Foods rich in beta-carotene (and other beneficial isoprenoids good for the body) include dark leafy green vegetables (kale, broccoli, collard greens) and bright red/orange fruits (papaw and carrots). These crops are difficult to cultivate in many of the countries whose populations suffer the most from Vitamin A deficiency because they tend to need drier and cooler climates to grow. Spinach will rot in very rainy areas such as Southeast Asia and carrots need cool dirt to grow properly. To avoid disease and to insure proper growth these plants require more expensive equipment and care. Carrots only provide 70 calories per cup, and kale only provides 42 calories per cup compared to the 242 calories per cup provided by white rice (Rombauer-The Joy of Cooking).
