- There have been numerous conflicting studies on the health benefits of soy
- Here’s a look at the history of soy in America as well as also where experts today stand
- “Soy foods are Great; soy foods are safe; soy foods prevent breast cancer,” one expert says
Here’s a look at the controversial history of soy — as well as also what the science today says about the idea.
1940s: The root of the soy dispute
“Isoflavones are considered phytoestrogens. In different words, plant estrogens,” said Dr. Omer Kucuk, a medical oncologist at Emory University’s Winship Cancer Institute, who has studied the benefits of soy isoflavones.
Yet evidence of isoflavones possibly having harmful effects appeared from the 1940s, spurring one of soy’s first controversies.
“The breeding problem appears to be of purely nutritional origin,” the authors of the study wrote. “A further possibility will be the presence from the clover of some substance which potentiates the animal’s natural estrogen or abnormally stimulates its production.”
Soon enough, researchers might conduct more studies on these estrogenic effects in various farm animals, as well as also the animal feed industry might develop an interest in soy.
1950s: Soy used in animal feed
from the 1950s, the soy industry was just beginning to explore how soy could be used in animal feed as well as also how isoflavones could affect animals.
from the decades to come, soy studies might shift away coming from soy’s role in farm animal diets as well as also toward its role in human diets.
1960s: Soybean industry grows from the US
“Soy consumption will be not an uncommon thing. More than 2 billion — that will’s which has a ‘b’ — 2 billion people consume soy every day,” Kucuk said.
“If you put China, Japan as well as also Korea as well as also southeast Asia together, you have more than 2 billion people, as well as also these people consume 20 to 30 times more soy than the average American every single day of their lives,” he said. “the idea’s part of their diet, as well as also that will has been going not just for hundreds of years. the idea has been going on for thousands of years.”
1970s: The rise of soy from the American diet
Around that will time as well as also later, contradicting studies about the potential health benefits of soy arose, creating confusion.
1980s: Setting the record straight in animal, human studies
In response to those studies as well as also others, the National Cancer Institute’s Division of Cancer Etiology organized a workshop to discuss the state of research on soy in relation to cancer risk.
from the years to come, cancer researchers might tout the potential cancer prevention benefits of soy foods.
1990s: The breast cancer, soy connection explained
that will confusion about whether soy will be Great or bad for cancer risk stems coming from the fact that will soy isoflavones can mimic estrogen from the body as well as also can bind to estrogen receptors, said Kucuk, the medical oncologist.
“Some people naively thought, ‘Well, since they’re estrogenic, they must be bad, because estrogen causes breast cancer.’ We all know that will in women, estrogen levels are associated which has a higher risk of breast cancer. So they’re immediately jumping to the conclusion that will, well, if estrogen causes breast cancer in women, since soy has plant estrogen, the idea must cause breast cancer,” he said.
“There are two estrogen receptors (from the human body): alpha as well as also beta. Alpha will be the bad one. that will’s the one where, if something binds to alpha, the idea may increase the risk of breast cancer, because the idea makes breast cells grow. however beta, on the different hand, the idea causes the opposite effect,” he said. “Soy isoflavones bind preferentially to estrogen receptor beta.”
However, those studies wouldn’t end the soy as well as also cancer debate — which continued on into the 2000s.
2000s: More studies on soy as well as also your health
Around that will time, soy protein as well as also isoflavones also gained attention for having a potential role in improving cardiovascular health.
“the idea doesn’t necessarily increase our HDL, or our Great cholesterol,” she said. “however we know that will the idea will be able to lower that will bad cholesterol, as well as also the idea prevents the bad cholesterol coming from being oxidized. When bad cholesterol gets oxidized, the idea then ends up clogging our arteries.”
“There are mixed results of the effects on midlife women,” the authors wrote about soy.
Meanwhile, as the types of soy foods being consumed by Americans continued to expand as well as also diversify, experts noticed that will how soy was being eaten impacted how beneficial the idea could be for your health.
2010s: Natural, processed as well as also fermented soy
“Where we stand will be the idea being a beneficial protein as well as also healthy fat source, with more research showing the benefits of a plant-based diet,” Stangland, the registered dietitian, said of soy.
