Menopause And Soy
A recent study by researchers from the Florida State University has found that eating soy is of little benefit to postmenopausal women hoping to reduce their cholesterol levels. The study was published in April 2010 and is likely to upset producers of soy products who have been promoting their wares as being good for heart health.
When a woman goes through menopause, her levels of the hormone estrogen plummet. This dramatic drop in estrogen causes her total level of cholesterol to go up. There are two types of cholesterol, informally referred to as "bad" and "good."
Bad cholesterol is called LDL (low density lipoprotein). If you have high levels of this cholesterol, you are greater risk of heart disease and stroke. LDL levels increase after menopause.
Good cholesterol is HDL (high density lipoprotein). A certain level of this cholesterol protects the heart. Therefore if you have low levels of HDL, your risk of heart disease is higher. HDL levels decrease in women after menopause.
How Would Soy Help?
Soy contains substances called isoflavones which have a similar function to estrogen. Therefore the theory has been (until recently) that eating soy products might help to replace some of the estrogen in a postmenopausal woman's body, thereby counteracting the rise in bad cholesterol and the drop in good cholesterol.
Some studies have backed this research up, but the organizers of the Florida study claim that this previous research was not conducted over a long enough period of time, and examined only the effects of individual soy components - not the effect of soy products such as snack bars, drinks and cereals.
These are exactly the types of products investigated in the 2010 study. 62 women took part and their progress was followed for a year. All the participants were post menopause, under the age of 65 and overweight. They all had total cholesterol readings which were slightly higher than the ideal level (which is 200 mg/dL). The women were randomly assigned to groups; some of them consumed soy products for a year, and some did not.
The women who ate the soy products consumed 25g of soy protein or 60 mg of isoflavones per day.
Total cholesterol levels and good (HDL) cholesterol levels actually increased in the women who consumed the soy products. However, the soy had no effect on the bad (LDL) cholesterol levels of these women.
On the one hand, this is bad news for postmenopausal women who've been eating soy in an effort to bring down cholesterol - not only does it not influence bad cholesterol, but it also appears to increase total cholesterol levels.
On the other hand, soy products do appear to boost good cholesterol levels. The potential benefits of good cholesterol for heart health should not be underestimated. HDL levels went up by 3 points from 57mg/dL to 60 mg/dL in the group of women who consumed the soy products. Having HDL levels lower than 50mg/dL is considered a significant risk factor for heart disease. Whereas having levels or 60mg/dL or more actually protects the heart.
The debate about soy, cholesterol and menopause will continue. Women after menopause will have to weigh the pros and cons for themselves. It's advisable, however, to speak to your doctor before taking any supplements, including soy, for the purpose of reducing cholesterol. It's worth bearing in mind that the official position of the American Heart Association on the benefits of soy are that they are "minimal at best."