Lycopene is the phytonutrient
that gives tomatoes their bright red color.
It’s among the most potent of carotenoid antioxidants,
so what happened when researchers
pitted lycopene and whole tomatoes
against prostate cancer?
Check it out.
"Lycopene Supplements vs. Prostate Cancer & Tomato Sauce vs. Prostate Cancer"
Back in the '80s, the Adventist Health Study found strong protective relationships
against prostate cancer with increasing consumption
of legumes, citrus, dried fruit, nuts, and tomatoes.
In the '90s, a Harvard study focused attention on tomatoes,
which appeared to be especially beneficial.
They suspected it might be the red pigment in tomatoes called lycopene,
which has greater antioxidant power than some of the other pigments,
like the orange beta-carotene pigment in carrots and cantaloupes.
And lycopene dramatically kills off prostate cancer cells in a petri dish,
even way down at the levels one would expect
in one's blood stream after just eating some tomatoes.
So of course the Heinz ketchup company,
along with manufacturers of lycopene supplements,
petitioned the FDA to allow them to print health claims on their products.
They were essentially denied, saying that the evidence was very limited
and preliminary, with no endorsement allowed for ketchup or supplements.
By that time, further population studies had cast doubt on the lycopene theory.
Consumers of high dietary intakes of lycopene
didn't seem to have lower cancer rates after all.
But who has high dietary intakes of lycopene?
Those that eat the most pizza;
so maybe it's no surprise there are mixed results.
What we need is to put lycopene to the test.
It started with a case study.
A 62-year old man with terminal prostate cancer, failed surgery,
failed chemotherapy, metastases all over, spread to the bone.
And so he was sent to hospice to die.
So he took it upon himself to initiate phytotherapy, plant-based therapy,
taking the amount of lycopene found in a quarter cup of tomato sauce
or a tablespoon of tomato paste every day.
His PSA, a measure of tumor bulk, started out as 365,
but dropped to 140 the next month, and then down to 8.
His metastases started disappearing, and as of his last follow-up
appeared to be living happily ever after.
But when given in higher dose pill form, lycopene didn't seem to work.
A 2013 review of all such lycopene supplement trials
failed to support the initial optimism.
In fact, they were just happy that the lycopene pills
didn't end up causing more cancer, like beta-carotene pills did.
But then came 2014.
Researchers in Italy had been giving the largest doses they could
of lycopene, selenium, and isolated green tea compounds
to men with precancerous prostate lesions,
hoping they could prevent full-blown cancer.
But in 2014, the expanded results of a similar trial were published
in which selenium and vitamin E supplements resulted in more cancer.
Yikes!
So these researchers stopped their trial
and broke the code to un-blind the results.
And indeed, those taking high doses of lycopene, green tea catechins,
and selenium appeared to get more cancer than those who just got sugar pills.
"The potential implications are dramatic," said the lead researcher,
"given the current massive worldwide use of such compounds
as alleged preventive supplementations in prostate and other cancers."
What went wrong?
Well, after the beta- carotene pill debacle,
researchers measured cellular damage at different
natural and unnatural doses of beta-carotene.
At dietary doses, beta-carotene suppressed cellular damage,
but at higher supplemental doses,
it not only appeared to stop working, but caused more damage.
And the same with lycopene.
Both lycopene and beta- carotene afforded protection
against DNA damage at the kinds of levels one might see
in people eating lots of tomatoes or sweet potatoes,
levels comparable with those seen in the blood of individuals
who consume a carotenoid- rich healthy diet.
However, at the kind of blood concentrations that one might get
taking pills, the ability to protect the cell against
such free radical damage was rapidly lost.
And indeed, the presence of high levels of beta-carotene and lycopene
may actually serve to increase the extent of DNA damage.
So no wonder high dose lycopene pills didn't work.
Phytochemicals may be guardians of our health,
but the safety of consuming concentrated extracts is unknown.
The protective benefits of a phytochemical-rich diet
are best obtained by whole plant foods.
The food industry has different ideas, though.
Soon there may be phytochemical- fortified bacon, martinis, and ice cream,
says this article in the Journal of Food Technology.
If they can find just the right mix of plant compounds,
they hope to reconstruct foods that once contributed to illness and disease
to offer significant health benefits.
"Occasionally...positive things happen in the field
of cancer prevention science to popular, good-tasting foods."
Yes, broccoli family vegetables are wonderful,
but may be a hard food for the public to swallow.
By contrast, who doesn't like tomatoes?
But studies using high dose supplements of lycopene,
the antioxidant red pigment in tomatoes thought to be
the active anti-cancer ingredient,
failed over and over again to prevent or treat cancer,
and may even end up promoting it,
since at the high levels one can get with supplements,
lycopene may actually act as a pro-oxidant.
