The Life Cycle of Malnutrition
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THE LIFE CYCLE OF MALNUTRITION By: STUART GILLESPIE RAFAEL FLORES From IFPRI 1999-2000 INTERNATIONAL FOOD POLICY RESEARCH INSTITUTE 2033 K. STREET WASHINGTON, DC 20006-1002 2000 THE LIFE CYCLE alnutrition is not a disease that runs its course, bringing immunity. MRather it is a process, with consequences that may extend not only into later life, but also into future generations. The process of becoming malnourished often starts in utero and may last, particularly for girls and women, throughout the life cycle. It also spans generations. A stunted girl (that is, one whose height is significantly low for her age) is likely to become a stunted adolescent and later a stunted woman. Besides posing threats to her own health and productivity, poor nutrition that contributes to stunting and underweight in her adult life increases the chance that her children will be born malnourished. And so the cycle turns. OF MALNUTRITION Stuart Gillespie and Rafael Flores BIRTH AND INFANCY and lowers muscle strength in the long This year some 30 million babies in the term. Recent research has linked IUGR to developing world—around 82,000 every neurological dysfunction, associated with day—will be born with impaired growth due attention deficits, hyperactivity, clumsiness, to poor nutrition during fetal life.Two-thirds and poor school performance. of these infants will be born in South and Central Asia. By any standard, this is a major Beyond childhood, there is growing global human development problem with evidence that IUGR increases the risk of profound short- and long-term consequences acquiring high blood pressure, non-insulin- for individuals, households, communities, dependent diabetes, coronary heart disease, and nations. and cancer in adult life.The "fetal origins of disease" hypothesis posits that poor nutrition In developing countries the main direct causes during critical periods of gestation and early of intrauterine growth retardation (IUGR) are infancy, followed by relative affluence, increases nutritional. IUGR occurs when women suffer the risks of chronic diseases in adulthood. from low weight and short stature before Urbanization and rapid economic development pregnancy—largely because of their own are changing people’s dietary patterns and childhood malnutrition—and then gain too lifestyles in ways that make such consequences little weight during pregnancy, primarily because more likely to emerge. they do not consume enough food or because infection compromises the absorption or Pregnant women and their fetuses not only utilization of the food they do eat. Other factors need to consume adequate amounts of food underlie these direct causes, including household but also need to get access to adequate food insecurity, poor caring practices, and micronutrients—the vitamins and minerals that inadequate health and environmental conditions. help the body function.Apart from the direct effects on the woman herself, micronutrient The consequences of being born malnourished malnutrition during pregnancy has serious are grave. IUGR infants suffer from impairment implications for the developing fetus. Iodine of most immune functions and face an increased deficiency can cause fetal brain damage or risk of diarrhea and pneumonia.The risk of stillbirth, folate deficiency may result in neural neonatal death is 10 times higher for infants tube defects, and iron deficiency anemia and weighing 2–2.5 kilograms than it is for those vitamin A deficiency can raise the future infant’s weighing 3–3.5 kilograms. IUGR also significantly risk of illness and death and impair vision and reduces body size, changes body composition, cognitive development. 9 CHILDHOOD Can these children catch up? Can IUGR infants are more likely to become malnutrition be reversed if children are stunted children. In addition, conditions adequately nourished later? The answer is yes, during infancy and early childhood, like to a point.The potential for catch-up growth frequent or prolonged infections and among stunted children is limited after age two inadequate consumption of nutrients— years, particularly when such children remain particularly energy, protein, vitamin A, zinc, in poor environments.A recent study in the and iron—can contribute to underweight Philippines, however, has shown that some and stunting among preschool children. catch-up between the ages of two and eight Inadequate food, health, and care in the and a half years is feasible for children who household or community again underlie were not born with low birthweight or these immediate causes. severely stunted in infancy. Children who were stunted at age two years, however, whether or The recently released Fourth Report on the not they later achieved catch-up growth, were World Nutrition Situation prepared by the found to suffer significantly from later deficits United Nations Sub-Committee on Nutrition in cognitive ability, a finding that further and IFPRI states that currently about one in emphasizes the need to prevent early stunting. three children under five years old in the developing world is stunted, with Eastern Data on the nutritional status of school-age Africa (48 percent) and South Central Asia children are increasingly being collected, as evi- (44 percent) having the highest levels.This dence mounts linking malnutrition or hunger translates into some 182 million stunted with poor school attendance, performance, children, 70 percent of whom live in Asia and learning. and 26 percent in Africa. ADOLESCENCE Almost 27 percent of all under-five children Adolescence, which covers most of the second are currently underweight (of low weight for decade of life, is a transition phase when chil- their age), a prevalence that dropped during dren become adults. During this time, growth the 1990s but not very rapidly. Most countries in stature or height accelerates, driven by hor- failed to achieve the ambitious goal set at the monal changes, and is faster than at any other 1990 World Summit for Children of halving time in the individual’s postnatal life except the childhood underweight prevalence by the first year. year 2000. Research has shown that better-nourished Childhood malnutrition has immediate girls grow faster before menarche and reach consequences. Underweight children tend to menarche earlier than undernourished girls, have more severe episodes of diarrhea and a who grow more slowly but for longer, as higher risk of pneumonia.They are also more menarche is delayed. Ultimately, these two likely to die. Over 50 percent of the nearly factors tend to balance out, and well-nourished 12 million child deaths that occurred in 1995 and undernourished adolescents may achieve were associated with low weight for age, the similar total height during adolescence.The majority of which derived from the effects of adult height finally attained, however, may still mild to moderate undernutrition. differ as a result of pre-existing childhood stunting. Studies of several countries have shown little change in average height-for-age during the adolescent years, indicating little catch-up. 10 Because underweight adolescent girls are Both underweight and overweight conditions growing for longer, they may not finish growing have serious health effects. Underweight adults before their first pregnancy. A still-growing allocate fewer days to heavy labor and are adolescent is likely to give birth to a smaller more likely to fail to appear for work owing baby than a mature woman of the same nutri- to illness or exhaustion. tional status, probably because of poor placen- tal function in the adolescent and because the At the other end of the spectrum, overweight growing adolescent and the growing fetus are conditions are associated with an increased competing for nutrients. Calcium status is a prevalence of cardiovascular risk factors particular concern, as the bones of adolescents such as hypertension, unfavorable blood still require calcium for growth at a time when lipid concentrations, and diabetes mellitus. fetal needs for bone growth are also high. Overweight is also a major risk factor for the development of gallstones and endometrial There remains little evidence to suggest that cancer and is related to osteoarthritis in sever- individuals who suffer from growth retardation al joints. As already mentioned, adults who in early childhood can significantly compensate were malnourished as infants have a height- for it in adolescence. Stunted children are thus ened risk of developing some of likely to become stunted adults. Moreover, these conditions. even if an intervention could lead to adolescent catch-up growth, which could OLD AGE reduce obstetric risk due to small maternal Populations are aging. By 2025, the earth will size, it would not necessarily reverse the house 1.2 billion elderly adults, of whom nearly effects of early childhood stunting on 70 percent will live in developing countries. cognitive function. For most of these older people, retirement is not an option. Poverty, a lack of pensions, the ADULTHOOD deaths of younger adults from AIDS, and the The economic livelihood of populations migration of younger people from rural to depends on the health and nutritional urban areas are among the factors that will well-being of adults. In adults the main cause compel older people to continue working. of a reduction in body weight is a decrease Adequate nutrition, healthy aging, and the abili- in food intake, often in combination with ty to function independently will be essential disease, but when energy intake