Small investments in nutrition could make the world brainier

Kebita Naima was a month pregnant when men with guns burned her home and stole everything she had. Terrified, she fled her village in eastern Congo. With a dozen relatives she walked for a week, hoping to reach Uganda, the calmer country next door. “We had nothing, no food at all,” she recalls—only water from streams and wild fruit. When she crossed the border she was “so weak and so hungry”.

That journey, and the months of deprivation that followed, affected her unborn daughter, Ms Kebita suspects. Sitting outside her home in Lobule, a village in northern Uganda, she notes how the girl, Amina, now 11, is noticeably slower than her younger brother, Mubaraka, who was better nourished both in the womb and in infancy. He started to talk a year earlier than his sister, and to walk nearly two years earlier. “He always wants to know things. He sees older kids climbing trees, and he wants to join in,” says his mother.

Just as muscles need food and exercise to grow strong, the brain needs good food and stimulation to develop properly. The first 1,000 days after conception, known as the “golden window”, are crucial. From the third trimester to the second birthday, a million synapses a second are formed in a well-nourished brain, creating the foundation on which “all learning, behaviour and health depend”, notes Meera Shekar of the World Bank. In a malnourished one, fewer connections are created. And if the brain is chronically deprived during this period, the damage is irreversible.

From nutrients to neurons

So a better diet for pregnant mothers and infants would eventually make humanity more intelligent. Alas, child malnutrition is far from being eradicated—and not just in poor, war-charred places like Congo. Many middle-income countries also have shockingly high rates.

How much of a cognitive boost would the world get from feeding babies better? Precision is tricky, but scientists agree it would be huge. If a fetus’s weight is below the tenth percentile, the child can expect to score half a standard deviation worse on all neuro-developmental measures—the rough equivalent of seven IQ points. After birth, the speeds at which a baby puts on weight (before four months) and length (before 12 months) are good predictors of IQ at the age of nine. A study in Bangladesh found that the combination of malnutrition and inadequate stimulation common in poor families was associated with an IQ gap of a whole standard deviation (about 15 points) by the age of five.

Even if a baby has enough macronutrients (protein, carbohydrates and fat), its brain development can be hobbled by a lack of micronutrients such as iron, iodine or zinc. Yet such deficiencies remain rife: half the world’s young children and two-thirds of women of reproductive age do not get enough micronutrients. For brain development, the most serious shortfall is iron. Two-fifths of children aged 6-59 months were anaemic (iron deficient) in 2019. Between 2012 and 2019, at least 92 countries saw no improvement on this score, laments Dr Shekar.

Over the past 14 years, UNICEF, the UN’s agency for children, has collected data on the proportion of children aged 24-59 months who are “developmentally on track in health, learning and psychosocial well-being” in a range of developing countries. For instance, can they say more than ten words, jump with both feet, or count to ten? The correlation with both stunting and anaemia is striking (see chart 1).

According to The Economist’s statistical analysis, stunting rates explain almost half the variation in how many kids are on track, and anaemia in pregnant women (a big contributor to stunting) explains over 40%. In contrast, GDP per person, adjusted to reflect the cost of living, explains less than 10%. Although the analysis cannot prove a causal connection, it suggests that malnutrition is a bigger obstacle to development than poverty more generally—and that income is no guarantee of a good diet.

The good news is that malnutrition is less widespread than it was. The share of children under five who are stunted (too short for their age) fell from 33% in 2000 to 22% in 2022, or roughly 150m. The proportion who were wasted (underweight for their age) fell from 9% to 7% over the same period. (The two categories overlap: one can be both stunted and wasted, or indeed stunted and overweight. Obesity among children is also rising globally.)

From nutrition to erudition

Big progress has been made against iodine deficiency, which gravely hampers brain development, simply by adding iodine to salt. The number of countries where children do not ingest enough iodine has plummeted from 113 in 1993 to 19 in 2022 (one of the laggards is Russia).

Yet grave worries remain. The overall pace of improvement in nutrition has slowed in the past decade (see chart 2). And because fertility is higher in poorer countries, future births will largely be in the parts of the world where nutrition is worst. The Economist estimates that by 2050, 67% of babies will be born in places where stunting is currently above 20%, up from 64% today. Such places include most of Africa and South Asia.

To assess more clearly where the world is heading, The Economist combined the UN’s population projections with estimates from the World Health Organisation (WHO) of stunting rates for under-fives and anaemia in pregnant women. We then calculated three scenarios.

