Nutrition is critical to normal growth and maintenance of skeletal tissue. This research program focuses on the nutritional regulation of skeletal tissues by examining the biochemistry and gene expression within the extracellular matrix (proteoglycans and collagen). Importantly, there are clinical trials of bone turnover and bone mass to determine how nutritional intake influences the development of osteoporosis.

The major focus in the laboratory is to determine how loss of body weight contributes to the risk of osteoporosis. Evidence shows that subjects who diet and lose weight also lose bone. Our goal is to determine mechanisms that regulate the rate of bone turnover and bone loss during caloric restriction. Bone turnover is measured in the urine and blood (e.g., pyridinium cross-links, serum osteocalcin) using techniques of spectrophotometry, HPLC, and radioimmunoassay. Calcium absorption (using stable isotopes) and bone-regulating hormones are examined in these studies to address mechanisms of regulation. In addition, studies examining gastric bypass patients are in progress to understand how obesity surgery influences calcium homeostatsis and bone mass. Due to the high rate of morbidity and mortality associated with osteoporotic fractures, we also use a rat model to better understand how nutrition regulates bone turnover, composition, and biomechanical properties. We also examine the regulation of bone turnover in disease states associated with changes in bone mass. For example, we have studied how glycemic control and hormones regulate bone turnover in insulin-dependent patients with diabetes. We have used biochemical markers of bone turnover to estimate the rate of growth in clinical and equine studies. In addition, the regulation of lipids in bone and connective tissue is an ongoing interest in the laboratory.

Field MP, Shapses SA, Cifuentes M, Sherrell R. Precise and accurate determination of calcium isotope ratios in urine using HR-ICP-SFMS. J Anal Atomic Spec, 18:727-733, 2003.

Cifuentes M, Riedt CS, Field MP, Sherrell RM, Brolin RE, Shapses SA. Weight loss and calcium intake influence calcium absorption in overweight postmenopausal women.  Am J Clin Nutr 80:123-130, 2004.

Shapses SA, Heshka S, Heymsfield SB.  Effect of Calcium Supplementation on Weight and Fat Loss in Women.  J Clin Endocrinol Metab 89(2):632-7, 2004.

* Riedt CS, Cifuentes M, Stahl T, Chowdhury HA, Schlussel Y, Shapses SA. Overweight Postmenopausal Women Lose Bone with Moderate Weight Reduction and 1 g/d Calcium Intake. J Bone Min Res, 20:455-463, 2005.

Shapses SA, Riedt CS. Bone, body weight, and weight reduction: What are the concerns?  J Nutr 136:1453-1456, 2006.

Riedt CS, Brolin RE, Sherrell RM, Field MP, Shapses SA. True fractional calcium absorption is decreased after Roux-en-Y gastric bypass, Obesity, 14(11):1940-8, 2006.

Shen W, Chen J, Punyanitya M, Shapses S, Heshka S, Heymsfield SB.  MRI-measured bone marrow adipose tissue is inversely related to DXA-measured bone mineral in Caucasian women. Osteoporos Int 18:641–647, 2007

Riedt CS, Schlussel Y, von Thun N, Ambia-Sobhan H, Stahl T, Field MP, Sherrell RM, Shapses SA.  Premenopausal overweight women do not lose bone during moderate weight loss with adequate or higher calcium intake, Am J Clin Nutr, 85:972– 80, 2007.

Shapses SA, Riedt CS, Schlussel Y, Gordon CL, Li WP, Brolin RE, Stahl T.  Body weight and menopausal status influence trabecular and cortical BMD. In: Nutritional Aspects of Osteoporosis. Eds. Burckhardt P, Dawson-Hughes B, Heaney RP.  Elsevier, 2007

* Award winning paper by Am. Soc. Bone Min Research for 2005.