Breasts: An Owner’s Manual: Every Woman’s Guide to Reducing Cancer Risk, Making Treatment Choices and Optimising Outcomes. Kristi Funk

with flavonoids and procyanidins, cacao powder (not Dutch-processed) can be added to berry smoothies to satisfy a sweet tooth.⁴⁹ Consuming 1.5 ounces (40 grams) of more than 70 percent cacao solid dark chocolate gets an anticancer thumbs up, as it delivers antioxidants more than it does cocoa fat and sugar.⁵⁰

      THERE’S SOMETHING SPECIAL ABOUT SOY—NO, REALLY

      It’s time to set the record straight on this healing ingredient because it gets an unfair bad rap. Soy contains isoflavones, some of which act as phytoestrogens (plant-based estrogen-like compounds), and estrogen fuels most breast cancers, so I’ll bet somebody somewhere told you, “Say no to soy!” and you spit that miso soup right out of your mouth. Most physicians believe this to be unchartered territory, so they err on the side of caution and advise you to avoid all phytoestrogens. I guess they haven’t seen the evidence, so let me show you.

      First of all, we have two totally different estrogen receptors (ER) in our bodies: ER-alpha and ER-beta. When estrogen from any source stimulates these receptors, the cells respond according to their programmed function. In the breast, ER-alpha sends signals to cancer cells to multiply and divide, whereas ER-beta actually exerts an antiestrogen effect. It turns out our natural estrogens love ER-alpha (yes, the ones implicated in cancer); but soy phytoestrogens, like genistein, bind 1,600 percent more to ER-beta than alpha.⁵¹ When bound to its ER-beta throne, soy actually blocks estrogen from sitting in the alpha chair. And if soy should land in ER-alpha, it has about one-tenth to one-hundredth of the signaling capacity of real estrogen, so soy essentially occupies but inactivates ER-alpha receptors.⁵² On top of that, soy stops the conversion of other steroids into estrogen.⁵³ Okay, if that’s true, then people who consume soy should drop their circulating estrogen, right? Right. A group of premenopausal women in Texas drank three twelve-ounce cups of soy milk a day for one month. Depending on where they were in their menstrual cycles, blood levels of estrogen dropped between 30 to 80 percent in all of them, and estrogen levels stayed lower than baseline for another two to three months.⁵⁴ Wow, so soy really does slow down estrogen production.

      With less estrogen from a few daily servings of soy, should we then expect to see less breast cancer forming? Yes. One study examined the dietary intake of over 73,000 Chinese women and concluded that consuming soy during childhood, adolescence, and adult life protects against breast cancer, especially when consumed in youth.⁵⁵ Early soy intake (more than 1.5 times per week, not much) during childhood reduced adult-onset breast cancer by 58 percent in a study of Asian women in California and Hawaii, so tell your daughters to soy it up.⁵⁶ Even among Korean BRCA gene mutation carriers, largely considered to be at the mercy of their DNA breaks, a reduction in breast cancer up to 43 percent was noted in high soy consumers.⁵⁷

      Okay, so far soy blocks estrogen effects on ER-alpha; it lowers estrogen levels in the blood; it protects against making breast cancer; but . . . what if you already had an estrogen-driven cancer, and now you’re on a drug that blocks estrogen’s actions in your body, like tamoxifen? Will the isoflavones in soy interfere with these drugs? Until 2009, we weren’t sure. In the Life After Cancer Epidemiology Study, 1,954 multiethnic survivors on tamoxifen (estrogen-driven cancers) were followed over six years; those eating the most tofu and soy milk products had a 60 percent reduction in breast cancer recurrence compared to women ingesting low soy amounts.⁵⁸ Isoflavones not only deal favorably with estrogen, they exhibit antiproliferative, antioxidant, anti-angiogenesis, and anti-inflammatory properties such that soy even keeps estrogen-negative tumors at bay.⁵⁹ The largest soy study to date in breast cancer patients followed over 6,200 multiethnic women from the United States and Canada for 9.4 years.⁶⁰ For those consuming merely 0.5 to 1.0 servings of soy a week, researchers observed a 21 percent decrease in all-cause mortality compared to lower soy consumption; this increased to 51 percent for estrogen-negative cancers, and 32 percent for those estrogen-positive cancer patients not taking antiestrogen therapy. Another study with over 5,000 breast cancer patients found a 29 percent decrease in death and a 32 percent drop in recurrence for high soy consumers, independent of receptor status.⁶¹ Even just one cup of soy milk a day provides enough phytoestrogens to reduce recurrence by 25 percent.⁶² So soy consumption after breast cancer is safe and protective.

