What every man should know about De Niro, tomatoes and their prostate…
Robert De Niro is one of my favorite actors. He also stars in two
of my favorite films — Heat and Ronin (which,
with due respect to Bullitt and The French Connection,
has the best car chase in cinema history).
So, it came as a shock to me when I heard that De Niro had been
diagnosed with prostate
cancer.
Prostate cancer
The causes of prostate cancer are not well understood. It's very
difficult to explain why one man gets prostate cancer and another
doesn't. Other than skin cancer, it's the most common type of cancer
in men in the United States.
Of all the men who are diagnosed with cancer each year, more than
one-fourth have prostate cancer. In the United States, prostate
cancer is found mainly in men over age 55. The average age of patients
at the time of diagnosis is 70.
The prostate is a gland about the size of a walnut. It's located
just below the bladder. The first sign of prostate cancer is usually
problems passing water — usually an increased frequency or
difficulty maintaining a full stream.
That's the bad news.
The good news is that there's an exciting body of evidence to show
that several components of the humble tomato act together to help
fight prostate cancer. It had been thought just one chemical, lycopene
(pronounced lie-co-peen) was responsible. But researchers at the
Universities of Illinois and Ohio State found lycopene's effect
is boosted by other chemicals in the fruit.
The study, published in the Journal of the National Cancer Institute,
suggests lycopene-only dietary supplements have a limited effect
[2].
"It has been unclear whether lycopene itself is protective,"
says researcher Professor John Erdman. "This study suggests
that lycopene is one factor involved in reducing the risk of prostate
cancer. But it also suggests that taking lycopene as a dietary supplement
is not as effective as eating whole tomatoes."
Lycopene
Lycopene, the substance that makes tomatoes red, is effective at
mopping up particles called free radicals, which can damage the
body's tissues.
Free radicals are molecules with an unpaired electron. Although
they've been implicated in many diseases, free radicals are a normal
part of your body chemistry, and can help to keep you healthy. White
blood cells, for example, use free radicals to "attack"
viruses and bacteria.
Optimal health, however, requires a balance between free radical
generation and antioxidant protection. One of the functions of an
antioxidant is to "quench" these free radicals before
they create too much damage.
Slice an apple in half, and watch it turn brown. That's an example
of free radical damage. Dip the apple in lemon juice, and the rate
at which it turns brown is slowed. That's because the vitamin C
in the lemon juice slows the rate of oxidative damage.
The researchers exposed laboratory rats to a chemical that causes
prostate cancer, and then fed them on diets containing whole tomato
powder, pure lycopene or no lycopene at all.
Rats fed tomato powder had a lower risk of dying from their cancer
than rats who ate no lycopene. But the rats fed lycopene had a risk
similar to control rats.
By the end of the study, prostate cancer had killed 8 out of 10
of the control group, 7 out of 10 of the lycopene-fed rats and 6
out of 10 of the rats fed tomato powder.
The researchers also found that restricting the amount of food
given to the rats cut their risk of developing prostate cancer,
regardless of which diet they were on.
Research by a separate group confirms the beneficial effect of
whole tomatoes. Phyllis Bowen, associate professor of human nutrition,
together with colleagues from the University of Illinois at Chicago,
studied a group of 32 prostate cancer patients who consumed one
tomato sauce-based pasta dish daily for three weeks [1].
Free radical damage and prostate specific antigen, or PSA levels,
were measured before and after the pasta regimen. Previous studies
suggest that human prostate tissue is particularly vulnerable to
free radical damage. This can lead to the formation of malignant
tumors.
A high level of lycopene was present in the prostate tissues after
the study. Free radical damage was reduced by 28%, while prostate
specific antigen levels dropped by 17.5%.
Although some consider PSA to be an important marker for the diagnosis
of prostate cancer, others suggest
that PSA testing is too unreliable to be recommended to patients.
The PSA test was developed and validated by Dr. Thomas Stamey and
colleagues at Stanford University in the early 1980s and was hailed
as a great breakthrough in the fight against prostate cancer.
In October 2004, however, Dr. Stamey and his group declared that,
"The prostate specific antigen era in the United States is over
for prostate cancer." [4]
Phytochemicals
You might see lycopene referred to as a phytochemical. The
term "phyto" (pronounced fight-o) comes from the Greek
word meaning plant. You'll see the terms "phytochemical"
and "phytonutrient" used interchangeably. They both mean
essentially the same thing.
Of all the phytonutrients, we probably know the most about carotenoids
(pronounced ka-rot-en-oids). They make tomatoes red, carrots orange
and corn yellow. The work of Dr Rui Hai Liu, assistant professor
of food science at Cornell University, shows that heating certain
foods increases the availability of some phytonutrients.
This contrasts with the conventional wisdom suggesting that cooking
vegetables reduces their nutritional value. Cooking tomatoes actually
triggers a rise in total antioxidant activity, mainly due to an
increase in lycopene [3].
Tomatoes, of course, are not a "magic bullet", and don't represent
a simple solution to what is clearly a complex problem. But a diet
that includes cooked tomatoes does appear to be an important nutritional
"weapon" in the fight against prostate cancer.
If you're healthy and you want to stay that way, more information
about the link between diet and disease is available here (The
Atkins Diet made healthy), here (The
dangers and benefits of vitamin C) and here (The
paleo diet made simple).
Related Articles
References
1. Chen, L., Stacewicz-Sapuntzakis, M., Duncan, C., Sharifi,
R., Ghosh, L., van Breemen, R., Ashton, D., & Bowen, P.E. (2001).
Oxidative DNA damage in prostate cancer patients consuming tomato
sauce-based entrees as a whole-food intervention. Journal
of the National Cancer Institute, 93, 1872-1879
2. Boileau, T.W., Liao, Z., Kim, S., Lemeshow, S., Erdman, J.W.
Jr,, & Clinton, S.K. (2003). Prostate carcinogenesis in N-methyl-N-nitrosourea
(NMU)-testosterone-treated rats fed tomato powder, lycopene, or
energy-restricted diets. Journal
of the National Cancer Institute, 95, 1578-1586
3. Dewanto, V., Wu, X., Adom, K.K., & Liu, R.H. (2002). Thermal
processing enhances the nutritional value of tomatoes by increasing
total antioxidant activity. Journal
of Agricultural and Food Chemistry, 50, 3010-3014
4. Stamey, T.A. (2004). The era of serum prostate specific antigen
as a marker for biopsy of the prostate and detecting prostate cancer
is now over in the USA. British
Journal of Urology International, 94, 963-964
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