Treating Advanced Prostate Cancer with Diet

Dr. Dean Ornish showed that a plant-based diet and lifestyle program could apparently reverse the progression of prostate cancer for early stage, localized, watch-and-wait cancer. What about for more advanced stage life-threatening disease?

Dr. Dean Ornish showed that a plant-based diet and lifestyle program could apparently reverse the progression of prostate cancer by making men’s bloodstreams nearly eight times better at suppressing cancer cell growth. But this was for early-stage, localized, watch-and-wait prostate cancer.

What about for more advanced-stage, life-threatening disease? There have been sporadic case reports in the literature suggesting benefit. For example, a man with extensive metastatic disease who had been given about three years to live went on a strict plant-based diet. Four years later, it appeared the cancer had disappeared. After six years, he got a little too comfortable, backslid a bit on the diet and began eating “turkey, tuna fish, and chicken,” then the cancer came raging back and he died. But that could have been a total coincidence. That’s the problem with case reports, which are kind of glorified anecdotes. You have no idea how representative the outcome is unless it’s studied formally. But, throughout the 20th century, all we had were these kinds of case reports for more advanced prostate cancer until 2001.

We had “preliminary evidence” based on all the case reports that “prostate cancer may be sensitive to diet even after metastasis develops. Plant-based diets may be associated with prolonged survival and instances of remission of bone metastasis in men with advanced disease.” So, researchers decided to put it to the test in a four-month intervention. They thought that too much saturated fat, too little fiber, and too much meat may be the biggest players in tumor promotion and progression, so they put people on a whole food plant-based diet of whole grains, beans, seeds, and fruits. Figuring this would be quite the departure from their regular diet, the researchers included a stress reduction component in hopes of improving dietary compliance.

Who were the subjects? The ten men in the study didn’t just have prostate cancer—they had all undergone a radical prostatectomy to remove their primary tumor and then subsequently had increasing PSA levels, indicative of probable metastatic disease. PSA stands for prostate-specific antigen. It’s only made by prostate cells, but the ten men had just had their entire prostates removed so their levels should have been zero. The fact that they not only still had some PSA, but that it was rising suggests that the surgery had failed, and the cancer had spread and was making a comeback.

At 2:43 in my video Treating Advanced Prostate Cancer with Diet: Part 1, you can view a graph showing the PSA levels for each of the men before the study began and see the speed at which their PSAs went up. If their PSA trajectories had stayed the same after four months of eating healthfully, it would mean the diet had had no effect. In that case, presumably, the cancer would have still been powering away and spreading just as fast as before. Instead, in two of the men, it looked as if the cancer had accelerated and grew even faster, but in the other eight men, the intervention appeared to work, apparently slowing down cancer growth. And, in three of the ten men, it didn’t just slow or stop, but appeared to reverse and shrink.

Why the different responses? Well, in the Ornish study, the more people complied with the diet and lifestyle recommendations, the better they did, as you can see at 3:31 in my video. Dietary changes only work if you actually do them. Just because you tell people to start eating a whole food plant-based diet, doesn’t mean patients actually do it. One can use fiber intake as a proxy for dietary compliance because all whole plant foods have fiber, and Ornish’s patients about doubled their fiber intake from 31 grams to 59 grams.

How did the ten men in the 2001 study do? They started out even worse, averaging 14 grams of fiber a day, and only made it up to 19 grams a day. That’s not a whole food plant-based diet—that doesn’t even meet the recommended minimum daily intake. As you can see at 4:18 in my video, only four of the ten men even increased their fiber intake at all, so that may explain the different responses. In fact, the man whose fiber improved the most had the best PSA result, and the man whose fiber intake dropped the most had the worst PSA result. Indeed, it appears the more changes they made to their diet, the better their results.

The researchers concluded that “a plant-based diet delivered in the context of MBSR [Mindfulness-Based Stress Reduction]…may slow the rate of tumor progression,” and, unlike other treatments, may give patients some control over their disease. And, as Ornish pointed out, “the only side effects are beneficial ones.”

Dr. Ornish and colleagues were able to show an apparent reversal in the progression of early-stage, localized prostate cancer with a plant-based diet and lifestyle program, and researchers at the University of Massachusetts and elsewhere showed a similar diet may help slow the progression of even advanced prostate cancer over a period of four months.

