A team of scientists has created a new microparticle-based platform that can preserve, protect and deliver micronutrients such as iron to rodents and human volunteers. The particles address issues with preservation that have plagued previous nutrient delivery approaches such as fortified foods and could help treat micronutrient deficiencies in developing countries. Up to two billion people worldwide suffer from micronutrient deficiencies, which can cause or worsen conditions such as birth defects, anemia and blindness. Large clinical trials have shown that fortified foods can help treat micronutrient deficiencies, but progress has been hindered in developing countries because of difficulties with maintaining the stability of micronutrients during storage and cooking. Aaron Anselmo and colleagues tackled this obstacle by creating heat-stable microparticles, which consist of a pH-sensitive material that can encapsulate up to four micronutrients at once. The particles, which are slightly larger than the diameter of a human hair, shield nutrients such as vitamin A and iron from environmental factors such as heat, light, moisture, and even boiling water. The scientists first gave their particles to rodents and saw they harmlessly dissolved and released absorbable nutrients into the intestines of the animals. After observing reduced bioavailability during an initial trial involving 20 human volunteers who ingested maize porridge containing iron microparticles, the authors used a human intestinal model to study iron absorption and to optimize their particle formulations. These improvements boosted iron loading and bioavailability in a second trial involving 24 human volunteers who ingested the particles in wheat bread. "We were able to scale this process to kilogram levels and now we are working with industrial partners ... to produce on the order of metric tons," said senior author Ana Jaklenec in a related explainer video. "I've eaten bread myself, and I think Bill Gates has, that has some of these [microparticles] in them and we're all doing fine," added senior author Robert Langer.