Chapter 4, Problem 4.25P

Certain vegetables and fruits contain plant pigments called carotenoids that are metabolized in the body to produce Vitamin A. Lack of Vitamin A causes an estimated 250,000 to 500,000 children worldwide to become blind every year. An approach to reducing blindness and other childhood health problems resulting from this deficiency is to use genetic engineering of rice—a food staple in developing countries and economically disadvantaged regions of the world—so that rice becomes a dietary source of Vitamin A. For example, a strain known as Golden Rice has been genetically engineered so that it can produce and store carotenoids such as p-carotene (which helps give carrots and squash their yellow-orange color). One type of Golden Rice contains approximately 30 micrograms of carotenoids (81% p-carotene, 16% a-carotene, and 3% P-cryptoxanthin) per gram of uncooked rice. A study has reported that when a person eats Golden Rice, their body metabolizes 1 microgram of Vitamin A for every 3.8 micrograms of p-carotene they consume.

1. It is recommended that children between 1 and 3 years of age should get 300 micrograms of Vitamin A per day. Considering only the metabolism of p-carotene given above, how many grams of Golden Rice would a child have to eat in order to obtain this much Vitamin A? Does this seem like a reasonable amount of rice to eat in one day, if one cup of cooked rice is approximately 175 g?
2. a-carotene and p-cryptoxanthin can also be converted into Vitamin A, but when compared to P-carotene, it takes twice as much of each of these compounds to produce one unit of Vitamin A. Considering all of the carotenoids in Golden Rice as potential sources of Vitamin A, how' many grams of Golden Rice would a three-year-old child have to eat in order to obtain the recommended daily amount of Vitamin A?
Exploratory Exercises—Research and Discover

Some individuals are not convinced that genetically modified foods are safe to grow or to eat. What kinds of risks or uncertainties are cited by these individuals? What kinds of measures are taken by farmers and suppliers of genetically modified seeds to minimize these risks?

Some people do not believe that Golden Rice is a practical, viable solution to Vitamin A deficiency around the world. Summarize the major arguments for and against production and distribution of Golden Rice.