The trend of a few years ago was beta carotene, a
substance found in fruits and vegetables that was
supposed to protect against cancer. Then scientific
studies showed no particular benefit from taking beta
carotene in pill form. Now it seems another substance
in fruits and vegetables may account for the health
protection associated with eating carotene-rich foods.
It is called lycopene (pronounced LIKE-o-peen), and it
is what makes tomatoes red. It had previously been
strongly linked to a reduced risk of developing various
deadly cancers, including those of the prostate, colon
and rectum.
A large new study of 1,379 European men has indicated
that those who consumed the most lycopene from foods
were half as likely to suffer a heart attack as those
who consumed the least lycopene.
The study is especially valuable because it assessed
lycopene consumption and absorption by measuring its
presence in body fat rather than by using a less
reliable method of asking men how much lycopene-rich
food they regularly consumed.
Like beta carotene, lycopene is fat-soluble. Dietary fat
is needed for it to be absorbed through the intestines,
and the amount stored in body fat is considered a
reliable reflection of how much people absorb from their
diets. Lycopene's protective role, however, stems not
from fat stores but from its ability as a potent
antioxidant, which means it can prevent free radical
damage to cells, molecules and genes as it circulates in
the blood. Free radicals are highly reactive molecules
that can combine with other substances and change them
in a harmful way.
Such damage can, for example, transform freely
circulating cholesterol into a form that sticks to
arteries and clogs them, setting the stage for a heart
attack. It can cause genetic changes that may in time
result in cancer. Free radical damage is also involved
in cataracts caused by exposure to sunlight and lung
disease caused by inhaling pollutants like ozone.
Lycopene was recently shown to become depleted in skin
that is exposed to ultraviolet light, suggesting that
the nutrient's antioxidant role is called into play to
protect the skin from sun damage.
Findings from the new study indicate that lycopene is
most likely the substance responsible for the protection
against heart disease and cancer that had long been
thought to result from consuming beta carotene. When the
research team examined levels in body fat of lycopene,
alpha and beta carotene and lutein, another carotenoid,
lycopene alone seemed to account for the reduced risk of
heart disease.
Lycopene is most prominent in tomatoes. But it is not
well absorbed into the body unless the tomatoes are
cooked. Thus, the best sources are concentrated
processed tomato products like tomato paste, ketchup and
tomato sauce. Tomato juice is a reasonably good source
if it has been heated, as would occur when it is canned
or bottled. In addition, tomatoes ripened on the vine
have more lycopene than those that ripen after they are
picked. Other sources of lycopene include watermelon,
red grapefruit and, to a lesser extent, shellfish like
lobster and crab meat.
Participants in the new study were middle-aged men, 662
of whom had suffered heart attacks. Lycopene was most
strongly associated with protection against heart
disease among men with the highest levels of
polyunsaturated fatty acids in their body fat.
A second study will determine if processed tomatoes can
protect people's lungs against oxidative damage caused
by ozone. Preliminary results indicate that lycopene
from the foods does indeed find its way to lung cells,
although beta carotene does not. The researcher said
that participants would be examined for genetic damage
to their lung cells after exposure to ozone and their
lung capacity would be measured to determine whether
lycopene was protective.