HORMONE CHOICES:

Phyto is the Greek word for plant. Phytoestrogens are plants that bind with estrogen receptors in the body to produce an estrogen-like effect.

Put simply:  Many body tissues are composed of cells that have estrogen receptors. These receptors act like tiny locks, and  estrogen acts like a key to open them. Because phytoestrogens have molecules similar to estrogen, they also can act like a key. 

Phytoestrogens compete at the receptor site with other estrogens--whether your own or those taken as a part of HRT.  They may have the ability to enhance estrogen's beneficial effect and/or block estrogen's negative effects. 

Many plants have phytoestrogenic activity, but the strongest still only have 2% of the potency of estradiol.  For this reason, only the most potent phytoestrogens are listed below:

Isoflavones

There is much interest about the role of the isoflavones in soy protein for the treatment of the menopausal symptoms of hot flashes, vaginal dryness, cardiovascular disease, bone metabolism, and cancer prevention. The sale of isoflavone supplements is increasing, and even the large pharmaceutical companies are introducing their own products.

A  growing amount of evidence shows that isoflavones have a physiologic effect, but it is uncertain whether the effect can be attributed to the isoflavones alone or to the isoflavones combination with some other substance in the whole food.  Studies seem to be indicating that the best source of isoflavones may be in whole food, particularly soy.  Although there seems to be no problem with soy, many researchers are concerned about the use of high-dose isoflavone supplements because no one knows what the long-term side effects may be.

The amount of isoflavones in different soy products varies depending on the type and degree of processing: The least processed soy products have the most isoflavones.  Green soy beans (often sold in stores as edamame) have the highest content of isoflavones.  While moderately processed products like tofu and tempeh are good sources, heavily processed products like tofu dogs and tofu breakfast sausage are not.  Soy protein found in powdered supplements may have high or low isoflavone contents depending on how they are manufactured.  Look for those that are labeled soy protein isolate for the most isoflavones.  IP Supro is the brand most often used in clinical studies.  (See the Resources page for an excellent book about adding soy to your diet).

A look at the evidence for the various benefits of soy:

Menopausal Symptoms: Although isoflavones are generally thought to be effective, there has been conflicting evidence on their ability to reduce the severity of hot flashes and vaginal dryness.  If you are concerned about HRT side effects, consider adding isoflavones to your diet first. There is little harm in trying them, and you will know if it works for you.

Bone Health: This is another area of conflicting studies.  Animal and some human studies indicate a potential benefit to the spine but not to the hip.  If you are at high risk for osteoporosis, there is not enough evidence to recommend soy or isoflavones alone as preventative treatment.  If you want to" hedge your bets", add some soy to your diet.

Cancer Prevention: There is a great interest in the benefit of soy protein in reducing cancer risk.  Many studies have shown that groups of people with high soy intake had lower cancer rates, but few studies have been able to isolate the soy as the only factor.  Soy protein in addition to isoflavones contains other phytochemicals that offer cancer protection,  so it is probably more effective than isoflavone supplements. Some nutritionists feel that isoflavones supplements are absorbed better when taken with soy foods.

The major debate is about soy and breast cancer.  When it comes to prevention, it seems that the greatest benefit comes from a high soy protein diet before puberty. Pre-menopausal women will get some benefit, but postmenopausal women seem  to receive no protection.

For those women with estrogen dependent breast cancer, most experts feel that they should avoid phtyoestrogen supplements.  These experts differ on the issue of the risk of soy protein in whole foods--some say because there is no conclusive evidence showing any harm, soy foods are ok;  others believe that phytoestrogens from any source pose a risk.

Cardiovascular Risk: This is the area with the greatest evidence of the benefits of isoflavones.  It appears that the soy protein from whole foods has a greater effect than those found in supplements.

Soy has a positive effect on blood cholesterol--raising HDL ("good" cholesterol), lowering LDL ("bad" cholesterol), and lowering triglycerides. Soy reduces the formation of plaque in the arteries.

Soy improves the elasticity of the arteries.  Many researchers feel that, like

estrogen, its ability to improve the flexibility of the arteries has a more profound effect on the reduction of coronary artery disease than on its ability to lower cholesterol.  

In conclusion, it appears that most women (and men also) will benefit from adding soy to their diet.  Although there hasn't been an exact amount of soy recommended, the FDA has allowed the claim that "25 grams/day of soy protein as part of a diet low in saturated fat and cholesterol may reduce the risk of heart disease".  This 25 grams would have approximately 50 mg of isoflavones, which is also the amount usually recommended to help bone health and to reduce menopausal symptoms.

A short list of food items that can be used to provide the 25 grams:

Flaxseed

Flaxseed is not as widely studied as soy, but flaxseed contains lignans, which are another form of phytoestrogen.  Although other grain and vegetables sources contain lignans, flaxseed contains up to 600 times that of any other source.

Flaxseed has other components that help to prevent disease and is a good source of soluble fiber that has been shown to reduce cholesterol.  It also contains alpha-linoleic acid, a substance similar to the omega-3 fatty acids found in fish oil that helps the cardiovascular system.

Flaxseed may likely have many of the same benefits as soy protein.  Although flaxseed oil probably protects the heart, some of the lignans and all of the fiber is removed in processing. Therefore, the best source of flaxseed may be the seed itself.  It can be ground very easily in a coffee grinder and sprinkled on food.  Two tablespoonfuls a day should provide adequate lignans and fiber. (See the Resources section for an excellent cookbook).

Herbal supplements

A walk down the women’s health aisle in any store will surely convince you that there are a wide variety of herbal products claiming to help menopausal symptoms--evening primrose oil, black cohosh root extract, dong quai, and chaste tree berry to name a few. Only recently has scientific research demonstrated the active ingredients, mechanism of action, and effectiveness of these plant products.

In the treatment of menopausal symptoms, only one herb has clearly been shown to be effective--black cohosh root extract.  The majority of the studies have been done on a commercial product called Remifemin.  It has been proven effective in relieving hot flashes and reducing some of the mental symptoms such as mood swings and anxiety.

Black cohosh root extract attaches to estrogen receptors, so there has been some concern as to whether it is safe to use in women with breast cancer.  Preliminary studies show that it does not stimulate breast cells.  Some experts feel that if no other therapy works for a breast cancer patient and a choice comes down to either prescription estrogen or black cohosh, it may be safer to try the black cohosh first.

Despite wide spread belief of its effectiveness, the Chinese herb dong quai itself has not been shown to help with menopausal symptoms.  In fairness, it must be said that Chinese herbs are not meant to be purchased off the shelf as single ingredients.  Yet,  when combined with other herbs in traditional formulas, dong quai does seem to help with PMS and menstrual irregularities. Chinese herbs are best taken under the supervision of an experienced herbalist.

Evening primose oil and chaste tree berry may be effective in treating PMS and other menstrual irregularities. Most controlled studies have shown no benefit of these herbs for menopausal symptoms.

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