Michael Fumento, in his AgBioView article "Golden Rice: A Golden Chance for the Underdeveloped World" (AgBioView archive #1134), interviews Dr. Ingo Potrykus about Golden Rice. Many of the claims made for Golden Rice in this article hinge on the continued lack of sufficient information on what levels of vitamin A are required to prevent vitamin A deficiency in people.

Well, folks, after a modicum of persistent hunting on the Internet, I am pleased to announce that decent "ball-park" numbers are now available. The relevant URL is the following:

http://www.fao.org/docrep/V1610t/V1610t04.htm

The article itself is a lengthy discussion of a project undertaken in three areas of Thailand to encourage people to grow a specific vitamin A-rich vegetable, ivy gourd, in their home gardens. Their diets at the time were providing about 20% of the (U.S.) RDA of vitamin A. This level of vitamin A is sufficient to prevent blindness and death for both children and adults, but is not sufficient to prevent high suceptibility to diarrheal diseases, measles, or a number of other infectious diseases. In other words, 20% of the (U.S.) RDA of vitamin A is enough to prevent clinical manifestation of severe vitamin A deficiency, but not enough to prevent clinical manifestation of moderate vitamin A deficiency.

After working with these people for a few years, the increased consumption of ivy gourd and other vitamin A-rich foods roughly doubled the daily amount of vitamin A consumed, to 40% of the (U.S.) RDA. A significant decrease in clinical manifestation of moderate vitamin A deficiency was observed. It's thus reasonable to conclude that daily consumption of about 50% of the (U.S.) RDA of vitamin A is needed to prevent clinical manifestation of both severe and moderate vitamin A deficiency. Given this, the reasons the (U.S.) RDA is double this is (1) to prevent clinical manifestations of mild vitamin A deficiency (a modestly increased susceptibility to infectious disease), and (2) to deal with the fact that a person's daily consumption of vitamin A varies, often significantly, from day to day.

Bottom line, the (U.S.) RDA of vitamin A is by no means a "luxurious" (Godiva-chocolate?) standard that Asian peoples can safely ignore, as Dr. Potrykus has asserted repeatedly since last December. On the contrary, it is precisely the level of daily vitamin A consumption that Asian peoples need to strive for if the elimination of vitamin A deficiency is to be achieved. Given that one bowl of golden rice (100 g dry weight) currently can provide no more than 5-8% of the (U.S.) RDA of vitamin A, the likelihood that (market-driven) golden rice consumption will make a significant dent in reducing vitamin A deficiency in Asia looks pretty remote. Indeed, it appears that Asian governments have made a firm decision to place their bets on (government-sponsored) foodstuff fortification and supplementation instead, with rather spectacular results, as can be seen at the following URL: http://www.unicef.org.vn/new030.htm

Asian governments may even succeed in eliminating vitamin A deficiency long before the first sack of golden rice appears in Asian markets.

Works, not faith.- Red

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