The first assumes no improvement in national rates of stunting or anaemia among pregnant women. In this gloomy world, the shift in births from rich to poor countries would make global rates somewhat worse. By 2050, 39% of babies would be born to anaemic mothers, up from 38%, and 24% would be stunted, up from 22%.

In the second scenario, the national trends of the past decade continue. The global stunting rate would keep falling, but more slowly, as births shifted to poorer countries. By 2050 some 15% of children would grow up stunted. Anaemia, too, would drop only slowly: the global rate for pregnant mothers would stay above 30%.

In a final scenario national rates fall twice as fast as they have in recent years, and no country gets worse. The benefits would be enormous. By 2050 worldwide anaemia rates would be cut by a third compared with the “continue at current rates” scenario and stunting rates by four-fifths.

From paucity to penury

The stakes are high. By hindering brain development, malnutrition in childhood makes people poorer as adults. A study by Linda Richter and others in the Lancet estimates that the 43% of children under five in low- and middle-income countries who were at high risk of poor development because of stunting or extreme poverty were likely to earn 25% less as adults. In 2000 Sue Horton of the University of Waterloo and Richard Steckel of Ohio State University estimated that inadequate diets cost the world about 6% of GDP in lost output, and double that in developing countries.

So why, in a world that grows more than enough food for everyone, has this problem not been solved? The answer is that nutrition is not just about food. It is affected by a host of other human ills, from war, poverty and pestilence to bad eating habits and bad policy.

Wars nearly always cause hunger. Men with guns force families to abandon their homes and farmers their fields. Of the 29 countries with very high stunting rates in 2022, more than half had ongoing conflicts. Armies sometimes deliberately starve rebellious regions, as Ethiopia’s has. Big wars, such as Russia’s invasion of Ukraine, can affect the global food supply.

The very poor, obviously, find it harder to afford nutritious food. Globally, extreme poverty is falling: the proportion of people who subsist on $2.15 a day or less has plunged from 38% in 1990 to 9% in 2022. Alas, rising income does not always cure malnutrition.

A new report from Unicef offers an intriguing finding. Globally, one child in four aged 6-23 months has a severely restricted diet, including no more than two food groups (for example, breast milk plus something starchy). Roughly half of these children belong to families in the poorest 40%, based on national surveys of household assets. But the other half do not, suggesting, “Factors other than income poverty are driving the problem.” One of these is “poor feeding practices”.

People everywhere are tempted by junky snacks. Small shops in poor countries tend to stock biscuits and crisps in preference to vegetables because they do not rot quickly—handy if you have no fridge. This contributes to a growing problem: children who are overweight but still malnourished, since they consume lots of empty calories.

Cultural norms matter, too. Many parents in poor countries think it is enough to fill a child with a stodgy staple, neglecting protein, vegetables and micronutrients. In patriarchal places women “tend to eat least and last”, says Saul Guerrero Oteyza of Unicef. Husbands hog the meat, even if their wives are pregnant. In Ethiopia many Christians observe more than 100 days of fasting a year, and though young children are not required to take part, their diets suffer. In some countries there are taboos on what expectant mothers may eat. Aslia Samporna, a young mother in Bugasan Norte, a village in the Philippines, recalls her mother warning her not to eat root vegetables during pregnancy. (“Because they come from the soil, and if you eat them your baby will die and be buried.”)

Disease plays tag-team with hunger. Sick parents find it harder to earn, so their children are more likely to go without food. Hungry children are more likely to fall ill. “Most child mortality is not just the disease, it’s the disease attacking a child who is weakened from malnutrition,” says Rasa Izadnegahdar of the Bill & Melinda Gates Foundation, a charity. Ms Kebita’s first, malnourished child was often sick, she remembers. Her better-fed second child “gets sick less often and recovers quicker”.

Sickness can affect a child’s ability to absorb nutrients. In early June an outbreak of bacterial disease hit Dhaka, the densely populated capital of Bangladesh. Your correspondent visited the only free diarrhoea hospital in the city, run by icddr,b. The atmosphere outside was frantic. Mothers with dangerously dehydrated children were thronging the entrance. An extra ward was hastily being erected under a tent in a car park. A television crew had arrived to beam the mayhem to the nation.

Yet inside, thousands of inexpensive miracles were being performed. Dehydrated children were quickly revived with oral rehydration solution. This mix of sugar, salt and electrolytes costs a few pennies a packet and, mixed with water, has saved an estimated 70m lives globally since it was developed—at this hospital—in the 1970s.

