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Back in the 80s, the Adventist Health Study found “[s]trong 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 bloodstream 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, with the FDA 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 at 365, 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, it 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 unblind 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 cells 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 “[t]he safety of consuming concentrated extracts…is unknown.” The protective benefits of a phytochemical-rich diet is best obtained [through 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 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.”

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