      Soy does not increase breast cancer but in fact decreases the occurrence, recurrence, and death rates in every single study exploring this matter since 2009.⁶³ What’s a safe soy to consume? Choose soy products specifically labeled USDA organic, 100 percent organic, or non-GMO. Although 94 percent of soy comes from genetically modified organisms (GMOs), non-GMO products shouldn’t be hard to find; most GMO-soy is fed to livestock and not you (unless you eat the livestock).⁶⁴ Soy is a “complete protein,” meaning it contains all of the essential amino acids necessary for biological function. Strive to consume two to three servings of soy food every day; whole food soy far outranks processed, and fermented whole soy products like tempeh, miso, tamari (a fermented soy sauce), and nattō are the best. The natural fermentation process accomplishes two things: it lessens gas and bloating with good-for-your-gut probiotics, and it converts soy’s powerful isoflavones into their most active form, making this superfood even more super. Tofu, soybeans (edamame), roasted soybeans, and soy milk are great ready-to-consume options. Avoid soy milk made from soy protein or soy isolate; you want to see whole organic soybeans written as the first ingredient on your milk label. Processed soy products lose some of the nutritional value found in whole foods but provide great substitutes for meat, sauces, cheese, eggs, yogurt, and milk.

      ESSENTIALS: VITAMINS, MINERALS, AND A LITTLE SUPPLEMENTAL INFO

      If your cells could write an editorial, “A Day in the Life of a Body,” they’d gush about how they hold in high esteem around thirty different essential vitamins and minerals that they cannot produce on their own. Cells use these raw materials to perform hundreds of life-sustaining functions. Your cells would say that consuming whole foods, and not supplements or pills like a single vitamin, exposes them to at least 25,000 phytochemicals, the complexities of which we only poorly understand. These bioactive food constituents can work individually, like what you get from a supplement, but I don’t want you to miss out on all the additive and synergistic ways this vast community of chemicals comes together to thwart disease development. For instance, sure, vitamin C is an antioxidant, but eating a whole orange unlocks other weapons, like limonene, which accumulates inside breast cells where it can protect against the onset of cancer.⁶⁵ Your chewable vitamin C didn’t know about limonene-flavored chemo! With rare exceptions—noted in the B₁₂, folate, and vitamin D sections below—balanced eating remains the safest and most efficient way to get adequate amounts of the vitamins and minerals you need. Here are the biggies:

      Vitamin A: Fenretinide (200 milligrams per day), an analogue of vitamin A, promises a 35 percent reduction in recurrent or new breast cancers in premenopausal women.⁶⁶ It’s found in carrots, sweet potatoes, kale, spinach, broccoli, and yellow squash.

      Beta-carotene: An eleven-study meta-analysis showed an 18 percent breast benefit from beta-carotene.⁶⁷ It becomes vitamin A in your body, so add apricots, cantaloupe, and sweet red peppers to our vitamin A-rich foods listed above.

      Vitamin B6: Vitamin B₆ confers a 30 percent reduction.⁶⁸ Eat avocado, pinto beans, molasses, sunflower seeds, sesame seeds, and pistachios; if you consume meat, you can find B₆ in tuna, chicken, and turkey breast.

      Vitamin B12: B₁₂ exerts a 64 percent breast advantage in premenopausal women.⁶⁹ Find it in shellfish, fish, meat, poultry, liver, dairy, eggs, fortified cereals. For vegans and adults under age sixty-five who do not consume adequate amounts of the stated B₁₂ sources, take cyanocobalamin (not methylcobalamin) 2,500 mcg weekly supplements,⁷⁰ and for those at or over sixty-five, ingest cyanocobalamin 1,000 micrograms a day.⁷¹

      Folic Acid (Folate): Folate works alongside B₆ and B₁₂ to engineer glutathione, the most powerful of all intracellular antioxidants, which detoxifies and eliminates carcinogens.⁷² You’ll find folate in foods like peas,