Methods for Assessing Aspects of Carotenoid Bioavailability

Abstract

Carotenoids are a group of C-40 isoprenoid-based molecules with >600 representatives in nature, of which approximately 30 are of importance within our daily diet. This class of phytochemicals has recently attracted much attention due to potential health beneficial effects associated with carotenoid consumption, including reduction of cardiovascular diseases, protection from age-related macular degeneration, various types of cancer, and perhaps, bone health. Therefore, an increasing number of studies have been carried out, focusing on carotenoid bioavailability from the diet, which is typically low, in the magnitude of 1-50%, successive metabolization and measuring carotenoid status. However, up to date, there is no clear consensus on how to measure carotenoid bioavailability and status. A number of methods have been developed to measure certain aspects of bioavailability, including in vitro studies assessing matrix release and micellarization, i.e. bioaccessibility, uptake or transport into cells simulating the human small intestine (e.g. Caco-2 cells), animal experiments, and also human studies. However, these techniques do not necessarily yield wellcorrelated results. In living beings, carotenoids may be determined in different tissues, including plasma, plasma triacylrich lipoprotein fraction reflecting newly absorbed carotenoids, or various target tissues where carotenoids do accumulate to some degree, including the retina, liver, or adipose tissue. Isotopic methods employing stable or radioactive labeled carotenoids have been developed to differentiate between endogenous and exogenous carotenoids and to estimate utilization from single meals. The relation between carotenoid intake, uptake, absorption, distribution, metabolization/ excretion, and status demand a good understanding of the existing methods to assess these various aspects of bioavailability across different models.

Investigation into the bioaccessibility and microstructure changes of β-carotene emulsions during in vitro digestion

“…β-Carotene dispersions were then prepared with compositions as described in Table 1. The prepared dispersions were directly transferred to a clean amber bottle and incubated for 120 min at 37°C with shaking at 95 rpm in an incubator shaker (Biehler & Bohn, 2010). Samples were extracted at given time (0, 5, 40, 80, 120 min) for further tests.…”

Total phenolics, flavonoids, anthocyanins and antioxidant activity following simulated gastro-intestinal digestion and dialysis of apple varieties: Bioaccessibility and potential uptake

“…Furthermore, it has been demonstrated that the evaluation of bioaccessibility by in vitro models can be well correlated with results from human studies and animal models (reviewed by Biehler & Bohn, 2010). Based on an in vitro study, it has been demonstrated that the digestion process decreased the phenolic content by at least 47% in digested fruit beverages compared to undigested ones (Cilla et al, 2009).…”

“…Despite their limitations, such as typically constituting only a static model of digestion, in vitro GI models have been developed for bioaccessibility assessment, allowing the study of changes in dietary components during the gastric and the intestinal stage, due to factors impacting their availability discussed above (Biehler & Bohn, 2010;Cilla, González-Sarrías, Tomás-Barberán, Espín, & Barberá, 2009;McDougall et al, 2005). Furthermore, it has been demonstrated that the evaluation of bioaccessibility by in vitro models can be well correlated with results from human studies and animal models (reviewed by Biehler & Bohn, 2010).…”

Chemical composition, antioxidant activity and bioaccessibility studies in phenolic extracts of two Hericium wild edible species

“…Those assays are described as being easy, cheap and reproducible, being possible to evaluate the digestive stability of the food constituents (Failla & Chitchumroonchokchai, 2005;Rodríguez-Roque et al, 2013). Furthermore, in some cases, the use of in vitro models to study the bioaccessibility of food constituents have proven to be well correlated with results from human studies and animal models (Biehler & Bohn, 2010;Bouayed et al, 2011).…”