But lycopene doesn't appear
to be effective at lower doses either.
There is a strong protective correlation
between the intake of actual whole fruit and vegetables
and the incidence of certain cancers,
but when we supplement with only a single compound
isolated in pill form, we may upset
the healthy natural balance of antioxidants.
It does seem to be quite the human hubris
to think we can reproduce the beneficial effects
of consuming entire fruits and vegetables
by giving supplements of a single phytochemical,
which would normally interact with thousands of other compounds
in the natural matrix Mother Nature intended.
In addition to lycopene, other carotenoids in tomatoes
include beta-carotene, gamma-carotene, zeta-carotene,
phytofluene, and phytoene, all of which are known
to accumulate in human prostate tissue.
And there are also numerous non-carotenoid compounds
in tomatoes that may have anti-cancer activity,
not to mention all the compounds we have yet to even characterize.
But it's not about finding the one magic bullet;
the anti-cancer effects of carotenoids
and other phytonutrients may reside in their combined activity.
For example, at low concentrations
of the tomato compounds phytoene, phytofluene,
and lycopene found in most people who eat normal amounts
of tomatoes, there's very little effect
on cancer cell growth in vitro, used separately,
but combine them all together
and a non-effective dose plus a non-effective dose
becomes effective somehow, significantly suppressing
prostate cancer cell growth.
And the same synergy can be seen across foods.
Curcumin, the yellow pigment in turmeric and curry powder,
tomato extracts, and the vitamin E found in nuts and seeds
do little to inhibit pro-growth signaling
of prostate cancer cells— less than 10%.
But all three together suppresses growth signaling like 70%.
The whole is greater than the sum of its parts.
So how about instead of giving cancer patients lycopene pills,
we give them some tomato sauce?
Thirty-two patients with localized prostate cancer
were given three quarters of a cup of canned tomato sauce every day
for three weeks before their scheduled radical prostatectomy.
In their bloodstream, PSA levels dropped by 17.5%.
PSA, prostate-specific antigen,
is a protein produced by prostate gland cells,
and elevated blood levels are routinely used
to monitor the success of cancer treatment.
It was surprising to find that in just 3 weeks,
a tomato sauce-based dietary intervention could decrease
PSA concentrations in men with prostate cancer.
Also, free radical damage of the DNA
in their white blood cells dropped by 21%.
Imagine how antioxidant poor their diet must have been beforehand,
if less than a cup of tomato sauce a day could reduce
DNA damage by more than a fifth.
OK, but what did they find in their prostates?
Human prostate tissue is thought to be particularly vulnerable
to oxidative DNA damage by free radicals,
which are thought to play a critical role
in all stages of cancer formation.
This may be for a number of reasons,
including fewer DNA repair enzymes.
Well, the researchers had tissue samples taken
before the tomato sauce from biopsies, and tissue samples
from the surgery after the three weeks of tomato sauce,
and resected tissues from tomato sauce-supplemented patients
had 28% less free radical damage than expected.
Here's the DNA damage in the prostate before the tomato sauce,
and here's after, just 20 days of sauce.
And what's interesting is that there was no association
between the level of lycopene in the prostate
and the protective effects.
Tomatoes contain a whole bunch of things,
some of which may be even more powerful than lycopene.
Regardless, in contrast to the lycopene supplements alone,
the whole food intervention seemed to help.
To see if lycopene plays any role at all,
one would have to test a lycopene-free tomato—
in other words, a yellow tomato.
So what if you compared red tomatoes to yellow tomatoes,
which have all the non-lycopene tomato compounds,
to straight lycopene in a pill.
So they fed people red tomato paste, yellow tomato paste,
lycopene pills, or placebo pills, and then dripped their blood
on prostate cancer cells growing in a petri dish.
Compared to those not eating anything, the red tomato serum,
the blood from those who ate red tomato paste
significantly decreased the prostate cancer cell's
expression of a growth-promoting gene called cyclin D1.
This downregulation of the gene by the red tomato consumption
may contribute to lower prostate cancer risk
by limiting cell proliferation.
The red tomato seemed to work better than the yellow,
so maybe the lycopene helped, but not in pill form.
This gene was not regulated by the lycopene pill serum,
indicating that maybe it's something else.
And lycopene alone significantly upregulated
procarcinogenic genes.
Therefore, it can be stated
that tomato consumption may be preferable.
So what's the best way?
A spouse wrote in to the editor of the Harvard Men's Health Watch
saying his or her husband wants to have pizza for his prostate,
to which the doctor replied, fine, but how about cheese-free pizza
with broccoli instead of pepperoni,
or he can just drink some tomato juice.