Significant factors related to the increased kidney stone risk, according to the study, are the acidic content of animal meat and the lack of alkaline foods in the diet. The findings are included in the August issue of The American Journal of Kidney Diseases.
Researchers report that acid excretion a marker for the acid load in the blood increased as much as 90 percent while subjects were on diets that severely restricted carbohydrates. Levels of urinary citrate, which inhibits kidney stones, fell by almost 25 percent in the group during the six-week study.
"People may lose weight on this diet, but this study shows that this is not a healthy way to lose weight," said Dr. Chia-Ying Wang, a co-author of the study and an assistant professor of internal medicine at UT Southwestern.
"When you restrict the amount of carbohydrates you can go into a state called ketoacidosis," Wang said. "Our body needs a certain source of energy and a quick source are carbohydrates, which are readily available. When you restrict carbohydrates the body then turns to other sources, one of which is fat. Ketone bodies are formed when the body is forced to burn fat for energy which may result in a state of ketoacidosis."
Ketoacidosis is a condition resulting from an accumulation of ketone bodies in the blood and increased blood acidity.
Ten healthy subjects ate a regular diet for two weeks at the start of the study. They followed that with a highly restrictive diet that included some vegetables but no fruits and less than 20 grams of carbohydrates for two weeks. Participants then ate a less-restrictive diet for the final four weeks. During the last
Contact: Amy Shields
UT Southwestern Medical Center