 |
 |
 |
|
Isoflavones are a class of phytochemicals, which are compounds found only in plants. They are also a type of phytoestrogen, or plant hormone, that resembles human estrogen in chemical structure yet are weaker. By mimicking human estrogen at certain sites in the body, isoflavones provide many health benefits that help you to avoid disease. Isoflavones are found in soybeans, chick peas and other legumes. However, soybeans are unique because they have the highest concentration of these powerful compounds, especially genistein and daidzein.
Isoflavones show tremendous potential to fight disease on several fronts. They have been shown to help prevent the buildup of arterial plaque, which reduces the risk of coronary heart disease and stroke. Isoflavones may help reduce breast cancer by blocking the cancer-causing effects of human estrogen. They may also prevent prostate cancer by hindering cell growth. Isoflavones can fight osteoporosis by stimulating bone formation and inhibiting bone resorption. They may even relieve some menopausal symptoms as well.
Soy isoflavones have antioxidant properties which protect the cardiovascular system from oxidation of LDL (the bad) cholesterol. Oxidized LDL cholesterol accumulates in the arteries as patches of fatty buildup which blocks the flow of blood, resulting in atherosclerosis. Genistein inhibits the growth of cells that form this artery clogging plaque. Arteries damaged by atherosclerosis usually form blood clots. This can lead to a heart attack if the clot goes to the heart, or a stroke if it goes to the brain.
Being a weak form of estrogen, isoflavones can compete at estrogen receptor sites, blocking the stronger version naturally produced by the body from exerting its full effect. Since high blood levels of estrogen are an established risk factor for breast cancer, weaker forms of estrogen may provide protection against this disease. Genistein has been found to hinder breast cancer as well as prostate cancer. Results from a new University of California study show that genistein slowed prostate cancer growth and caused prostate cancer cells to die. It acts against cancer cells in a way similar to many common cancer-treating drugs.
All these findings suggest that eating soy foods - natural sources of isoflavones - can protect and enhance your overall health. Isoflavones work together with soy protein in fighting disease. Studies show that isoflavones account for approximately three-fourths of soy's protection, while its protein is responsible for about one-fourth. The best way to consume isoflavones is in food form, so that you can benefit from all of soy's nutrients and beneficial compounds.
The highest amounts of isoflavones and soy protein are found in tempeh, whole soybeans (such as edamame), textured soy protein, soynuts, tofu and soy milk. Researchers recommend consuming at least one to two servings per day. A serving is equal to 1 ounce of soynuts; 4 ounces of tempeh, textured soy protein (cooked), or edamame; or 8 ounces of soymilk.
|
|
 |
|
 |
Soy Isoflavones (genistein, daidzein) can help with the following: | | | | | Digestion |  Constipation | Amongst 65 children aged 11 to 72 months with chronic constipation, 68% had a positive response with regard to bowel movements while receiving soy milk. |
|
Lab Values |
 High Total Cholesterol| | Soybean isoflavone fraction, which contains primarily genistein, daidzein and glycetein, has been shown to have a hypocholesterolemic effect.
A soy protein isolate reduced total and LDL-cholesterol concentrations in a study of 60 patients with high cholesterol levels. [Eur J Clin Nutr 2002;56(4): pp. 352-35] |
|
Musculo-Skeletal |
Osteoporosis - Osteopenia| | Higher intake of dietary phytoestrogens (isoflavones) was associated with higher lumbar spine and hip bone mineral densities in a study of 357 postmenopausal southern Chinese women. [J Clin Endocrinol Metab 2001;86(11): pp.5217-5221]
A one-month of treatment with a soy isoflavone extract reduced the excretion of bone resorption markers, in a placebo-controlled study of 23 healthy perimenopausal women. [J Am Coll Nutr 2002;21(2): pp.97-102]
It should be noted, however, that this benefit has not been seen in other studies. It seems that the best chance of receiving any benefit by this means is if you are a Japanese premenopausal woman. The closer you are to menopause, the less likely to be benefitted. [Am J Epidemiol 2002;155(8): pp.746-754] |
|
Nutrients |
 Bioflavonoid Need |
Organ Health |
Poor Bone Health| | Preliminary and sometimes conflicting research suggests that soy foods have a positive effect on bone health. Two small 6-month studies showed that soy protein and isolated isoflavones (a component of soy), respectively, had beneficial effects on spinal bone density [Potter et al. 1998; Alekel et al. 2000]. |
|
Tumors, Benign |
Colon Polyps| | Men who eat one or more servings of soy per week reduce the risk of developing colon polyps by half. [ Am J Epidemiol 1996;44(11): pp.1015-25] |
|
Tumors, Malignant |
Prostate Cancer| | Soy protein is one of the dietary elements that has been talked about for a long time as having a potentially beneficial effect for preventing prostate cancer. Soybeans are full of chemicals called isoflavones which closely resemble the structure of estrogen-like hormones once widely used to treat prostate cancer.
