Soy and Menopause

Many women are looking for treatment alternatives because of the risks associated with hormone therapy. Soy Isoflavones are one of the many supplements marketed for women in menopause. Soy certainly appears to fit the bill for a safe and effective natural treatment.

The reality is more complicated than that. Numerous studies have found no significant effect of soy supplements on hot flashes. The only scientifically proven benefit of soy was on cholesterol levels and even this claim is controversial.

But before we can draw the conclusion that soy does not work at all, let’s look a little deeper into the issue.

Soy Isoflavones
The benefits of soy for menopause come from the Isoflavones in the soybean. Isoflavones are plant hormones called phytoestrogens. Phytoestrogens work similar to the hormone estrogen that our body produces naturally. So theoretically, if menopausal women take a soy supplement their hot flashes should disappear, just like they would with estrogen therapy.

Now researchers have found that Isoflavones act very differently. If estrogen levels are high they block the more potent natural estrogen by binding to the estrogen receptors. But in menopausal women with low estrogen levels, they provide a mild estrogenic effect when they bind to the receptors.

But this does not explain why the studies found no effect on menopause symptoms. Here are two explanations:
- Soy isoflavone supplementation vs whole soy products
- Genetic differences in women with Asian vs Western European ancestors.

Soy Isoflavone Supplementation vs Whole Soy Products
Newer research has indicated that results may depend on the kind of soy that is used. A typical soy supplement contains either isolated Genestein (the main isoflavone), soy protein, or a combination of both. It appears that these isolates don’t work as well as whole soy products.

There are also questions about the quality of the supplements. Several years ago a government study found that most Isoflavones do not contain the amount that was indicated on the label.

In contrast, whole soy products use all the active compounds of the soybean. The best way to get all the benefits of soy is to eat a diet that contains largely unprocessed soy foods, such as edamame, tofu, soy milk etc. which is difficult to do with the traditional western diet.

But there are also whole soy products in powder form. Dr. Christiane Northrup is a great proponent of these products. The powder form is mixed into a drink which makes it easier to consume the daily recommended amount of soy isoflavones (about 40mg).

Genetic Differences in Women
It is clear that the effect of Isoflavones depend to a great extend on how they are metabolized. This depends on the presence of specific bacteria in the intestine. The bacteria help to break down the Isoflavones into specific active chemicals that in turn causes the estrogenic effect.

There is some evidence, that only a third of the population with western ancestors has these bacteria and can break down the Isoflavones to produce the estrogenic effect. Most of the Isoflavones are digested without being adequately processed by the body. For more information about the effect of Soy metabolites, read the article from the Linus Pauling Institute of the University of Oregon.

In conclusion: Soy is a very healthy food, especially if it is used in its most natural form. As such it may help some women with their menopause symptoms. However, it is not the cure-all for menopausal women as advertised.