Wednesday, September 4, 2019

Compositional analysis shows beta-carotene biofortified Golden rice is safe and has potential to address Vitamin A deficiency

The introduction of any new product or technology is often met with questions and concerns. For food crops like Golden Rice, which is genetically modified to produce beta-carotene in its grains, most people want to know whether it is safe to eat, and if it has any additional health benefits. In an article published in the Journal of Agriculture and Food Chemistry in June 2019, Dr. B.P. Mallikarjuna Swamy and the Healthier Rice team at IRRI and PhilRice, presented findings showing the nutrient content of Golden Rice, and the potential nutritional impact of the added beta-carotene content. 

Leading regulatory agencies evaluate food safety claims based on the concept of substantial equivalence, a term coined by the Organisation of Economic Co-operation and Development (OECD) in 1993 and adopted by international organizations like the Food and Agriculture Organization of the United Nations (FAO) and World Health Organization (WHO), which refers to the need to provide evidence demonstrating that a genetically modified food crop is as safe as its existing counterparts. Compositional analyses, such as those presented in Swamy’s publication, measure and compare specific components of new food crops and compare this with existing plant counterparts.

When the results are within the range of naturally occurring variability, this provides evidence for regulators to determine that the genetic modification of the food crop did not result in any unintended consequences to the nutritional profile.   

Swamy and the Healthier Rice team examined the content of key nutritional components, proximates, and minerals in the paddy rice, straw and bran of Golden Rice and compared these with a control sample of PSBRc82, the rice variety cross-bred with the genetically modified Kaybonnet GR2E Golden Rice to produce a Golden Rice variety suitable for Philippine planting conditions. All components of Golden Rice, including its protein content, were found to be substantially equivalent to ordinary rice, with one exception: Golden Rice grains contains up to 7.31 ppm of beta-carotene, while ordinary rice had amounts too insignificant to measure. 

“The results of the compositional analysis show that Golden Rice is as safe as ordinary rice, but with the added benefit of beta-carotene content,” says Swamy. “Rice has a simple and easily digestible food matrix, which allows for a high bioavailability and bioconversion of beta-carotene to vitamin A.”  Put simply, this means that the beta-carotene in Golden Rice can easily be converted by the human body into the amount of Vitamin A that it needs. Previous studies show that the bioconversion efficiency of Golden Rice compares favorably to other beta-carotene biofortified crops, like cassava and yellow maize.  Compared to spinach, a vegetable widely recognized as a rich source of vitamin A, the beta-carotene in Golden Rice is converted by the body into vitamin A about 5-times more efficiently.   

For rice-eating countries like the Philippines and Bangladesh--where Golden Rice is currently undergoing regulatory review--this could help reduce Vitamin A deficiency in vulnerable populations. 100 g of uncooked Golden Rice could supply up to 57% of the estimated average requirement (EAR) for Vitamin A of  pre-school children and from 38-47% of the EAR for pregnant and lactating women.

Despite the success of existing nutrition interventions like diet diversification, food fortification, and oral supplementation, vitamin A deficiency continues to be the leading cause of preventable childhood blindness and increased risk of infection in over 190 million children worldwide. This suggests that Golden Rice and other rice biofortification initiatives can serve as a complementary pathway to improved nutritional status. Biofortification, as defined by the WHO, is the “process by which the nutritional quality of food crops is improved through agronomic practices, conventional plant breeding, or modern biotechnology.”

The data evaluated in the paper was gathered from the multi-location field trials held in four different locations in the Philippines during the 2015-16 planting seasons. This formed part of the biosafety dossier submitted for regulatory applications to the Department of Agriculture-Bureau of Plant Industry in the Philippines, Food Standards Australia New Zealand, Health Canada, and the United States Food and Drug Administration. To date, Golden Rice has received positive safety assessments from the latter three agencies, and is still undergoing regulatory review in the Philippines and Bangladesh. 

“As developers of Golden Rice, it is our responsibility to demonstrate its safety and benefits to the public,” says Dr Russell Reinke, Healthier Rice Program lead at IRRI. “The next step is to evaluate its efficacy in providing 30% of the EAR for Vitamin A for micronutrient deficient women and children, but this will only take place once all regulatory approvals have been received.” 

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