This is very funny, in that a relative who had a real nasty streak used
to say about me: "how could someone so skinny be so fat." Now I get a
good laugh from it, but at the time, when I was in my late teens also,
it was just irritating. When I switched to a vegan diet around the age
of 20, that puffiness in the torso went away. I didn't know what to
attribute it to at the time, but now I'd say it was the oxidative
stress, due to the oils I consumed. I went from a corn oil based diet
to a low fat diet, with nuts, seeds, beans, and grains being my fat
sources. I ate the seeds and nuts raw. Thus, I ate less fat and the
fat I ate had much more antioxidant protection than the cheap, refined
corn oil (that was then fried).
The evidence has been around a long time. You can look up some of
JoAnn Braganza's papers (about the dangers of highly unsaturated oils)
from the 1980s at pubmed.com
Here's a report that is clear, yet not too technical, from
www.sciencedaily.com:
5/2/2005
Food Fried In Vegetable Oil May Contain Toxic Compound
MINNEAPOLIS / ST. PAUL -- University of Minnesota researchers A. Saari
Csallany, a professor of food chemistry and nutritional biochemistry,
and graduate student Christine Seppanen have shown that when highly
unsaturated vegetable oils are heated at frying temperature (365 F) for
extended periods--or even for half an hour--a highly toxic compound,
HNE (4-hydroxy-trans-2-nonenal) forms in the oil.
Previously, vegetable oils such as soybean, sunflower and corn were
regarded as heart-healthy because of their high levels of linoleic
acid, a polyunsaturated fatty acid. HNE is incorporated into fried food
in the same concentration as it forms in the heated oil. Also, Csallany
and her colleagues have found three toxic HNE-related compounds (known
as HHE, HOE and HDE) in heated soybean oil. They will present their
work at a poster session from 9 a.m. to 2 p.m. Wednesday, May 4, at the
96th annual meeting of the American Oil Chemists Society in the Salt
Lake City Convention Center.
"HNE is a well known, highly toxic compound that is easily absorbed
from the diet," said Csallany. "The toxicity arises because the
compound is highly reactive with proteins, nucleic acids--DNA and
RNA--and other biomolecules. HNE is formed from the oxidation of
linoleic acid, and reports have related it to several diseases,
including atherosclerosis, stroke, Parkinson's, Alzheimer's,
Huntington's and liver diseases."
Csallany's work underscores the risk of repeated heating, or reusing,
highly unsaturated oils for frying because HNE accumulates with each
heating cycle. In future studies, Csallany and her colleagues plan to
determine how long polyunsaturated oil must be heated at lower
temperatures in order to form HNE and its related compounds. The study
was funded by the University of Minnesota.