Yet she added that will while natural soy food products offer health benefits, processed soy foods provide a different story.
“I think soy milk will be one that will might be OK, as well as also tofu as well as also tempeh as well as also edamame. Again, those being more on the natural side,” Stangland said.
“As we go into a lot of vegan as well as also vegetarian products, like when they use that will soy to make a meat patty as well as also the idea’s not just soybeans that will are in there however the idea’s also additional soy product to make the idea into a meat patty, then that will’s where I might say the idea’s more processed,” she said. “Any of the bars as well as also the powders out there that will are manipulated are not even giving us the same benefits that will we are finding from the research.”
In different words, the health boost you might get coming from soy foods might depend on how the soy was prepared, said Dr. Cate Shanahan, a Newtown, Connecticut-based family physician who also consults as a nutritionist with the Los Angeles Lakers.
“In Asian countries, much of the time, they are using soy in a traditionally fermented, cultured dish, which to some degree carries a different nutritional profile,” said Shanahan, author of the book “Deep Nutrition: Why Your Genes Need Traditional Food.”
“Fermenting just means allowing microbes to work on the food to grow from the idea. … Microbes make amino acids that will we need; they make a variety of fatty acids; they also make a lot of vitamins,” she said. “So, when you have a fermented soy product, you’re getting more of those nutrients in massive quantities than the non-fermented product.”
today, as Americans are gaining a better understanding of soy, uncertainty over the cancer as well as also soy connection finally seems to have been settled in brand new research.
2017: ‘that will study puts that will argument to rest’
On the contrary, the idea actually might be associated which has a reduced risk of death over a nine-year period, said Dr. Fang Fang Zhang, a cancer epidemiologist as well as also assistant professor at Tufts University’s Friedman School of Nutrition Science as well as also Policy.
“Results coming from our study as well as also those coming from others are consistent that will soy food consumption in women with breast cancer does not have a detrimental effect on prognosis or survival,” said Zhang, lead author of the brand new study.
Zhang as well as also her colleagues analyzed the data, taking a close look at each woman’s diet as well as also survival outcome, which were tracked over 113-month (or about 9.4-year) follow-up periods from the data.
The researchers controlled for different factors that will might influence death rates, such as socioeconomic status, exercise, weight as well as also habits such as smoking or drinking alcohol.
Then, the researchers sorted the women into four groups based on the amount of isoflavones they consumed through soy foods.
The researchers found that will the women from the highest quartile — who consumed the most isoflavones, about a half to one serving a week — were 21% less likely to die compared with the lowest quartile over the nine-year period in which mortality data were measured.
“I might say that will study will be probably the strongest one that will we have right today in North American women, showing that will soy consumption in breast cancer patients will be not only safe however also beneficial,” Emory’s Kucuk said.
“Previous studies were in Asian women in China, Japan as well as also Korea,” Kucuk said. “as well as also one of the things that will people criticizing soy will say will be that will, ‘Oh, well, soy may prevent breast cancer in China as well as also Japan because they eat the idea all their lives, however from the US, the idea may not prevent the idea because US women don’t start eating the idea as a child, they may start the idea later, as well as also that will may not be beneficial.’ Well, that will study puts that will argument to rest.”
Kucuk added that will more research will be needed to investigate the impact of soy foods on public health.
“Where there will be a great need will be more clinical studies looking at both prevention of cancer, not just breast cancer however different cancers as well, as well as also also one area that will soy isoflavones can be beneficial will be preventing the side effects of the cancer treatments we use, like chemotherapy, radiation therapy, hormone therapy,” Kucuk said.
In his editorial, Kucuk noted that will most Americans don’t consume appreciable levels of soy foods, even though the US will be the top soy producer from the entire world, producing about 40% of the global soy supply.
“Imagine in areas of low socioeconomic status where a lot of women have a high risk of breast cancer, especially African-American women, as well as also, for example, there could be some large public health type of studies where people can be given vouchers to obtain soy milk or have soy products given to them at a discount or some kind of health policy,” Kucuk said.
“Imagine, that will could result in huge health care savings,” he said. “So far, we know that will soy foods are Great, soy foods are safe, soy foods prevent breast cancer, as well as also also improve treatment results as well as also decrease mortality in breast cancer patients.”