Globally, diarrhoea no longer kills nearly as many children as it used to, but it is still one of the leading causes of malnutrition in the under-fives. It is one of many diseases that can be curbed through better public sanitation and personal hygiene, so it helps that the share of humanity with access to basic toilets has risen from 55% in 2000 to 81% in 2022. When babies at icddr,b’s hospital in Dhaka have been successfully treated, staff teach their mothers about hand-washing and a balanced diet.

Bangladesh shows that rapid progress is possible—and that much more remains to be done. The country has seen a huge fall in stunting, from 63% in 1990 to 24% in 2022. Tahmeed Ahmed, the head of icddr,b, credits economic growth, which has been healthy, and a spirit of collaboration between the state and ngos.

Bangladesh’s (fairly autocratic) government allows a legion of charities to work and innovate freely. Icddr,b is currently researching another important factor in nutrition: gut bacteria. Healthy children have, by the age of two, a thriving community of intestinal microbes that help them digest their food. Those without the right bugs are more likely to be malnourished. A study in the slums of Dhaka found that more than 90% of undernourished women had inflamed intestines, suggesting they had the wrong gut bacteria. Their children may inherit this handicap.

So icddr,b has been experimenting with food supplements designed to nurture the best bugs. A trial found that a mix of chickpeas, soyabeans, green banana, sugar, soya oil and micronutrients helped undernourished children gain more weight than other food supplements. A new version, using powdered banana instead of pulp, has a longer shelf life. (It tastes like extra-rich peanut butter.) Another idea is to give pregnant mothers packets of dried bacteria which, if mixed with water and swallowed, will colonise their guts. This could prove a very cheap way to improve nutrition, suggests Tafsir Hasan, a scientist who works in the city of Matlab, as he waves a packet of the dried bugs. Both these ideas are being tested in multiple countries.

Since nutrition is so complex, collecting good data is essential. Dr Ahmed’s team use a portable MRI scanner (donated by the Gates Foundation) to study brain development in well and poorly nourished children. The difference is clearly visible. Colleagues have also been gathering data since the 1960s on every household in Matlab, which is now home to 250,000 people.

This lets researchers study the long-term effect of different schemes. For example, Dr Tania Barham of the University of Colorado, Boulder looked at the results of a programme of vaccination in the 1980s against diseases such as tuberculosis, which can affect nutrition and development. By comparing men who were eligible to be jabbed as babies with similar ones who missed out, she found that they were 30% likelier to have professional or semi-professional jobs at the age of 24-30.

From ill-advised to ill-nourished

Plenty of governments get the basics wrong. Many subsidise starchy staples but not other foods, thus skewing diets unhealthily. Many offer free grain when cash and education work better. India has focused too much on school-age children, complains a veteran observer, and not enough on the very young. The Philippines recently banned golden rice, a life-saving variant with extra vitamin A, after a campaign by Luddite ngos that oppose genetically modified food.

Nonetheless, serious efforts are being made to get nutrition right, especially since the Lancet published a groundbreaking report in 2008 on the costs of getting it wrong, argues Abigail Perry of the WFP. Much depends on teaching families the basics. Ngos often train ordinary folk to educate their peers, since a neighbour is more trusted than a stranger with a tablet. Dr Tafsir describes how even chauvinist men can be persuaded to share the meat with their pregnant wives if told that the baby needs it: “They respond to that.”

Another trick is to use cash to inculcate good habits. For example, a WFP pilot programme with the Ugandan government, known as Nutricash, offers $20 a month for two years to 13,000 mothers such as Ms Kebita, provided they listen to useful advice on how to grow vegetables in their backyards, on how to feed their babies better and how to stimulate them.

Mothers interviewed by The Economist seemed to have absorbed the message. Some described in detail how they wash their hands and utensils before preparing food. Others boasted that the goats and ducks they bought with the subsidy have multiplied. All reported more varied diets. Ms Kebita says she had weaned her first child on boiled water with sugar dissolved in it. “I knew nothing about nutrition then,” she recalls. Now she does. As for stimulation: “When breastfeeding, I talk to [my baby] a lot, while looking in his eyes.”

Ms Perry wants nutrition to be a part of all health-care systems. Dr Shekar estimates it would cost $12bn a year to fight deficient nutrition “at scale”. The benefits comfortably outweigh the costs. The World Bank estimates that each $1 spent curbing wasting generates $3.50 in returns. For stunting, maternal anaemia and promoting breastfeeding, the figures are $29, $8 and $11 respectively. Getting babies’ diets right would make the next generation brainier and more productive, at a modest price tag. But for every cohort of children, the golden window closes fast.

© 2024, The Economist Newspaper Limited. All rights reserved. From The Economist, published under licence. The original content can be found on www.economist.com