New tools to improve nutrient delivery

Researchers from the Adolphe Merkle Institute's BioNanomaterials group have developed an improved method for studying how nutrients survive their journey through our digestive system. Their work advances techniques for characterizing nanocarriers for oral delivery of essential vitamins that would be incorporated into food and supplements.

The research focused on beta-carotene, a natural antioxidant and a form of vitamin A, found in plants such as carrots, orange-fleshed sweet potatoes, and leafy greens. Since the human body cannot synthesize vitamin A, it must be acquired through diet, where absorbed beta-carotene is converted into its active form. This vitamin is essential for vision, immune function, and cell growth.

In wealthy countries, beta-carotene provides approximately one-third of vitamin A requirements, but in developing nations, this proportion reaches 80%. However, beta-carotene breaks down quickly during food processing and in the stomach’s acidic environment, and because of its poor water solubility, its absorption in the intestine is limited. With vitamin A deficiency affecting over 330 million children globally, improving beta-carotene bioavailability could have a significant impact in reducing this public health problem. Scientists have attempted to protect beta-carotene by encapsulating it, but measuring what happens to these carriers in simulated digestive fluids has proven challenging.

Traditional measurement techniques are compromised by the complex mixture of enzymes, acids, and salts present in the digestive environment. The BioNanomaterials team addressed this by employing Taylor dispersion analysis, a technique that tracks particles as they flow through narrow capillaries. Unlike conventional methods that depend on light scattering, this approach measures light absorption as particles move within the complex medium. This makes the technique significantly less susceptible to interference from digestive components, enabling researchers to study nanoparticles directly in simulated gastrointestinal conditions without sample purification.

With this clearer picture, the team could properly compare two types of protective capsules: PLGA polymer nanoparticles and liposomes made from natural fats. They also discovered that adding vitamin C at the right concentrations dramatically reduced beta-carotene breakdown, 5% vitamin C worked best in acidic stomach conditions, while 3% was optimal in the more neutral intestinal environment. Using this approach, the team was able to accurately track the release of beta-carotene from the carrier systems and observed that the two delivery methods exhibited distinct release profiles. PLGA nanoparticles released only 9% of their beta-carotene over seven days, making them suitable for sustained nutrition applications. Liposomes released more than half their contents within 36 hours, which may be preferable for applications requiring rapid vitamin delivery.

 "This research represents a significant step forward in addressing the challenges of beta-carotene delivery," said Dr. Patricia Taladriz-Blanco, lead researcher at the Adolphe Merkle Institute. "Our findings not only improve the bioavailability of this essential nutrient but also open new possibilities for functional food development and drug delivery systems." The measurement technique has applications beyond beta-carotene research. It gives scientists a more reliable tool for studying how various nutrients and bioactive compounds behave in digestive environments, which could support the development of better delivery systems.

This study was supported by the Swiss Excellence Scholarship through the State Secretariat for Education, Research, and Innovation.

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