How about over six months? As I discuss in my video Treating Advanced Prostate Cancer with Diet: Part 2, researchers at University of California, San Diego put cancer patients through the same protocol as the four-month study. Once again, these were patients who had already been treated for invasive prostate cancer by either radical prostatectomy or radiation therapy, yet still had rising PSA levels, suggesting the treatment didn’t work and the cancer was on the move. “In those who have undergone a [cancer] recurrence, PSA typically tends to rise exponentially after prostatectomy or radiation therapy, reflecting the gradual, inexorable growth of the cancer in the body. After local treatment, the rate of PSA rise is the single best predictor of…development of overt metastatic disease, as well as of overall survival.” The next step would be hormonal therapy, which is chemical or surgical castration, but that has a list of side effects, including loss of libido, sexual function, strength, and vitality. “Therefore, many physicians employ a strategy of active surveillance” and try to hold off for as long as possible. If we’re just waiting, why not give diet a try?

Patients were “taught to increase intake of whole grains, vegetables, fruit, and legumes and to decrease meat, dairy, and refined carbohydrates.” Of all possible lifestyle interventions, why a whole food plant-based diet? If you look around the world, there are huge differences in prostate cancer rates, as you can see at 1:42 in my video, and our We’re #1! USA! USA! rates are up to a hundred times higher than some places in Asia, for example—and it’s not just genetic. Within one generation of migrating to the United States, cancer rates shoot up, and the grandkids of the immigrants end up with the same top-of-the-pile “approximate US rates.” A whole range of lifestyle factors have been looked at, but diet appears to have the greatest influence.

Specifically, “consumption of meat and dairy appears to increase risk, and consumption of plant-based foods appears to decrease risk.” Hence, the plant-based diet. A possible mechanism found in both meat and dairy products is arachidonic acid, an inflammatory compound that we make from omega-6-rich oils, like corn, sunflower, safflower, and cottonseed oils. It also comes “preformed” in animal-based foods and, in the American diet, is found particularly in chicken and eggs. In a petri dish, arachidonic acid appears to stimulate prostate cancer cell growth as much 200 percent, as you can see at 2:43 in my video.

So what happened when those researchers at University of California, San Diego asked men to remove processed and animal foods from their diet for six months? At 2:57 in my video, you can see a graph showing how fast the cancer patients’ PSA levels had been rising before starting the study. “In the absence of treatment, absolute levels of PSA tend to increase exponentially,” but upon eating more healthfully, nine of the ten study subjects showed an apparent slowing of cancer growth and four of the nine showed an apparent reversal in cancer growth. The average doubling time, an estimate of how long it would take for their cancer to double in size, slowed from doubling every year to closer to every ten years.

Other studies have used various diets and nutritional interventions, like vitamin supplements, but none has worked as well as this one—and the subjects’ compliance wasn’t even all that great. As you can see at 3:41 in my video, they did well in boosting their whole grain consumption in the first three months, but then backslid a bit, and they ate more vegetables, including a serving of greens, and an extra serving of fruit, at least early on. And, in the beginning, they at least ate one whole serving of legumes a day. So the researchers “did observe some [dietary] recidivism by 6 months,” with subjects sliding back into old habits. Given that, they checked to see if the study participants were better able to beat off the disease during that earlier period. And, indeed, at the end of the first three months, on average, there was PSA reversal. “Changes in the rate of rise in PSA, an indicator of disease progression, were in the opposite direction as changes in the intake of plant-based food groups, raising the provocative possibility that PSA may have inversely tracked intake of these foods and suggesting that adoption of a plant-based diet may have therapeutic potential in the management of this condition.”

Their findings suggest that, without further surgery, radiation, or chemotherapy, disease progression can be slowed or even reversed, despite “the prevailing scientific consensus…that cancer progression is largely irreversible.” The researchers state their “findings do not refute the benefits of standard therapies or guarantee that a plant-based diet and stress reduction will always induce remission,” but their results “do contribute to a growing [medical] literature that suggests that in at least some circumstances, cancer may be partly reversible and that modification of dietary and lifestyle factors may be able to help prevent disease spread”—all without getting their testicles cut off.

Hold on. We can make men’s bloodstreams nearly eight times better at suppressing cancer cell growth? See How Not to Die from Cancer.

It’s not all or nothing, though. Any movement we make towards healthy eating may help. See Prostate Cancer Survival: The A/V Ratio .


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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:

Saffron for Erectile Dysfunction

What are the effects of both oral and topical application of the spice saffron for impotence in men?

“Saffron has traditionally been considered an aphrodisiac.” The spice has been shown to improve Prozac-induced sexual dysfunction in women and men, significantly improving erectile function. If it works for drug-induced dysfunction, might it also work for just regular erectile dysfunction? This is the topic of my video Saffron for Erectile Dysfunction.