Phytochemicals in soy protect against cancer via several different mechanisms, including interacting with intracellular enzymes, regulating protein synthesis, controlling growth factor actions, inhibiting malignant cell proliferation, inducing differentiation, deterring cancer cell adhesion, and inhibiting angiogenesis.
Soy extracts also provide doses of soy isoflavones such as genistein. Cancer cells use the enzyme protein kinase as a growth factor and genistein is a potent inhibitor of its activity. Genistein may reduce the metastasic capacity of hormone-dependent cancers. Studies have shown that genistein inhibits proliferation of prostatic cancer cells.
Laboratory studies are backed up by observations in Asian countries, particularly Japan, where men may develop small prostate tumors but rarely the kind of large, aggressive tumors seen in American men. However, the aggressive form of the cancer becomes more prevalent when Asian immigrants come to the US and are likely to substitute their soy-rich diet with one based mainly on animal protein.
Since prostate cancer cells usually multiply slowly, the development of prostate cancer can take many years before symptoms appear. During this time period, the benefits of natural therapies like soy consumption are more effective at dealing with the problem while it is still small.
Note: Do not take any soy genistein products 10 days prior to, during, or 3 weeks after any form of radiation therapy. Genistein may protect cancer cells against radiation-induced death. |
|
Uro-Genital |
Menopausal Issues| | Although study results are sometimes confusing on the issue of soy extracts and menopause, some studies have shown clear benefit. One such study concluded that a particular soy product "...may be a safe and efficacious therapy for relief of hot flushes in women who refuse or have contraindications for hormone replacement therapy." [Menopause 2000;7: pp.105-111]
The North American Menopause Society suggests that soy isoflavones can also be a natural alternative to estrogen replacement therapy for relief of mild menopausal symptoms. It may help offset the drop in estrogen and regulate its fluctuations that occur at menopause. Many women have reported a reduction in their hot flashes and night sweats when they regularly consume soy foods, such as tempeh or tofu.
Another study found that consuming one capsule tid of a soy extract totaling 100mg of soy isoflavones per day effectively alleviated vasomotor symptoms, such as hot flashes associated with menopause, over a 4-month period compared with a placebo. Total cholesterol and low-density lipoproteins were reduced also in the soy isoflavone group compared to placebo. No difference in FSH and LH levels were observed between the placebo and the soy isoflavone group. An increase in estrogen levels was observed only in the soy isoflavone group but this did not result in an increased endometrial thickness. [Obstet Gynecol 2002;99: pp.389-94]
Four months of treatment with a soy isoflavone product reduced the number of hot flashes and other menopausal symptoms in a study of 190 postmenopausal women in Spain. [Phytomedicine 2002;9(2): pp.85-92] |
Perimenopausal Issues| | A randomized double-blind placebo controlled clinical trial (the "gold standard" study design) has shown that the isoflavones in soy appear to protect menopausal women from bone loss just as powerfully as hormone replacement therapy, but without the side-effects [Nutrition Reviews 61 (2003): pp.346]. In other words, drinking the equivalent of about 2 cups of soymilk each day, women can go through menopause with strong bones, and without the cancer, heart disease, a stroke or two and blood clots in the lung. And, using soymilk instead of Premarin (now known to increase risk of these conditions), your smoothies won't taste like urine! |
|
| | | | |
KEY | | May do some good | | | Likely to help | | | Highly recommended |
GLOSSARY
Antioxidant (Antioxidants)
A chemical compound that slows or prevents oxygen from reacting with other compounds. Antioxidants are substances that protect cells from oxidative damage caused by molecules called free radicals. These chemicals can damage important parts of cells, such as proteins, membranes, and DNA. Some antioxidants have been shown to have cancer-protecting potential because they neutralize free radicals. Examples include vitamins C and E, beta carotene, the minerals selenium and germanium, superoxide dismutase (SOD), coenzyme Q10, catalase, and some amino acids.
