UAMS Medical Center
UAMS, ACHRI Researchers Discover How Soy-Based Diets Protect Against Hardening of the Arteries
LITTLE ROCK – Soy-based diets protect against hardening of the arteries by interrupting its early development, according to University of Arkansas for Medical Sciences (UAMS) researchers at the Arkansas Children’s Nutrition Center (ACNC) housed at the Arkansas Children’s Hospital Research Institute (ACHRI).
Previous studies showed soy-based diets protected against development of plaque on the arteries, which hardened the blood vessel and increased the risk of stroke or heart attack, but the reasons why were unknown. In a study published in the September issue of the Journal of Nutrition by the American Society of Nutrition, researchers said that chemical compounds in soy, known as soy isoflavones, block a cellular interaction at an early stage of atherosclerosis, or hardening of the arteries.
“The data suggests the artery hardening protection occurs as the soy isoflavones disrupt the cell interactions that cause this condition,” said the study author Shanmugam Nagarajan, an assistant professor in the Department of Microbiology and Immunology of the UAMS College of Medicine and an investigator at ACNC. “The results reconfirm the powerful influence diet can have on preventing atherosclerosis and understanding these mechanisms can lead to potential treatments or new prevention methods.”
The article, “Soy Isoflavones Attenuate Human Monocyte Adhesion to Endothelial Cell-Specific CD54 by Inhibiting Monocyte CD11a,” is available online at http://jn.nutrition.org/.
Nagarajan’s colleagues in the study were Bradford W. Stewart, an investigator in the ACNC, and Thomas M. Badger, Ph.D., director of the ACNC and a professor in the Department of Physiology and Biophysics in the UAMS College of Medicine.
In the study, the researchers compared blood samples from rats fed a soy-based diet and from rats fed a control diet. Those fed the soy-based diet showed that a certain protein prevented cellular interactions attributed to early development of atherosclerosis.
In atherosclerosis, substances such as cholesterol and calcium form plaque on the arteries, causing them to harden. Past clinical studies have demonstrated that soy protein intake reduces serum cholesterol concentration, the researchers noted, although later studies showed that it was not necessarily the lowered cholesterol level that reduced the size of atherosclerotic lesion sizes in animals fed soy-based diets.
Instead, the researchers pointed to a cellular interaction between monocytes, a type of white blood cell, and endothelial cells lining the blood vessels that occurred early in the development of atherosclerosis. In the study by the UAMS-ACHRI researchers, the soy isoflavones prevented those cellular interactions.
Previous ACNC studies also have shown that lifetime consumption of soy or whey proteins reduced the incidence of colon cancer and high blood pressure in rats.