Nutritional impact of elevated calcium transport activity in carrots

Vegetable and Fruit Improvement Center, Texas A&M University, College Station, TX 77845, USA.
Proceedings of the National Academy of Sciences (Impact Factor: 9.67). 03/2008; 105(5):1431-5. DOI: 10.1073/pnas.0709005105
Source: PubMed

ABSTRACT 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 approximately 2-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.

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Available from: Steven A Abrams, Dec 25, 2014
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    • "This approach is also being successfully demonstrated in other crops such as maize, orange, cauliflower, tomato, yellow potatoes and golden canola (White and Broadley 2009). Similarly, GM carrot expressing high levels of a deregulated transporter which accumulated about 2-fold more Ca in the edible tissues was also developed (Morris et al., 2008, Carvalho and Vasconcelos 2013). In contrast with the 'Golden Rice', the feeding trials using this labeled carrot proved that Ca absorption was considerably increased in both animal models with diets having the GM carrot but not all the increased Ca was bioavailable (Murray-Kolb et al., 2002). "
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    ABSTRACT: Malnutrition and hunger among the world population at alarming rates poses serious threat to global food security. Further, the FAO Hunger Report (2012) depicts that, about 12.5% of the global population (one in eight people) is starving, excluding 100 million children under the age of five. Irrespective of the adults, about 2.5 million children die every year due to starvation and malnutrition which ultimately hinders human potential (FAO Hunger Report 2012). Since, plants are the primary producers in the food chain, they serve as versatile biochemical factories capable of producing almost complete complement of essential dietary micronutrients. However, the dietary micronutrients are unevenly disseminated among different plant parts. For instance, iron content in a rice leaf is as high as 100–200 ppm (parts per million), but very low in the polished rice grain (~3 ppm) (Mayer et al. 2008). Similarly, provitamin A carotenoids are present only in rice leaves but not in its edible part. Unfortunately, economically backward people rely predominantly on starchy staples such as rice, wheat, maize, or cassava, but these crops do not supplement the biochemical diversity needed for a healthy life which leads to micronutrient malnutrition (MNM). Plant science has a central role in addressing these issues of both hunger and malnutrition. Since, MNM affects more than half of the world population, biofortification offers an economical and sustainable approach of the delivering micronutrients via micronutrient-dense crops to the human population. Hence, this book chapter summarizes the strategies of generating biofortified-crop plants along with the significant achievements reported in biofortification of major crop plants such as orange sweet potato, maize, cassava, rice, wheat and other crops like lentils, banana, cowpea, sorghum and potato.
    Horticulture for Nutritional Security, 1 edited by KV Peter, 06/2015: chapter 7: pages 125-140; Astral International (P) Ltd, India., ISBN: 978-93-5124-660-2
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    • "Filipino women by measuring serum-ferritin, total body iron and hemoglobin during a 9- month trial with modest results.[7] Furthermore, Morris et al. investigated whether the increase of calcium accumulation in carrots leads to an increase in calcium intake upon consumption in both humans and mice.[8] Recently, Castorena-Torres et al. reported on the folate bio-availability from lyophilized biofortified tomatoes using a murine model, making a comparison with orally dosed synthetic 5-methyltetrahydrofolate (5-MTHF) and folic acid (FA). "
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    ABSTRACT: ScopeThe biological impact of folates from folate rice, a metabolically engineered (biofortified) rice line, rich in folates, was investigated. Its consumption may be helpful to fight folate deficiency. Our objective was to investigate the potential of folate rice to supply the organism with folates and evaluate its biological effectiveness using a rat model.Methods and resultsFive groups of 12 Wistar rats were monitored during a 7/12-wk depletion/repletion trial. Animals receiving folate-free diet (0 μg/rat/day) and those additionally receiving wild-type rice (on average 0.11 μg/rat/day) suffered from decreased hematocrit and lower folate concentrations in both plasma and RBCs. This resulted in serious morbidity and even lethality during the trial. In contrast, all animals receiving a daily supplement of folate rice or folic acid fortified rice (on average 3.00 μg/rat/day and 3.12 μg/rat/day, respectively) and those receiving a positive control diet (11.4 to 25.0 μg/rat/day), survived. In these groups, the hematocrit normalized, plasma and RBC folate concentrations increased and pronounced hyperhomocysteinemia was countered.Conclusion Using an animal model, we demonstrated that biofortified folate rice is a valuable source of dietary folate, as evidenced by folate determination in plasma and RBCs, the alleviation of anemia and counteraction of pronounced hyperhomocysteinemia.
    Molecular Nutrition & Food Research 12/2014; 59(3). DOI:10.1002/mnfr.201400590 · 4.60 Impact Factor
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    • "Genetically modified carrots with different traits have been developed, e.g. resistance against biotic and abiotic stress (Chen and Punja, 2002; Kumar et al., 2004) and increased nutritional content (Morris et al., 2008), though none has been approved for commercialization yet. Given its already present propensities for weediness, the introgression of transgenes with fitness advantages into wild populations may turn the wild carrot into a more serious weed. "
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    ABSTRACT: Background and aims: Transgene introgression from crops into wild relatives may increase the resistance of wild plants to herbicides, insects, etc. The chance of transgene introgression depends not only on the rate of hybridization and the establishment of hybrids in local wild populations, but also on the metapopulation dynamics of the wild relative. The aim of the study was to estimate gene flow in a metapopulation for assessing and managing the risks of transgene introgression. Methods: Wild carrots (Daucus carota) were sampled from 12 patches in a metapopulation. Eleven microsatellites were used to genotype wild carrots. Genetic structure was estimated based on the FST statistic. Contemporary (over the last several generations) and historical (over many generations) gene flow was estimated with assignment and coalescent methods, respectively. Key results: The genetic structure in the wild carrot metapopulation was moderate (FST = 0·082) and most of the genetic variation resided within patches. A pattern of isolation by distance was detected, suggesting that most of the gene flow occurred between neighbouring patches (≤1 km). The mean contemporary gene flow was 5 times higher than the historical estimate, and the correlation between them was very low. Moreover, the contemporary gene flow in roadsides was twice that in a nature reserve, and the correlation between contemporary and historical estimates was much higher in the nature reserve. Mowing of roadsides may contribute to the increase in contemporary gene flow. Simulations demonstrated that the higher contemporary gene flow could accelerate the process of transgene introgression in the metapopulation. Conclusions: Human disturbance such as mowing may alter gene flow patterns in wild populations, affecting the metapopulation dynamics of wild plants and the processes of transgene introgression in the metapopulation. The risk assessment and management of transgene introgression and the control of weeds need to take metapopulation dynamics into consideration.
    Annals of Botany 09/2013; 112(7). DOI:10.1093/aob/mct208 · 3.65 Impact Factor
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