Can Soybean Reduce The Risk Of Prostate Cancer?

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Phytoestrogens found in soy exhibit antioxidant, antimicrobial properties that may reduce your risk of prostate cancer by ~30%. These properties have been shown to inhibit the growth of cancer cells by inducing cell death (apoptosis), inhibiting the growth of secondary tumors (metastasis), preventing tumors from developing their own blood supply (angiogenesis).

For most of us, soy sauce is the faithful condiment which gives that dish of Chinese an extra kick. But soy is much more than just a staple ingredient at your favorite Chinese joint. A good source of protein and soluble fiber, soy has many powerful phytonutrients and is low in saturated fats.1. And now, this versatile ingredient is proving to be a cancer fighter too.

Research has found that isoflavones, which are phytoestrogens found in soy, may protect against cancer. Phytoestrogens are chemically and structurally similar to human estrogen and have estrogenic properties, although in smaller measures. They have now been found to have a protective influence against prostate cancer and other hormone-dependent cancers.2 Isoflavones also have antioxidant, antimicrobial, and antifungal properties.3 In animal studies they have been shown to inhibit the growth of cancer cells by influencing genes that affect the cell cycle, inducing cell death (apoptosis), and interfering with the signaling pathways of these cells. They can also prevent tumors from developing their own blood supply (angiogenesis) and can inhibit the growth of secondary tumors (metastasis).4

Soy Isoflavones And Prostate Cancer

A number of studies have looked at the effect of soy components on prostate cancer cells. One study across 42 countries found that soy products have a significantly protective influence against prostate cancer. In fact, per kilocalorie it had at least four times as large an effect as that of any other dietary factor.5

The impact of soy is attributed to the major isoflavones in the soybean, namely glycitein, daidzein, and genistein (which may be the most bioactive).6 Genistein especially can inhibit the synthesis of prostaglandins, which encourages inflammation and plays a role in cell proliferation, apoptosis, and metastasis.7

In one study, human prostate cancer cells were treated with genistein or daidzein. They were found to down-regulate the interleukin-8 gene, which is connected to cancer progression, and the growth factors associated with angiogenesis.8

Powering On Together

Some studies have compared the effects of individual isoflavones with isoflavone combinations on prostate cancer cells. When human prostate cancer cells were treated with a soy extract (containing glycitein, genistein, and daidzein), daidzein, and genistein individually, the soy extract induced cell cycle arrest and cell death in prostate cancer cells to a greater degree than did treatment with either daidzein or genistein. It was also found that genistein and daidzein induced cell death in noncancerous benign prostatic hyperplasia (BPH) cells. However, the soy extract didn’t affect the noncancerous cells. This suggests that a combination of these bioactive compounds is better than individual compounds – therefore, making a case for whole foods than individual compounds.9

Go The Asian Way: Say Yes To Soy!

Soy products are an important part of the diet in many Asian countries. And it’s worth noting that the rate of prostate cancer is much lower in Asian countries than in the United States and European countries.10

So how much soy should you have? Americans and Europeans consume less than 1 gram of soy protein per day, while Asian diets seem to have a much higher amount. The Japanese have about 8.7 g of soy protein per day; Indonesians, about 7.4 g; Koreans, 6.2–9.6 g; and the Chinese, 3.4 g. About 2–3 servings of soy a day should be beneficial.11

There are many ways to get soy in – try pancakes made with soy flour, ice cream made from soy milk, or just plain stir-fried soybeans. Research has also shown that the consumption of soy foods like soy milk and tofu is associated with a reduction in prostate cancer risk of ~30%.12 So to protect your prostate, try some soy milk with your cereal today!

References   [ + ]

1. Hou, Mak and Zhang, Louisa. Your Heart Matters (Revised and Expanded Edition). Armour Publishing Pte Ltd. 2010.
2. Plant, Jane A. Prostate Cancer: Understand, Prevent and Overcome Prostate Cancer. Random House, 2007.
3. Plant, Jane A. Prostate Cancer: Understand, Prevent and Overcome Prostate Cancer. Random House, 2007.
4. Sarkar, Fazlul H., and Yiwei Li. “The role of isoflavones in cancer chemoprevention.” Front Biosci 9, no. 1 (2004): 2714-2724.
5. Hebert, James R., Thomas G. Hurley, Barbara C. Olendzki, Jane Teas, Yunsheng Ma, and Jeffrey S. Hampl. “Nutritional and socioeconomic factors in relation to prostate cancer mortality: a cross-national study.” Journal of the National Cancer Institute 90, no. 21 (1998): 1637-1647.
6. Prostate Cancer, Nutrition, and Dietary Supplements (PDQ®)–Health Professional Version, Soy, National Cancer Institute. 2016.
7. Swami, Srilatha, Aruna V. Krishnan, Jacqueline Moreno, Rumi S. Bhattacharyya, Christopher Gardner, James D. Brooks, Donna M. Peehl, and David Feldman. “Inhibition of prostaglandin synthesis and actions by genistein in human prostate cancer cells and by soy isoflavones in prostate cancer patients.” International journal of cancer 124, no. 9 (2009): 2050-2059.
8. Rabiau, Nadège, Myriam Kossaï, Martin Braud, Nasséra Chalabi, Samir Satih, Yves-Jean Bignon, and Dominique J. Bernard-Gallon. “Genistein and daidzein act on a panel of genes implicated in cell cycle and angiogenesis by polymerase chain reaction arrays in human prostate cancer cell lines.” Cancer epidemiology 34, no. 2 (2010): 200-206.
9. Hsu, Anna, Tammy M. Bray, William G. Helferich, Daniel R. Doerge, and Emily Ho. “Differential effects of whole soy extract and soy isoflavones on apoptosis in prostate cancer cells.” Experimental biology and medicine 235, no. 1 (2010): 90-97.
10, 12. Yan, Lin, and Edward L. Spitznagel. “Soy consumption and prostate cancer risk in men: a revisit of a meta-analysis.” The American journal of clinical nutrition 89, no. 4 (2009): 1155-1163.
11. Barrett, Julia R. “The science of soy: what do we really know?.” Environmental Health Perspectives 114, no. 6 (2006): A352.

Disclaimer: The content is purely informative and educational in nature and should not be construed as medical advice. Please use the content only in consultation with an appropriate certified medical or healthcare professional.

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