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Is Soy Bad For Breast Cancer Survivors

What Is Komen Doing

Soy and Breast Cancer: Good or Bad?

According to Komen Scholar, Carol Fabian, M.D., Professor, Department of Internal Medicine at the University of Kansas Medical Center, After more than three decades of asking questions about the role of soy in breast cancer risk and recurrence we still do not have the answers. Thus Komens role in funding research on soy and other weak estrogen-like substances in plants is very important. It is possible that the soy may help prevent breast cancer if soy ingestion is started at a young age, but the primary concern has been in postmenopausal breast cancer survivors and the potential for soy to have an estrogen like action on the cancer cells if any remain. Although research is ongoing, there is little evidence to suggest that there is danger in consuming moderate amounts of soy in food even for survivors. However, until more is known it is probably best to avoid soy supplements after a breast cancer diagnosis.

Komen has invested more than $3.3 million in research investigating the effects of soy, and its components, on various aspects of breast cancer. Studies include:

  • Determining how soy effects breast cancer risk, including studies on high soy or soy-supplemented diets.
  • Testing whether soy, or its active components can protect against genetic damage and prevent the development of breast cancer.
  • Testing whether soy can enhance the effectiveness of breast cancer treatments or prevent drug resistance.

As A Survivor Does Soy Improve Survival And Lower The Chances Of Recurrence

Current evidence suggests that a diet high in soy may improve survival and lower the risk of recurrence in women with breast cancer.7-9 The benefits dont appear limited to Asian populations either.

One analysis combined data from three large, long-running studies of survivors from both Asian and Western countries. It found that women who ate at least 10 mg of soy per day after a breast cancer diagnosis had a 25 percent lower risk of recurrence compared to those eating less than 4 mg per day.9

However, soy is not currently recommended as a way for breast cancer survivors to lower the risk of recurrence. There are still some open questions about these findings because the studies were looking at many different types of soy, and because women who regularly eat soy simply tend to be healthier than those who dont.9

Sunflower And Pumpkin Seeds

These seeds contain high amounts of plant estrogen-like compounds.

A study of nearly 3,000 breast cancer patients and 5,000 women without the disease suggested that higher consumption of these seeds, as well as soybeans, reduced the risk of breast cancer after menopause. The study was published in the journal Nutrition and Cancer in 2012.

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Soy Milk Benefits For Women

Soy milk is a good alternative to cow’s milk for many people. For women who don’t like cow’s milk or have an intolerance to dairy, soy milk is a good way to get needed protein and calcium.

Soy milk has lots of isoflavones which have been found to protect against cancer. But their estrogen-like qualities have caused some concerns, because estrogen had been linked to breast cancer., as outlined in a 1996 study in the journal Cancer Epidemiology, Biomarkers and Prevention. However, the latest research indicates that soy milk isn’t linked to higher rates of breast cancer in women.

Women with normal thyroid levels can also safely drink soy milk. Women who take thyroid medication should check with their doctor before drinking soy milk. Typically, it’s best to wait four hours after taking thyroid medicine before consuming any soy product. If you don’t, your body may have trouble absorbing your thyroid medication.

Read more:Soy Milk Advantages and Disadvantages

Try To Avoid Isoflavone Extracts

Is soy OK for breast cancer patients?

Dr. Roesch does advise women to avoid soy isoflavone extracts, especially in large doses.

And as a general rule youre better off getting your nutrition through food sources than through supplements.

When youre taking doses of isoflavones from a vitamin store that can be several hundred times higher than what you would ingest from eating tofu or drinking soy milk, that could be a potential problem, she says.

Whether youre concerned about your risk or if youre high-risk for breast cancer its always best to make sure to talk to your doctor about everything you put into your body, she emphasizes. Together you can cut through any misinformation and identify what works best to keep you healthy.

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Nutrients In Soy Milk

One cup of Silk Original Soy Milk has:

  • 110 calories
  • 4.5 grams of fat
  • 8 grams of protein

Soy milk has no cholesterol, because it doesn’t come from animal fat. If you’re looking to add probiotics or fermented food to your diet, probiotic and fermented soy milk are also available.

The calorie content in 1 cup of soy milk, about 80 to 110 calories, is lower than that of a comparable serving of dairy whole milk. One cup of whole dairy milk is 149 calories with 8 grams of fat, 8 grams of protein and 12 grams of carbohydrates.

Soy milk, on the other hand, has 7 grams of protein, 5 grams of fat and 4 grams of carbohydrates.

Read more:Can Drinking Soy Milk Every Day Have Side Effects?

Findings From Studies On Soy Foods And Breast Cancer

1. Soy Intake and Breast Cancer Risk in Chinese women

A recent study published in the European Journal of Epidemiology evaluated the relationship between soy intake and risk of breast cancer incidence. The researchers used data from a large-scale prospective cohort study called the China Kadoorie Biobank cohort study for the analysis. The study involved over 300,000 women aged between 3079 from 10 geographically and economically diverse regions in China. These women were enrolled between 2004 and 2008, and followed-up for breast cancer incidence for approximately 10 years. Additionally, the researchers obtained details of soy consumption from food frequency questionnaires in baseline, two resurveys and twelve 24-h dietary recalls.

