Soy has been developing an almost “silver bullet” reputation of late, with those affected by type 2 diabetes piling it onto their plates at every opportunity.

Conflicting findings reported in the online American Journal of Clinical Nutrition on Marsh 24, 2010 give cause to re-thinking the playing field… while historic scientific findings have found that soy protein and soy isoflavone compounds, (phytoestrogen), are structurally similar to human estrogen and may actually help to control blood sugar levels. A few clinical trials have been held to create an empirical link to people actually suffering from type 2 diabetes.

In the reported study… Hong Kong researchers, Zhao-min and Associates at the Chinese University in Hong Kong, selected one hundred and eighty post-menopausal ladies who either displayed:

• pre-diabetes (where blood sugar levels are higher than they should be but not high enough to earn entry into the “type 2 diabetes club”), or
• early pre-treatment type 2 diabetes (where although the ladies had been diagnosed with type 2 they had not yet started treatment)

After randomly assigning the subjects to three groups, the researchers imposed the following treatment regimes:

• Group 1 took a powdered supplement that contained milk proteins
• Group 2 took the same supplement plus soy isoflavones
• Group 3 took a soy protein supplement plus soy isoflavones

The three groups were instructed to mix their prescriptions with liquid every morning but to otherwise stick to their normal diets. After six months the researcher’s found no clear evidence of Groups 2 and 3 having improved when compared to Group 1.

Although they did find marginal improvements among the Group 3 women, these peaked after two hours and then soon dissipated, leaving the researchers to conclude that neither soy nor isoflavone supplements had a beneficial effect on blood sugar levels among women.

Is this the final word on the subject? Surprisingly, Zhao-min and Associates say no. Noting that theirs appears to have been the first controlled trial of its nature, they ended their report with a remark that “additional studies that are based on longer trials and using different soy and phytoestrogen regimens are warranted before a final decision can be reached”.

A further study out of Japan, the Japan Public Health Center-Based Prospective Study, revealed a higher intake of soy products by overweight women was associated with a lower risk of type 2 diabetes. In view of this, researchers have declared the possible protective association of the intake of soy protein and soy isoflavone by overweight women deserves to be investigated further.

These findings are no reason for people living with type 2 diabetes to give up on their soy. At the worst it’s neutral and good for many other reasons besides lowering blood sugar levels.