Tomato Sauce Put to the Test for Prostate Cancer

What happened when cancer patients were given three quarters of a cup of canned tomato sauce every day for three weeks?

“Occasionally…positive things happen in the field of cancer prevention science to popular, good-tasting foods.” Cruciferous vegetables like broccoli are wonderful, but they may be “a hard food for the public to swallow.” By contrast, who doesn’t like tomatoes?

As I’ve discussed previously, 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. In fact, it may even end up promoting cancer, since lycopene may actually act as a pro-oxidant at the high levels one can get with supplements. But, lycopene in supplement form doesn’t appear to be effective at lower doses either. “There is a strong inverse [protective] correlation between the intake of fruit and vegetables and the incidence of certain cancers.” However, 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] known carotenoids in tomatoes and tomato-based products include β-carotene, γ-carotene, ζ-carotene, phytofluene, and phytoene, all of which…have been found to accumulate in human prostate tissue.” There are also numerous non-carotenoid compounds in tomatoes that may have anti-cancer activity, not to mention all of the compounds we have yet to even characterize.

It’s not about finding the one magic bullet, though. As one study title reads, “The anti-cancer effects of carotenoids and other phytonutrients resides in their combined activity.” For example, as you can see at 1:52 in my video Tomato Sauce vs. Prostate Cancer, at the low concentrations of the tomato compounds phytoene, phytofluene, and lycopene that are found in most people who eat normal amounts of tomatoes, there’s very little effect on cancer cell growth in vitro when used separately. But, when they are combined together, a non-effective dose of phytoene and phytofluene plus a non-effective dose of lycopene somehow become effective, significantly suppressing prostate cancer cell growth. 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 individually to inhibit pro-growth signaling of prostate cancer cells—less than 10 percent—but all three together suppress growth signaling about 70 percent. The whole is greater than the sum of its parts.

So, instead of giving cancer patients lycopene pills, what if we give them some tomato sauce? Researchers gave 32 patients with localized prostate cancer 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 percent. PSA, prostate-specific antigen, is a protein produced by prostate gland cells, and elevated blood PSA levels are routinely used to monitor the success of cancer treatment. “It was surprising to find that the 3-week, tomato sauce-based dietary intervention” could decrease PSA concentrations in men with prostate cancer. As well, free radical damage of the DNA in their white blood cells dropped by 21 percent. Imagine how antioxidant-poor their diet must have been beforehand if less than one cup of tomato sauce a day could reduce DNA damage by more than a fifth! 

What did they find in their prostates, though? 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 carcinogenesis,” that is, of cancer formation. This may be for a number of reasons, including fewer DNA repair enzymes. Well, the researchers had tissue samples taken from biopsies before the tomato sauce regimen started, as well as tissue samples from surgeries after three weeks of tomato sauce, and resected tissues from tomato sauce-supplemented patients had 28 percent less free radical damage than expected. I show a graph of the DNA damage in the prostate before the tomato sauce and after just 20 days of sauce at 4:18 in my video. You can see the drop yourself. What’s interesting is 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? Researchers fed people red tomato paste, yellow tomato paste, lycopene pills, or placebo pills, and then dripped their blood onto prostate cancer cells growing in a petri dish. As you can see at 5:18 in my video, 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, compared to those not eating anything. 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 tomato, so maybe the lycopene helped—but not in pill form. This gene “was not regulated” by the lycopene pill serum, indicating that it may be something else. And, lycopene alone significantly upregulated procarcinogenic genes. “Therefore, it can be stated that tomato consumption may be preferable to pure lycopene…”

So, what’s the best way? A spouse wrote to the editor of the Harvard Men’s Health Watch, saying their husband wants to have pizza for his prostate but they don’t think it’s a healthy food. The doctor replied with the suggestion of a “cheese-free pizza (with broccoli instead of pepperoni, please)” or just some “tomato juice.”

Why eat tomato sauce when you can just take lycopene supplements? See my video Lycopene Supplements vs. Prostate Cancer.

Are there any foods we should avoid? Check out, for example, Prostate Cancer Survival: The A/V Ratio and How Our Gut Bacteria Can Use Eggs to Accelerate Cancer.


We may be able to prevent cancer and even reverse the progression of cancer with diet. See: 

It isn’t always easy to get guys to change, though. See Changing a Man’s Diet After a Prostate Cancer Diagnosis.

In health, 

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Lycopene Supplements Put to the Test

High doses of lycopene—the red pigment in tomatoes—were put to the test to see if it could prevent precancerous prostate lesions from turning into full-blown cancer.

