American Society For Nutrition

What is new with “Golden Rice”?

What is new with “Golden Rice”?

Excellence in Nutrition Research and Practice
Posted on 06/18/2010 at 04:26:01 PM by Student Blogger
By: Bobban S.

There was a recent news on the safety of the genetically modified (GM) crops by US National Academies of Science (1) which broadly concluded that GM crops benefit many farmers, but the technology needs proper management to remain effective. In the light of this news on GM, what rushed to my mind was golden rice and I immediately become curious on what is new with golden rice. Just quick background, golden rice is the product of a genetically engineered variety of rice plant which contains beta-carotene, a precursor of Vitamin A, synthesizing genes. This was originally developed by Ingko Potrykus and Peter Beyer as a biofortification strategy against Vitamin A deficiency (VAD).

Although the initial breakthrough on golden rice was received by the typical scientific excitement and widespread media attention, the technology soon caught on the radar of regulatory groups and other non-GM advocacy groups. Many agri-biotech companies, various NGO's either supporting or against golden rice and many governments were caught in the golden rice conundrum for more than a decade now. So I just pubmeded with golden rice as keyword to see what's going on scientific front with golden rice. There was a study from Tufts University by Tang et al. which caught my attention AJCN published in 2009 (2). I was happy because of the thought that there are still scientific groups actively pursuing the basic and nutritional aspects of golden rice. This study was designed to determine the vitamin A value of intrinsically labeled dietary golden rice in humans and the study concluded that beta-carotene derived from golden rice is effectively converted to vitamin A in humans with a conversion factor of golden rice beta-carotene to retinol is 3.8 +/- 1.7 to 1 with a range of 1.9-6.4 to 1 by weight or 2.0 +/- 0.9 to 1 with a range of 1.0-3.4 to 1 by moles.

Vitamin A is essential for growth and differentiation of a number of cells and tissues. Notably during pregnancy and throughout the breastfeeding period, vitamin A has an important role in the healthy development of the fetus and the newborn, with lung development and maturation being particularly important. Further, the intake of vitamin A provides humans with an important nutrient for vision (ocular malfunctions), growth, reproduction, cellular differentiation and proliferation, and integrity of the immune system. The VAD is a global phenomenon with millions of children being affected annually (Figure). As far as GM crops, genetically engineered crops now constitute more than 80 percent of soybeans, corn, and cotton grown in the United States and some of the byproducts of these such as soybean meals are also used in animal feeds for rearing farm food organisms such as chicken and fish. So although GM crops are such pervasive now and technologies such as golden rice to fight against VAD are available, it still hasn't reached to a point where it can be used for meaningful changes in the lives of poor children in developing nations. As any other hot and sensitive issues, golden rice also seems to have a golden haze of issues. Surely, I don't want to read or write more about the regulations of GM rice, but I want to toss a question to you all:

At what stage do you think that the global community will accept golden rice or in other words how can we derive a fine balance between under nutrition-mediated child deaths and regulatory barriers of golden rice as a means to save the lives of these children?

Reference
1.    Impact of Genetically Engineered Crops on Farm Sustainability in the United States Committee on the Impact of Biotechnology on Farm-Level Economics and Sustainability; National Research Council.
2.    Tang et al. Golden Rice is an effective source of vitamin. Am J Clin Nutr. 89, 1776-83 (2009).

AN INTERVIEW WITH ADRIAN DUBOCK, A MEMBER OF GOLDEN RICE HUMANITARIAN BOARD

Adrian Dubock is a member of the Golden Rice Humanitarian Board (see www.goldenrice.org ‘who are we') and also Project Manager for the Golden Rice Project.  He works closely with the inventors of Golden Rice Professors Peter Beyer and Ingo Potrykus, and other collaborators, in managing the project towards its conclusion: making Golden Rice available, without additional cost or complication compared to white rice, to those who will benefit from, and want  it.

Bobban: What is new with golden rice, especially on a research front?

AD:
We are very excited by the developing data concerning bioconversion of the β-carotene in Golden Rice to retinol, the most useful form of Vitamin A for combating Vitamin A Deficiency, and we want to encourage more data collection from properly designed and executed research protocols. The bioconversion in children is as good as from β-carotene in oil, at around 2:1.  Adults appear to convert at around 4:1. 

In both cases the bioconversion from the simple food matrix of Golden Rice is better than for β-carotene from other more complex food sources which have been measured.  The results of the children studies have been presented as an abstract and a poster in a recent science meeting, and are in preparation for publication. The adult studies have been published already in AJCN. Further research examining the effect of fat in the diet on the bioconversion ratio has been undertaken, and a paper is in preparation.

