Environmental Problems, Their Causes, and Sustainability 1

Calories per day per person3,7003,5003,3003,1002,9002,7002,5002,3002,1001,90019607619701980Developed countries1990WorldYearDevelopingcountries2000201020202030Figure 14-17 The average daily food intake in calories per personin the world, developing countries, and developed countries:1961–2003 and projected increases to 2030. The averageadult male needs about 2,500 calories per day for good health.(Data from UN Food and Agriculture Organization)(such as measles and diarrhea) because of their weakenedcondition. This means that each day an averageof 15,100 people—80% of them children under age 5—die prematurely from these causes related to poverty.Studies by the United Nations Children’s Fund(UNICEF) indicate that one-half to two-thirds of childhooddeaths from nutrition-related causes could beprevented at an average annual cost of $5–10 per childby taking the following measures:■ Immunizing children against childhood diseasessuch as measles■ Encouraging breast-feeding (except for motherswith AIDS)■ Preventing dehydration from diarrhea by givinginfants a mixture of sugar and salt in a glass of water■ Preventing blindness by giving children a vitaminA capsule twice a year at a cost of about 75¢ per childor fortifying common foods with vitamin A and othermicronutrients at a cost of about 10¢ per child annually■ Providing family planning services to help mothersspace births at least 2 years apart■ Increasing education for women, with emphasis onnutrition, drinking water sterilization, and child careSome people in developed countries also sufferfrom lack of access to enough food for good health. Inthe United States, about 11 million people (half ofthem children under age 5) do not have access toenough food on a regular basis for good health.How Serious Are MicronutrientDeficiencies? Important but LimitedProgressOne of every three persons has a deficiency of one ormore vitamins and minerals, especially vitamin A,iron, and iodine.According to the World Health Organization (WHO),about one out of three people suffer from a deficiencyof one or more vitamins and minerals. The most widespreadmicronutrient deficiencies in developing countriesinvolve vitamin A, iron, and iodine.According to the WHO, 120–140 million childrenin developing countries are deficient in vitamin A.Globally about 250,000 children under age 6 go blindeach year from a lack of vitamin A and up to 80% ofthem die within a year.Scientists recently spliced genes into rice to makeit rich in beta-carotene, the source of vitamin A. Eatingnormal amounts of this vitamin-fortified rice—calledGolden Rice—should provide 20–40% of the daily requirementsof vitamin A. But the beta-carotene in thisrice is not converted to vitamin A in the body of apoorly nourished person.Other nutritional deficiency diseases are causedby lack of minerals. Too little iron—a component of hemoglobinthat transports oxygen in the blood—causesanemia. According to a 1999 survey by the WHO, oneof every three people in the world, mostly women andchildren in tropical developing countries, suffers fromtoo little iron. Iron deficiency causes fatigue, makes infectionmore likely, and increases a woman’s chancesof dying in childbirth and an infant’s chances of dyingof infection during its first year of life.Elemental iodine is essential for proper functioningof the thyroid gland, which produces a hormone thatcontrols the body’s rate of metabolism. Chronic lack ofiodine, found in seafood and crops grown in iodinerichsoils, can cause stunted growth, mental retardation,and goiter—an abnormal enlargement of the thyroidgland that can lead to deafness. According to theUnited Nations, about 26 million children suffer braindamage each year from lack of iodine and 600 million—mostlyin South and Southeast Asia—suffer fromgoiter.How Serious Is Overnutrition? Badand Getting WorseIn developed countries overnutrition is a majorcause of preventable deaths.Overnutrition occurs when food energy intake exceedsenergy use and causes excess body fat. Overnourishedpeople are classified as overweight if they are roughly4.5–14 kilograms (10–30 pounds) over a healthy bodyweight and obese if they are more than 14 kilograms(30 pounds) over a healthy weight. Too many calories,too little exercise, or both can cause overnutrition.288 CHAPTER 14 Food and Soil Resources