The study, published in the Journal of Nutrition (2004, vol. 134), investigated the effect of soy isoflavone supplementation on neurons in normal elderly rats. Researchers in Korea administered a low isoflavone diet (0.3 grams/kilogram soy isoflavones), a high isoflavone diet (1.2 grams/kilogram soy isoflavones), or a control diet to 48 male rats, 10 months old, for sixteen weeks. The scientists measured memory and learning performance using a water maze test and brain enzymes activity, including choline acetyltransferase (produces acetylcholine) and acetylcholine esterase (breaks down acetylcholine). Acetylcholine is a neurotransmitter that has been found to be decreased in aged brains and Alzheimer's disease.
The researchers found that choline acetyltransferase was higher in two areas of the brain in the low isoflavone group and in one area in the brain in the high isoflavone group, compared to the control group. In addition, acetylcholine esterase was lower in several areas of the brain in both isoflavone groups, compared to the control group. Findings also revealed that the low isoflavone group demonstrated a superior memory and learning performance compared to the control group. "These findings show that soy isoflavones can influence the brain cholinergic system and reduce age-related neuron loss and cognition decline in male rats," the study authors conclude.
Posted by Kristopher Foster on February 16, 2006 05:05 PM
