Nano-emulsions may boost beta-carotene availability from supplements

Scientists from the Department of Food Science, University of Massachusetts, Amherst report that excipient nanoemulsions formulated from long chain triglycerides (LCT) could significantly boost the bioaccessiblity of the carotenoid.

Data from an in vitro​ gastrointestinal tract (GIT) model – which included mouth, stomach, and small intestine phases – indicated that the bioaccessibility of the beta-carotene from the tablets and soft gels was found to be low, at 0.3% and 2.4%, respectively.

The LCT nanoemulsions, however, were found to increase beta-carotene bioaccessibility in tablets to 20% and in soft gels to 5%, according to findings published in the Journal of Agricultural and Food Chemistry​.​

“Our results may be useful in formulating dietary supplements with improved bioavailability characteristics,” ​wrote Laura Salvia-Trujillo and David Julian McClements. “For example, soft gels could be formulated to contain an LCT nanoemulsion (rather than a bulk oil) inside the capsules, or tablets could be formulated to contain a spray-dried LCT nanoemulsion within them.”​

Bioaccessibility ​

Salvia-Trujillo and McClements explained that the bioaccessibility of carotenoids – which are fat soluble molecules - is dependent on the type of oil used to deliver them.

“Excipient emulsions are an effective strategy for improving the bioavailability of lipophilic nutrients and nutraceuticals,” ​they wrote. “An excipient emulsion may achieve this goal by modulating the bioaccessibility, absorption, and/or stability of the coingested nutraceuticals in the GIT. ​

“In the current work, the focus was on the utilization of oil-in-water nanoemulsions as excipients for carotenoids delivered in the form of dietary supplements. These excipient nanoemulsions consist of small lipid droplets (diameter less than 200 nm) dispersed within an aqueous phase. An advantage of using nanoemulsions as excipients is their rapid digestion within the GIT due to their small droplet dimensions (high surface area), which can lead to rapid solubilization of any lipophilic bioactives into the mixed micelle phase.”​

The researchers tested the accessibilityof beta-carotene from tablets and soft gels manufactured by Whole Foods Market and Country Life, respectively. They also tested the accessibility of the carotenoid when long or medium chain triglycerides (LCT or MCT) were co-administered.

Results showed that the bioaccessibility of the beta-carotene from the tablets and soft gels was poor, and that the MCT nanoemulsions only slightly improved bioaccessibility. Significant improvements were observed for the LCT nano-emulsions, particularly from tablets.

“These results were attributed to the ability of large carotenoid molecules to be incorporated into large mixed micelles formed by LCT digestion but not by small ones formed by MCT digestion,”​ wrote Salvia-Trujillo and McClements.

“Our results indicate that excipient nanoemulsions have considerable potential for improving nutraceutical bioavailability from dietary supplements.”​

Source: Journal of Agricultural and Food Chemistry​​
Published online ahead of print, Article ASAP​, doi: 10.1021/acs.jafc.6b00804
“Improvement of beta-Carotene Bioaccessibility from Dietary Supplements Using Excipient Nanoemulsions”​
Authors: L. Salvia-Trujillo, D.J. McClements