previous studies have shown lycopene may help prevent prostate, lung and stomach cancer, and even heart disease, according to the American Cancer Society.
For this study, which appeared in the Journal of Agriculture and Food Chemistry, the scientists heated tomatoes to just over 190 degrees Fahrenheit for two, 15 and 30 minutes.
Total antioxidant levels rose by 28 percent after two minutes and as high as 62 percent after a half an hour. Lycopene levels rose 6 percent at the two-minute mark, 17 percent after 15 minutes and 35 percent after 30 minutes.
But if you want to add variety to your healthful diet, certain breads, too, contain antioxidants.
German researchers recently discovered that during the baking of bread, an antioxidant called pronyl-lysine is created, especially in the crust. This antioxidant is particularly helpful in preventing certain cancers, the scientists said.
"[Pronyl-lysine] is more present in the crust because you need higher temperatures to generate that compound," says study author Thomas Hofmann, a professor and head of the Institute for Food Chemistry at the University of Muenster.
Hofmann and his colleagues analyzed a sourdough bread mixture that contained rye and wheat flour, and discovered the pronyl-lysine after baking. The antioxidant was not present in the flour used to make the bread.
The antioxidant is created during a chemical reaction between the amino acid L-lysine and starch and sugars in the bread. This same reaction causes the crust to have a darker color than the rest of the bread, Hoffmann says.
And finally, there’s a bit of good news if you want to imbibe a bit. Pronyl-lysine is also found in malt, as well as in beer. The antioxidant is present in higher amounts in dark bread and beer, Hofmann says.
On the Web
The U.S. Department of Agriculture has an excellent review of foods high in antioxidant content.
SOURCES: Paula Bickford, Ph.D., professor, Department of Neurosurgery, Center for Aging & Brain Repair at the Veterans Administration Medical Center, University of South Florida, Tampa; Rui Hai Liu, M.D., associate professor, food sciences, Cornell University, Ithaca, N.Y.; Thomas Hofmann, professor and head, the Institute for Food Chemistry at the University of Muenster, Germany; July 15, 2002, Journal of Neuroscience ; April 2002 Journal of Agriculture and Food Chemistry ; Nov. 6, 2002, Journal of Agricultural and Food Chemistry
Publication date: November 1, 2005
Author: Kathleen Doheny, HealthDay Reporter
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