How Not to Die

  These carcinogens are formed in a high-temperature chemical reaction between some of the components of muscle tissue. (The lack of some of these substances in plants may explain why even fried veggie burgers don’t contain measurable HCAs.)55 The longer meat is cooked, the more HCAs form. This process may explain why eating well-done meat is associated with increased risk of cancers of the breast, colon, oesophagus, lung, pancreas, prostate, and stomach.56 The situation creates what the Harvard Health Letter called a meat preparation “paradox”57: Cooking meat thoroughly reduces the risk of contracting foodborne infections (see chapter 5), but cooking meat too thoroughly may increase the risk of foodborne carcinogens.

  Just because heterocyclic amines cause cancer in rodents doesn’t mean they cause cancer in humans. In this case, though—it turns out people may be even more susceptible. The livers of rodents have shown an uncanny ability to detoxify 99 percent of the HCAs scientists stuffed down the animals’ throats (a technique known as gavage).58 But then, in 2008, researchers discovered that the livers of humans fed cooked chicken were only able to detoxify about half of these carcinogens, suggesting that the cancer risk is far higher than was previously thought based on experiments in rats.59

  The carcinogens found in cooked meat are thought to explain why, as the Long Island Breast Cancer Study Project reported in 2007, women who eat more grilled, barbecued, or smoked meats over their lifetimes may have as much as 47 percent higher odds of breast cancer.60 And the Iowa Women’s Health Study found that women who ate their bacon, steak, and burgers “very well done” had nearly five times the odds of getting breast cancer compared with women who preferred these meats served rare or medium.61

  To see what was happening inside the breast, researchers asked women undergoing breast-reduction surgery about their meat-cooking methods. The scientists were able to link the consumption of fried meat with the amount of DNA damage found within the women’s breast tissue,62 the type of damage that can potentially cause a normal cell to mutate into a cancer cell.63

  HCAs appear able both to initiate and to promote cancer growth. PhIP, one of the most abundant HCAs in cooked meat, was found to have potent estrogen-like effects, fueling human breast-cancer cell growth almost as powerfully as pure estrogen,64 on which most human breast tumors thrive. But that result was based on research in a petri dish. How do we know that cooked-meat carcinogens find their way into human breast ducts, where most breast cancers arise? We didn’t, until researchers measured the levels of PhIP in the breast milk of nonsmoking women. (HCAs are also found in cigarette smoke.)65 In this study, PhIP was found in the breast milk of women who ate meat at the same concentration known to significantly boost breast cancer cell growth.66 No trace of PhIP was found in the breast milk of the one vegetarian participant.67

  A similar finding was reported in a study comparing the levels of PhIP in people’s hair. The chemical was detected in hair samples of all six of the meat eaters tested, but in only one of the six vegetarians.68 (HCAs can also be found in fried eggs.)69

  Your body can rapidly rid itself of these toxins once exposure ceases. In fact, urine levels of PhIP can drop to zero within twenty-four hours of refraining from eating meat.70 So if you practice Meatless Mondays, the level of PhIP passing through your body may become undetectable by Tuesday morning. But diet is not the only source of PhIP. HCA levels in vegetarians who smoke may approach those of nonsmoking meat eaters.71

  The heterocyclic amine PhIP is not just a so-called complete carcinogen, able to both initiate cancers and then promote their growth. PhIP may also then facilitate cancer spread. Cancer develops in three major stages: 1) initiation, the irreversible DNA damage that starts the process; 2) promotion, the growth and division of the initiated cell into a tumor; and 3) progression, which can involve the invasion of the tumor into surrounding tissue and metastasis (spread) to other areas of the body.

  Scientists can test how invasive, or aggressive, a certain cancer is by putting its cells into an instrument called an invasion chamber. They place cancer cells on one side of a porous membrane and then gauge their ability to penetrate and spread through the membrane. When researchers placed metastatic breast cancer cells from a fifty-four-year-old woman in an invasion chamber all by themselves, relatively few were able to breach the barrier. But within seventy-two hours of adding PhIP to the chamber, the cancer cells became more invasive, crawling through the membrane at an accelerated rate.72

  PhIP in meat may therefore represent a three-strikes-you’re-out type of carcinogen, potentially involved in every stage of breast cancer development. Staying away from the stuff isn’t easy, though, eating the standard American diet. As the researchers note: “Exposure to PhIP is difficult to avoid because of its presence in many commonly consumed cooked meats, particularly chicken, beef and fish.”73

  Cholesterol

  Remember earlier when we discussed the American Institute for Cancer Research? A study found that following its guidelines for cancer prevention appeared to reduce not just breast cancer risk but also heart disease risk.74 What’s more, not only may eating healthier to prevent cancer help to prevent heart disease but eating to prevent heart disease may also help to prevent cancer. One of the reasons? Cholesterol may play a role in the development and progression of breast cancer.75

