Nutrition recommendations worldwide emphasize ingestion of plant-based diets rather than diets that rely primarily on animal products. However, this plant-based diet could limit the intake of essential nutrients such as calcium. Osteoporosis is one of the world's most prevalent nutritional disorders, and inadequate dietary calcium is a known contributor to the pathophysiology of this condition. Previously, we have modified carrots to express increased levels of a plant calcium transporter (sCAX1), and these plants contain Ϸ2-fold-higher calcium content in the edible portions of the carrots. However, it was unproven whether this change would increase the total amount of bioavailable calcium. In randomized trials, we labeled these modified carrots with isotopic calcium and fed them to mice and humans to assess calcium bioavailability. In mice feeding regimes (n ‫؍‬ 120), we measured 45 Ca incorporation into bones and determined that mice required twice the serving size of control carrots to obtain the calcium found in sCAX1 carrots. We used a dual-stable isotope method with 42 Ca-labeled carrots and i.v. 46 Ca to determine the absorption of calcium from these carrots in humans. In a cross-over study of 15 male and 15 female adults, we found that when people were fed sCAX1 and control carrots, total calcium absorption per 100 g of carrots was 41% ؎ 2% higher in sCAX1 carrots. Both the mice and human feeding studies demonstrate increased calcium absorption from sCAX1-expressing carrots compared with controls. These results demonstrate an alternative means of fortifying vegetables with bioavailable calcium.absorption ͉ bioavailability ͉ radioactive isotope ͉ stable isotope

Education about pharmaceutical marketing practices and more restrictive policies governing medicine-industry interactions seem to increase medical students' skepticism about the appropriateness of such marketing practices and disapproval of pharmaceutical representatives in the learning environment.

Background: Biotechnology to increase the nutrient content of fruits and vegetables is an innovative strategy to address insufficient mineral intakes. A novel biotechnologically modified carrot which has higher levels of calcium than control carrots has been developed.

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.