Abstract:
Natural carotenoids (CARs) such as β-carotene, lutein, astaxanthin, bixin, norbixin, capsanthin, lycopene, canthaxanthin, β-Apo-8-carotenal, zeaxanthin, and β-apo-8-carotenal-ester are gaining attention in various fields including food, feed, nutraceuticals, and cosmeceuticals. The research on CARs is progressing in three primary areas:
- CAR production from natural sources and optimization of its downstream processing.
- Encapsulation to enhance its physical and chemical properties.
- Preclinical, clinical, and epidemiological studies to understand CARs’ health benefits.
This review provides a comprehensive overview of the chemistry, antioxidant activity, market trends, dietary sources, extraction methods, bioaccessibility, bioavailability, encapsulation techniques, dietary intake, and health benefits of CARs. The health benefits explored include their role in preventing cancer, obesity, type 2 diabetes (T2D), cardiovascular diseases (CVD), osteoporosis, neurodegenerative diseases, mental health, and their impact on eye and skin health.
Clinical and epidemiological studies have shown a negative correlation between the dietary intake of fruits and vegetables and the prevalence of chronic diseases such as T2D, CVDs, and cancer. The bioactive antioxidant compounds in fruits and vegetables, including carotenoids, help neutralize free radicals in cells, thereby reducing oxidative damage and the risk of associated diseases.
Carotenoids in Nature:
Carotenoids are red, yellow, and orange tetraterpenoid pigments synthesized by all terrestrial and aquatic photoautotrophs, including plants, microalgae, and macroalgae. Some nonphotosynthetic bacteria, certain insects, and fungi can also produce CARs. In microalgae and plant cells, CARs are synthesized and stored in plastids, playing crucial roles in photosynthesis, photoprotection, and signaling pathways. Moreover, CARs serve as precursors for phytohormones in plants, regulating various developmental and adaptation processes.
Health Benefits of Carotenoids:
Apart from their primary functions in plants and photosynthetic microbes, CARs are essential dietary sources of provitamin A (e.g., α- and β-carotene and β-cryptoxanthin). Their antioxidant activities help regulate oxidative stress and inflammatory mediators, offering protection against metabolic syndromes (like CVD and T2D), cancer, neurodegenerative diseases, and photooxidative damage to the skin and eyes.
Capsaicin: Plants of the Genus Capsicum and Positive Effect of Oriental Spice on Skin Health
Dietary Supplements and Animal Feed:
Most animals cannot biosynthesize CARs and must obtain them from their diets. The intake of CARs can be enhanced through dietary supplements, which have seen significant growth in recent years. CAR-based formulations are available for sports nutrition, bone health, anti-aging, and vision. Additionally, CARs are used in poultry feed to improve egg yolk pigmentation and the health of birds. Astaxanthin is a common supplement in the feed of aquatic animals like salmon, trout, and ornamental fishes for better pigmentation and improved health.
