We fast approach
March ... National Nutrition Month! And the theme designated
by the American Dietetic Association the largest group
of nutrition professionals in the world is
"Nutrition from the Ground Up." How appropriate,
then, this question from a reader in Jacksonville, Fla.:
"Dear Ms. Quinn: I am having difficulty getting a
straight answer to a simple question: Are the pink tennis
balls formerly tomatoes now genetically engineered
as nutritious in vitamins and micro-nutrient content as were
the tomatoes of yesteryear? My question also applies to
other fruits and vegetables. I had some oversized
blueberries the other day, which were absolutely tasteless.
Along with the taste, is the nutrition of these foods also
disappearing?"
W.C. Rust, MD
Dear Dr. Rust: This is question for food
scientist Julie Jones, Ph.D., (with added comments from
other experts in the field). Dr. Jones writes: "The
tomatoes he is speaking about are not genetically engineered
rather, they are a varietal (one of thousands of tomato
varieties in an array of shapes, colors and sizes) that
ships well. To make matters worse (on the taste front),
these tomatoes often are picked green and then shipped. They
also may be hydroponically grown (growing plants in a
nutrient liquid without soil) although some of these in
my supermarket are tasty. Hint: In general, smaller-size
tomatoes taste better."
Jones suggests never refrigerating
tomatoes, which nullifies a volatile compound known as Z-3
hexemel that gives ripe tomatoes their characteristic scent
and taste.
"If they are not optimal ripeness
usually the case for winter tomatoes place them on a
sunny window sill and wait until they have more color and
are softer. The flavor will improve ... but it will never be
like a summer tomato."
She added that the nutrient content of a
tomato varies with a whole range of things.
"One of the most important is variety
(the type of tomato)," she said. "A recent study
(in the Journal of Agricultural Food Chemistry, February
2009) compared nutrient and antioxidant quality of tomatoes
grown organically and conventionally. The main cause of
differences in the major nutrients such as vitamin C and the
phytochemical, lycopene, was the variety (type) of tomato
grown. Growing method made no significant difference."
All of this "pales in comparison to
the loss of nutrition if consumers fail to eat the correct
number of servings of fruits and vegetables," she
reminds us. She suggests using canned tomato products in
chili and sauces during the winter months when fresh local
produce is not as available. By the way, canned and
heat-processed tomatoes actually contain higher amounts
lycopene the pigment that makes ripe tomatoes red.
Lycopene is a natural antioxidant that appears to protect
our body against a broad range of epithelial cancers (those
that affect the lining of body tissues and organs). Lycopene
is generally more "bioavailable" (available to
nourish the body) in processed (such as canned and frozen)
tomato products than in fresh tomatoes, according to
experts.
So back to your simple question. Color and
taste develop as fruits and vegetables mature. Nutrient
content depends on the variety or type of produce grown. And
donΉt forget that nutrients (such as vitamin C) can also be
lost when fresh produce is allowed to languish on kitchen
counters or in refrigerators.
