That's a strong argument, and much better than any of the other replies. It's not entirely convincing to me, since vitamin A deficiency is spread very widely,

That's a strong argument, and much better than any of the other replies. It's not entirely convincing to me, since vitamin A deficiency is spread very widely, including in many countries that don't eat much rice. That said, the general idea of addressing specific deficiencies with enhanced food sounds very promising.