Researchers encapsulate nutrients to prevent cooking degradation

Approximately two billion people globally are said to suffer from deficiencies of key micronutrients such as iron and vitamin A. Two million children die from these deficiencies every year, and people who do not get enough of these nutrients can develop blindness, anemia and cognitive impairments.

Vitamin A is sensitive to heat and can be degraded during cooking, and iron can bind to other molecules in food, giving the food a metallic taste. To overcome this, a team from Massachusetts Institute of Technology (MIT) set out to find a way to encapsulate micronutrients in a material that would protect them from being broken down or interacting with other molecules, and then release them after consumption.

The MIT researchers developed a biocompatible polymer that encapsulates the nutrients and prevents them being degraded during storage or cooking.

“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,” said Robert Langer, the David H. Koch Institute Professor at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research.

The researchers tested approximately 50 different polymers and ultimately used one known as BMC. This polymer is currently used in dietary supplements, and is classified as “generally regarded as safe” in the US.

Using this polymer, the researchers showed that they could encapsulate 11 different micronutrients, including zinc, vitamin B2, niacin, biotin, and vitamin C, as well as iron and vitamin A. They also demonstrated that they could encapsulate combinations of up to four of the micronutrients together.

Tests in the lab showed that the encapsulated micronutrients were unharmed after being boiled for two hours. The encapsulation also protected nutrients from ultraviolet light and from oxidising chemicals, such as polyphenols, found in fruits and vegetables. When the particles were exposed to very acidic conditions (pH 1.5, typical of the pH in the stomach), the polymer become soluble and the micronutrients were released.

In tests in mice, the researchers showed that particles broke down in the stomach, as expected, and the cargo travelled to the small intestine, where it could be absorbed.

The researchers then conducted human trials. The trial was led by Michael Zimmerman, a Professor of health sciences and technology at ETH Zurich who studies nutrition and food fortification.

In the first trial, the researchers incorporated encapsulated iron sulfate into maize porridge. They found that people who ate the fortified maize – female university students in Switzerland, most of whom were anemic – did not absorb as much iron as the researchers hoped they would. The amount of iron absorbed was approximately half of what was absorbed by subjects who consumed iron sulfate that was not encapsulated.

The researchers then reformulated the particles and found that if they boosted the percentage of iron sulfate in the particles from three percent to about 18 percent, they could achieve iron absorption rates very similar to the percentage for unencapsulated iron sulfate. In that second trial, also conducted at ETH, they mixed the encapsulated iron into flour and then used it to bake bread and shows that people were able to absorb iron from the food.

“Reformulation of the microparticles was possible because our platform was amenable to large-scale manufacturing approaches,” said Aaron Anselmo. the paper’s lead author. “This allowed us to improve our formulation based on the feedback from the first trial.”

The next step, according to Ana Jaklenec, a Research Scientist at the Koch Institute and senior author of the study, is to try a similar study in a country where many people experience micronutrient deficiencies. The researchers are now working on gaining regulatory approval from the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives. They are also working on identifying other foods that would be useful to fortify, and on scaling up their manufacturing process so they can produce large quantities of the powdered micronutrients.