when you begin a raw food
diet, do you really have spend mental energy worrying about
While there's no question that onions look relatively benign when
lined up against the great disease-causing foods humans regularly
consume, such as meat, dairy,
and eggs, they have enough downsides that I've eliminated them from my
Do they have beneficial compounds? Sure. You can find the upside to
virtually any plant food if you look hard enough. Even poison hemlock
has plenty of nutrients. The question is if a food's downsides are
outweighed by its potential for good.
Whether you think
onions pass muster is up to you, but you should be informed about what
Onion Toxicity: Are Onions Good For You?
Are onions good for you? Their miraculous qualities are often touted
today among the foods-are-healthy-drugs crowd, as they have been for
millenia. They can cure soar throats and act as an aphrodisiac, ancient
Indian texts tell us (1). The Egyptian nobility and peasants were so
enamored with the
onion's supposedly life-giving properties that they worshiped it, and
the Romans believed onions could induce sleep and heal mouth sores, dog
bites, toothaches, dysentery and lumbago (2).
Do these healing properties sound familiar? They should.
hear million-dollar marketing machines touting very similar properties
for name-brand drugs all the time.
Onions may have been around longer, but it's hard to make a profit off
them so their promotion is
mostly relegated to home remedy and herbalism books.
Yet the message is the same for onions and drugs: this is a substance
that can act on your body to get rid of a symptom of disease, a message
that should immediately set off warning bells in your head.
Onion Toxicity: What Are Onions, And What Do They
Onions, like the very similar shallots, leeks, chives, scallions, and garlic, are
part of the Allium family (lilies). Allium is a genus of
perennially-growing bulbous plants that produce a series of chemical
compounds such as cysteine sulfoxide, isoalliin, syn-Propanethial
S-oxide, allicin, and mustard oil, which are responsible for their
distinctive taste, smell, and the irritation they cause to your
Different members of Allium have varying levels of these chemicals, and
their pungency generally depends on how much they carry.
Onion Toxicity: What Is Allicin?
Allicin is a sulfur compound found in onions responsible for a lot of
the irritation the plant causes.
Why is it there?
According to chemist Eric Block of the University of Missouri at St.
Louis, who has been studying onions since 1971:
"Since allicin is
anti fungal as well as antibiotic, it could offer the garlic plant
protection against the bulb decay induced by fungi. And since the
lacrimatory factor is irritating and repugnant to certain animals,
it too has survival value."
-Eric Block, Ph.D.,
"The Chemistry of Garlic and Onions."
Essentially what we have is an element - just one of several sulfur
compounds present - that is intended to repel and injure things that
would devour the plant and bulb, be they fungi, bugs, of mammals. When
onion extract is
applied to bacteria and fungi it literally destroys them.
Many a canny gardener
has realized this and strategically planted onions, garlic, leeks, and
other members of the Allium family to ward off pests. Many creatures
will not cross a phalanx of allium, and so can't get to the juicy
tomatoes waiting beyond. Their senses warn them that this is a food to
Although we like to think of ourselves as a species apart, at the end
of the day we are just
big, smarter-than-average animals with vulnerable physical bodies, and
if a food is damaging enough that it destroys fungi
and other bacteria and drives hungry animals away, it probably isn't
wise for us to ignore the fact.
Onion Toxicity: Onions Sicken And Kill
While working as a newspaper reporter several
years ago I
ran across a
man in a retirement home in Meriden, Connecticut that grew up on a
onion farm in California. Always interested in agricultural life, I
struck up a conversation and he told me something interesting: onion
toxicity had almost killed him.
His mother died when he was 13 and since his father wasn't much of a
cook, the boy was frequently hungry. To supplement his unappetizing
meals, he would take breaks during his farm chores to eat onions.
"I didn't like them raw at first, but after awhile they started tasting
great," he told me when I informed him that I found the taste of onions
to be sickening.
