Soy Story

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You've heard the buzz about soy. Now here's the scoop.

Soy Sensation

Lately soy has been attributed to decreasing hot flushes, reducing the risk of fracture and of osteoporosis, decreasing levels of blood cholesterol, and lowering the risk of developing certain cancers.

Why would one bean, enjoyed for centuries in Asian cuisine, be receiving such acclaim now?

Studies

Soy has recently been the subject of many studies. At a recent North American conference on menopause, you couldn't turn anywhere without hearing about a new study on the bean.

So while there are some interesting things to note from recent reports on soy protein, expect to hear more results from ongoing studies.

Of the studies done on Asian populations that eat large amounts of soy, results have shown that women in these areas are less likely to develop breast cancer, osteoporosis and heart disease than women in North America.

This could be due to many other factors (such as the common Asian diet with more fibre, less fat and meat and no dairy), but it's worth noting that other research has confirmed some of soy's health benefits.

New research on phytoestrogens (estrogens found in plants and similar in structure to human estrogen) has brought soy protein, with its high phytoestrogen content, into the limelight.

So, while it is clear soy has some health benefits, no single food source will be the panacea for prevention of major illnesses.

Phytoestrogens

The phytoestrogens found in soy are called isoflavones. There are two types - genistein and daidzein. Isoflavones found in the protein part of soy make-up about 75% of the bean.

Menopause Symptoms

Because a phytoestrogen can block the activity of a stronger estrogen, the isoflavones in soy can help mute the impact of hormonal fluctuations.

Three well-designed studies - and much anecdotal evidence from individual women's experiences - suggest that soy helps to alleviate hot flashes, however it's worth remembering that hot flashes often show a large placebo effect response.

Osteoporosis

It is thought that the weak estrogenic effect of soy may help to reduce the risk of fracture and of osteoporosis in women, because soy may help women maintain and strengthen bone. More evidence is needed for this.

Cholesterol

A 1995 study published in the New England Journal of Medicine pooled data from thirty-eight controlled clinical trials on soy consumption and blood cholesterol levels. Their analysis concluded that eating soy does indeed lower levels of blood cholesterol (LDL) and triglycerides, particularly in people with very high and moderate levels of cholesterol.

These cholesterol-lowering benefits seem significant for postmenopausal women. Soy may increase arterial flexibility and inhibit formation of plaque that clogs the arteries.

Cancers

In preventing breast cancer, soy protein is said to inhibit tumour formation in two ways. One, it prolongs the phase of the menstrual cycle when breast tissue is dormant. Two, it can block the growth of new blood vessels to cancer cells, and inhibit key enzymes required for tumour growth.

This second method may also be helpful in preventing the growth of other cancers.

While he benefits of soy for preventing breast cancer may have been overplayed, in vitro studies have shown that genistein inhibited the growth of human breast cancer cells, but some research showed it increased the proliferation of normal breast cells.

Cautions

Soybeans contain molecules that can affect hypothyroid and goitre conditions. It may prevent the uptake of thyroid medications.

It is recommended that women who already have breast cancer be cautious about even dietary soy. We also don't know much about taking soy with drugs like tamoxifen or raloxifene.

Soy Food

The best way to take soy is through dietary sources like tofu, soy "milk" (check recommended amounts). This ensures you get isoflavones and that you won't overdo it and take too much - be more wary of pills for this reason.

If you do take supplements, read the ingredients carefully for the breakdown of different types of isoflavones (genistein should account for 50% of the total amount of isoflavones in the pill).

Soy has come a long way in North American cuisine, enjoyed in many restaurants and kitchens across the country - and not just in Asian meals.

Try Soyfoods Cooking for a Positive Menopause by Bryanna Clark Grogan, published by The Book Publishing Company, 1999.