Calcium content , digestibility , and bioaccessibility in in vitro leaves of spinach ( ) , sweet potato ( Spinacia oleracea Ipomea ) , and drumstick tree ( ) batatas Moringa oleifera

Low calcium intake, poor calcium absorption, excessive calcium losses, or some combination of these factors contribute to calcium deficiency diseases. Calcium insufficiency is associated with osteoporosis, hypertension and colon cancer among other diseases. For individuals who do not have access to milk and dairy products, do not tolerate them, or prefer not to consume them, plants may be alternative sources of calcium. However, calcium bioavailability may be low in plant foods because calcium forms complexes with oxalates, phytate and other competing minerals. The objective of this study was to compare the calcium content, digestibility and bioaccessibility in the leaves of spinach ( , sweet potato ( Spinacia oleracea) ), and drumstick tree ( ). Calcium content was Ipomea batatas Moringa oleifera analyzed in dry leaf powder by atomic absorption, followed by a two-stage in digestion and dialysis against a mock serum solution to determine calcium vitro digestibility and bioaccessibility. had higher calcium content Moringa oleifera than spinach and sweet potato leaves: 1.54±0.11% of dry matter for three samples (two African and one from India), and 0.99±0.001 and Moringa 1.06±0.001, respectively, in spinach and sweet potato leaves. The mean in calcium digestibility was 1.62±0.08% in spinach, 3.4±0.68% in sweet vitro potato leaves and 33.7±9.6% for . A dialysis system was designed to Moringa model bioaccessibility of calcium, revealing that bioaccessible calcium in sweet potato leaves was a non-significant 1.4 times higher and in was 9.2 to Moringa 19.4 times higher than in spinach. Therefore, the calcium contained in Moringa leaves does not appear to be associated with poorly bioavailable complexes such as oxalate. We confirmed previous reports that bioaccessibility of the calcium is low in spinach. These findings imply that increased utilization of and leaves might increase calcium intake in Ipomea batatas Moringa oleifera people in tropical and warm temperate regions where these plants grow, or these plants might become a valuable export crop. 1 2