Human nutrition studies help us understand how well the beta carotene in Golden Rice is converted to vitamin A or how “bioavailable” it is. Knowing more about the bioavailability of the beta carotene in Golden Rice helps determine if it can improve vitamin A status.
Many human nutrition studies have been done to determine and compare the bioavailability of beta carotene in different types of foods1. These foods include commonly eaten fruits and vegetables, as well as crops that have been developed to contain more beta carotene than usual, including orange sweet potatoes, maize, cassava, and Golden Rice.
Nutritional research on Golden Rice has been carried out by a number of prestigious institutions, including Tufts University and the US Department of Agriculture (USDA) Children’s Nutrition Research Center.
As of October 2012, two important human nutrition studies on Golden Rice have been published, both in the American Journal of Clinical Nutrition.
- The paper “Golden Rice is an effective source of vitamin A”, published in 2009, reported that conversion of beta carotene from Golden Rice into vitamin A was estimated to occur at a rate of 3.8 to 12. This is much better than the rates of 10:1 to 27:1 estimated previously for colored vegetables such as spinach and carrots. In a summary statement about the research, the American Society for Nutrition reported that a very modest amount – about a cup - of Golden Rice could probably supply 50% of the Recommended Dietary Allowance (RDA) of vitamin A. if consumed daily3.
- A more recent paper published in2012, “Beta carotene in Golden Rice is as good as beta carotene in oil at providing vitamin A to children”, showed that the beta carotene produced by Golden Rice is as valuable to the human diet as beta carotene in oil (the most bioavailable way of delivering beta carotene) and better than spinach4. The study demonstrates that children, who are among those most vulnerable to vitamin A deficiency, could possibly benefit from Golden Rice as a steady source of the nutrient.
These results provide strong evidence that Golden Rice may help improve vitamin A status among children and adults.
1. Tang, Guangwen. 2010. Bioconversion of dietary provitamin A carotenoids to vitamin A in Humans. American Journal of Clinical Nutrition 91 (suppl): 1468S-73S.
2. Tang G, Qin J, Dolnikowski GG, Russell RM, Grusak MA. 2009. Golden Rice is an effective source of vitamin A. American Journal of Clinical Nutrition 89:1776–83.
3. Researchers determine that Golden Rice is an effective source of vitamin A. American Society for Nutrition. June 2009.
4. Tang G, Hu Y, Yin S, Wang Y, Dallal GE, Grusak MA and Russell RM. 2012. Beta carotene produced by Golden Rice is as good as beta carotene in oil at providing vitamin A to children. American Journal of Clinical Nutrition 96:3 658-664.
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