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:

Is the Risk of Skin Cancer From Sun Exposure Overblown?

By the turn of the 20th century, rickets, the vitamin D deficiency disease, was rampant, thanks to city life with the shade of buildings and coal soot in the air. The dairy industry jumped at the opportunity to fortify milk with vitamin D, and so did the beer industry. According to one print ad: “Beer is good for you—but Schlitz, with Sunshine Vitamin D, is extra good for you…[so] drink Schlitz regularly—every day.” There are, of course, healthier fortified options, like vitamin D-fortified orange juice, but to reach recommended intake levels, it could take 15 to 20 cups of fortified milk, beer, and/or juice a day. As I discuss in my video The Risks and Benefits of Sensible Sun Exposure, to get those kinds of doses, it really comes down to sun or supplements.

Sunlight supplies 90 to 95 percent of vitamin D for most people. The threat of skin cancer is real, however it’s mostly from chronic excessive sun exposure and sunburns. “There is little evidence that minimal sensible exposure to sunlight will considerably increase the risk of skin cancer”—though why accept any risk when we can get our vitamin D just from supplements?

For the sake of argument, what if there were no supplements available? What if we were just trying to balance the positive and negative effects of sun exposure? On one side, we have entities like the American Academy of Dermatology that recommend that “no one should ever be exposed to direct sunlight without sun protection.” After all, the UV rays in sun are proven carcinogens, responsible for more than half of all Caucasian malignancies, blaming the tanning industry for downplaying the risk.

Even those who accept research dollars from the tanning industry acknowledge that excessive sun exposure can increase skin cancer risk, but argue for moderation, advocating for “sensible sun exposure” and blaming the sunscreen industry for overinflating the risk. However, it’s harder to impugn the motives of the dermatologists, who are essentially arguing against their financial interest since skin cancer is their bread and butter. The concern raised by UV advocates is that “sunphobic propaganda” may do more harm than good, pointing to studies such as this one from Sweden that found that those diagnosed with skin cancer tended to live longer and have less heart attacks and hip fractures. Not surprisingly, the media loved this and ran headlines like “Sunbathers live longer.” Only natural UV exposure was associated with reduced mortality, however; artificial UV exposure, like from tanning beds, was associated with increased mortality. This probably has nothing to do with vitamin D, then. Why then would those who run around outside enough to get skin cancer live longer? Maybe it’s because they’re running around outside. More exercise may explain why they live longer. And here in the United States, more UV exposure was associated with a shorter, not longer, lifespan.

There are modeling studies that suggest that at least 50,000 American cancer deaths may be attributable to low vitamin D levels that could be avoidable with more sunlight exposure that would kill at most 12,000 Americans from skin cancer. So, on balance, the benefits would outweigh the risks—but, again, why accept any risk at all when we can get all the vitamin D we need from supplements? In fact, where did they get those estimates about vitamin D preventing internal cancers? From intervention studies involving giving people vitamin D supplements, not exposing them to UV rays. So, it’s not much of a controversy after all. “In essence, the issue is framed as needing to choose between the lesser of two evils: skin cancer…versus cancer of various internal organs and/or the long list of other ailments” from vitamin D deficiency. The framework ignores the fact that there’s a third way. When we were evolving, we didn’t live long enough to worry about skin cancer, and vitamin “D was not available at the corner store.”

If we just want to look more attractive, how about eating more fruits and vegetables? When high kale models were pitted against high UV models, the golden glow from carotenoid phytonutrients won out, and the same result has been found in Caucasian, Asian, and African American faces. So, may I suggest the produce aisle to get a good healthy tan…gerine?

That’s the gist of what the last 15,950 studies on vitamin D have added to our understanding. Unless something particularly groundbreaking comes out, you can expect the next update in 2021. If you missed the first five videos in this series, see:

I also explore vitamin D as it relates to specific diseases:

The physical attractiveness is from carotenoid deposition in the skin. For more on this, 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, year-in-review presentations:

Health Benefits of Citrus Zest

New data demonstrating a DNA protective agent present in at least some fruits and vegetables found that the agent was heat sensitive and determined it was not vitamin C. This was confirmed in a study that tried vitamin C directly and found no effect on DNA protection or repair of DNA strand breaks.

If not vitamin C, what could the DNA protective agent be? The carotenoid beta-cryptoxanthin, found primarily in citrus, seems to be at least one candidate, as I discuss in my video Citrus Peels and Cancer: Zest for Life? If you expose cells to a mutagenic chemical, you can cause physical breaks in the strands of DNA. However, in less than an hour, our DNA repair enzymes can weld most of our DNA back together. What happens if we add some of that citrus phytonutrient? We can effectively double the speed at which DNA is repaired. But, this was determined in a petri dish. What about in a person?

In one study, subjects drank a glass of orange juice and their blood was drawn two hours later. The DNA damage induced with an oxidizing chemical dropped, whereas if they had just had something like orange Kool-Aid instead of orange juice, it didn’t help.

So, do people who eat more fruit walk around with less DNA damage? Yes, particularly women. Does this actually translate into lower cancer rates? It appears so: Citrus alone is associated with a 10 percent reduction in odds of breast cancer.

Given to newly diagnosed breast cancer patients, citrus phytonutrients were found to concentrate in breast tissue, though many complained of “citrus burps” due to the concentrated extract they were given. So, researchers evaluated topical application as an alternative dosing strategy, recruiting women to apply orange-flavored massage oil to their breasts daily. This request was met with excellent compliance, but it didn’t work. We actually have to eat, not wear, our food. 

Why not just take carotenoid supplements to boost our DNA repair? Because it doesn’t work. Although dietary supplements did not provoke any alteration in DNA repair, dietary supplementation with carrots did. This suggests that “the whole food may be important in modulating DNA repair processes…”

Though orange juice consumption was found protective against childhood leukemia, it was not found protective against skin cancer. “However, the most striking feature was the protection purported by citrus peel consumption” . Just drinking orange juice may increase the risk of the most serious type of skin cancer. Daily consumption was associated with a 60 percent increase in risk. So, again, better to stick with the whole fruit. We can eat citrus extra-whole by zesting some of the peel into our dishes.

Now you know why my favorite citrus fruit is kumquat—because you can eat the peel and all!

For other foods that may keep our DNA intact, see my Which Fruits and Vegetables Boost DNA Repair? video. Kiwifruit (Kiwifruit and DNA Repair), broccoli (DNA Protection from Broccoli), and spices (Spicing Up DNA Protection) may also fit the bill.

Interested in learning more about citrus? Check out:

In health,
Michael Greger, M.D.

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