When taken together with the level of β-carotene in the Golden Rice which would be consumed, the bioconversion data suggests that around 100g of Golden Rice a day in the diet of VAD susceptible populations would have a significant impact on alleviation of VAD morbidity and mortality – currently an unacceptable 6000 per day globally - in rice consuming populations.  In developing countries where rice is the staple even very small children eat more than this amount of rice daily.  It is important to remember that at the levels found in foods, including Golden Rice, β-carotene is GRAS (generally recognized as safe) with amounts in excess of bodily requirement for conversion to Vitamin A, being excreted.

Bobban: Is golden rice is being eaten in any countries? Do you fore see a near future adoption of this rice in developing nations?

AD: 
We anticipate that the first availability of Golden Rice to growers and consumers will be in 2012.  Adoption is expected principally, but not only, in Asia.

Bobban: What are the main regulatory constraints?

AD:
  Several regulatory requirements have to be satisfied using the actual transformation event which will be made available to the growers and consumers.  Of the several transformation events available to the project introgression (breeding into) and evaluation of them in Asian varieties of rice was only completed recently, as was the initial work on bioconversion ratios. Only after that data was carefully evaluated by the Humanitarian Board was it possible, within the last 6 months, to select the lead transformation event.  Only this transformation event will be utilized in all Golden Rice, in all countries, following introgression into locally adapted and preferred rice varieties. (There are over 20,000 different varieties of rice, but only a handful of these varieties or their local derivatives are extremely important for cultivation.)

Now Golden Rice is being introgressed into local rice varieties in each country, and a regulatory package is being developed which will be made available in each country, like the Golden Rice trait itself, without cost. This lead transformation event used genetic modification techniques to create it, once in about 2004.  Since then the programme has been a breeding programme.

The main regulatory constraint is the set of regulations triggered by the single use of the genetic modification technique 6 years ago which used a natural system which routinely and naturally inserts foreign DNA into plant genomes to insert two genes – one from maize and one from a common soil bacterium – into rice in a way which turned on the existing carotenoid biosynthetic pathway in rice endosperm only. 

(As there is no carotenoid in the endosperm of any white rice, there is no natural variation from which a breeding programme for Golden Rice could start without using genetic modification to introduce the necessary genes.)
Many people consider the regulations governing registration of crop plants which have utilized genetic modification in their creation to be unnecessarily complex, or completely unjustified, from a scientific perspective.  However, although the regulatory framework may change in the future, for Golden Rice it will be too late. We are happy to work with the regulators appointed by each country who work hard to fulfil their mandate.

Bobban: How do you react to the Green peace's claim that: “It takes more than 3 kilos of golden rice daily were needed to meet dietary standards of vitamin A”?

AD:  It was clear at the time that Greepeace's publicity stunt was based on multiplying together a series of variables taking the least beneficial in each case to result in a large number. See the answer to the first question above.  (Incidentally, even the initial ‘proof of concept' Golden Rice from the teams of Beyer and Potrykus contained sufficient β-carotene to significantly contribute to VAD relief.)

Scientists understand that judgments must be based on data.

Bobban: At what stage do you think that the global community will accept golden rice or in other words how can we derive a fine balance between under nutrition-mediated child deaths and regulatory barriers of golden rice as a means to save the lives of these children?

AD: Social marketing research has already informed us that cost is a greater impediment in developing countries to intentions of adoption Golden Rice for growing or consuming it than any other factor.  (Golden Rice will cost no more to grow or process or consume than white rice).  These people are very keen to supply their families with nutritious food which they can afford and which is available locally to them, and they know that the diet they can normally afford is not very nutritious.
Governments in the countries where the populations suffer from VAD and consume rice are very supportive of Golden Rice.

Bobban: Is there any message from you to ASN audience on solving nutritional challenges via novel biotechnological applications?

AD: Nutritionists and the medical community need to play their part in taking the time to understand the facts about Golden Rice (and other biofortified foods becoming available) rather than the rhetoric from GMO opponents who are often motivated by negative sentiments about capitalism and globalization which they confuse with technology, rather than concern for VAD sufferers.  

Golden Rice is intended as a complement to, not a substitute for - other VAD interventions, including Vitamin A capsule distribution, education and home gardens.  Potential growers and consumers should have choice. Having taken the time to understand the issues, don't stand silently by and let the detractors, who may be well intentioned but misinformed, attack Golden Rice without comment! Please pass on your learning to others>

www.senseaboutscience.org.uk/PDF/MakingSenseofGM.pdf is an excellent guide for intelligent and interested non-experts which puts the genetic modification of plants into the context of biology and crop science generally.  It is an easy read of about 20 pages.
And more on Golden Rice is available from www.goldenrice.org or, after visiting that website: contact@goldenrice.org 

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