According to the data collected, mean soy intake of these women was 9.4 mg/day. 2289 women developed breast cancers during a follow up period of 10 years. Detailed analysis of the data found no significant association between soy intake and breast cancer incidence overall.

Meanwhile, the researchers also searched and obtained 8 previous prospective cohort studies from public domain and carried out doseresponse meta-analysis. The analysis showed that for every 10 mg/day increase in soy intake, there was a 3% reduction in breast cancer risk.

Key Take-aways :

2. Soy isoflavone Intake and Menopausal Symptoms among Chinese women with early stage breast cancer

Key Take-aways :

Key Take-aways :

Key take-aways :

Key Take-aways:

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Lower Risk Of Breast Cancer

Research shows that women who consume soy are less likely to get breast cancer. One study found that women averaging one cup of soy milk or about one half cup of tofu daily have a 30% lower risk of developing breast cancer compared with women who eat little or no soy. This may be due in part to protective substances called isoflavones found in soy foods.

In a 2013 meta-analysis that analyzed data from 22 studies, researchers found that, among Asian women, those who consumed the most isoflavones had a 32% lower risk of breast cancer. A protective effect was observed for both pre- and postmenopausal cancers. A 2014 meta-analysis reached similar conclusions. Western women dont typically eat much soy, so its harder to compare between high and low levels of intake. However, eating soy foods during the preteen and teen years, when breast tissue is forming, may be especially protective.

Are Phytoestrogens Protective Or A Risk For Breast Cancer

Soy Foods: Good or bad in breast cancer?

Some studies link consumption of lignans to reduced tumor cell growth:

  • When lignan was added to the highly aggressive and invasive human breast cancer cell line MDA-MB-321, researchers observed signs associated with a decrease in cell proliferation.
  • In women with recent diagnoses of breast cancer, higher intake of flax increased cell death, therefore leading to slower growth of the tumor and lower proliferative rates.

Some studies link consumption of soy products to reduced breast cancer risk and reduced risk of recurrence:

  • Phytoestrogens, especially when consumed regularly during childhood, have been linked to a decreased risk of breast cancer. One study found that a decreased risk of breast cancer was associated with greater soy intake during childhood, adolescence and adulthood, and the protective effect of dietary soy intake during childhood was the strongest.
  • For Chinese women previously diagnosed with breast cancer, higher consumption of soy was correlated with decreased recurrence of cancer.
  • In one strain of rats, dietary exposure to soy from conception through adulthood decreased the incidence of mammary tumors in adult animals by 20 percent.
  • Exposure of another strain of rats to phytoestrogens in soy from conception through weaning led to decreases in tumor number and incidence.

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Should Cancer Patients Avoid Soy

Do soy foods increase your cancer risk? April marks National Soy Foods Month, so let’s explore that question.

According to historical documents and archaeological finds, soybeans were first cultivated sometime in the 11th century BC in the eastern half of northern China, and soy has remained an important part of Asian diets ever since. Soy was first introduced to the United States in the mid-1700s. These days, soy sometimes gets a bad rap, but it can be part of a healthy pattern of eating.

Does Soy Pose A Breast Cancer Risk

There has been a lot of news attention about it and you have probably heard a family member or friend talking about it the connection between soy and cancer. More specifically, many people were worried for a time that there is a connection between soy consumption and breast cancer. There are many foods that contain soy, such as tofu, edamame, soy sauce, tofu, soy flour, soybean oil, miso, soy milk, tamari, teriyaki sauce, tempeh and more. Soy is a plant fiber full of important vitamins and amino acids. With soy being in so many foods, many women became very concerned they were increasing their risk of cancer. The American Cancer Society explains the concern behind soy consumption to provide a more clear background for the discussion, Soy foods contain isoflavones, which are chemically similar to estrogens. Two major types, genistein and daidzein, can act like estrogen in the body, although at a very small fraction of the potency of circulating free estrogen in women. These effects can be good or bad. Let me explain. It is well established that estrogen is linked to hormonally-sensitive cancers in women, such as breast and endometrial cancer. Breast cells contain estrogen receptors, and when the key joins with the lock , a series of signals are sent which can spur on estrogen-receptor positive breast tumor growth.

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Eating Soy Foods May Offer Benefits For Women Diagnosed With Hormone

Soybeans are the most widely used, least expensive, and least caloric way to get large amounts of protein with very little fat and no cholesterol. Soy is the main source of protein for billions of people around the world.

Some doctors are concerned about the safety of soy foods for women whove been diagnosed with breast cancer. Thats because soy contains a protein, called isoflavone, which can act like a weak estrogen. Soy supplements, such as powders, pills, and capsules, contain more isoflavones than soy eaten as food, such as tofu, soy milk, and the beans themselves . Some doctors are concerned that the growth of hormone-receptor-positive breast cancers may be turned on by isoflavones.

Other doctors think soy might protect breast health because the hormone-like strength of isoflavones is much weaker than the estrogen your body naturally makes. So it might be healthier if soys weak isoflavones wash out or replace some of your bodys stronger estrogen.

