Billions of people around the world are likely to remain vulnerable to the serious health effects of micronutrient deficiency for decades to come, even under the most optimistic scenarios for global economic and income growth, new research shows.

In a study released today in Nature Sustainability, researchers projected the dietary availability of several important nutrients and micronutrients through 2050, relative to levels needed to maintain good health. The study considered different scenarios for future trends in economic and real income growth; some of these scenarios also factored in the impact of climate change on food and nutrient availability.

The authors project that insufficient dietary intake of critical micronutrients such as iron, zinc, and vitamin A—which account for a significant share of micronutrient-related disease burdens—“are likely to remain problematic in 2050 under all modelled scenarios,” even in a high economic growth scenario that does not incorporate the impacts of climate change.

The projections are particularly worrisome for low-income countries, where widespread undernutrition and its negative health consequences take big tolls on human well-being. The World Health Organization estimates that more than two billion people worldwide currently suffer from “hidden hunger,” or micronutrient deficiency. The damaging effects include stunted growth, weakened immune systems, and impaired intellectual development.

The primary challenge to global food security through midcentury will be to ensure that people have nutritious diets, according to the authors. “Research priorities and policies should place a stronger emphasis on addressing nutritional quality by increasing availability and affordability of nutrient-dense foods and improving dietary diversity,” they argue.

While balanced diets are the ultimate objective in addressing the micronutrient challenge, the authors also urged stepped-up research activity in other interventions to help fill micronutrient gaps, particularly for low-income individuals. One intervention they cite is biofortification, in which staple crops are bred to increase their levels of micronutrients.

“The ideal is to increase availability and access to animal source foods, fruits and vegetables. But the poorest people often miss out because they can’t afford or can’t access these types of foods,” said Keith Lividini, one of the study’s authors and head of strategy and policy research at HarvestPlus, which develops and promotes staple crops biofortified with vitamin A, iron, or zinc. “Biofortification puts the micronutrients in affordable staple foods that low-income families already consume,” he noted.

This study breaks new ground by combining analysis of the effects of both economic growth and climate change on nutritional outcomes, and complements the findings of other recent studies, such as this paper in Nature Climate Change, which found that rising levels of carbon dioxide will harm the nutritional value of crops.