Researchers at the University of Illinois have recently announced the findings of a study which compared the merits of a diet based on the currently recommended food pyramid and a diet based on lean meats and low fat dairy products. Diets high in meats and dairy have been thought to leach calcium from the bones, diminishing their strength and threatening osteoarthritis over time.
Working with a group of 130 study participants reporting to the University of Illinois and Pennsylvania state University, the research team randomly assigned one diet or the other to the participants, who were all overweight and of middle age. The study called for active weight loss for the first four months of the study, followed by eight months of weight maintenance.
At the beginning of the study, each participant’s bone mineral density and content were measured using scans of the entire body, the hip, and the lumbar spine. Comparative scans were conducted again four months into the study and at the eight- and 12-month marks.
Study participants following the lean meats and dairy diet maintained an overall stable rate of bone density throughout the study period. The group eating according to the food pyramid experienced a decline in the health of their bones over the study period. Ellen Evans, an associate professor in the kinesiology and community health departments at the University of Illinois, attributes the stability in bone health in the lean-meat diet group to the dietary protein, calcium, and vitamin D fortification in the foods they were eating. Evans is a member of the University of Illinois Division of Nutritional Sciences and is primary author of this study.
High-protein diets have been strongly associated with elevated levels of urinary calcium, thought to signal the leaching of minerals from the bones, also called demineralization. The research team cites a different mechanism for the increased calcium in the urine.
Using a process called radiolabeling, the researchers determined that the increased level of urinary calcium comes from the intestinal tract’s ability to absorb calcium better on the lean meat-based diet and not a result of bone loss at all.
Details of the study can be found in the Journal of Nutrition’s June issue. The study was funded by The Beef Board, the Illinois Council on Food and Agricultural Research, Kraft Foods, the National Cattlemen’s Beef Association, and the US Department of Agriculture.
Source: University of Illinois at Urbana-Champaign