Although he didn't connect it to the onions, he became increasingly
pale and weak over the course of a few months until one day he
collapsed while doing his chores.
He awoke in the hospital getting a blood transfusion, and was told that
he'd come down with severe case of onion-induced anemia and had been
dangerously close to death. After treatment he went on to a full
recovery, but, he said, "I haven't eaten an onion since. When they try
to put them in my food here I throw a fit."
Onion Toxicity: Humans Are Not Exempt
Although no full-scale tests have been done on onion toxicity in
humans, for obvious reasons, there are plenty of instances of all types
animals, large and small, being sickened and killed by onions when
their senses don't do a good enough job warning them away.
For instance, a group of water buffalo that ate some onions dumped in
their field all died (4). A study on geese found that onions killed
them too, with an autopsy revealed swelling of the liver and spleen
(5). In a herd of cows that had 20 onions a day per cow added to their
feed for six weeks, five cows died and two pregnant cows lost their
calves. Anemia is the initial result of onion toxicity, the researchers
found, but it eventually lead to organ damage and death (6).
Onion Toxicity: Thinning Out The Blood
It's is certainly one of the bizarre peculiarities of our mind that we
can look at something in animals and see the cause of sickness and look
at the same thing in ourselves and see a potential benefit.
Despite the well-documented ability of onion intake to bring on anemia
in sheep (7), Cats (with just onion powder added to their food) (8),
horses (eating wild onions) (9), and dogs (10), researchers have cooed
over new studies showing this effect in humans and praised the onion's
ability to thin the blood in the hopes that it might help us fight
blood clots and prevent heart attracts, which folk lore says it does.
A 1979 study in India compared three groups of
vegetarian Jains who ate
an average of 600 grams of onions per week, 200 grams per week, or
never in their lives. The study found that the onion abstainers had the
shortest blood clotting time and that those who ate more onions had the
longest time till clotting (11).
"The (positive health) folklore concerning garlic and onions seemed to
be gaining some credence," said chemist Eric Block of the finding,
noting the food's potential as an antithrombotic (11).
The mature way to deal with atherosclerosis is to eat a low fat
plant-based diet that prevents and reverses it (12), and given that
blood clots almost always affect sedentary, overweight individuals
eating poor diets, the way to prevent them is to get regular exercise
and eat a healthy diet.
Poisoning ourselves in the perverse hope of escaping the consequences
of a bad lifestyle won't work.
Onion Toxicity: Weeping Over Onions
When you slice into an onion and start to get teary eyed, doesn't it
strike you as a bit odd? You haven't even put the thing in your mouth
yet your body is already irritated.
When an onion is sliced and the cell walls are broken, enzymes called
alliinases begin a complex chemical reaction that results in the
release of volatile gas known as the onion lachrymatory factor. This
gets released into the air and eventually enters your eyes if you're
hovering over the onion. The gas stings and irritates your eyes, and
the tears that well up are your body's attempt to wash the toxic gas
I've sliced into a lot of peaches and hacked apart more than my fair
share of lettuce, but none of these foods have been so irritating that
had to wash the resulting chemicals away with bodily fluids.
You have to wonder about exactly how toxic an onion is when the gas of
it alone makes your eyes tear up. What's it doing to you when you put
it into your stomach?
Onion Toxicity: But What About All Those Benefits?
The cures attributed to onions are essentially drug reactions and
the resulting stimulation of your body attempting to rid itself of
harmful substances. Treating yourself with an onion is like taking a
drug in the
hopes that your body will stop producing that symptom. And just like
drugs, when you rely on such a treatment you never remove the
underlying cause and merely hope any side effects brought about by the
drug reaction will be bearable.
If the entire Allium family were a drug, there would have to be a
warning attached to the commercials, undoubtedly spoken by an
agreeable-sounding women reading the list as if she were chatting about
the pleasant weather:
The Allium Family Warning Label
Onions and other members of the Allium
family may cause bad breath, indigestion and acid reflux (15), anemia,
reduced blood clotting, or even
death. Pregnant women should avoid the Alliuin family because its
members have been known to cause accidental abortions in humans (13).
