Improved bioavailability of calcium in genetically‐modified carrots

Abstract

Osteoporosis is one of the world's most prevalent nutritional disorders and inadequate absorbed calcium is a known contributor to the pathophysiology of this condition. In a cross‐over study of 15 male and 15 female young adults, we used a dual stable isotope method with 42Ca‐labeled genetically‐modified (sCAX1) and control carrots and intravenous 46Ca to determine the absorption of calcium from these carrots in humans. Subjects also consumed 48Ca‐labeled milk for comparison. Calcium absorption efficiency was 42.6 +/− 2.8% and 52.1 +/− 3.2% (p<0.001) for the sCAX1 carrots and control carrots, respectively (all data are Mean +/− SEM); however, total calcium absorption per 100 g of carrots was 41 +/− 2% higher in sCAX1 carrots compared to control carrots (26.50 vs. 15.34 mg Ca/100g, p<0.001). Calcium absorption efficiency from the milk was similar to that from the control carrots (50.1 +/− 3.0% vs. 52.1 +/− 3.2%, p=0.7) but was slightly higher than that from the sCAX1 carrots (50.1 +/− 3.0% vs. 42.6 +/− 2.8%, p<0.05). These results demonstrate the first human study to establish the nutritional consequences of a genetically‐modified calcium increase in food and support the use of novel approaches to enhance the micronutrient content of vegetables. Funding: NIH Grants IR01 DK 062366 and USDA CSRESS#2005‐34402‐16401.