Back in 1980s, the Adventist Health Study found “strong protective relationships” against prostate cancer with increasing consumption of legumes, citrus, dried fruit, nuts, and tomatoes. In the 1990s, a Harvard study focused attention on tomatoes, which appeared to be “especially beneficial regarding prostate cancer risk.” Researchers suspected it might be the red pigment in tomatoes called lycopene, which has greater antioxidant power than some of the other pigments, such as the orange beta-carotene pigment in carrots and cantaloupes. Lycopene dramatically kills off prostate cancer cells in a petri dish, even down at the levels you might expect in your bloodstream after just eating some tomatoes. So, not surprisingly, the Heinz ketchup company, along with manufacturers of lycopene supplements, petitioned the FDA to allow them to print health claims on their products.

As I discuss in my video Lycopene Supplements vs. Prostate Cancer, they were essentially denied. The FDA said the evidence was “very limited and preliminary” and didn’t allow any endorsements 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 who eat the most pizza. So, maybe it’s no surprise there are mixed results. What we needed was to put lycopene to the test.

It started with a case study of a 62-year-old man with terminal prostate cancer. Both surgery and chemotherapy had failed. He had metastases all over that had spread to the bone and was sent to hospice to die. So, he took it upon himself to initiate “phytotherapy”—plant-based therapy. Every day, he took the amount of lycopene found in a quarter cup of tomato sauce or a tablespoon of tomato paste. His PSA, a measure of tumor bulk, started out at 365, dropped to 140 the next month, and then down to just 8 the month after that. His metastases started disappearing, and, “at last followup he was asymptomatic”—living happily ever after.

When lycopene was given at a higher dose in pill form, however, it didn’t seem to work. A 2013 review of all such lycopene supplement trials failed to support the initial “optimism.” In fact, the researchers were just happy that the lycopene pills didn’t end up causing more cancer, like beta-carotene pills did. Then came 2014. 

Researchers in Italy had been giving the largest doses they could have 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, the researchers in Italy 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, as you can see at 3:32 in my video. At dietary doses, beta-carotene suppressed cellular damage, but at supplemental doses, which are higher, it not only appeared to stop working, but it caused more damage. The same with lycopene. “Both lycopene and [beta]-carotene only afforded protection against DNA damage…at relatively low concentrations”—at the kinds of levels one might see in people eating lots of tomatoes or sweet potatoes. That is, “levels [that] are comparable with those seen in the plasma [blood] of individuals who consume a carotenoid-rich diet.” However, at the kind of blood concentrations that one might get taking pills, “the ability to protect the cells against such oxidative [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. It’s 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 from frequent consumption of fruits, vegetables, and whole grain products”—by whole plant foods. The food industry has different ideas, though. Soon, there may be phytochemical-fortified bacon, martinis, and ice cream, says an article in the journal Food Technology. If they can find just the right mix of plant compounds, it “is not inconceivable that foods that once contributed to illness and disease may be reconstructed…to offer significant health benefits.”

So what are the Best Supplements for Prostate Cancer? Watch the video to find out!


More on natural treatments for prostate cancer in:

Instead of tomato-compound supplements, what if we just fed some cancer patients some tomato sauce? That’s the subject of my video Tomato Sauce vs. Prostate Cancer

In health, 

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Are Avocados Associated with Greater Risk or Reduced Risk of Cancer?

Avocado consumption can improve artery function, but what effect might guacamole have on cancer risk?

In my last video about avocados, The Effects of Avocados and Red Wine on Meal-Induced Inflammation, I described their anti-inflammatory effects and cholesterol- and triglyceride-lowering effects, but what about the Are Avocados Good for You? video I did years ago about the chromosome-damaging effects in a petri dish? That goes back to 1975, when a pesticide naturally produced by the avocado tree was discovered, thought to explain why lactating livestock suffer mammary gland damage after nibbling on the leaves. The toxin, named persin, was also found to be damaging to the heart, which is why you should never feed avocado to your pet birds.

But, if persin attacks mammary cells in animals, might it attack breast cancer cells in humans? As you can see at 0:52 in my video Are Avocados Healthy?, it did seem to have the same kind of cellular cytoskeleton-clumping effect in vitro that chemotherapy can have, demonstrating potent cell growth stopping and killing effects of the novel plant toxin among various lines of human breast cancer cells. So, researchers are thinking about how it might one day be used as chemo itself, but I’m thinking, Holy guacamole, Batman! Please tell me it doesn’t have toxic effects on normal cells, too.