  Cancer appears to feed on cholesterol. LDL cholesterol stimulates the growth of breast cancer cells in a petri dish—they just gobble up the so-called bad cholesterol. Tumors may suck up so much cholesterol that cancer patients’ cholesterol levels tend to plummet as their cancer grows.76 This is not a good sign, as patient survival tends to be lowest when cholesterol uptake is highest.77 The cancer is thought to be using the cholesterol to make estrogen or to shore up tumor membranes to help the cancer migrate and invade more tissue.78 In other words, breast tumors may take advantage of high circulating cholesterol levels to fuel and accelerate their own growth.79 Cancer’s hunger for cholesterol is such that pharmaceutical companies have considered using LDL cholesterol as a Trojan horse to deliver antitumor drugs to cancer cells.80

  Though data has been mixed, the largest study on cholesterol and cancer to date—including more than a million participants—found a 17 percent increased risk in women who had total cholesterol levels over 240 compared with women whose cholesterol was under 160.81 If lowering cholesterol may help lower breast cancer risk, what about taking cholesterol-lowering statin drugs?

  Statins looked promising in petri-dish studies, but population studies comparing breast cancer rates among statin users and nonusers showed inconsistent results. Some suggested statins decreased breast cancer risk, while others showed increased risk. Nearly all these studies were relatively short term, however. Most considered five years to be long-term statin use, but breast cancer can take decades to develop.82

  The first major study on the breast cancer risk of statin use for ten years or longer was published in 2013. It found that women who had been taking statins for a decade or more had twice the risk of both common types of infiltrating breast cancer: invasive ductal carcinoma and invasive lobular carcinoma.83 The cholesterol drugs doubled the risk. If confirmed, the public health implications of these findings are immense: Approximately one in four women in the United States over the age of forty-five may be taking these drugs.84

  The number-one killer of women is heart disease, not breast cancer, so women still need to bring down their cholesterol. You can likely achieve this without drugs by eating a healthy enough plant-based diet. And certain plant foods may be particularly protective.

  Preventing (and Treating) Breast Cancer by Eating Plants

  Not long ago, I received a very moving note from Bettina, a woman who had been following my work on NutritionFacts.org. Bettina had been diagnosed with stage two “triple-negative” breast cancer—the hardest type to treat. She underwent eight months of treatment, including surgery, chemotherapy, and radiation. A breast cancer diagnosis is stressful enough, but the anxiety and depression can b
e compounded by this type of rigorous cancer regimen.

  Bettina, however, used the experience to make positive changes in her life. After watching a number of my videos, she started to eat healthier. She followed many of the recommendations you’ll find in this chapter for helping to prevent a recurrence of cancer, such as eating more broccoli and flaxseeds. The good news: Bettina has been cancer-free for more than three years now.

  Given all the studies I read through, it’s easy for me to forget that the statistics refer to people’s lives. Stories like Bettina’s help me put faces to all the dry facts and figures. When real people make real changes, they can see real results.

  Sadly, even after a breast cancer diagnosis, most women may not make the dietary changes that could help them most, such as consuming less meat and more fruits and vegetables.85 Maybe they don’t realize (or their doctors never told them) that a healthier lifestyle may improve their survival chances. For example, a study of nearly 1,500 women found that remarkably simple behavior changes—such as eating just five or more servings of fruits and veggies per day along with walking for thirty minutes six days a week—were associated with a significant survival advantage. Those who followed these recommendations appeared to have nearly half the risk of dying from their cancer in the two years following diagnosis.86

  While stories like Bettina’s can help make the statistics more inspiring, it all has to come back to the science. Over time, what to eat and feed our families are life-or-death decisions. How else can we decide but based on the best available balance of evidence?

  Fibre

  Inadequate fibre consumption may also be a risk factor for breast cancer. Researchers at Yale University and elsewhere found that premenopausal women who ate more than about six grams of soluble fibre a day (the equivalent of about a single cup of black beans) had 62 percent lower odds of breast cancer compared with women who consumed less than around four grams a day. Fibre’s benefits appeared even more pronounced for estrogen-receptor-negative breast tumors, which are harder to treat: Premenopausal women on a higher fibre diet had 85 percent lower odds of that type of breast cancer.87

  How did the researchers arrive at these figures? The Yale study was what’s called a case-control study. Scientists compared the past diets of women who had breast cancer (the cases) to the past diets of similar women who did not have breast cancer (the controls) to try to tease out if there is something distinctive about the eating habits of women who developed the disease. The researchers found that certain women with breast cancer reported eating significantly less soluble fibre on average than the cancer-free women. Hence, soluble fibre may be protective.

  The women in the study weren’t getting their fibre from supplements, though; they were getting it from food. But this could mean that eating more fibre is merely evidence that the cancer-free women are eating more plant foods, the only place fibre is found naturally. Therefore, fibre itself might not be the active ingredient. Maybe there’s something else protective in plant foods. “On the other hand,” noted the researchers, “an increased consumption of fibre from foods of plant origin . . . may reflect a reduced consumption of foods of animal origin. . . . ”88 In other words, maybe it’s not what they were eating more of but what they were eating less of. The reason high fibre intake is associated with less breast cancer may be because of more beans—or less luncheon meat.