Arterial (Arteries, Artery)
Blood that leaves the heart. When it leaves the right ventricle, it is venous blood; and when it leaves the left ventricle, through the aorta, it is fresh and oxygenated. After it has passed out to the capillaries and started to return, it is venous blood.
Atherosclerosis
Common form of arteriosclerosis associated with the formation of atheromas which are deposits of yellow plaques containing cholesterol, lipids, and lipophages within the intima and inner media of arteries. This results in a narrowing of the arteries, which reduces the blood and oxygen flow to the heart and brain as well as to other parts of the body and can lead to a heart attack, stroke, or loss of function or gangrene of other tissues.
Cancer
Refers to the various types of malignant neoplasms that contain cells growing out of control and invading adjacent tissues, which may metastasize to distant tissues.
Cardiovascular
Pertaining to the heart and blood vessels.
Cholesterol
A waxy, fat-like substance manufactured in the liver and found in all tissues, it facilitates the transport and absorption of fatty acids. In foods, only animal products contain cholesterol. An excess of cholesterol in the bloodstream can contribute to the development of atherosclerosis.
Chronic (Chronicity)
Usually referring to chronic illness: Illness extending over a long period of time.
Colon (Colonic)
The part of the large intestine that extends to the rectum. The colon takes the contents of the small intestine, moving them to the rectum by contracting.
Constipation (Constipated)
Difficult, incomplete, or infrequent evacuation of dry, hardened feces from the bowels.
Cup (Cups)
A unit of volume measurement equal to 8 fluid oz, or roughly 250ml. It also equals 1/2 pint, 1/4 quart and 1/16 gallon.
Enzymes (Enzyme)
Specific protein catalysts produced by the cells that are crucial in chemical reactions and in building up or synthesizing most compounds in the body. Each enzyme performs a specific function without itself being consumed. For example, the digestive enzyme amylase acts on carbohydrates in foods to break them down.
Estrogen (Oestrogen)
One of the female sex hormones produced by the ovaries.
Hormones (Hormone)
Chemical substances secreted by a variety of body organs that are carried by the bloodstream and usually influence cells some distance from the source of production. Hormones signal certain enzymes to perform their functions and, in this way, regulate such body functions as blood sugar levels, insulin levels, the menstrual cycle, and growth. These can be prescription, over-the-counter, synthetic or natural agents. Examples include adrenal hormones such as corticosteroids and aldosterone; glucagon, growth hormone, insulin, testosterone, estrogens, progestins, progesterone, DHEA, melatonin, and thyroid hormones such as thyroxine and calcitonin.
Lipoproteins (Lipoprotein)
Molecules composed of lipids and proteins that carry fats and cholesterol through the bloodstream.
Low-Density Lipoprotein (LDL)
Also known as "bad" cholesterol, LDLs are large, dense, protein-fat particles composed of a moderate proportion of protein and a high proportion of cholesterol. Higher levels of LDLs are associated with a greater risk of cardiovascular disease.
Lumbar (Lumbar Region)
Lumbar Region: The lower back, five segments of the spinal chord and column, between the sacrum and thoracic regions.
Lung (Lungs, Pulmonary)
Organ of the body, located in the chest cavity which is designed to bring oxygen from the air into the blood stream, while also expelling carbon dioxide and other waste gases out of the body. Pulmonary: Related to the lungs.
Malignant (Cancerous)
Dangerous. Mainly used to describe a cancerous growth -- when used this way, it means the growth is cancerous and predisposed to spreading.
