Golden Rice is meant to force environmentalists to bite a bullet. The introduction of Golden Rice into any debate about genetic manipulation swifts the discussion to: “Your concern over environmental destabilization allows hundreds of thousands of third world children to die every year!” This then forces anyone against genetic manipulation of crops into a corner. Once Golden Rice is accepted, other crops would then follow.
The obvious issue to point out here is that Golden Rice does a poor job of addressing the real problem, which is that people have a poor diet. It’s a technological solution to a social problem. People suffer nutrient deficiencies because they eat high amounts of rice. People eat high amounts of rice because they suffer from poverty. One of the many potential symptoms of poverty is vitamin A deficiency, resulting in blindness or death. We can artificially add vitamin A to rice, but then we risk running into other deficiencies. The Bill and Melinda Gates foundation thus funds research to make Golden Rice with more iron, zinc and vitamin E.
Even this won’t solve the underlying problem however. Just in India alone more people die from diabetes every year than from vitamin A deficiency worldwide, and eating white rice drastically increases the risk of diabetes. In the hypothetical example where golden rice allows us to solve vitamin A deficiency, we’re setting children up for a lifetime of chronic disease, if further increases in population forces them to subsist on a diet composed of rice. A diverse diet isn’t just essential for human health, it’s essential to have a life worth living.
In practice however, it’s beginning to look increasingly unlikely that Golden Rice will ever be introduced for public consumption. Golden Rice strains are found to have a significantly lower yield than regular Rice strains.1 The reason for this is anyone’s guess. It may be that the genetic damage caused by genetic manipulation reduces the overall productivity of the plant. It could also be that a high amount of beta carotene production interferes with other mechanisms in the plant. Whether the issue will be successfully solved or not remains to be seen.
For now however, it would serve us well to look at what has actually been accomplished. The latest available trial in the Phillipines found that Golden rice strains perform systematically worse than regular rice strains, under some conditions up to forty percent.
The highest beta carotene content found in any of the tested strains in any location was 6.16 microgram per gram of rice. This means that feeding a child 100 grams of Golden rice would deliver 0.616 milligram of beta carotene. In comparison, eating 100 grams of carrot would deliver a child 8.285 milligram of beta carotene. Sweet potato, baked with the skin, would deliver a child 11.5 milligram of beta carotene.
All else being equal, a child would thus receive as much beta carotene from 10 gram of sweet potato as you would from 150 grams of rice. The worst performing strain had 3.50 microgram per gram of rice, which means 0.350 milligram per 100 gram. In this case, we’re looking at eating 300 grams of rice, to meet the equivalent of just 10 grams of sweet potato.
The amount of sweet potato needed to deliver enough vitamin A to all 200 million people at risk of vitamin A deficiency was estimated by one study to lie between 2% and 11% of global sweet potato production.2 The average global yield of sweet potato is 13.2 tonnes per hectare. The average yield of Golden rice in the study in the Phillipines was around 4 to 5 tonnes per hectare.
If we consider that sweet potato delivers around 150% more tonnes of food per hectare than Golden rice and 15 times the beta carotene of the best performing Golden rice variety, the solution to the crisis seems clear to me. We could solve vitamin A deficiency with sweet potatoes, using just a fraction of the land needed to grow Golden Rice.
There are other benefits to consider as well. Whereas white rice has diabetes promoting effects, sweet potatoes are found to reduce blood glucose in diabetics.3 In addition, sweet potatoes taste good in combination with fat, which helps beta carotene absorption.
In regards to practical considerations, the balance of evidence suggests that sweet potatoes will respond better to climate change than rice, which requires low temperatures at night. Sweet potatoes are also unlikely to compete with other crops or natural ecosystems, as sweet potatoes naturally tolerate poor soils. In Vietnam they are grown on degraded soils that have been overexploited.
For now, Golden Rice is a horrible solution to vitamin A deficiency. It removes resources from the very real options we have available already to eliminate vitamin A deficiency in susceptible individuals. As our world continues to change we are challenged with adapting to it, which is done by growing a more diverse scala of crops, instead of aiming to preserve our cereal based diets through genetic manipulation. The earlier we learn to adapt, the better the outcome for our health and well being will be.
1 – http://www.philrice.gov.ph/Rice_R&D/conferencedocs/POSTERS_21.pdf
2 – http://onlinelibrary.wiley.com/doi/10.1111/j.1541-4337.2010.00146.x/pdf
3 – http://cabdirect.org/abstracts/20083154639.html;jsessionid=C70116B1B884125FECBE42E09719DD5C
4 – http://books.google.nl/books?id=yJ6SOTpGnw0C&lpg=PA58&ots=LYlNv430tM&dq=soil%20erosion%20rice%20sweet%20potatoes&hl=nl&pg=PA58#v=onepage&q&f=false