Phytates in Beans: Anti-Nutrient or Anti-Cancer?

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In my videos, Phytates in the Prevention of Cancer and Phytates for Rehabilitating Cancer Cells, I described how phytates in beans may be the reason why legumes are so successful in preventing cancer and re-educating cancer cells. What about phytates for the treatment of cancer?

Colorectal cancer is the second leading cause of cancer death in the United States. It arises from "adenomatous polyps," meaning that colon cancer starts out as a benign little bump called a polyp and then grows into cancer that can eventually spread to other organs and kill. So the National Cancer Institute funded the Polyp Prevention Trial, highlighted in my video, Phytates for the Treatment of Cancer, to determine the effects of a high-fiber, high fruit and vegetable, low-fat diet.

Researchers found no significant associations between polyp formation and overall change in fruit and vegetable consumption. However, those with the greatest increase in bean intake only had about a third of the odds of advanced polyps popping up. It could have been the fiber in the beans, but there's lots of fiber in fruits and vegetables, too. So it may have been the phytate.

If the tumors develop from polyps, they still need to spread. Tumor growth, invasion, and metastasis are multistep processes that include cell proliferation, digestion through the surrounding tissue, and migration through barrier membranes to reach the bloodstream so the tumor can establish new proliferating colonies of cancer cells. A critical event in tumor cell invasion is the first step: the tunneling through the surrounding matrix. To do this, the cancer cells use a set of enzymes called matrix metalloproteinases. This is where phytates might come in. We've known that phytates inhibit cancer cell migration in vitro, and now perhaps we know why. Phytates help block the ability of cancer cells to produce the tumor invasion enzyme in the first place (at least for human colon and breast cancer cells).

So what happens if you give phytates to breast cancer patients? Although a few case studies where phytates were given in combination with chemotherapy clearly showed encouraging data, organized, controlled, randomized clinical studies were never done--until now. Fourteen women with invasive breast cancer were divided randomly into two groups. One group got extra phytates; the other got placebo. At the end of six months, the phytate group had a better quality of life, significantly more functionality, fewer symptoms from the chemo, and did not get the drop in immune cells and platelets chemo patients normally experience.

What are the potential side effects of phytates? Less heart disease, less diabetes, and fewer kidney stones.

Because cancer development is such an extended process--it can take decades to grow--we need cancer preventive agents that we can take long-term. Phytates, which naturally occur in beans, grains, nuts, and seeds, seem to fit the bill.

In the past, there were concerns that the intake of foods high in phytates might reduce the bioavailability of dietary minerals, but recent studies demonstrate that this co-called "anti-nutrient" effect can be manifested only when large quantities of phytates are consumed in combination with a nutrient poor diet. For example, there used to be a concern that phytate consumption might lead to calcium deficiency, which then led to weakened bones, but researchers discovered that the opposite was true, that phytates actually protect against osteoporosis (See Phytates for the Prevention of Osteoporosis). In essence, phytates have many characteristics of a vitamin, contrary to the established and, unfortunately, still existing dogma among nutritionists regarding its 'anti-nutrient' role.

As one paper in the International Journal of Food Science & Technology suggests:

"Given the numerous health benefits, phytates participation in important intracellular biochemical pathways, normal physiological presence in our cells, tissues, plasma, urine, etc., the levels of which fluctuate with intake, epidemiological correlates of phytate deficiency with disease and reversal of those conditions by adequate intake, and safety - all strongly suggest for phytates inclusion as an essential nutrient, perhaps a vitamin."

The paper concludes that inclusion of phytates in our diet for prevention and therapy of various ailments, cancer in particular, is warranted.

More on preventing tumor invasion and metastasis in:

Other foods that can help stop the progression of precancerous lesions (like the adenomatous polyps) are profiled in Strawberries versus Esophageal Cancer and Black Raspberries versus Oral Cancer.

There's a substance in mushrooms that's also another "essential" nutrient candidate. See Ergothioneine: A New Vitamin?

-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 Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: The Ewan / Flickr

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How Phytates Fight Cancer Cells

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Phytate is a compound found in beans, grains, nuts and seeds. The average daily intake of phytate in vegetarian diets is about twice that of those eating mixed diets of plant and animal foods, which may help explain their low cancer rates. Aside from helping to prevent cancer, dietary phytate has been reported to help prevent kidney stone formation, protect against diabetes mellitus, dental cavities, and heart disease.

Do all these potentially beneficial effects sound too good to be true? Are there other examples of compounds made by plants that can have benefits across multiple diseases? Why yes! Aspirin, for example, which is found throughout the plant kingdom may also account for a variety of plant-based benefits (See Aspirin Levels in Plant Foods).

