Determinants and determination of carotenoid bioavailability from infant food formulas and adult nutritionals including liquid dairy products

Carotenoids are typically tetraterpenoid phytochemicals that cannot be synthesized by humans, some of which such as β-carotene can be metabolized into vitamin A. Sufficient carotenoid intake and tissue levels have been associated with several health benefits including the reduction of cardiovascular diseases and some types of cancer and also the amelioration of age-related macular degeneration. Carotenoids and their metabolites have also been related to reduced inflammation and oxidative stress via interacting with transcription factors, such as NF-κB and Nrf-2, as well as with the nuclear receptors retinoic acid receptor/retinoid X receptor, implicated in immune functions and cellular differentiation. Therefore, carotenoids are important for growth and development. They could mark beneficial constituents in infant food formulas and adult nutritionals, the latter typically constituting protein-rich liquid foods targeting meal replacements. Carotenoids may be present by nature (typically below 20 μg/100 mL) or following fortification (up to 200 μg/100 mL), such as for lutein and β-carotene. However, carotenoid bioavailability may be low and variable, especially in low-fat items. Although most infant foods and adult nutritionals are rich in lipids and proteins, facilitating absorption and availability of carotenoids, unfortunately, very little data is available. In addition, carotenoid detection for such lipid-rich matrices may be challenging as a result of low concentrations and matrix effects. This review aims to highlight considerations for carotenoid bioavailability from infant food formula and adult nutritionals as well as summarize detection methods for carotenoids from these items.