Thwarting malnutrition by adding nutrient-loaded microcapsules to food
Getting people to change their eating habits in order to get more nutrients is difficult at the best of times – and it’s even harder in developing countries, where people might not have the luxury of choice. To help with the problem of malnutrition, researchers at MIT have fortified staple foods like flour with new microparticles containing vital nutrients like vitamin A and iron.
Deficiencies in different nutrients can have pretty dramatic results over time. Vitamin A deficiency, for example, can negatively impact the immune system and even lead to blindness, while iron deficiencies can cause anemia and impair cognitive development.
These kinds of deficiencies are most common in developing countries, where access to healthier foods is harder to come by. But they still occur even in developed countries, due to a reluctance to change unhealthy diets.
In the past, one of the most effective ways around this was to “fortify” foods, by adding nutrients to staples that people already eat a lot of. The most famous example may be iodized salt, where iodine was added to table salt in the US in the 1920s to fight a deficiency that was causing goiters – a swelling of the thyroid. By incorporating the nutrients into commonly-eaten foods, these health problems can be largely avoided without having to rely on people changing their habits.
For the new study, the researchers developed a new way to fortify foods with different micronutrients. Unfortunately, just adding them straight into food doesn’t always work, since they can affect the taste or break down while cooking. So the team investigated wrapping them up in biocompatible polymers.
After testing about 50 different materials, they eventually settled on a polymer called BMC, which is regarded as safe and commonly used in dietary supplements. They managed to encapsulate 11 different micronutrients into these shells, including zinc, niacin, biotin, iron, and vitamins A, B2 and C. Up to four of the nutrients could be combined into microparticles together, too.
Then the team ran a series of experiments to test how well the capsules stood up to punishment, and how well the body would absorb the nutrients in them. First, the researchers boiled the microparticles for two hours, and exposed them to ultraviolet light and oxidizing chemicals. In all cases, the micronutrients inside were unharmed.
Those results suggest that the microparticles should be able to survive in ingredients during storage, preparation and cooking. But if they’re that sturdy, how do you get the payloads out when you actually want them?
Next up, the team tested exactly that. They exposed the particles to highly acidic conditions – similar to those you’d find in the stomach – and sure enough, the BMC shells broke down, releasing the micronutrients inside. Tests on mice showed that this worked in vivo, with the capsules reaching the stomach, breaking down and the released nutrients traveling to the small intestine where they can be absorbed.
Human tests seem equally promising. In a first trial on women with anemia, the team found that people who were eating fortified maize porridge weren’t absorbing as much iron as hoped. So the researchers increased the iron sulfate content in the particles from three percent to 18 percent. When these were added to flour and then baked into bread, iron absorption rates increased.
“We are really excited that our team has been able to develop this unique nutrient-delivery system that has the potential to help billions of people in the developing world, and taken it all the way from inception to human clinical trials,” says Robert Langer, senior author of the study.
The next steps will be to test the technique in countries where people are suffering from certain deficiencies, to see if it can help address the problem. Approval from regulatory bodies is on the agenda, as is scaling up the process and finding new foods to incorporate the capsules into.
The research was published in the journal Science Translational Medicine.