Soy and HRT - links to heart disease inconclusive

Both soy supplements and hormone replacement therapy appear to improve risk factors for heart disease in women with diabetes, according to a report on two new studies published this week. The findings present conflicting evidence to the large clinical trials which caused controversy this summer.

Both soy supplements and hormone replacement therapy appear to improve risk factors for heart disease in women with diabetes, according to a report by USA Today on two new studies published this week.

Studies in the journal Diabetes Care, one on HRT and another on soy, add to the debate on how postmenopausal women can reduce their risks for heart disease, claims the report.

"This is an area where we have a great deal of data, none of it perfect, and people are trying to make decisions based on it, which is not easy," Eugene Barrett, professor of medicine at the University of Virginia in Charlottesville and president-elect of the American Diabetes Association told the paper.

In one of the studies, researchers at the University at Buffalo studied more than 2,700 postmenopausal women enrolled in the Third National Health and Nutrition Examination Survey. They found that those with diabetes and currently on hormone replacement therapy (HRT) had lower cholesterol and blood-sugar levels than those who previously used or never used hormone supplements. Levels of certain blood proteins associated with heart health also appeared better in women on hormone therapy, reported the scientists.

The finding seems to conflict with data from large clinical trials suspended this summer when HRT was found to possibly increase the risk of heart disease and stroke.

Carlos Crespo, lead author of the Buffalo study, said his study suggests that women with diabetes who were not included in the halted trial might be among a "segment of women who would be better off using" hormone therapy.

Barrett however stressed that this is not clear. "It may be that women on (hormones) see their doctors more and take better care of themselves. It may not be because they're on hormone therapy that their cholesterol is a bit lower."

In the soy study, researchers at the Michael White Centre for Diabetes and Endocrinology in Hull, England, gave 32 women with diabetes soy supplements or a placebo for 12 weeks and found those taking soy had improved control of blood-sugar levels and a significant drop in LDL or "bad" cholesterol and insulin resistance, suggesting a reduced risk of heart disease.

Neither study looks at long-term outcomes, Barrett noted. "The best you could say is the soy didn't have deleterious effects, as far as we could tell, but whether that's going to translate into clinical benefits is not known."

He said that the hormone study looked favourable biochemically, but other studies designed to isolate the effect of hormone supplements from other factors "would suggest it's not so favourable."