But of all the things phytates can do, the anticancer activity of phytate (also known as phytic acid, IP6, or inositol hexaphosphate), is considered one of its most important beneficial activities. Dietary phytates are quickly absorbed from the gastrointestinal tract and rapidly taken up by cancer cells throughout the body, and have been shown to inhibit the growth of all tested cancerous cell lines in vitro. Phytates have been shown to inhibit the growth of human leukemia cells, colon cancer cells, both estrogen receptor-positive and negative breast cancer cells, voicebox cancer, cervical cancer, prostate cancer, liver tumors, pancreatic, melanoma, and muscle cancers. All at the same time not affecting normal cells. That's the most important expectation of a good anticancer agent: the ability to only affect cancerous cells and to leave normal cells alone.

In my video, Phytates for Rehabilitating Cancer Cells, you can see how leukemia cells taken from cancer patients are killed by phytates, whereas normal bone marrow cells, are spared. This may explain why bean extracts kill off colon cancer cells in vitro, but leave normal colon cells alone.

What are the mechanisms of action by which phytates battle cancer? In other words, how do phytates fight? How don't they fight? Phytate targets cancer through multiple pathways, a combination of antioxidant, anti-inflammatory, immune-enhancing activities, detox, differentiation, and anti-angiogenesis. In other words, phytate appears to affect all the principal pathways of malignancy.

The antioxidative property is one of the most impressive characteristics of phytate. In fact that's why the meat industry adds phytates to meat to prevent the fat oxidation that begins at the moment of slaughter. Phytates can also act on our immune functions by augmenting natural killer cell activity, the cells in our body that hunt down and dispose of cancer cells, as well as neutrophils, which help form our first line of defense. And then phytates starve tumors as more of a last line of defense. Not only can phytates block the formation of new blood vessels that may be feeding tumors, but disrupt pre-formed capillary tubes, indicating that phytates may not just help blockade tumors, but actively cut off existing supply lines.

What's really remarkable about phytate, though, is that unlike most other anti-cancer agents, it not only causes a reduction in cancer cell growth but also enhances differentiation, meaning it causes cancer cells to stop acting like cancer cells and go back to acting like normal cells. You can see this with colon cancer cells for example. In the presence of phytates, human colon cancer cells mature to structurally and behaviorally resemble normal cells. And this has been demonstrated in leukemia cells, prostate cancer, breast cancer, and muscle cancer cells as well.

For more on the cancer and phytate connection, check out Phytates for the Prevention of Cancer and Phytates for the Treatment of Cancer.

This video reminds me of my video on the spice, turmeric, Turmeric Curcumin Reprogramming Cancer Cell Death.

What else can we eat to improve the cancer-fighting front of our immune system? See Boosting Natural Killer Cell Activity.

More on the concept of starving tumors of their blood supply in Anti-Angiogenesis: Cutting Off Tumor Supply Lines.

Is there clinical evidence of plants actually reversing cancer progression? You won't believe your eyes:

-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 Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Avi / Flickr

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Testing Turmeric on Smokers

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Researchers are becoming increasingly aware of "plant-derived substances that act as chemopreventive agents." Chemopreventatives are substances that help prevent cancer, as opposed to chemotherapy agents aimed at treating cancer. These plant-derived substances are not only inexpensive, they are also easily available and may have no or limited toxicity.

Since 1987, the "National Cancer Institute has tested more than a thousand different potential agents for chemopreventive activity, of which only a few dozen were moved to clinical trials. Curcumin, present in the Indian spice, turmeric, which is used in curry powder, is one such agent that is currently under clinical investigation for cancer chemoprevention."

According to their mode of action, chemopreventive agents are classified into different subgroups: antiproliferatives, antioxidants, or carcinogen-blockers. Curcumin belongs to all three, given its multiple mechanisms of action. Curcumin appears to play a role helping to block every stage of cancer transformation, proliferation, and invasion, and may even help before carcinogens even get to our cells.

A study back in 1987, highlighted in my video, Carcinogen Blocking Effects of Turmeric, investigated the effects of curcumin on the mutagenicity (DNA mutating ability) of several toxins and found that curcumin was an effective antimutagen against several environmental and standard mutagenic and cancer-causing substances. However, this was in vitro (from the Latin meaning "in glass," as in a test tube or petri dish). What about in people? We can't just take a group of people and expose them to some nasty carcinogen so we can give half of them turmeric and see what happens. We could wait until some toxic waste spill happens or nuclear accident, but 0therwise, how could researchers find people who would voluntarily expose themselves to carcinogens--unless, they smoke! That's why researchers test antimutagenic agents on smokers, who have carcinogens coursing through their veins every day.

If smokers pee on some bacteria, the number of DNA mutations shoot up dramatically. Remember, all life is encoded by DNA, whether bacteria, banana, or bunny rabbit. (When measuring urinary mutagens, it's easier to just pee on some bacteria.)

The urine of nonsmokers caused far fewer DNA mutations. It makes sense: nonsmokers have fewer chemicals running through their system. If we have nonsmokers eat some turmeric for a month, nothing really happens. But what if we do the same for smokers, in just fifteen days the mutagenic potential of their urine noticeably decreases, and it drops even more by day 30. The turmeric the researchers used was not some concentrated curcumin supplement, but just plain turmeric you might buy at the store. They also used less than a teaspoon of turmeric a day, indicating that dietary turmeric is an effective anti-mutagen.

However, in the same study the researchers found an even more effective anti-mutagen: not smoking. Even after eating turmeric for a month, the DNA-damaging power of smoker pee exceeded that of nonsmokers.

To find out more, check out Back to Our Roots: Curry and Cancer and Turmeric Curcumin Reprogramming Cancer Cell Death.

Other foods that may protect DNA include kiwifruit (Kiwifruit and DNA Repair), cruciferous vegetables (DNA Protection from Broccoli), leafy vegetables (Eating Green to Prevent Cancer), garlic (Cancer, Interrupted: Garlic & Flavonoids), green tea (Cancer, Interrupted: Green Tea (but which is better? Antimutagenic Activity of Green Versus White Tea), and plants in general (Repairing DNA Damage).

Smokers are common research subjects for carcinogen studies. But other groups of people following similar lifestyles are used. For example, see what happens to carcinogen levels when those eating processed meat start eating vegetarian in my video Heterocyclic Amines in Eggs, Cheese, and Creatine?

More information on cancer prevention, treatment, and reversal can be found in my latest annual presentations Uprooting the Leading Causes of Death, More Than an Apple a Day: Combating Common Diseases, and From Table to Able.

-Michael Greger, M.D.

Image Credit: Ed Schipul / Flickr

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Organic Milk and Prostate Cancer

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Researchers have expressed concern that since cow's milk contains estrogens, dairy could stimulate the growth of hormone-sensitive tumors. The thought is that the consumption of dairy products could both "promote the conversion of precancerous lesions or mutated cells to invasive cancer and enhance the progression of hormone-dependent tumors."

This was initially postulated based on suggestive population-scale data like a 25 fold increase in prostate cancer in Japan since World War II. What was happening to their diets during that period? A 5, 10, and 20 fold increase in eggs, meat, and dairy consumption, respectively, whereas the rest of their diet remained pretty stable.

But diet wasn't the only major change in Japanese lifestyles over the latter half century. Similarly, even though countries with higher milk consumption tend to have more prostate cancer deaths and countries with lower milk consumption fewer deaths, there could be hundreds of confounding variables. But it certainly does spur interest in studying the possibility.

A recent study from Clemson University represents the other extreme, controlling for as many factors as possible by isolating prostate cancer cells out of the body in a petri dish and dripping cow milk on them directly. The researchers chose organic cow's milk, because they wanted to exclude the effect of added hormones so that they could test the effect of all the growth hormones and sex steroids found naturally in milk.

They found that cow's milk stimulated the growth of human prostate cancer cells in each of 14 separate experiments, producing an average increase in cancer growth rate of over 30%. In contrast, almond milk suppressed the growth of these cancer cells by over 30%.

But just because something happens in a petri dish or a test tube doesn't mean the same thing happens in a person. It's just suggestive evidence that we can use in a grant application to get money to study actual people. This can be done with a retrospective (looking backward) study where we take prostate cancer patients and figure out what they ate in the past, or a prospective (looking forward) study where we look at people's diets first and follow them for a few years and see who gets cancer. The looking back kind are typically referred to as case-control studies, because researchers look at cases of cancer and compare their diets to controls. The looking forward kind are often called cohort studies because a cohort of people is followed forward. Then, if we want to get fancy, we can do a so-called meta-analysis, where you combine all the best studies done to date and see what the balance of available evidence shows.

The latest meta-analysis of all the best case control studies ever done on the matter concludes that milk consumption is a risk factor for prostate cancer. And the latest meta-analysis of all the best cohort studies ever done also concludes that milk consumption is a risk factor for prostate cancer. An even newer study profiled in my video, Prostate Cancer and Organic Milk vs. Almond Milk, suggests that milk intake during adolescence may be particularly risky in terms of potentially setting one up for cancer later in life.

Despite hormone-related cancers being among our top killers, as pointed out in the Journal of the National Cancer Institute, "we simply do not know which hormones, and how much, are in the food that we ingest. More effort has been directed at the investigation of illicit use of designer steroids by Olympians and ballplayers than to the investigation of the effect of dietary hormones on cancer and other diseases that affect millions." A proposal is therefore made to monitor levels of steroid and other hormones and growth factors in all dairy and meat-containing foods, though to date this has not been done.

I touched previously on the prostate cancer data in one of my oldest videos, Slowing the Growth of Cancer. Other factors may play into the link between cancer and dairy consumption including industrial pollutants (Industrial Carcinogens in Animal Fat) and IGF-1 (How Plant-Based to Lower IGF-1?), but for more on the hormones in dairy see:

What about all the studies suggesting milk "does a body good"? See my video Food Industry "Funding Effect".

-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 Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Tilemahos Efthimiadis / Flickr

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Can Eating Soy Prevent Breast Cancer?

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In my video, Increased Lifespan From Beans, I discuss how beans may be the single most important dietary predictor of a long lifespan. But why do people who eat legumes such as beans, chickpeas, split peas, and lentils live longer? It may be because men and women who eat legumes have been shown to be lighter, have a slimmer waist, lower blood pressure, lower blood sugars, lower cholesterol, lower triglycerides, and better kidney function. Interestingly, bean intake is a better protector against mortality in women than in men. This may be because cancer--especially breast cancer--was the leading killer of women in the population studied.

Breast cancer survivors who eat soy foods, for example, have a significantly lower likelihood of cancer recurrence. A 2012 review looked at the three studies done to date on the link between soy and breast cancer survival. It showed that women who ate the most soy had a 29% lower risk of dying from breast cancer and a 36% lower risk of cancer recurrence. A fourth study has since been published that reaffirms these results. With an average intake of soy phytonutrients above 17 mg/day--the amount found in about a cup of soymilk--the mortality of breast cancer may be reduced by as much as 38%.

In my video, BRCA Breast Cancer Genes and Soy, you can see a five-year survival curve for Chinese women with breast cancer. After two years, all of the breast cancer survivors that ate lots of soy were still alive, while only about two-thirds of the women who ate the least amount of soy were alive. After five years, 90% of the tofu lovers were still alive and kicking, whereas half of the tofu haters had kicked the bucket. There is a similar relationship between breast cancer survival and soy protein intake, as opposed to just soy phytonutrient intake.

How does soy so dramatically decrease cancer risk and improve survival? Soy may actually help turn back on women's BRCA genes. BRCA is a so-called "caretaker gene," an oncosuppressor (cancer-suppressing) gene responsible for DNA repair. Mutations in this gene can cause a rare form of hereditary breast cancer, popularized by Angelina Jolie's public decision to undergo a preventive double mastectomy. But only about 5% of breast cancers run in families; 95% of breast cancer victims have fully functional BRCA genes. So if their DNA repair mechanisms are intact, how did breast cancer form, grow, and spread? It does so by suppressing the expression of the gene through a process called methylation. The gene's fine, but cancer found a way to turn it down or even off, potentially facilitating the metastatic spread of the tumor.

And that's where soy may come in.

The reason soy intake is associated with increased survival and decreased cancer recurrence may be because the phytonutrients in soy turn back on the BRCA protection, removing the methyl straightjacket the tumor tried to place on it. To find out if this is indeed the case, a group of researchers put it to the test.

In the video mentioned earlier, BRCA Breast Cancer Genes and Soy, you can see normal cells side-by-side with three different types of human breast cancer cells, specially stained so that the expression of BRCA genes shows up brown. Column 1 (far left) shows what fully functioning DNA repair looks like--what normal breast cells should look like--lots of brown, lots of BRCA expression. Column 2 shows raging breast cancer cells. If you add soy phytonutrients to the cancer (columns 3 and 4), the BRCA genes get turned back on and DNA repair appears to start ramping back up. Although this was at a pretty hefty dose (equivalent to about a cup of soybeans), the results suggest that treatment with soy phytonutrients might reverse DNA hypermethylation and restore the expression of the tumor suppressor genes BRCA1 and BRCA2. Soy appears to also help with other breast cancer genes as well, and women at increased genetic risk of breast cancer may especially benefit from high soy intake.

No matter what genes we inherit, changes in diet can affect DNA expression at a genetic level. No matter what bad genetic cards we've been dealt, we can reshuffle the deck with diet. For examples, see:

I've previously covered the available science in Breast Cancer Survival and Soy. Other effects detailed in:

It may be possible to overdo it, though. See my video How Much Soy Is Too Much?

-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 Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Craig Dugas / Flickr

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Why the Egg-Cancer Link?

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Two million men in the U.S. are living with prostate cancer -- but that's better than dying from prostate cancer. Catch it when it's localized and the five-year survival is practically guaranteed, but once it really starts spreading, chances drop to one in three. "Thus, identification of modifiable factors that affect the progression of prostate cancer is something that deserves study," noted Dr. Erin Richard and colleagues at Harvard. So, they took more than a thousand men with early stage prostate cancer and followed them for a couple years to see if there was anything in their diet associated with a resurgence of the cancer, such as spreading to the bone.

Compared to men who hardly ate any eggs, men who ate even less than a single egg a day had a significant 2-fold increased risk of prostate cancer progression. The only thing worse was poultry consumption, with up to four times the risk of progression among high-risk men. They think it might be the cooked meat carcinogens that for some reason build up more in chicken and turkey muscle than in other meats. For more on these so-called heterocyclic amines, see my videos: Heterocyclic Amines in Eggs, Cheese, and Creatine?, Estrogenic Cooked Meat Carcinogens, and PhIP: The Three Strikes Breast Carcinogen.

But what about the eggs? Why would less than once-a-day egg consumption double the risk of cancer progression? "A plausible mechanism that may explain the association between eggs and prostate cancer progression is high dietary choline," the researchers suggested. Egg consumption is a determinant of how much choline you have in your blood, and higher blood choline has been associated with a greater risk of getting prostate cancer in the first place. So the choline in eggs may both increase one's risk of getting it and having it spread.

Studies have associated choline consumption not just with getting cancer and spreading cancer, but also with significantly increased risk of dying from it. Those who ate the most had a 70% increased risk of lethal prostate cancer. Another recent study found that men who consumed two and a half or more eggs per week -- that's just like one egg every three days -- had an 81 percent increased risk of lethal prostate cancer.

Maybe that's why meat, milk, and eggs have all been associated with advanced prostate cancer--because of the choline. Choline is so concentrated in cancer cells that doctors can follow choline uptake to track the spread of cancer throughout the body. But why may dietary choline increase the risk of lethal prostate cancer? Dietary choline is converted in the gut to trimethylamine (see my video Carnitine, Choline, Cancer and Cholesterol: The TMAO Connection), so the Harvard researchers speculated that the TMAO from the high dietary choline intake may increase inflammation, which may promote progression of prostate cancer to a lethal disease.

In one of my videos, Eggs and Choline: Something Fishy, I talked about what trimethylamine might do to one's body odor.

In the New England Journal of Medicine, the same Cleveland Clinic research team that did the famous study on carnitine repeated the study, but instead of feeding people a steak, they fed people some hard-boiled eggs. Just as they suspected, a similar spike in that toxic TMAO. So it's not just red meat. And the link between TMAO levels in the blood and strokes, heart attacks, and death was seen even in low-risk groups like those with low-risk cholesterol levels. Thus, because of the choline, eating eggs may increase our risk regardless of what our cholesterol is.

It's ironic that the choline content of eggs is something the egg industry actually boasts about. And the industry is aware of the cancer data. Through the Freedom of Information Act, I was able to get my hands on an email (which you can view in my video, Eggs, Choline, and Cancer) from the executive director of the industry's Egg Nutrition Center to an American Egg Board executive talking about how choline may be a culprit in promoting cancer progression. "Certainly worth keeping in mind," he said, "as we continue to promote choline as another good reason to consume eggs."

With regard to the prevention of prostate cancer progression, chicken and eggs may be the worst foods to eat, but what might be the best? See my video Prostate Cancer Survival: The A/V Ratio.

To prevent prostate cancer in the first place, see videos such as:

What about reversing cancer progression? See Dr. Ornish's work Cancer Reversal Through Diet?, followed up by the Pritikin Foundation: Ex Vivo Cancer Proliferation Bioassay. Flax may help as well (Flaxseed vs. Prostate Cancer).

-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 Uprooting the Leading Causes of Death, More Than an Apple a Day, and From Table to Able.

Image Credit: Christopher Craig / Flickr

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Cancer and the Animal-to-Plant Protein Ratio

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It is now eight years since the famous Ornish study was published, suggesting that 12 months on a strictly plant-based diet could reverse the progression of prostate cancer. For those unfamiliar with that landmark Ornish study, see Cancer Reversal Through Diet?, which the Pritikin Foundation followed up on with Ex Vivo Cancer Proliferation Bioassay.

Wait a second. How were they able to get a group of older men to go vegan for a year? They home delivered prepared meals to their doors, I guess figuring men are so lazy they'll just eat whatever is put in front of them.

But what about out in the real world? Realizing that we can't even get most men with cancer to eat a measly five servings of fruits and veggies, in a study profiled in my video, Prostate Cancer Survival: The A/V Ratio, researchers settled on just trying to change their A to V ratio--the ratio of animal to vegetable proteins--and indeed were successful in cutting this ratio by at least half, from about two to one animal to plant, to kind of half vegan, one to one.

How'd the men do? Their cancer appeared to slow down. The average PSA doubling time (an estimate of how fast the tumor may be doubling in size) in the "half vegan" group slowed from 21 months to 58 months. So the cancer kept growing, but with a part-time plant-based diet they were able to slow down the tumor's expansion. What Ornish got, though, was an apparent reversal in cancer growth--the PSA didn't just rise slower, it trended down, which could be an indication of tumor shrinkage. So the ideal A to V ratio may be closer to zero.

If there's just no way grandpa's going vegan, and we just have half-measures, which might be the worst A and the best V? Eggs and poultry may be the worst, respectively doubling and potentially quadrupling the risk of cancer progression in a study out of Harvard. Twice the risk eating less than a single egg a day and up to quadruple the risk eating less than a single daily serving of chicken or turkey.

And if we could only add one thing to our diet, what would it be? Cruciferous vegetables. Less than a single serving a day of either broccoli, Brussels sprouts, cabbage, cauliflower, or kale may cut the risk of cancer progression (defined as the cancer coming back, spreading to the bone, or death) by more than half.

The animal to plant ratio might be useful for cancer prevention as well. For example, in the largest study ever performed on diet and bladder cancer, just a 3% increase in the consumption of animal protein was associated with a 15% higher risk of bladder cancer, whereas a 2% increase in plant protein intake was associated with a 23% lower risk. Even little changes in our diets can have significant effects.

What else might help men with prostate cancer? See Flaxseed vs. Prostate Cancer and Saturated Fat & Cancer Progression. What about preventing it in the first place? See:

Poultry and eggs may be related to cancer risk in a variety of ways:

Crucifers may also help with other cancers. See:

Breast cancer is highlighted in my video Breast Cancer Survival Vegetable.

-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 Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image Credit: Greg Habermann / Flickr

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A Low Methionine Diet May Help Starve Cancer Cells

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When designing an antibiotic, we can't create a drug that destroys DNA because that's something that both humans and bacteria share in common. It would kill bacteria, but it might kill us, too. Instead, many antibiotics work by attacking bacterial cell walls, which is something bacteria have that we don't.

Similarly, antifungals can attack the unique cell walls of fungus. Pesticides can work by attacking the special exoskeleton of insects. But fighting cancer is harder because cancer cells are our own cells. So fighting cancer comes down to trying to find and exploit differences between cancer cells and normal cells.

Forty years ago, a landmark paper was published showing for the first time that many human cancers have what's called "absolute methionine dependency," meaning that if we try to grow cells in a Petri dish without giving them the amino acid methionine, normal cells thrive, but without methionine, cancer cells die. Normal breast cells grow no matter what, with or without methionine, but cancer cells need that added methionine to grow.

What does cancer do with the methionine? Tumors use it to generate gaseous sulfur-containing compounds that, interestingly, can be detected by specially trained diagnostic dogs. There are mole-sniffing dogs that can pick out skin cancer. There are breath-sniffing dogs that can pick out people with lung cancer. Pee-sniffing dogs that can diagnose bladder cancer and--you guessed it--fart-sniffing dogs for colorectal cancer. Doctors can now bring their lab to the lab!

It gives a whole new meaning to the term pet scan :)

Methionine dependency is not just present in cancer cell lines in a Petri dish. Fresh tumors taken from patients show that many cancers appear to have a biochemical defect that makes them dependent on methionine, including some tumors of the colon, breast, ovary, prostate, and skin. Pharmaceutical companies are fighting to be the first to come out with a drug that decreases methionine levels. But since methionine is sourced mainly from food, a better strategy may be to lower methionine levels by lowering methionine intake, eliminating high methionine foods to control cancer growth as well as improve our lifespan (see Methionine Restriction as a Life-Extension Strategy).

Here's the thinking: smoking cessation, consumption of diets rich in plants, and other lifestyle measures can prevent the majority of cancers. Unfortunately, people don't do them, and as a result hundreds of thousands of Americans develop metastatic cancer each year. Chemotherapy cures only a few types of metastatic cancer. Unfortunately, the vast majority of common metastatic cancers, such as breast, prostate, colon, and lung, are lethal. We therefore desperately need novel treatment strategies for metastatic cancer, and dietary methionine restriction may be one such strategy.

So, where is methionine found? In my video, Starving Cancer with Methionine Restriction, you can see a graph of foods with their respective methionine levels. Chicken and fish have the highest levels. Milk, red meat, and eggs have less, but if we really want to stick with lower methionine foods, fruits, nuts, veggies, grains, and beans are the best. In other words, "In humans, methionine restriction may be achieved using a predominately vegan diet."

There are also compounds in animal products that may actually stimulate tumor growth. See, for example, How Tumors Use Meat to Grow: Xeno-Autoantibodies. Animal protein may also boost levels of the cancer-promoting hormone IGF-1 (The Answer to the Pritikin Puzzle). Combined, this could all help explain why plants and plant-based diets have been found effective in potentially reversing some cancer processes. See Cancer Reversal Through Diet?, Strawberries versus Esophageal Cancer, and Black Raspberries versus Oral Cancer.

So why isn't every oncologist prescribing a low-methionine diet? One researcher notes that "Despite many promising preclinical and clinical studies in recent years, dietary methionine restriction and other dietary approaches to cancer treatment have not yet gained wide clinical application. Most clinicians and investigators are probably unfamiliar with nutritional approaches to cancer." That's an understatement! "Many others may consider amino acid restriction as an 'old idea,' since it has been examined for several decades. However, many good ideas remain latent for decades if not centuries before they prove valuable in the clinic....With the proper development, dietary methionine restriction, either alone or in combination with other treatments, may prove to have a major impact on patients with cancer."

Why might the medical profession be so resistant to therapies proven to be effective? The Tomato Effect may be partially to blame.

In my video, Anti-Angiogenesis: Cutting Off Tumor Supply Lines, researchers come to the same plant-based conclusion from a different perspective, starving cancers of their blood supply.

-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 Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image Credit: PNNL - Pacific Northwest National Laboratory / Flickr

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Starving Tumors of Their Blood Supply









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About a third of common cancers may be prevented by eating a healthy, plant-based diet; being physically active; and maintaining a healthy weight. One of the ways plants may help is by cutting off the supply lines to cancerous tumors.

A tumor cannot grow without a blood supply. Currently, it is believed that a tumor mass cannot exist in a volume greater than about the size of the ball at the tip of a ballpoint pen without a proper blood supply. This indicates that angiogenesis, the creation of new blood vessels, is critical to tumor growth.

Each one of us has cancer cells in us right now. One study describes how "by age 70, microscopic cancers are detected in the thyroid glands of virtually everyone. Most of these tumors never cause problems or become clinically significant, leading to the concept of 'cancer without disease' as a normal state during aging." Cancer cells are commonly present in the body, but they can’t grow into tumors any bigger than that tiny dot size–no more than 10 million cancer cells–before needing to get hooked up to a blood supply. One way cancer turns on the tap is silencing certain tumor suppressor genes. How do we turn them back on? See, for example, Apple Skin: Peeling Back Cancer.

Another way tumors commandeer a blood supply is by diabolically releasing angiogenic factors, chemicals that cause new blood vessels to sprout into the tumor. The most important one is called vascular endothelial growth factor (VEGF). But we may be able to suppress VEGF with veggies.

Many of the phytonutrients we know and love in tea, spices, fruit, berries, broccoli, and beans can block cancer’s stimulation of new blood vessels. They’re ideal for prophylactic long-term use against breast cancer because of their reliability, availability, safety, and affordable price. A recent review concluded that we now have "convincing evidence that dietary plant constituents possess the unique ability to affect tumor angiogenesis, which may be deemed advantageous in the prevention and treatment of human breast cancer and other tumors."

Most of these studies have only been done in a petri dish, though. Researchers stimulate human blood vessel cells and they start forming tubular structures trying to make new capillaries to feed the tumor. This tube formation can be substantially blocked by adding add plant compounds such as apigen or luteolin, found throughout the plant kingdom in foods such as citrus, celery, and peppers. In a study outlined in my video, Anti-Angiogensis: Cutting Off Tumor Supply Lines, you can see the effect of fisitin, a phytonutrient found in strawberries, shrinking the beginnings of new blood vessel formation. How else can strawberries smack on the cancer kibosh? See Strawberries versus Esophageal Cancer and Cancer Fighting Berries.

Where do researchers get their hands on human blood vessels? They get them from discarded umbilical cords or, more controversially, from the eyes of aborted fetuses. Either way, we can stimulate blood vessel formation with the tumor compound VEGF and then abolish that effect with plant compounds. Therefore, "the daily consumption of natural foods containing adequate flavonoids could be beneficial for the prevention of cancer metastasis or could improve cancer prognosis." Given the power of plants, one might speculate that the foundation of an anti-angiogenic approach to cancer might be a whole food vegan diet.

Because we all likely have cancer cells inside us, Cancer Prevention and Treatment May Be the Same Thing. To die with cancer rather than from cancer, we need to slow down cancer doubling time. Check out one of my oldie-but-goodie video Slowing the Growth of Cancer.

The cancer-promoting growth hormone IGF-1 is another angiogenic factor, helping tumors turn on the gravy train. This may be another reason plant-based diets protect against cancer, since as few as two weeks on a healthy diet can lower IGF-1 levels. If you’re interested, check out my video series on the elegant experiments that discovered this:

-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 Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image credit: David Eriksson-Wigg / Flickr

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Strawberries Can Reverse Precancerous Progression









Strawberries Can Reverse Precancerous Progression

In my last two posts, Which Fruit is Best at Fighting Cancer? and Anti-Cancer Nutrient Synergy in Cranberries I described what various common fruits could do to human cancer cells in a petri dish.  Studies showing which foods can best suppress the growth of cancer in a test tube are all well and good, but we need to know if they can do the same thing within the human body. It’s considered unethical to withhold conventional cancer therapies to test out some fruit or vegetable, so what do you do?

One direction researchers have taken is to use so-called “combinatorial strategies,” for example adding phytonutrients from the spice turmeric and green tea along with chemotherapy to see if that works better than chemo alone, but this gets complicated because chemo and radiation often work by killing cancer cells with free radicals and so though antioxidants may certainly reduce the toxicity of the treatment there’s a theoretical concern it could reduce the efficacy as well.

Another way you can study the effects of plants on cancer is by testing dietary interventions on slow growing cancers like prostate, which is how Ornish and colleagues were able to show his apparent reversal in cancer growth with a plant-based diet (see Cancer Reversal Through Diet?). They could get away with treating cancer with a vegan diet alone (no chemo/surgery/radiation) because prostate can be such a slow growing cancer that patients with early disease can be placed in a holding pattern. So if you’re not going to do anything but watch and wait, you might as well test out a dietary intervention. Are there other cancers like that we can try plants on?

Esophageal cancer is not the cancer to get. Five-year survival is only about 13 percent, with most people dying within the first year of diagnosis, but the development of esophageal cancer is a multistage process. We start out with a normal esophagus (the tube that connects you mouth to your stomach), then precancerous changes start to take place, then localized cancer starts to grow, then eventually it spreads and we most likely die.

Because of the well-defined, stepwise progression of esophageal, researchers jumped on it as a way to test the ability of berries—the healthiest fruits—to reverse the progression of cancer. A randomized phase 2 clinical trial of strawberries for patients with precancerous lesions of the esophagus was undertaken. Six months of eating the equivalent of over a pound of fresh strawberries a day, and the progression of disease was reversed in 80 percent of the high dose strawberry treatment.

At the beginning of the study, no subjects had a normal esophagus. They either had mild or moderate precancerous disease. But by the end of the study most lesions either regressed from moderate to mild, or disappeared completely. If you watch my 5-min video Strawberries versus Esophageal Cancer you can see some representative before and after pictures of the lesions literally disappearing. By the end of the study half of those on the high dose of strawberries walked away disease free.

This landmark study is one of the most important papers I’ve seen recently. Why isn’t this headline news? If there was instead some new drug that reversed cancer progression, you can bet it would be all over the place. But who’s going to profit from revelations about berries? Other than, of course, the millions of people at risk for this devastating cancer.

The findings were heralded as groundbreaking in an editorial in the journal of the American Association for Cancer Research. Given that it was written by a pair of pharmacy professors, though, they of course concluded “that the active components and molecular targets responsible for the efficacy of strawberries must be identified.” Instead of just eating strawberries they suggested that Big Pharma should try to make a strawberry-derived drug.

Recent population studies suggest that other plant foods may be protective against esophageal cancer as well. Diets with lots of meat and fat appear to double the odds of cancer; and lots of fruits and vegetables may cut one’s odds of esophageal cancer in half. Studies have shown diets rich in foods from animal origin and poor in plant foods appear to increase esophageal cancer risk. And now we know at least one plant that may even reverse the course of disease if caught early enough.

I touched previously on esophageal cancer in Bacon and Botulism and Poultry and Penis Cancer.

More on strawberries in Cancer Fighting Berries and Maxing Out on Antioxidants. My favorite way to eat them? My chocolate ice cream recipe.

Ornish’s line of anti-cancer work was continued by the Pritikin Foundation in an elegant series of experiments that I describe starting with Ex Vivo Cancer Proliferation Bioassay (along with the “prequel” Engineering a Cure).

For more berried treasure, see Black Raspberries versus Oral Cancer.

-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 Uprooting the Leading Causes of Death and More Than an Apple a Day.

Image credit: Manchester-Monkey / Flickr

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