  Either way, an analysis of a dozen other breast cancer case-control studies reported similar findings, with lower breast cancer risk associated with indicators of fruit and vegetable intake, such as vitamin C intake, and higher breast cancer risk associated with higher saturated-fat intake (an indicator of meat, dairy, and processed food intake). And according to these studies, the more whole plant foods you eat, the better it is for your health: Every twenty grams of fibre intake per day was associated with a 15 percent lower risk of breast cancer. 89

  One problem with case-control studies, though, is that they rely on people’s memory of what they’ve been eating, potentially introducing what’s known as “recall bias.” For example, if people with cancer are more likely to selectively remember more of the unhealthy things they ate, this skewed recall could artificially inflate the correlation between eating certain foods and cancer. Prospective cohort studies avoid this problem by following a group (cohort) of healthy women and their diets forward (prospectively) in time to see who gets cancer and who doesn’t. A compilation of ten such prospective cohort studies on breast cancer and fibre intake came up with similar results to the dozen case-control studies mentioned above, a 14 percent lower risk of breast cancer for every twenty grams of fibre intake per day.90 The relationship between more fibre and less breast cancer may not be a straight line, though. Breast cancer risk may not significantly fall until at least twenty-five grams of fibre a day is reached.91

  Unfortunately, the average American woman appears to eat less than fifteen grams of fibre per day—only about half the minimum daily recommendation.92 Even the average vegetarian in the United States may only get about twenty grams daily.93 Healthier vegetarians, though, may average thirty-seven grams a day, and vegans forty-six grams daily.94 Meanwhile, the whole-food, plant-based diets used therapeutically to reverse chronic disease contain upward of sixty grams of fibre.95

  Peeling Back Breast Cancer

  “Does an Apple a Day Keep the Oncologist Away?” This was the title of a study published in the Annals of Oncology that set out to determine if eating an apple (or more) a day was associated with lower cancer risk. The results: Compared with people who average less than one apple a day, daily apple eaters had 24 percent lower odds of breast cancer, as well as significantly lower risks for ovarian cancer, laryngeal cancer, and colorectal cancer. The protective associations persisted even after considering these subjects’ intake of vegetables and other fruits, suggesting daily apple consumption was more than just an indicator of eating a healthier diet.96

  The cancer protection apples appear to offer is assumed to arise from their antioxidant properties. Apple antioxidants are concentrated in the peel, which makes sense: The skin is the fruit’s first line of defense against the outside world. Expose the inner flesh, and it starts to brown (oxidize) within moments. The antioxidant power of the peel may be between two times (Golden Delicious) to six times (Idared) greater than the pulp.97

  Beyond protecting against the initial free-radical hit to your DNA, apple extract has been shown to suppress the growth of both estrogen-receptor-positive and -negative breast cancer cells in a petri dish.98 When researchers at my alma mater, Cornell University, separately dripped extracts of peel and flesh from the same apples on cancer cells, the peel stopped cancer growth ten times more effectively.99

  Researchers found something in the peels of organic apples (presumably present in conventional ones as well) that appears to reactivate a tumor-suppressor gene called maspin (an acronym for mammary serine protease inhibitor). Maspin is one of the tools your body appears to use to keep breast cancer at bay. Breast cancer cells find a way to turn off this gene, but apple peels appear to be able to turn it back on. The researchers concluded that “apple peels should not be discarded from the diet.”100

  Preventing Breast Cancer by Any Greens Necessary

  Earlier, I discussed the 2007 study of Long Island women that linked breast cancer risk to the heterocyclic amines formed in meat. Older women consuming the most grilled, barbecued, or smoked meat over their lifetimes were found to have 47 percent increased odds of breast cancer. Those with high meat intake who also had low fruit and vegetable intake had 74 percent higher odds.101

  Low fruit and vegetable intake may just be a sign of unhealthy habits overall, but increasing evidence suggests that there may be something in produce that is actively protective against breast cancer. For example, cruciferous vegetables like broccoli boost the activity of detoxifying enzymes in your liver. Research has shown that if you feed people broccoli and brussels sprouts, they clear caffeine more quickly—meaning that
if you eat a lot of cruciferous vegetables, you’d have to drink more coffee to get the same buzz because your liver (the body’s purifier) has become so revved up.102 Might this process work for those cooked meat carcinogens as well?

  To find out, researchers fed a group of nonsmokers pan-fried meat. They then measured the levels of heterocyclic amines circulating in their bodies by sampling their urine. For two weeks, the study subjects added about 500 grams of broccoli and brussels sprouts to their daily diets and then ate the same meat meal. Though they consumed the same quantity of carcinogens, significantly less came out in their urine, consistent with the subjects’ broccoli-boosted liver detox ability.103

  What happened next was unexpected. The subjects stopped eating their veggies and, two weeks later, tried eating the meat meal again. Presumably, their ability to detox carcinogens would by then have reverted back down to baseline. But instead, the subjects’ liver function remained enhanced even weeks later.104 This finding suggests that not only might a heaping side of broccoli with your steak decrease carcinogen exposure but also that eating your veggies days or even weeks before the big barbecue may help shore up your defenses. Choosing the veggie burger may be the safest choice, though, as it may have no heterocyclic amines to detoxify.105