New UN policy brief reveals double-edged role of irrigation in child health

Irrigation improves child nutrition in areas where water resources are already under severe stress, finds a new policy brief by the UN University Institute for Water, Environment and Health, Canada. Nutrition Insight explores this health and environmental tension with the lead author, unveiling solutions that pair nutrition and sustainability goals. 

The study, published in Nature Sustainability, analyzed data from over 70,000 households across 26 low- and middle-income countries and found that boosting irrigation leads to higher dietary diversity among children under five. This is essential for micronutrient sources and long-term health. 

“Irrigation is often promoted as a way to boost food production and reduce malnutrition, especially in rural communities that face food insecurity,” Marc F. Muller, associate research professor at the university, tells us.

“We found that these benefits vary a lot across contexts. In fact, they are strongest in areas where water is already scarce, raising concerns about long-term sustainability. In water-abundant areas, irrigation often supports export-oriented crops, which offer fewer nutritional gains for local communities. So while irrigation holds potential, our findings caution against one-size-fits-all approaches.”

Should irrigation be banned?

The study questions the long-term sustainability of irrigation, as although it improves child nutrition, it overuses water. Despite this, Muller stresses irrigation should not be dismissed outright. “But it must be used thoughtfully.”

Irrigation improves children’s diets in water-scarce areas — but deepens the water crisis.“The key message from our research is not ‘don’t irrigate,’ but rather ‘don’t assume irrigation is always a win-win.’ In some contexts, irrigation supports staple crops that improve local diets. In others, the benefits of irrigation — whether in terms of food production or wealth and income gained from export — might struggle to reach local households.”

“In some situations, there is enough water available to practice it. In others, it will strain limited water resources. The challenge is to align irrigation projects with nutritional needs and water realities. That means assessing water availability, crop choices, and local food systems before expanding irrigation,” explains Muller.

He suggests against abruptly stopping irrigation in water-scarce regions, as cases have shown it could do more harm than good, as many depend on it for food and income. “But continuing unsustainable irrigation unchecked is equally risky.”

Although the study did not study particular technologies, Muller suggests shifting to the most efficient irrigation available as a solution that also supports alternative livelihoods and crops that are drought-tolerant and nutritious.

Irrigation improves children’s diets in water-scarce areas — but deepens the water crisis.

“It also means regulating water withdrawals and monitoring water resources. Phasing in these changes requires coordination, investment, and political will. It’s not easy, but it’s essential for long-term resilience.”

Deciding power over irrigation

Muller advocates for a need to rethink how, where, and for whom irrigation is deployed so that agricultural activity is linked to nutritional, economic, and environmental benefits. 

UN researchers urge smarter irrigation policies to align nutrition, sustainability, and equity.However, the authority deciding who gets to use irrigation must be made at the national or donor level and involve communities from the outset, he says.

“Farmers, especially women and smallholders, must have a voice in how irrigation is planned and implemented. Governments and development agencies have a responsibility to create inclusive decision-making spaces and ensure that benefits reach the most vulnerable.”

“Technical decisions, such as what crops are grown or how water is allocated, must also be guided by social and nutritional priorities, not just economic returns. That means integrating ministries of agriculture, health, and water, and fostering cross-sector collaboration.”

According to Muller, funders and governments must decide that nutrition is a priority for large-scale investments. They should set measurable targets and appropriate regulations so that communities benefit. 

“Directly through improved availability or affordability of nutritious foods or indirectly through improved incomes,” he adds.

Balancing export- and locally-oriented crops

Muller believes there is a delicate balance regarding whether to halt or reduce export-oriented cash crops in water-abundant areas so locals can cultivate nutritious foods instead. 

“Export crops can bring income and investment but don’t always translate into better diets locally. In water-abundant regions, promoting the cultivation of more nutritious, locally consumed crops could improve food security. But shifting away from cash crops may reduce export revenues or jobs if not managed carefully.” 

“The solution isn’t necessarily to stop cash crops, but to diversify cropping systems and invest in local value chains that make healthy food accessible and profitable. Policies should encourage farmers to grow nutrient-rich crops without undermining their livelihoods,” he advises.