Menopause (Menopausal)
The cessation of menstruation (usually not official until 12 months have passed without periods), occurring at the average age of 52. As commonly used, the word denotes the time of a woman's life, usually between the ages of 45 and 54, when periods cease and any symptoms of low estrogen levels persist, including hot flashes, insomnia, anxiety, mood swings, loss of libido and vaginal dryness. When these early menopausal symptoms subside, a woman becomes postmenopausal.
Milligram (mg, Milligrams)
0.001 or a thousandth of a gram.
Mineral (Minerals)
Plays a vital role in regulating many body functions. They act as catalysts in nerve response, muscle contraction and the metabolism of nutrients in foods. They regulate electrolyte balance and hormonal production, and they strengthen skeletal structures.
Osteoporosis
A disease in which bone tissue becomes porous and brittle. The disease primarily affects postmenopausal women.
Ounce (Ounces, oz)
Approximately 28 grams.
Perimenopause (Perimenopausal)
A transition time during which menstrual periods can become irregular and symptoms of menopause may be experienced prior to menopause. On average, the onset of perimenopause occurs around age 47 and the average duration is 4-5 years. It is increasingly seen in women even up to 12-15 years before menopause. An array of physical, mental and emotional symptoms can occur during this time.
Phytochemicals (Phytochemical)
Substances such as vitamins and minerals that occur naturally in plants and have been shown in research to possibly prevent or cure disease.
Phytoestrogen (Phytoestrogens)
A plant substance with activity similar to human estrogen, but with important differences. Like real estrogen, plant estrogens bind to estrogen receptors in cells, thereby preventing real estrogen from binding to these cells. Unlike real estrogen, however, plant estrogens do not stimulate cell growth, therefore, plant estrogens are believed to inhibit the growth of tumors that would normally be stimulated to grow by real estrogen.
Placebo (Placebos)
A pharmacologically inactive substance. Often used to compare clinical responses against the effects of pharmacologically active substances in experiments.
Polyp (Polyps)
A usually nonmalignant growth or tumor protruding from the mucous lining of an organ such as the nose, bladder or intestine, often causing obstruction.
Postmenopause (Postmenopausal)
The postmenopausal phase of a woman's life begins when 12 full months have passed since the last menstrual period and any menopausal symptoms have become milder and/or less frequent.
Premenopause (Premenopausal)
The period when women of childbearing age experience relatively normal reproductive function (including regular periods).
Prostate
The prostate gland in men that surrounds the neck of the bladder and the urethra and produces a secretion that liquefies coagulated semen.
Protein (Proteins)
Compounds composed of hydrogen, oxygen, and nitrogen present in the body and in foods that form complex combinations of amino acids. Protein is essential for life and is used for growth and repair. Foods that supply the body with protein include animal products, grains, legumes, and vegetables. Proteins from animal sources contain the essential amino acids. Proteins are changed to amino acids in the body.
Radiation Therapy (Radiotherapy)
The use of high-energy rays to kill cancer cells. Depending on the stage of the disease, treatment with radiation may be given alone or with chemotherapy. Radiation therapy is local therapy; it affects cancer cells only in the treated area. External radiation does not cause the body to become radioactive. Most often, treatment is given on an outpatient basis in a hospital or clinic.
Stroke (Stroke-Type Event)
A sudden loss of brain function caused by a blockage or rupture of a blood vessel that supplies the brain, characterized by loss of muscular control, complete or partial loss of sensation or consciousness, dizziness, slurred speech, or other symptoms that vary with the extent and severity of the damage to the brain. The most common manifestation is some degree of paralysis, but small strokes may occur without symptoms. Usually caused by arteriosclerosis, it often results in brain damage.
TID
Three times a day.
Tumor (Tumors, Tumour, Tumours)
An abnormal growth of tissue resulting from uncontrolled, progressive multiplication of cells and serving no physiological function; a neoplasm. Literally, a swelling; in the past the term has been used in reference to any swelling of the body, no matter what the cause. However, the word is now being used almost exclusively to refer to a neoplastic mass, and the more general usage is being discarded.
Last updated: Feb 14, 2009
|
 |
|
|
