It isn't just an apple a day that keeps the doctor away. Many
fruits and vegetables contain combinations of three antioxidant
pigments -- lycopene, lutein and zeaxanthin -- that have been linked
to reduced rates of prostate cancer and age-related vision loss,
according to new scientific evidence.
Researchers, led by Dr. Omer Kucuk, professor of medicine and
oncology at the Barbara Ann Karmanos Cancer Institute at Wayne
State University in Detroit, randomly assigned 26 men with
localized prostate cancer to either remain on their normal diets or
also receive 25 milligrams of supplements of lycopene -- the red
pigment found in tomatoes -- twice daily for three weeks prior to
radical prostate surgery.
Results were presented Tuesday at a press conference held at
Rockefeller Plaza in New York.
The study showed that there is an inverse relationship between
lycopene levels and prostate cancer growth -- as lycopene levels
increased, cancer growth decreased.
As expected, the prostate glands of the intervention subjects
showed higher levels of lycopene than those of the control
subjects. However, the patients treated with lycopene supplements
also had malignant prostatic tissue with higher levels of connexin
43 -- a protein that inhibits growth of malignant cells and promotes
cancer cells to differentiate and die.
Additionally, within the lycopene group, 11 of 15 (73 percent)
participants were found with cancer confined to the prostate,
compared to only two of 11 (18 percent) in the control group. Kucuk
said this was especially important, because if the tumor spreads
beyond the prostate, the majority of patients will suffer a cancer
relapse, even if the original surgery is successful.
Also significant, Kucuk said, is that 12 of the 15 (84 percent)
patients treated with lycopene had smaller tumors than those in the
control group.
``This is the first study to show that a lycopene supplement can
protect against the occurrence or spread of prostate cancer,''
Kucuk said. ``However, because the study was small, we cannot come
to any definite conclusions,'' he added, suggesting that larger,
long-term studies need to be conducted in order to prove that
lycopene reduces the risk of prostate cancer.
While there are no official guidelines, experts recommend that
people consume approximately seven tomato-rich meals per week or a
1/4 cup of tomato sauce a day to meet the goal of five to 10
milligrams per day.
Further research conducted by John T. Landrum, a professor in
the department of chemistry at Florida International University in
Miami, showed that consumption of fruits and vegetables containing
lutein and zeaxanthin -- commonly found in broccoli, corn, squash
and dark green leafy vegetables such as spinach and kale -- may
reduce the risk for age-related macular degeneration (AMD), the
leading cause of vision loss in people over the age of 50.
Lutein and zeaxanthin are concentrated in the fovea, the central
region of the retina, which is the light-sensitive area of the eye.
The macula rests at the back of the eye and is necessary for fine
vision.
Participants who were given large doses (approximately 30
milligram per day) of supplemental lutein and zeaxanthin were found
to develop significant increases in macular pigment.
In a small-scale study, subjects were given 2.4 milligrams of
lutein daily for six months. Even with the low levels of lutein,
macular pigment levels increased between 20 and 300 percent in most
participants, 50 percent of whom showed significant increases. The
highest levels of lutein and zeaxanthin were associated with a 75
percent reduction in the risk of AMD.
``Because lutein and zeaxanthin concentrations in the eye and at
the point of greatest visual acuity are extremely high, we believe
they play an important role in the health of the macula,'' Landrum
said.
``As the macula has the highest level of lutein in the body, it
makes sense that additional levels would increase macular
pigmentation and reduce the risk for AMD,'' said Ross Pelton, a
pharmacist and clinical nutritionist in San Diego.
Pelton recommended that the elderly, baby boomers and diabetics
-- who often suffer from diabetic retinopathy -- consume higher doses
of lutein.
Approximately 1.7 million Americans over age 65 have AMD; there
is no known cure. Symptoms include blurred vision, the illusion
that straight lines are wavy and the appearance of a dark or empty
area in the center of vision.