Why not just use pills like Viagra? They can work, but many men stop using them for “various reasons such as adverse side-effects.” In fact, nearly half of men decide the cons outweigh the pros. For men who don’t like drugs, there’s always surgery—the implantation of penile prosthetics. Unbelievably, penile implant usage evidently dates back to the 16th century. Early experiments involved transplanting patients’ rib cartilage or even their actual rib into their penis. Thankfully, space-age technologies in the 1960s allowed men to keep their ribcages intact. Originally, the implants left men in a “permanently erect state,” but then the “Flexirod” was invented with a hinge in the middle so the device could be bent down in half “for improved concealment.” Of course, proper sizing is important: If the implants are too small, there can be drooping at the tip, leading to a “supersonic transport (SST) deformity.” Why supersonic? “Because of its resemblance to the nose of the Concorde [jet]. Overlong prostheses can also be a problem, and with the semi-rigid rods erosion [out of the penis] can occur.” “Although a penile prothesis generally perforates into the urethra, it can also extrude through the glans [tip] or corporeal shaft.” Ouch.

Now, there are inflatable devices, as you can see at 2:06 in my video, and, perhaps one day, there will be “expandable foams that respond to external magnetic fields” or metal-mesh technology “that could expand and retract in a cage-like fashion.” (Can you imagine trying to get through airport security with that?)

There’s got to be a better way.

In one study, twenty men with erectile dysfunction took 200 mg (about a quarter teaspoon) of saffron a day and were followed for ten days. But first, they were brought into the “RigiScan room,” where they were hooked up to a “computer-controlled, battery-powered system for recording of penile tumescence”—meaning swelling—“and rigidity.” They were then “monitored while watching a visual sexual stimulation (VSS) video tape,” though use of the device is controversial, described as an “expensive, complicated, and time-consuming effort.” But, as you can see at 3:00 in my video, after the ten days of taking saffron, there did appear to be a significant improvement in tip and base rigidity and tumescence. “Whether it is possible to replace [Viagra-type drugs] with this golden plant requires further research with a bigger sample size.” But it’s not just size that matters. The researchers didn’t use a control, so all of this could have just been one big placebo effect.

Finally, though, researchers pitted saffron against Viagra in a head-to-head challenge. Normally there’s a third group—a placebo group—as well, but evidently, they felt it would be unethical to let men go 12 weeks without an effective treatment. The saffron appeared safer than the drug, with significantly fewer side effects like severe headaches, hot flushes, nasal congestion, and nausea, but…it was not effective at all. That’s why I never produced a video on the subject—it just doesn’t seem to help erectile dysfunction. Could it be, though, that they made the mistake of taking the saffron orally, as opposed to rubbing it on their penis? About half of middle-aged men in the United States appear to suffer from erectile dysfunction, so how about a randomized, double-blind, placebo-controlled study. Researchers studied the effects of a gel containing either 1 percent saffron or a “golden yellow food color” so the two gels looked the same. “Both groups were trained to rub a pea-sized amount of the gel on their penis half an hour before a sexual intercourse. One month later, all patients were reassessed using the same questionnaire.” As you can see at 4:40 in my video, compared to the food-coloring gel, the saffron gel led to significant improvements in erectile function, sexual desire, and overall satisfaction. The effects are attributed to a compound in saffron that enhances nitric oxide production in the arteries. But, if that’s the case, then it’s probably better to treat the cause and prevent the vascular dysfunction in the first place by eating a diet packed with nitrate-rich vegetables.

Those who want to clean out all their arteries and treat the cause may want to check out my video Survival of the Firmest: Erectile Dysfunction and Death.


Another video worth watching is Best Food for Antidepressant-Induced Sexual Dysfunction. I have a few others on the golden spice:

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:

Can Soy Prevent and Treat Prostate Cancer?

As I discuss in my video The Role of Soy Foods in Prostate Cancer Prevention and Treatment, a compilation of 13 observational studies on soy food consumption and the risk of prostate cancer found that soy foods appear to be “protective.” What are observational studies? As opposed to interventional studies, in observational studies, researchers observe what people are eating but don’t intervene and try to change their diets. In these studies, they observed that men who ate more soy foods had lower rates of prostate cancer, but the problem with observational studies is that there could be confounding factors. For example, “people who choose to eat soy also make other lifestyle decisions that lower the risk of cancer (e.g., lower fat intake, higher vegetable and fruit intake, more frequent exercise),” maybe that is why they have less cancer. Most of the studies tried to control for these other lifestyle factors, but you can’t control for everything. What’s more, most of the studies were done in Asia, so maybe tofu consumption is just a sign of eating a more traditional diet. Is it possible that the reason non-tofu consumers got more cancer is that they had abandoned their traditional diet? If only we could look at a Western population that ate a lot of soy. We can: the Seventh-Day Adventists.

