Eggs are cheap healthy antioxidant source

20-Sep-2011

One of nature’s most perfect foods may be even better for us than
previously thought
//11 Jul 2011
While eggs are well known to be an excellent source of proteins, lipids, vitamins and
minerals, researchers at the University of Alberta recently discovered they also contain
antioxidant properties, which help in the prevention of cardiovascular disease and
cancer.
Jianping Wu, Andreas Schieber, graduate student Chamila Nimalaratne and research
associate Daise Lopes-Lutz examined egg yolks produced by hens fed typical diets of
either primarily wheat or corn.
They found the yolks contained two amino acids, tryptophan and tyrosine, which have
high antioxidant properties.
After analyzing the properties, the researchers determined that two egg yolks in their
raw state have almost twice as many antioxidant properties as an apple and about the
same as half a serving (25 grams) of cranberries.
Processing is detrimental
However, when the eggs were fried or boiled, antioxidant properties were reduced by
about half, and a little more than half if the eggs were cooked in a microwave.
“It’s a big reduction but it still leaves eggs equal to apples in their antioxidant value,”
said Wu.
The discovery of these two amino acids, while important, may only signify the
beginning of finding antioxidant properties in egg yolks, says Wu.
“Ultimately, we’re trying to map antioxidants in egg yolks so we have to look at all of
the properties in the yolks that could contain antioxidants, as well as how the eggs are
ingested,” said Wu, adding that he and his team will examine the other type of
antioxidant already know to be in eggs, carotenoids, the yellow pigment in egg yolk, as
well as peptides.
Lowering blood pressure
In previous research, Wu found that egg proteins were converted by enzymes in the
stomach and small intestines and produced peptides that act the same way as ACE
inhibitors, prescriptions drugs that are used to lower high blood pressure.
That finding defied common wisdom and contradicted the public perception that eggs
increased high blood pressure because of their high cholesterol content. Additional
research by Wu suggests the peptides can be formulated to help prevent and treat
hypertension.
Wu is convinced the peptides also have some antioxidant properties, which leads him to
suggest that when he completes the next step in his research, the result will likely be
that eggs have more antioxidant properties than we currently know.
The findings were published in the peer-reviewed journal Food Chemistry.
Source: Alberta University
http://www.news.ualberta.ca/article.aspx?id=0EBCC8DBD6EE400D9CC9F60028D7953E

Alberta University