New research suggests that more than a third of child deaths around the world are as a result of poor nutrition among mothers and their young.
Researchers from the UK, US and Pakistan said if effective work was carried out to tackle undernutrition in developing countries infant mortality could be cut by up to 25%.
The study, which was published in the Lancet, said the greatest potential for improving child death rates would be to give women vitamin A supplements and advice on how to breastfeed safely.
The authors said: "Maternal and child undernutrition is highly prevalent in low-income and middle-income countries, resulting in substantial increases in mortality and overall disease burden."
Undernutrition includes stunting, wasting and deficiencies of essential vitamins and minerals, as well as over-consumption of specific nutrients.
The scientists said that growth stunting, wasting and problems with babies not developing properly in the womb accounted for 2.2 million deaths in 2005.
A separate report, co-authored by Professor Simon Cousens of the London School of Hygiene and Tropical Medicine, said young children at risk of undernutrition should be given supplements of vitamin A, zinc and iron.
He said such measures could reduce infant mortality by 25% if they were implemented across the 36 countries with the highest rate of undernutrition.