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Effects of Food Processing, Storage, and Cooking on Nutrients in Plant-Based Foods
Published in Nicole M. Farmer, Andres Victor Ardisson Korat, Cooking for Health and Disease Prevention, 2022
The main carotenoids found in human tissues are beta-carotene, alpha-carotene, beta-cryptoxanthin, lutein, zeaxanthin, and lycopene. Carotenes are characterized by possessing long carbon chains with unsaturated double bonds that are responsible for providing color. Beta-carotene is naturally orange in color and is one of the most common precursors of vitamin A. Alpha-carotene is found in orange vegetables (pumpkins, carrots, and squash). Alpha-carotene has one fewer double bond than beta-carotene, which makes it paler in color than beta-carotene, and lycopene has one more, thus responsible for its intense red color. Lycopene is found in tomatoes, watermelon, grapefruit, and papaya. Xanthophylls are derivatives or carotenes containing oxygen, which are naturally yellow orange in color. Xanthophylls are found in leafy greens such as spinach, kale, and Swiss chard (Figures 2.4–2.6).
Carotenoids in Alzheimer’s Disease
Published in Atanu Bhattacharjee, Akula Ramakrishna, Magisetty Obulesu, Phytomedicine and Alzheimer’s Disease, 2020
Studies have shown that combination treatments between xanthophyll carotenoids (e.g. lutein) and omega-3 fatty acids improved retinal concentrations of xanthophyll in healthy female subjects (Johnson et al., 2008b; Nolan et al., 2018). This is due to the enhanced carotenoid uptake and bioavailability when carotenoids are administered in the presence of oils or cholesterol (Van Het Hof et al., 2000; Nolan et al., 2018). Although the combination intake of xanthophyll carotenoids and omega-3 fatty acids substantially ameliorated AD symptoms, further studies are needed to corroborate these findings (Nolan et al., 2018).
Lutein in Neural Health and Disease
Published in Robert E.C. Wildman, Richard S. Bruno, Handbook of Nutraceuticals and Functional Foods, 2019
Carotenoids are hydrocarbon molecules consisting of linked isoprene units, joined head to tail. The majority are derived from a C-40 backbone, containing 3 to 15 conjugated double bonds, whose structure determines the absorptive and antioxidant characteristics of the molecule. Modifications to the basic structure include chain elongation, isomerization, or degradation.1 Carotenoids are divided into two main classes: carotenes and xanthophylls, the latter containing at least one oxygen atom. The carotene family members are non-polar molecules, containing carbon and hydrogen only, and include α-carotene, β-carotene, and β-cryptoxanthin. Xanthophylls are oxygenated carotenoids, structurally characterized by the presence of hydroxyl groups attached to each of the two terminal β ionone rings in the molecule. Lutein and zeaxanthin are examples of xanthophylls. Zeaxanthin is a close structural isomer of lutein, and typically occurs in similar foods as lutein. The presence of hydroxyl groups increases the polarity and hydrophilicity of these compounds, facilitating reaction with singlet oxygen more readily than nonpolar carotenoids.6 An additional benefit to this polarity is the ability to modulate cell membrane dynamics. Polar carotenoids restrict the molecular motion of lipids, thereby increasing membrane rigidity.7
Factors determining the oral absorption and systemic disposition of zeaxanthin in rats: in vitro, in situ, and in vivo evaluations
Published in Pharmaceutical Biology, 2022
Seong‑Wook Seo, Dong‑Gyun Han, Eugene Choi, Min‑Jeong Seo, Im‑Sook Song, In‑Soo Yoon
Carotenoids are a class of naturally occurring yellow, orange, and red pigments, synthesized de novo by photosynthetic plants, algae, bacteria, and fungi (Maoka 2020). Generally, α‑carotene, β‑carotene, β‑cryptoxanthin, lutein, lycopene, and zeaxanthin (Figure 1) are the major dietary carotenoids prevalent in human serum and tissues (Mein et al. 2011; Bernstein et al. 2016; Toti et al. 2018). Carotenoids can be structurally categorized into two classes: carotenes and xanthophylls. Carotenes, such as α‑carotene, β‑carotene, and lycopene, are non‑polar compounds that are pure hydrocarbons without oxygen atoms (Jia et al. 2017). Xanthophylls, such as lutein, zeaxanthin, and β‑cryptoxanthin, are relatively polar carotenoids that contain at least one oxygen atom (Jia et al. 2017). α‑Carotene, β‑carotene, and β‑cryptoxanthin are provitamin A carotenoids that can be metabolized to retinol after administration in the body, whereas lutein, zeaxanthin, and lycopene are non‑provitamin A carotenoids that cannot be metabolized to retinol (Mein et al. 2011).
Changes in Aqueous Humor Lutein Levels of Patients with Cataracts after a 6-Week Course of Lutein-Containing Antioxidant Supplementation
Published in Current Eye Research, 2022
Rijo Hayashi, Shimmin Hayashi, Shigeki Machida
The presence of hydroxyl groups in lutein, zeaxanthin, and their metabolites may be the structural requirements for selective uptake of these xanthophylls to ocular tissues from other dietary carotenoids. In addition, specific binding proteins have been reported to mediate the transport of xanthophylls in the human retina30. Several cell surface selective binding proteins, such as scavenger receptor class B (SR-BI)31, glutathione S-transferase P1 (GSTP1),32 and steroidogenic acute regulatory protein (StAR),33 have been reported to aid in the transportation of xanthophylls into retinal cells. The presence of GSTP1 in the iris and ciliary body has also been reported.34 Furthermore, cell lines originally from both the non-pigmented and pigmented bovine ciliary epithelium have also been shown to exhibit high levels of GSTP1 mRNA expression.35 The presence of SR-BI was reported in ciliary epithelium, lens epithelium, and lens nuclear fibers, and SR-BI is colocalized with StAR in these ocular tissues.36 Xanthophylls in uveal structures (iris, ciliary body, and RPE/choroid) account for approximately 30% of that observed in the ocular tissues,37 which are presumably helpful in filtering out short-wavelength light and preventing the phototoxic reaction, in addition to acting as antioxidants in uveal structures.
The Effects of Adjuvant Tamoxifen Use on Macula Pigment Epithelium Optical Density, Visual Acuity and Retinal Thickness in Patients with Breast Cancer
Published in Current Eye Research, 2020
Tolga Bicer, Goksen Inanc Imamoglu, Sinan Caliskan, Burcu Kucuk Bicer, Canan Gurdal
We think that routine retinal examination is important for BC patients, especially those undergoing long-term TMX treatment. The limited literature, it was difficult to compare the new findings of our study. The literature includes few data on the effects of adjuvant treatment on MPOD in BC patients. Nevertheless, the present findings provide a starting point for additional research on adjuvant therapies and their ocular side effects in BC patients. Due to the negative effects of TMX on the MP distribution, females tend to have more risk to develop macular degeneration as discussed above. Hereby these patients should be informed to obtain lutein and zeaxanthin from dietary sources such as green leafy vegetables and orange and yellow fruits and vegetables. It has been shown in AREDS2 study that these xanthophyll carotenoids consumed through the diet or supplements have brought attention to the potential ocular health and functional benefits.49