A study suggests that eating soy foods may help improve survival in women diagnosed with hormone-receptor-negative breast cancer.

To determine the quantity of isoflavones the women ate, they filled out a food questionnaire.

Population Research Among 6000 Women With Breast Cancer Found A 21% Reduction In Mortality Among Those Who Consumed More Soya

Soy for Breast Cancer Survivors: What You Need to Know

Its benefits were strongest in women with hormone-receptor-negative breast cancer, a more aggressive type of breast cancer where tumours lack oestrogen and progesterone receptors, and therefore doesnt respond well to hormone therapies.

Our findings suggest that, for women with hormone-receptor-negative breast cancer, soya food consumption may potentially have a beneficial effect to improve survival, Zhang says.

Not soy easy

Even so, its difficult to conclusively isolate soyas benefits if there are any.

Soya is often consumed as part of a healthy diet and as a substitute for red meat, which is associated with a higher risk of heart disease and cancer.

Soya products often replace foods like red meat, which could be why soya intake is associated with healthier outcomes

No one has given people soya foods, then looked at whether theyre more or less likely to get breast cancer over time than those not given soya, says Leena Hilakivi-Clarke, professor of oncology at Georgetown University School of Medicine in Washington DC.

One review of evidence into soyas effect on breast cancer risk found that studies that adjusted for body mass index , a common marker of health, showed a weaker association for soya than those that didnt.

This means a reduced risk of breast cancer could have been due to lower BMI, not to soya consumption.

So where did the concern that soya causes cancer come from?

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Should Soy Be Part Of An Overall Healthy Diet

Though soys breast health benefits are still unclear, moderate amounts of soy are likely safe to eat and can be part of an overall healthy diet.

Soybeans are high in fiber, healthy oils and protein. Cutting back on animal products by moving toward a more plant-based diet that is rich in fruits, vegetables, whole grain and legumes has overall health benefits and can also help with weight control a key factor in breast cancer risk.

Soy supplements, however, are not recommended.

Dos And Donts For Estrogen

Breast cancer is not just one disease it comes in many variations.

One of the primary factors in determining the type of breast cancer is the sensitivity of the tumor cells to estrogen. If a breast tumor is hormone-sensitive or estrogen receptor-positive, it means there are specific estrogen receptors on the tumor cells, and when estrogen binds with these receptors, it transfers a message to the cancer cells. Like a lock and key effect, the breast tumor cells are stimulated by estrogen to grow and reproduce. Therefore, one of the main goals of therapy or intervention with hormone-positive cancer is to reduce hormonal stimulation as much as possible.

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One Reason There Isnt A More Definitive Answer Is Because Isoflavone Either Acts Like Oestrogen In The Body Or Its Opposite

One reason there isnt a more definitive answer is because isoflavone either acts like oestrogen in the body, or its opposite. When we eat soya, isoflavone either binds to the alpha oestrogen receptor in the body, which stimulates a tumours growth rate, or the beta receptor, which decreases growth rate and induces apoptosis.

Isoflavone prefers to bind to beta receptors, says Bruce Trock, professor of epidemiology and oncology at Johns Hopkins School of Medicine in Maryland in the US. That makes it more likely to reduce potential cancer risk.

The impact of soya on breast cancer risk may depend on when we start eating it.

Most studies on Asian populations included women who have eaten it since early childhood and were probably also exposed to it in the uterus, says Trock, compared to Western studies involving women who mostly didnt eat soya until later in life.

Starting to consume soya products at an earlier age may make soya more beneficial

Giving soya to animals at the equivalent of middle age doesnt seem to reduce risk or growth rate of tumours, he says.

But if researchers feed mice prior to puberty, then expose them to carcinogens, they get fewer and smaller tumours than if you dont give them soya.

Soya cycle

Meanwhile, clinical and population data shows daily soya intake can halve the frequency and severity of hot flashes even when the placebo affect is taken into consideration, says Mindy Kurzer, professor of nutrition at the University of Minnesota.

Soy And Cancer Risk: Our Experts Advice

Soy Isoflavones for Cancer Patients & Survivors

Theres a lot of conflicting information going around about soy: Is it healthy? Is it dangerous? And if its OK to eat, why do some people say it isnt?

Some of the misunderstandings come from the fact that studies in people and studies in animals may show different results. In some animal studies, rodents that were exposed to high doses of compounds found in soy called isoflavones showed an increased risk of breast cancer. This is thought to be because the isoflavones in soy can act like estrogen in the body, and increased estrogen has been linked to certain types of breast cancer.

But rodents process soy differently from people, and the same results have not been seen in people. Also, doses of isoflavones in the animal studies are much higher than in humans. In fact, in human studies, the estrogen effects of soy seem to either have no effect at all, or to reduce breast cancer risk . This may be because the isoflavones can actually block the more potent natural estrogens in the blood.

According to Marji McCullough, ScD, RD, strategic director of nutritional epidemiology for the American Cancer Society, soy foods are healthy and safe. But she advises against taking soy supplements which contain much higher isoflavone concentrations than food until more research is done.

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