We got an answer in 2010 with an evaluation of the genotoxicity—the toxicity to our chromosomes—of avocado extracts on human white blood cells in a petri dish. As you can see at 1:35 in my video, normally, less than 10 percent of our dividing cells have any chromosome abnormalities, but if you drip some avocado fruit extracts on them, up to half come out defective in some way. The researchers concluded that there’s something in avocado fruit that “can potentially induce significant genomic instability and some genetic damage in human lymphocytes in vitro,” that is, in white blood cells in a petri dish. If the same effect occurs in actual people, it could, for example, result in transforming cells into cancer. That is a big if, though. These were blood cells. You don’t inject guacamole into the vein. For something to get into our bloodstream, it first has to survive our stomach acid, get absorbed through our intestines, and then sneak past our liver’s detoxification enzymes. And indeed, persin may be affected, changed by acidic conditions. So, given all the differences between what happens in a petri dish and inside a person, it’s essential to carry out further studies “before making a final remark on the genotoxicity.” Sounds reasonable, but what do you do before these studies come out? I was concerned enough that I provisionally moved avocados from being a don’t-hold-back green-light food to a moderate-your-intake yellow-light food to err on the side of caution until we knew more.

Even if persin were utterly destroyed by stomach acid, what about oral cancer? As you can see at 3:01 in my video, avocado extracts at high enough concentrations can harm the growth of the kinds of cells that line our mouths. This was in a petri dish, though, where the avocado is coming in direct contact with the cells—but that’s also kind of what happens in your mouth when you eat it. However, it harms oral cancer cells even more. At 3:32 in my video, you can see a bunch of oral cancer cells. In the first image, the mitochondria, the power plants of the cells fueling cancer growth, are seen in red. In the second image, you can see they’ve been extinguished by the avocado extract—no more red-colored mitochondria. Since it does this more to cancerous cells than normal cells, the researchers conclude that avocados may end up preventing cancer.

What about the esophagus, which lies between the mouth and the stomach? Researchers similarly found that an avocado fruit extract appeared to inhibit cancer cell growth more than normal cell growth when it came to both colon cancer cells and esophageal cancer cells, as you can see at 3:53 in my video. But, rather than comparing the effects to normal colon and esophagus cells, they compared them to a type of blood cell, which, again, is of limited relevance in a petri dish study of something you eat.

A study I found to be pretty exciting looked at p-cresol, which is a “uremic toxin” and may also be toxic to the liver. “Found to be associated with autism,” it comes from eating high-protein diets, whereas if you eat a more plant-based diet, which is the only source of prebiotics like fiber and resistant starch, your levels go down. See, fermentation of carbohydrates in the colon, like fiber, is considered beneficial, whereas fermentation of protein, which is called putrefaction, is considered detrimental. So, if you switch people to a high-protein diet, within days, the excess protein putrefying in their gut leads to an increase in ammonia as well as p-cresol—in fact, a doubling of levels within a week. But, might phytonutrient-rich plant foods, like apples, cranberries, grapes, or avocados, protect the cells lining our colon “from the deleterious effects of p-cresol…in terms of cell viability, mitochondrial function, and epithelial integrity,” meaning protection against gut leakiness? At 5:12 in my video, I show the data on barrier function integrity. You can see that it is damaged by p-cresol, but rescued by all the cranberry, avocado, grape, and apple extracts. Mitochondrial function, however, was only improved by the cranberries and avocados, which also were the only ones that appeared to prevent the deleterious effect of p-cresol on colon cell viability. The bottom line, though, is that avocados appear to have beneficial effects on colon lining cells. Okay, but enough of these in vitro studies, already. Yes, an avocado extract can inhibit cancer cell growth in a petri dish, but unless you’re doing some unspeakable things to that avocado—like guacamole with benefits—there’s no way that avocado is going to come in direct contact with your prostate cells. So, what does this study mean?

This is why I was so excited to see the first study to actually look for a link between avocado consumption and prostate cancer. Actual human beings eating avocados! So, do avocado eaters have more cancer risk or less cancer risk? Men who ate the most avocado, more than about a third of an avocado a day, had reduced risk of prostate cancer—in fact, less than half the odds. So, with the data on improved artery function, lower cholesterol, and, if anything, an association with decreased cancer risk, I’d suggest moving avocados back up with the other green-light foods.


How Not to Die from Cancer is an overview on dietary approaches to cancer prevention and treatment, and I also have hundreds of videos on all of the common cancers.

What if you’ve already been diagnosed? Even if you already have prostate cancer, for example, it’s not too late to improve your diet. See: 

In health, 

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: