Encapsulated micronutrients fortify food

Fortifying foods with nutrients is not as simple as it sounds. Iodised salt is one that’s successful, but adding iron or vitamin A to other staples? Chemically speaking, a lot can happen during the process, and usually the process affects the nutrients and the food.  

Recently MIT researchers found a way to fortify food with a technology that they say could help fight malnutrition. Their method involves encapsulating micronutrients in a biocompatible polymer that prevents the nutrients from being degraded during storage or cooking.

In a clinical test, women who were given iron-fortified bread were able to absorb this nutrient. This success is motivating the MIT team to run further clinical trials in developing countries where malnutrition is high.

“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, the David H. Koch Institute Professor at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research, in a press release.

Langer and Ana Jaklenec, a research scientist at the Koch Institute, are the senior authors of the study, which appears in Science Translational Medicine. The paper’s lead authors are former MIT postdocs Aaron Anselmo and Xian Xu, and ETH Zurich graduate student Simone Buerkli.

Other authors of the paper are Yingying Zeng, Wen Tang, Kevin McHugh, Adam Behrens, Evan Rosenberg, Aranda Duan, James Sugarman, Jia Zhuang, Joe Collins, Xueguang Lu, Tyler Graf, Stephany Tzeng, Sviatlana Rose, Sarah Acolatse, Thanh Nguyen, Xiao Le, Ana Sofia Guerra, Lisa Freed, Shelley Weinstock, Christopher Sears, Boris Nikolic, Lowell Wood, Philip Welkhoff, James Oxley, and Diego Moretti. The MIT team was funded by the Bill and Melinda Gates Foundation.

MIT engineers encapsulate nutrients in a biocompatible polymer, making it easier to use them to fortify foods. (Image credits: Second Bay Studios)

Material for encapsulating micronutrients

Furthermore, the researchers explained that vitamin A is heat-sensitive and degrades during cooking, while iron gives food a metallic taste. Therefore, micronutrients have to be encapsulated well before they can be added to food staples. The material – chosen from 50 polymers tested –is BMC, which is currently used in dietary supplements, and is classified as “generally regarded as safe” in the United States.  BMC can protect nutrients from breaking down or interacting with other molecules, and releases nutrients after being consumed.

Researchers said this polymer could encapsulate 11 different micronutrients, including zinc, vitamin B2, niacin, biotin, and vitamin C, as well as iron and vitamin A. They could even encapsulate combinations of up to four of the micronutrients together.

Lab tests showed that the encapsulated micronutrients were intact after being boiled for two hours. The encapsulation also protected nutrients from UV 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 can be absorbed.

Test on human subjects

The initial trial on women who were mostly anemic, led by Michael Zimmerman, a professor of health sciences and technology at ETH Zurich who studies nutrition and food fortification, was to find out if iron could be absorbed. Subjects were given iron sulfate in maize porridge (common in developing countries), and vegetable sauce. Because the test subjects absorbed only half of the iron,  the researchers reformulated the particles, boosting the percentage of iron sulfate in the particles from 3% to about 18%. Having done so achieved iron absorption rates very similar to the percentage for unencapsulated iron sulfate. In that second trial, also conducted at ETH Zurich, they mixed the encapsulated iron into flour and then used it to bake bread.

“Reformulation of the microparticles was possible because our platform was tunable and amenable to large-scale manufacturing approaches,” Anselmo says. “This allowed us to improve our formulation based on the feedback from the first trial.”

The next step, Jaklenec says, 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.