A new 12-week study of 302 adults with high-normal or mildly elevated blood pressure found that those who ate special cookies containing 40 grams of soybean protein had significantly larger decreases in pressure levels compared to those who ate similar cookies made of complex wheat carbohydrate (Article, p. 1).

The soybean group had net reduction of 4.3 mm Hg systolic and 2.1 mm Hg diastolic blood pressure at the end of the study. Neither group reported significant side effects.

Editorial writers say, "We should require good evidence of benefit and safety before recommending soybean protein to the much larger population that is at risk for hypertension," (Editorial, p. 74).

The writers say that 40 grams of soybean protein amounts to about one 'soy burger' plus one to two cups of soy milk. Many people may not be able to consume this much soy protein every day and no one knows if that amount is safe, the writers say.

Both the study authors and the editorial writers cite some evidence of an association between soy protein and increased risk for bladder cancer.

Might a mixed vegetable protein product have the same blood pressure lowering effect without the risk for bladder cancer? the editorial writers ask. A major study to be released later in 2005 may answer some of these questions.

Annals of Internal Medicine tip sheet for July 5, 2005