In the 1970s, more than 12,000 Adventist men were asked about their use of soy milk and then were followed for up to 16 years to see who got cancer and who did not. So, what did they find? Frequent consumption of soy milk was associated with a whopping 70 percent reduction of the risk of prostate cancer, as you can see at 1:33 in my video. Similarly, in a multiethnic study that involved a number of groups, soy intake appeared protective in Latinos, too.

Prostate cells carry beta type estrogen receptors, which appear to act as a tumor suppressor, a kind of “gatekeeper…inhibiting invasion, proliferation and…preventing” the prostate cells from turning cancerous. And, those are the receptors targeted by the phytoestrogens in soy, like genistein, which inhibits prostate cancer cell invasion and spread in a petri dish at the kind of levels one might get consuming soy foods. The prevention of metastases is critical, as death from prostate cancer isn’t caused by the original tumor, but its spread throughout the body, which explains why it “is recommended that men with prostate cancer consume soy foods, such as soybeans, tofu, miso and tempeh.”

Wait a moment. Dean Ornish and his colleagues got amazing results, apparently reversing the progression of prostate cancer with a plant-based diet and lifestyle program. Was it because of the soy? Their study didn’t just include a vegan diet, but a vegan diet supplemented with a daily serving of tofu and a soy protein isolate powder. There have been studies showing that men given soy protein powders develop less prostate cancer than the control group, but what was the control group getting? Milk protein powder. Those randomized to the milk group got six times more prostate cancer than the soy group, but was that due to the beneficial effects of soy or the deleterious effects of the dairy? Dairy products are not just associated with getting prostate cancer, but also with dying from prostate cancer. Men diagnosed with prostate cancer who then ate more dairy tended to die sooner, and “both low-fat and high-fat dairy consumption were positively associated with an increased risk of fatal outcome.”

The best study we have on soy protein powder supplementation for prostate cancer patients found no significant benefit, and neither did a series of soy phytoestrogen dietary supplements. But, perhaps that’s because they used isolated soy components rather than a whole soy food. “Taking the whole-food approach may be more efficacious,” but it can be hard to do controlled studies with whole foods: You can make fake pills, but how do you give people placebo tofu?

A group of Australian researchers creatively came up with a specially manufactured bread containing soy grits to compare to a placebo regular bread and gave slices to men diagnosed with prostate cancer awaiting surgery. As you can see at 4:31 in my video, they saw a remarkable difference in just about three weeks time. It was the first study to show that a diet incorporating a whole soy food could favorably affect prostate cancer markers, but you can’t just go out and buy soy grit bread. Another study was a little more practical. Twenty men with prostate cancer who had been treated with radiation or surgery but seemed to be relapsing were asked to drink three cups of regular soy milk a day. The PSA levels in each of the 20 patients were all rising before they started the soy milk, suggesting they had relapsing or metastatic cancer growing inside of them. However, during a year drinking soy milk, 6 out of the 20 subjects got better, 2 got worse, and the remaining 12 remained unchanged, as you can see from 5:02 in my video. So, they concluded that soy food may help in a subset of patients.

Based on all these studies, the results Ornish and his colleagues got were probably due to more than just the soy. Similarly, the low prostate cancer rates in Asia are probably because of more than just the soy, since the lowest rates are also found in parts of Africa, where I don’t think they’re eating a lot of tofu. Indeed, in the multiethnic study, other types of beans besides soy also appeared protective for Latinos and all the groups put together, when looking at the most aggressive forms of prostate cancer. So, the protection associated with plant-based diets may be due to eating a variety of healthy foods. 


That soy milk stat from the Adventist study is astounding. What about fermented soy foods, though? That was the subject of Fermented or Unfermented Soy Foods for Prostate Cancer Prevention?.

Reversing the progression of cancer? See How Not to Die from Cancer.

Given the power of diet, it’s amazing to me how difficult Changing a Man’s Diet After a Prostate Cancer Diagnosis can be. It’s not all or nothing, though. Check out Prostate Cancer Survival: The A/V Ratio.

For soy and breast cancer survival, see Is Soy Healthy for Breast Cancer Survivors?.

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: