However, since humans aren’t rodents, researchers investigated the connection between milk intake and mortality, as well as fracture risk in large populations of milk drinkers.27 In addition to significantly more bone and hip fractures, researchers found higher rates of premature death, more heart disease, and significantly more cancer for each daily glass of milk women drank. Three glasses a day was associated with nearly twice the risk of dying early.28 Men with higher milk consumption also had a higher rate of death, although they didn’t have higher fracture rates.29
Overall, the study showed a dose-dependent higher rate of mortality (in both men and women) and fracture (in women), but the opposite was found for other dairy products, such as soured milk and yogurt, which would go along with the galactose theory, because the bacteria in these foods can ferment away some of the lactose.30
The medical journal editorial accompanying the published study emphasized that, given the rise in milk consumption around the world, the “role of milk in mortality needs to be established definitively now.”31
Eggs, Choline, and Cancer
More than two million men are currently living with prostate cancer, but living with prostate cancer is better than dying from it. If the cancer is caught while still localized within the prostate, the chances of it killing you within the next five years are practically nil. However, if the cancer spreads far enough, your chances of surviving five years may be as low as one in three.32 For this reason, scientists have been desperate to identify factors involved in the spread of prostate cancer once it has emerged.
Hoping to identify possible culprits, Harvard University researchers recruited more than one thousand men with early-stage prostate cancer and followed them for several years. Compared with men who rarely ate eggs, men who ate even less than a single egg a day appeared to have twice the risk of prostate cancer progression, such as metastasizing into the bones. The only thing potentially worse for prostate cancer than eggs was poultry: Men with more aggressive cancer who regularly ate chicken and turkey had up to four times the risk of prostate cancer progression.33
The researchers suggested that the link between consuming poultry and advancing cancer may be due to cooked-meat carcinogens (such as heterocyclic amines as discussed in chapter 11). For unknown reasons, these carcinogens build up more in the muscles of chickens and turkeys than in those of other animals.34
But what cancer-promoting substance is there in eggs? How could eating less than an egg a day double the risk of cancer invasion? The answer may be choline, a compound found concentrated in eggs.35
Higher levels of choline in the blood have been associated with increased risk of developing prostate cancer in the first place.36 This may explain the link between eggs and cancer progression.37 But what about cancer mortality? In a paper entitled “Choline Intake and Risk of Lethal Prostate Cancer,” the same Harvard team found that men who consumed the most choline from food also had an increased risk of cancer death.38 Men who consume two and a half or more eggs per week—basically an egg every three days—may have an 81 percent increased risk of dying from prostate cancer.39 The choline in eggs, like the carnitine in red meat, is converted into a toxin called trimethylamine40 by bacteria that exist in the guts of those who eat meat.41 And trimethylamine, once oxidized in the liver, appears to increase the risk of heart attack, stroke, and premature death.42
Ironically, the presence of choline in eggs is something the egg industry boasts about even though most Americans get more than enough choline.43 Mind you, the industry executives are aware of the cancer connection. Through the Freedom of Information Act, I was able to get my hands on an e-mail from the executive director of the Egg Nutrition Board directed to another egg industry executive that discussed the Harvard study suggesting that choline is a culprit in promoting cancer progression. “Certainly worth keeping in mind,” he wrote, “as we continue to promote choline as another good reason to consume eggs.”44
Diet Versus Exercise
Nathan Pritikin, the man who helped launch a lifestyle medicine revolution—and saved my grandma’s life—wasn’t a nutritionist or a dietitian. He wasn’t even a doctor. He was an engineer. When he was diagnosed with heart disease in his forties, Pritikin reviewed all the available research himself and decided to try eating the type of diet followed by populations in places like rural Africa, where heart disease was rare. He figured that if he stopped eating a heart-disease-promoting diet, he could stop the advancement of the disease. What he found was even more remarkable. He didn’t just stop the disease from getting worse, he reversed his condition.45 He then went on to help thousands of others do the same.
After vanquishing our number-one killer, heart disease, Dr. Dean Ornish and Pritikin Research Foundation researchers moved on to killer number two: cancer. They developed an elegant series of experiments, placing people on different diets and then dripping their blood on human cancer cells growing in a petri dish. Whose bloodstream would be better at suppressing cancer growth?
The research showed that the blood of people randomized to a plant-based-diet group was dramatically less hospitable to cancer-cell growth than the blood of people in the control group who continued to eat their typical diet. The blood of those eating the standard American diet does fight cancer—if it didn’t, many of us would be dead!—but the blood of people eating plant-based diets was shown to fight cancer about eight times better.46
The blood of men on the standard American diet slowed down the rate of prostate cancer cell growth by 9 percent. Place men on a plant-based diet for a year, though, and the blood circulating within their bodies can suppress cancer cell growth by 70 percent—that’s nearly eight times the stopping power compared to a meat-centered menu.47 Similar studies have shown that women eating plant-based diets appear to strengthen their bodies’ defenses against breast cancer in just fourteen days (as detailed in chapter 11).48 It’s as if we’re a totally different person inside after eating and living healthfully for just a couple of weeks.
It should be noted that the strengthening of cancer defenses in all these studies involved eating a plant-based diet and exercising. For example, in the breast cancer study, the women were asked to walk thirty to sixty minutes a day. How, then, do we know it was the diet that made their blood more effective at suppressing cancer growth? To tease out the effects of diet and exercise, a UCLA research team compared three groups of men: a plant-based diet-and-exercise group, an exercise-only group, and a control group of sedentary people eating standard fare.49
The diet-and-exercise group had been following a plant-based diet for fourteen years, along with participating in moderate exercise, such as a daily walk. The exercise-only group eating the standard American diet, on the other hand, had spent about fifteen years exercising strenuously for an hour a day at the gym at least five times a week. The researchers wanted to know if people who exercise hard enough for long enough develop cancer-fighting abilities that rival that of strolling plant eaters.50
To find out, blood from each of the three groups was dripped onto human prostate cancer cells growing in a petri dish to see whose blood kicked more cancer butt. The blood of the control group wasn’t completely defenseless. Even if you’re a french fry-eating couch potato, your blood may still be able to kill off 1–2 percent of cancer cells. But the blood of those who exercised strenuously every weekday for fifteen years killed 2,000 percent more cancer cells than the control groups’. Fantastic results, but the blood of those in the plant-based diet-and-exercise group wiped out an astounding 4,000 percent more cancer cells than that of the first group. Clearly exercise alone had a dramatic effect, but at the end of the day, thousands of hours in the gym appeared to be no match for a plant-based diet.51
Prostate Cancer Reversal Through Diet?
If a healthy diet can turn your bloodstream into a cancer-fighting machine, what about using it not just to prevent cancer but also to treat it? Other leading killers, including heart disease, type 2 diabetes, and hypert
ension, can be prevented, arrested, and even reversed, so why not cancer?
To test this question, Dr. Ornish and his colleagues recruited ninety-three men with prostate cancer who had chosen not to undergo any conventional treatment. Prostate cancer can be so slow growing and the side effects of treatment so onerous that men diagnosed with it often choose to be placed in a medical holding pattern called “watchful waiting” or “expectant management.” Because the next step is often chemotherapy, radiation, and/or radical surgery that may leave men incontinent and impotent, doctors try to delay treatment as long as possible. And since these patients aren’t actively doing anything to treat the disease, they represent an ideal population in whom to investigate the power of diet and lifestyle interventions.
The prostate cancer patients were randomized into two groups: a control group that wasn’t given any diet or lifestyle advice beyond whatever their personal doctors told them to do, and a healthy-living group prescribed a strict plant-based diet centered around fruits, vegetables, whole grains, and beans, along with other healthy lifestyle changes, such as walking for thirty minutes, six days a week.52
Cancer progression was tracked using PSA levels, a marker of prostate cancer growth inside the body. After a year, the control group’s PSA levels increased by 6 percent. That’s what cancer tends to do: grow over time. But among the healthy-living group, PSA levels decreased by 4 percent, suggesting an average shrinkage of their tumors.53 No surgery, no chemotherapy, no radiation—just eating and living healthfully.
Biopsies taken before and after the diet and lifestyle intervention showed that the expression of more than five hundred genes was affected. This was one of the first demonstrations that changing what you eat and how you live can affect you at a genetic level, in terms of which genes are switched on and off.54 Within a year after the study ended, the cancers in the patients in the control group grew so much that 10 percent of them were forced to undergo a radical prostatectomy,55 a surgery that involves the removal of the entire prostate gland and surrounding tissues. This treatment can lead not only to urinary incontinence (urine leakage) and impotence but to alterations in orgasmic function in approximately 80 percent of men undergoing the procedure.56 In contrast, none in the plant-based diet and lifestyle group ended up on the operating table.
How were the researchers able to convince a group of older men to basically eat a vegan diet for a year? They evidently delivered prepared meals to their homes.57 I guess the researchers figured men are so lazy they’ll just eat whatever is put in front of them—and it worked!
Now, how about in the real world? Realizing that doctors apparently can’t get most men with cancer to eat even a measly five servings of fruits and veggies daily,58 a group of researchers at the University of Massachusetts settled on just trying to change their A:V ratio, or the ratio of animal to vegetable proteins in their diets.59 Maybe just a reduction in meat and dairy and an increase in plant foods would be enough to put cancer into remission?
To test this, the researchers randomized prostate cancer patients into two groups, one group that attended classes on eating a more plant-based diet and a conventional-care group that received no dietary instruction. The healthy-eating advice group was able to drop their A:V ratio down to about 1:1, getting half their protein from plant sources. In contrast, the control group’s ratio stayed up around 3:1 animal-to-plant protein.60
Those on the half-vegan diet did appear to slow down the growth of their cancer. Their average PSA doubling time—an estimate of how fast their tumors may have been doubling in size—slowed from twenty-one months to fifty-eight months.61 In other words, the cancer kept growing, but even a part-time plant-based diet appeared to be able to significantly slow down their tumors’ expansion. It is worth noting, though, that Dr. Ornish and colleagues were able to demonstrate that a full-time plant-based diet allowed for an apparent reversal in cancer growth: The subjects’ PSA levels didn’t just rise more slowly, but they trended downward. Thus, the ideal animal-to-plant protein ratio may be closer to zero to one.
The Worst A and the Best V
What if there’s just no way Grandpa’s going vegan, leaving you with only half measures? What would be on the short list of foods for him to avoid, or to include, in his diet?
Based on the Harvard University prostate cancer progression and mortality data detailed above, eggs and poultry may be the worst offenders: Patients may face twice the cancer progression risk from eating less than a single egg per day and up to quadruple the risk from eating less than a single serving of chicken or turkey daily.62
On the other hand, if you were to add only one thing to your diet, consider cruciferous vegetables. Less than a single serving a day of broccoli, brussels sprouts, cabbage, cauliflower, or kale may cut the risk of cancer progression by more than half.63
Watching your animal-to-plant protein ratio might be useful for cancer prevention in general. For example, the largest study ever performed on diet and bladder cancer—comprising nearly five hundred thousand people—found that an increase in animal protein consumption of just 3 percent was associated with a 15 percent increased risk of bladder cancer. On the other hand, an increase in plant protein intake of only 2 percent was associated with a 23 percent decreased cancer risk.64
Flaxseed
Prostate cancer rates vary tremendously around the world. African Americans, for example, may have an incidence of clinically apparent prostate cancer that is some 30 times greater than that of Japanese men and 120 times greater than that of Chinese men. This discrepancy has been attributed in part to the higher amounts of animal protein and fat in Western diets.65 Another factor, though, may be the soya common in many Asian diets, which contains protective phytoestrogens called isoflavones.66
As detailed in chapter 11, the other major class of phytoestrogens is lignans, found throughout the plant kingdom but especially concentrated in flaxseeds. Higher levels of lignans tend to be found in the prostate fluids of populations of men with relatively low rates of prostate cancer,67 and lignans have also been shown to slow the growth of prostate cancer cells in a petri dish.68
Researchers decided to put lignans to the test by asking men with prostate cancer scheduled for prostate-removal surgery the following month to consume three tablespoons a day of flaxseed. After surgery, their tumors were examined. Within just those few weeks, the flaxseed consumption appeared to have lowered their cancer-cell proliferation rates, while at the same time increasing their rate of cancer-cell clearance.69
Even better, flaxseeds may also be able to prevent prostate cancer from advancing to that stage in the first place. Prostatic intraepithelial neoplasia (PIN) is a precancerous prostate lesion found during a biopsy; it is analogous to ductal carcinoma in situ of the breast. Those with PIN have a high risk for cancer to appear during subsequent biopsies—25–79 percent.70 Because men are repeatedly biopsied to monitor their condition, the procedures provide a perfect opportunity to see if a dietary intervention can keep these lesions from progressing to cancer.
After the first biopsies of their prostates came back PIN positive, fifteen men were asked to eat three tablespoons of flaxseed a day for the six months until their next biopsy. After that time, they showed a significant drop in PSA levels and biopsy cell-proliferation rates, suggesting that flaxseeds may indeed thwart the progression of prostate cancer. Two of the men saw their PSA levels drop to normal and didn’t even need a second biopsy.71
Bottom line: The evidence suggests that flaxseed is a safe, low-cost source of nutrition and may reduce tumor-proliferation rates.72 Why not give it a try? Just make sure to grind the flaxseeds first if you don’t buy them preground—otherwise, the seeds may pass right through your body undigested.
Enlarged Prostate
If a healthy diet can slow down the abnormal growth of prostate cancer cells, can it also slow down the abnormal growth of normal prostate cells? Benign prostatic hyperplasia (BPH) is a condition characterized by enlargement of the prost
ate gland. In the United States, BPH affects millions of men73—as many as half of men by their fifties and 80 percent of men by their eighties.74 Because the male prostate surrounds the outlet from the bladder, it can obstruct the normal flow of urine if it grows too large. This obstruction can cause a weak or hesitant stream and inadequate emptying of the bladder, requiring frequent trips to the bathroom. The stagnant urine retained in the bladder can also become a breeding ground for infection.
Unfortunately, the problem only seems to get worse as the gland continues to grow. Billions of dollars have been spent on drugs and supplements, and millions of American men have undergone surgery for BPH.75 Surgical procedures involve a variety of Roto-Rooter techniques with innocent-sounding acronyms, such as TUMT, TUNA, and TURP. The Ts stand for transurethral—meaning going up the penis with an instrument called a resectoscope. TUMT stands for transurethral microwave thermotherapy, in which doctors basically tunnel up the penis using an antenna-like tool and burn out a shaft with microwaves.76 TUNA stands for transurethral needle ablation; here, a column is burned out with a pair of heated needles. And these are so-called minimally invasive techniques!77 The gold standard procedure is the TURP, wherein surgeons essentially use a loop of wire to core out the prostate. Side effects include “postoperative discomfort.”78 Ya think?!
There has to be a better way.
BPH is so common that most doctors may assume that it’s just an inevitable consequence of aging. But it wasn’t always so. In China in the 1920s and 1930s, for example, a medical college in Beijing reported that BPH affected not 80 percent of male patients but about eighty cases total over fifteen years. Both the historic rarity of BPH and prostate cancer in Japan and China have been attributed to the countries’ traditional plant-based diets.79
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