The typical American diet lacks in isoflavones, lignans, and other natural phytoestrogens. These compounds are vital for your health – a reason why several new isoflavone-rich soy products have hit the market. Soybeans, the high-protein seeds of the soy plant, contain isoflavones, which are phytochemical compounds similar to the female hormone estrogen. Soy has a high nutritional value and provides major health benefits for women and even men. For most vegetarians, soy is a major protein source in their diet.
Benefits Of Soy Isoflavones For Women
The two predominant isoflavones present in soy are genistein and daidzein. Studies confirm that soy reduces menopausal symptoms, lowers blood pressure and results in a healthier blood lipoprotein profile, without the side-effects associated with conventional hormone replacement therapy. Soy isoflavones perform four major functions:
- Estrogens and antiestrogens
- Cancer-enzyme inhibitors
- Immune enhancers
Here are the health benefits of soy isoflavones.
1. Inhibits Cancer Cell Growth
Since soy is widely consumed in Southeast Asian countries, studies performed here showed interesting results. Asian women who eat traditional high-soy diets have a relatively low risk of breast cancer, but their risk increases when they move to the United States and adopt a Western diet. Similarly, Asian men who eat high-soy diets have a low risk of invasive prostate cancer.
Isoflavones reduce cancer risk by inhibiting the activity of tyrosine kinase, an enzyme that promotes cancer cell growth.1 It also appears to reduce the risk of other reproductive-organ cancers including endometrial cancer, without causing the harmful side-effects of drugs.
Some researchers believe that the inhibition of tyrosine kinase is the primary anti-cancer mechanism of isoflavones. Other studies show that genistein is anti-angiogenic, which blocks the growth of blood vessels that tumors require to expand.2
2. Eases Menopausal Symptoms
Recent studies show that consuming soy either in the form of isoflavone-rich protein or pure isoflavone supplements, can reduce menopausal hot flashes and increase bone density in women. Most menopausal and postmenopausal health problems are a result of the lack of isoflavones in the typical American diet.
Italian researchers observed that women who consumed soy experienced a 26 percent reduction in hot flashes during the study. By the end of the study, they had a 45 percent reduction in hot flashes.3 When women have insufficient natural estrogen production post-hysterectomy or postmenopause, isoflavones can attach to open estrogen receptor sites on cells and produce a weak estrogen effect.
3. Reduces Heart Disease Risk
Soy isoflavones have shown to reduce cardiovascular disease risk by several distinct mechanisms. Researchers have found that soy consumption was strongly associated with low blood cholesterol levels.4 People who obtained about half their protein from soy had 10 percent lower cholesterol levels than those not eating soy. Soy isoflavones help maintain normal vascular function.
A study performed on monkeys showed that the monkeys that ate soy without isoflavones developed heart abnormalities. Animals receiving the soy isoflavones for 14 months had the lowest levels of low-density lipoproteins (LDL) and very-low-density lipoproteins (VLDL), suggesting that soy has a protective effect against heart disease. These animals also had the smallest lesions in their arteries.5
4. Promotes Bone Health
Estrogen promotes bone formation in women and the postmenopausal decrease in estrogen production increases the risk of osteoporosis. Research has found that women consuming soy isoflavones had a considerable increase in bone mineral content and density in their lumbar spines.6 Weak bones are a primary cause of fractures, especially in the elderly. Consumption of soy beans and other soy products increases the estrogen levels, which in turn promotes bone formation. In fact, the European drug ipriflavone that is used to treat osteoporosis is a synthetic isoflavone.
5. Contains Powerful Antioxidants
Research has demonstrated that isoflavones are also powerful antioxidants. Like other antioxidants, they reduce the long-term risk of cancer by preventing free radical damage to the DNA. The research points out that genistein is the most potent antioxidant among the isoflavones, followed by daidzein.7 Genistein functions as a superoxide dismutase (SOD) mimic and can also increase the body’s production of superoxide dismutase (SOD), a powerful antioxidant that quenches superoxide radicals.
6. Enhances The Immune System
Two recent studies conducted by a team of American and Chinese researchers found that daidzein reduces the risk of cancer by activating immune cells. The experiments conducted on lab mice found that daidzein, but not genistein, increased the activity of lymphocytes (T cells) and macrophages (a type of white blood cell).8 9 Soy food consumption can boost immunity and fight against free radicals that can cause cancer.
A Word Of Caution
Except for people with soy allergies, soy is considered to be safe when consumed in moderation. However, the safety of long-term use of high doses of soy extracts has not yet been established. The most common side-effects of soy are stomach pain and diarrhea. Before including soy into your diet, consult your physician to ascertain if soy is suitable to you.
The standard American diet is poor in phytoestrogens. Research shows that most American diets lack the natural phytoestrogens because of which they are paying the price of an increased risk of diseases. Replacing phytoestrogen intake through a good vegetarian diet that includes soy and supplements (in some cases) can result in a more natural and balanced diet.
|↑1, ↑7||Ruiz-Larrea, M. Begoña, Aarthi R. Mohan, George Paganga, Nicholas J. Miller, G. Paul Bolwell, and Catherine A. Rice-Evans. “Antioxidant activity of phytoestrogenic isoflavones.” Free radical research 26, no. 1 (1997): 63-70.|
|↑2||Fotsis, Theodore, Michael Pepper, Herman Adlercreutz, Tapio Hase, Roberto Montesano, and Lothar Schweigerer. “Genistein, a dietary ingested isoflavonoid, inhibits cell proliferation and in vitro angiogenesis.” The Journal of nutrition 125, no. 3 (1995): 790S.|
|↑3||Albertazzi, Paola, Francesco Pansini, Gloria Bonaccorsi, Laura Zanotti, Elena Forini, and Domenico De Aloysio. “The effect of dietary soy supplementation on hot flushes.” Obstetrics & Gynecology 91, no. 1 (1998): 129-135.|
|↑4||Nagata, Chisato, Naoyoshi Takatsuka, Yoko Kurisu, and Hiroyuki Shimizu. “Decreased serum total cholesterol concentration is associated with high intake of soy products in Japanese men and women.” The Journal of nutrition 128, no. 2 (1998): 209-213.|
|↑5||Anthony, Mary S., Thomas B. Clarkson, Bill C. Bullock, and Janice D. Wagner. “Soy protein versus soy phytoestrogens in the prevention of diet-induced coronary artery atherosclerosis of male cynomolgus monkeys.” Arteriosclerosis, Thrombosis, and Vascular Biology 17, no. 11 (1997): 2524-2531.|
|↑6||Erdman JW, et al. Short-term effects of soybean isoflavones on bone in postmenopausal women. Second International Symposium on the Role of Soy in Preventing and Treating Chronic Disease; 1996 Sept 15-18; Brussels, Belgium: 21.|
|↑8||Wang, Weiqun, Carl M. Higuchi, and Rongqing Zhang. “Individual and combinatory effects of soy isoflavones on the in vitro potentiation of lymphocyte activation.” (1997): 29-34.|
|↑9||Zhang, Rongqing, Yaping Li, and Weiqun Wang. “Enhancement of immune function in mice fed high doses of soy daidzein.” (1997): 24-28.|