December 10, 2009
In the wake of my breast cancer diagnosis, I took a long, hard look at my diet. I stared down the contents of my refrigerator the way a crime victim glares at a line-up of possible perps. I wanted justice. I wanted revenge. I wanted to guarantee this wouldn’t happen to me again. (All the time knowing there are no guarantees.) Still, out went cheese, yogurt, and wheat (mostly). In came raw nuts, rice milk, and a staggering amount of fruits and vegetables. But one of the hardest transitions was saying goodbye to soy. I hung on with desperation, like a child hanging on to the last threads of her favorite blankie.
Eating soy meant I could still order a latte at Starbucks and—somehow—feel like I still had a toehold in the land of “foods normal people eat.” Saying yes to soy meant I could still indulge in things like eggless-egg salad and stir-fried tofu. But, after looking at the scientific research, I wasn’t convinced the natural phytoestrogens in soy wouldn’t ratchet up my body’s estrogen load. And, since I was going to the trouble of taking Tamoxifen to block the estrogen in my body, why possibly add to it?
My oncologist was no help, but, at least, he was honest. “We really don’t know if soy is helpful or harmful for breast cancer patients,” he said. Then he followed up with the mantra “in moderation it’s probably fine.” But “probably” was a far cry from the certainty I craved and when another health care professional questioned my continued intake of soy (saying something along the lines of “why play with fire?”) I decided he had a point. Maybe it was fine but what if it wasn’t? So, I said sayonara to soy foods.
But today I saw some news that made my shriveled taste buds perk up in hopes they may once again know the joys of soy. A study published in this week’s issue of the Journal of the American Medical Association found a higher intake of soy foods was associated with a lower risk of death and breast cancer recurrence among breast cancer patients in China. Researchers enrolled more than 5,000 breast cancer survivors (a nice big number) and followed them for nearly four years (not a decade or more, which would have been nice, but a solid length of time). Interviewers asked them detailed questions about their diet and closely tracked the amount of tofu, soy milk, and other soy foods the women ate. In the end, they found that soy intake was inversely associated with mortality and recurrences in the group. Meaning, the more soy the women ate (up to 11 grams a day), the lower their odds of dying or having a breast cancer relapse.
So, what about those plant estrogens? The scientists are placing their bets on the anti-estrogenic theory of soy. In other words, that plant estrogens directly compete with the body’s own estrogens for cellular parking spaces. When a plant estrogen glides into a parking space, other estrogens are forced to keep circling. Eventually, the game of musical chairs ends and the estrogen (now dizzy from driving in circles) is booted from the body. As far as we know, beyond being parking-space hogs, plant estrogens don’t continue to impersonate “real” estrogen and, therefore, they subtract rather than add to the body’s estrogen load. At least, that’s the theory this group is espousing. While this notion isn’t new to me, it’s nice to see some new scientific oomph behind it.
Of course I would be remiss in my duties as a medical writer if I ever suggested one should make a dietary change based on a single study. And, no, you won’t find me bingeing on tofu and washing it down with great gulps of soy milk. But I may just indulge in the occasional soy latte. (After all, who can afford them more than occasionally?) So, thank you to scientists who keep exploring the hinderlands of breast cancer research, and Starbucks here I come…