Health, Nutrition and Development

Why healthier, better-nourished people drive development, illustrated by deworming, micronutrients, bed nets and the lasting effects of early childhood nutrition.

Health is both a goal of development and a cause of it. Healthy children learn more in school, healthy adults work more productively, and families that are not constantly fighting illness can save and plan for the future. Development economists have found that some of the cheapest, most cost-effective ways to improve lives, meaning those that achieve the most benefit per dollar spent, involve basic health and nutrition.

Nutrition in the first thousand days

The period from pregnancy to a child’s second birthday, often called the first thousand days, is especially important. Poor nutrition during this window can lead to stunting, meaning a child is too short for their age because of long-term undernutrition. Stunting is linked to weaker cognitive development, lower school achievement and lower adult earnings. Estimates suggest that around one in five children under five worldwide is stunted, with high rates in South Asia and sub-Saharan Africa.

A long-running study in Guatemala, begun in the 1960s, gave some villages a protein-rich supplement for young children. Decades later, researchers found that men who received it as small children earned noticeably higher wages as adults.

Hidden hunger

A person can eat enough calories yet still lack essential vitamins and minerals, called micronutrients. This is sometimes called hidden hunger. Iodine deficiency during pregnancy can harm a baby’s brain development; iron deficiency causes anemia and fatigue; vitamin A deficiency weakens immunity and can cause blindness. Some solutions are remarkably cheap. Adding iodine to table salt, now standard in most countries, costs only a few cents per person per year and has been one of the most successful public health measures in history.

Deworming in Kenyan schools

In the late 1990s, economists Edward Miguel and Michael Kremer studied a program in western Kenya that gave schoolchildren inexpensive pills to treat intestinal worms, costing well under a dollar per child per year. Schools were phased into the program in random order. The researchers found that school absence fell by roughly a quarter in treated schools. Because worms spread through contaminated soil, treating some children also reduced infections among untreated children nearby, a benefit economists call spillover effects. Follow-up studies years later reported higher earnings among those who had been dewormed.

The deworming debate

The Kenya findings made deworming famous, and it was promoted as one of the best uses of charitable money. But in 2015, other researchers re-analyzed the original data and argued that some effects were weaker or less certain than first reported. The exchange became known online as the “worm wars.” Larger reviews of many deworming trials found smaller average effects on children’s weight and school performance. Many economists still consider mass deworming worthwhile because it is so cheap, but the debate is a useful reminder that even celebrated findings deserve scrutiny.

Disease and productivity

Malaria, diarrhea, tuberculosis and HIV have imposed enormous economic costs on poor countries. Insecticide-treated bed nets are one of the best-studied tools against malaria. Randomized studies in Kenya found that when bed nets were given away free, far more families used them than when they had to pay even a small price, and people who paid were not more likely to use the nets properly. This helped shift policy toward free mass distribution, and the spread of bed nets is credited with preventing hundreds of millions of malaria cases in Africa since 2000.

Assuming health improves only after countries get rich

It might seem that nations must first grow wealthy and then spend on health. But health gains can come early and cheaply, through vaccines, iodized salt, clean water and bed nets, and they help cause later growth. Countries such as Sri Lanka achieved long life expectancy while still relatively poor.

Key takeaways

Health is both an outcome of development and a driver of it.
Undernutrition in the first thousand days can cause stunting with lifelong effects.
Cheap measures such as iodized salt address hidden hunger from missing micronutrients.
Deworming in Kenya reduced school absence and had spillover effects, though its size is debated.
Free bed net distribution greatly increased use and helped reduce malaria.