Onions with a NutritionalNot
By Erin Peabody
March 13, 2007
Wipe away those tears. The onion,
famous for causing eyes to water and digestive systems to rumble, is being
primed for a makeover.
An Agricultural Research Service (ARS)
plant geneticist is trying to bring out the best in onionstheir copious
heart-healthy compounds, good-for-the-body antioxidants and soluble
fiberwhile still retaining what consumers love most about the veggie: its
sweet, mildly sharp taste.
Havey of the
Vegetable Crops Research Unit at Madison, Wis., considers onions to be one
of the most important health-promoting, or functional, foods. They contain
three different groups of health-enhancing compounds: thiosulfinates, fructans
The thiosulfinates that give onions their pungency are also a great boon to
the body's bloodstream. The vegetable world's answer to aspirin, these
blood-thinning compounds can bust up platelets that might otherwise form
troubling plugs at sites of vascular damage.
Fructans are a source of soluble fiber shown to reduce rates of colorectal
cancers. And onions' flavonoids, such as quercetin, show proven antioxidant
But to get optimal amounts of these beneficial compounds, onion lovers need
to reach for denser, more pungent varieties. The popular "sweet and
mild" onion varieties contain a lot of water, which dilutes their nutrient
To help him package all of the onion's desirable taste and nutrient
qualities into one bulb, Havey is pinpointing which genes are linked to various
He and colleagues have found several genes of importance, including one they
recently discovered that helps onions accumulate the fibrous fructans. The more
fructans there are, the more heart-healthy thiosulfinates there'll be, too.
Havey has also identified a gene that coordinates the buildup of sucrose in
onion bulbs. This means it may be possible to boost the veggie's naturally
sweet flavors, while still increasing the compounds that are linked to good
more about ARS vegetable research in the latest issue of Agricultural
ARS is the chief scientific research agency of the
U.S. Department of Agriculture.