Nursing women should not eat them because the chemical Allicin enters
into their breast milk and disturbs a baby's ability to breast feed
Those at risk for major bleeding, such as those soon to undergo
surgery or enter into labor are urged not to eat members of the
Allium family because they have been shown to prevent the clotting of
open wounds (14).
Onion Toxicity: But What If I just Eat A Little?
Although dogs have shown the beginning stages of anemia after only a
single dose of onions (10), it's probably true that it takes sustained
intake to bring about any noticeable negative impact. The average
westerner only uses onions as a condiment, so irregular use may be
But don't fool yourself, a little
bit of poison is still a poison. Even the Jains eating fairly modest
portions of onions showed reduced blood clotting ability.
could gorge all day on watermelons or bananas and show no ill effects
beyond a bloated stomach. Take the same dose of onions, though, and
probably be very sick.
Although like all foods, onions have some up sides,
the overwhelming force of them is negative.
I don't eat onions or garlic, but I have periodically tried the weaker
variates of the Allium family, such as the leaves of the chive plant.
After so long without these foods I find them unpleasantly strong and
that my breath reeks of them for days, but overall I don't run into any
If you want to include these foods in your diet periodically, I
it's going to be a deal breaker, but it's probably safe to say that
onions and the Allium family should not be a regular part of your meals.
Frederick (1998). Plants of life, plants of death. Univ of Wisconsin
Press. p. 568. ISBN 0299159043. Retrieved 2009-07-13. 2) "About Onions:
History". The National Onion Association. Retrieved 2011-3-29.
http://www.onions-usa.org/about/history.php 3) Eric Block,
"Garlic and Other Alliums: The Lore and the Science" (Cambridge: Royal
Society of Chemistry, 2010) 4) Borelli V, et
al. "Fatal onion (Allium cepa) toxicosis in water buffalo (Bubalus
bubalis)." J Vet Diagn Invest. 2009 May;21(3):402- 5) Crespo R, et al.
"Effect of feeding green onions (Allium ascalonicum) to White Chinese
geese (Threskiornis spinicollis)." J Vet Diagn Invest. 2004
Jul;16(4):321-5. 6) Rae, Ha. "Onion
toxicosis in a herd of beef cows." Can Vet J. 1999 Jan;40(1):55-7. 7) Knight, AP. Et
al. "Adaptation of pregnant ewes to an exclusive onion diet." Vet Hum
Toxicol. 2000 Feb;42(1):1-4. 8) Kaplan, AJ.
"Onion powder in baby food may induce anemia in cats." J Am Vet Med
Assoc. 1995 Dec 1;207(11):1405. 9) Pierce, KR. Et
al. "Acute hemolytic anemia caused by wild onion poisoning in horses."
J Am Vet Med Assoc. 1972 Feb 1;160(3):323-7. 10) Harvey, JW. Et
al. "Experimental onion-induced hemolytic anemia in dogs." Vet Pathol.
1985 Jul;22(4):387-92. 11) Block, Eric.
"The Chemistry of Garlic and Onions." Scientific American, v252 n3
p114-19 Mar 1985 12) Ornish D, Brown
SE, Scherwitz LW, Billings JH, Armstrong WT, Ports TA, McLanahan SM,
Kirkeeide RL, Brand RJ, Gould KLCan lifestyle changes reverse coronary
heart disease? The Lifestyle Heart Trial. Lancet. 1990 Jul
21;336(8708):129-33. 13) Barnes J,
Anderson LA, Phillipson JD. Herbal Medicines. 2nd edition. London:
Pharmaceutical Press; 2002. 14) Ang-Lee MK,
Moss J, Yuan C. Herbal Medicines and perioperative care. JAMA 2001;
286:208-216 15) Allen ML The
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