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United States Department of Agriculture

Agricultural Research Service

Title: Biotechnologically-modified carrots: Calcium absorption relative to milk

item Hawthorne, Keli
item Morris, Jay
item Hotze, Tim
item Hirschi, Kendal
item Abrams, Steven

Submitted to: Journal of Bioequivalence and Bioavailability
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2009
Publication Date: 5/15/2009
Publication URL:
Citation: Hawthorne, K.M., Morris, J., Hotze, T., Hirschi, K.D., Abrams, S.A. 2009. Biotechnologically-modified carrots: Calcium absorption relative to milk. Journal of Bioequivalence and Bioavailability. 1(1):34-38.

Interpretive Summary: Many people do not eat and drink enough dairy products to get enough calcium in their diet. Genetically modified carrots have been developed to contain higher amounts of calcium than conventional carrots. In order to understand how a food like this would fit into a real-world diet, we compared the calcium absorption of the genetically modified carrots to the absorption of milk, the reference standard, by using stable isotopes in 30 young adults. We learned that genetically modified carrots have calcium bioavailability levels only slightly below that of milk. The total amount of calcium absorbed from the genetically modified carrots is still quite low compared to a glass of milk, making it unreasonable to totally switch out these carrots for milk. However, genetically modified carrots could have a place in the diet as an additive to other calcium-rich foods in order for a person to get all the calcium they need from foods instead of a pill.

Technical Abstract: Biotechnology to increase the nutrient content of fruits and vegetables is an innovative strategy to address insufficient mineral intakes. A novel biotechnologically modified carrot that has higher levels of calcium than control carrots has been developed. For dietary guidance, it is necessary to understand the relative servings of any specific product that would be needed to provide calcium compared to a standard source, such as milk. In a crossover study we used stable isotopes to measure calcium absorption from milk in 30 young adults and compared it to calcium absorption from both biotechnologically modified (MOD) and control (CON) carrots. Using a total meal calcium of 300 mg of which 35-40 mg of the calcium is derived from the test product, fractional calcium absorption from milk was slightly higher than from the MOD carrot (50.1 +/- 3.0% vs. 42.6 +/- 2.8%, Mean +/- SEM, p<0.05) but was similar to that from the CON carrot (50.1 +/- 3.0% vs. 52.8 +/- 3.3%; p=0.7). Biotechnologically modified carrots have calcium bioavailability levels only slightly below that of milk. Serving sizes of enhanced carrots remain too large to be considered full substitutions for usual sources such as milk, but can supplement these sources effectively. Further biotechnological enhancements of a range of vegetable sources may lead to substantial benefits in nutritional status for minerals such as calcium with significant population-deficient intakes.

Last Modified: 06/26/2017
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