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"Do Tomatoes Prevent Prostate Cancer."
(January 2003)
When talking "Tomato" think lycopene. Lycopene is what
makes tomatoes red and it's an antioxidant more potent than beta carotene.
Also consider that tomatoes contain many other important antioxidants that
may provide cellular protection from harmful mutations to the DNA.
Mutations result unavoidably from the oxidative stress resulting from our
vital metabolic processes.
The most comprehensive review on this topic was published in the February
2002 issue of UROLOGIC CLINICS OF NORTH AMERICA under the title "Tomato
products, lycopene, and prostate cancer risk" by researchers at Harvard,
Ohio State, and the University of Illinois.
The first hint of tomato products' usefulness in PC prevention came from
dietary studies of Seventh Day Adventist men wherein a high tomato product
intake was associated with a 40% decrease in PC. Probably the biggest and
most informative study was the Health Professionals study in which 47,000
physicians provided 13 years of careful dietary reports (every six months
I accounted for my intake of broccoli, tomatoes, etc). Since dietary
analysis is inherently a bit inaccurate, the comparisons are best made
between the cohorts with the highest intake versus the lowest. In this
study the group consuming more than 10 servings of tomato products per
week versus less than 1.5 had a 35% reduction in PC. There are many such
epidemiological trials with most pointing to some benefit of tomato
products, but certainly not all.
The clues from these studies require support from scientific data. In the
Health Professionals Study the best protection resulted from a lycopene
intake of >6.5 mg/day versus 2.3 mg. About 80% of our lycopene intake
comes from tomato products. In practical parlance a 3" diameter tomato has
.9 -4.2 mg lycopene; 100 grams (about 1/4 cup) tomato sauce, 7.3- 8 mg;
one cup tomato soup, 8 - 11 mg; 8 oz tomato juice 5 - 11 mg. But lycopene
per se is poorly absorbed and resides mainly in the fibrous portion of the
tomato. It is absorbed best when heated with oil. Hence, tomatoes in the
form of pasta sauce, pizza topping, and soup provide the best vehicles for
optimal absorption. Some studies indicate that better protection results
from consuming the whole tomato product as opposed to pure lycopene.
Hypotheses guide clinical research, but eventually basic scientific
evidence must provide the foundation for confirmation. In this regard the
study by Bowen et.al. in Exp Biol Med, November 2002 was fascinating. The
title is: "Tomato Sauce Supplementation and Prostate Cancer: Lycopene
Accumulation and Modulation of Biomarkers of Carcinogenesis." Their study
involved 32 men whose biopsies showed PC. The men consumed tomato
sauce-based pasta (30 mg lycopene/day) for three weeks before
prostatectomy. Serum lycopene levels and PSAs were checked before and
after the three-week period. The biopsy and prostatectomy specimens were
evaluated with conventional pathologic parameters, but also for PC cell
lycopene concentration and a specific marker of oxidative damage. The
result: a mean decrease in PSA of 17.5%, a 40% decrease in evidence of
oxidative damage, and evidence for some cancer cell death. Whether this
short time snapshot can be extrapolated into a general recommendation of
usefulness will have to be addressed by further studies. A current trial
following the same study design is now open at the Lee Moffitt Cancer
Center in Tampa, FL. In this trial 30 mg lycopene provided by two 15 mg "Lyc-O-Mato
Lycopene Solfgels" (Healthy Origins, manufacturer) will be compared to a
broader presentation of isoflavinoids.
The preponderance of work so far deals with the prevention of PC.
Different cellular events are involved in the initiation of cancer as
opposed to the progression of established cancer, but there is hope that
tomato products will be beneficial in the latter instance. Studies are in
progress. At this point the usefulness of tomato products in combating PC
is a very strong hypothesis, but awaits additional confirmation.
The UROLOGIC CLINIC article concluded that it was "reasonable ... to
consume tomato products at approximately one serving per day or five
servings a week...[and this may] reduce the risk of prostate cancer."
Bottom Line: If you put your chips on "Tomato", the house can't win ... if
you enjoy tomato products.
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