From the Guidelines
Carotenoids are generally safe for most people when consumed in normal dietary amounts, but high-dose supplements may pose risks for certain groups, such as smokers taking beta-carotene supplements, who have shown an increased lung cancer risk. They are natural pigments found in many fruits and vegetables that give them their yellow, orange, and red colors. Carotenoids function primarily as antioxidants in the human body, helping to neutralize harmful free radicals that can damage cells. The most well-known carotenoids include beta-carotene, lycopene, lutein, and zeaxanthin. Beta-carotene converts to vitamin A in the body, supporting vision, immune function, and skin health. Lycopene, found in tomatoes, may help reduce the risk of certain cancers and heart disease. Lutein and zeaxanthin concentrate in the eyes and may protect against age-related macular degeneration and cataracts.
Some of the key benefits and risks of carotenoids include:
- Antioxidant properties that help protect cells from damage
- Potential to reduce the risk of certain cancers and heart disease
- Support for vision, immune function, and skin health
- Risks associated with high-dose supplements, particularly for smokers taking beta-carotene
- Potential for carotenodermia, a harmless yellowing of the skin, with excessive supplementation
According to the US Preventive Services Task Force (USPSTF) 1, the evidence on the effectiveness of multivitamin supplements, including carotenoids, for the primary prevention of cardiovascular disease and cancer is lacking, and the balance of benefits and harms cannot be determined. However, the USPSTF concludes with moderate certainty that the net benefit of beta-carotene supplementation is negative, particularly for smokers, due to the increased risk of lung cancer.
Overall, getting carotenoids from a varied diet rich in colorful fruits and vegetables is the safest and most beneficial approach. This allows individuals to reap the benefits of carotenoids while minimizing the risks associated with high-dose supplements.
From the Research
Safety of Carotenoids
- Carotenoids are generally considered safe when consumed through dietary sources, such as fruits and vegetables 2, 3.
- However, high doses of beta-carotene supplements have been linked to an increased risk of lung cancer in smokers and workers exposed to asbestos 2, 4.
- There is limited evidence on the toxicity of carotenoids, and more research is needed to determine the optimal dosage and potential risks of supplementation 3, 5.
Functions and Benefits of Carotenoids
- Carotenoids have antioxidant properties, which can help protect against cell damage and reduce the risk of certain diseases 2, 3, 6.
- Specific carotenoids, such as lutein and zeaxanthin, have been shown to be beneficial for eye health, reducing the risk of age-related macular degeneration and cataracts 2, 3, 6, 4, 5.
- Beta-carotene can be converted to vitamin A, which is essential for vision and other biological processes 2, 6.
- Carotenoids may also have benefits for cognitive function and cardiovascular health, although more research is needed to confirm these effects 3.
Food Sources and Supplementation
- Carotenoids can be found in a variety of fruits and vegetables, such as tomatoes, leafy greens, and egg yolks 2, 3, 5.
- Supplements containing carotenoids are available, but their efficacy and safety are not well established, and dietary recommendations are advised instead 2, 3.
- The Age-Related Eye Disease Study 2 (AREDS2) found that adding lutein and zeaxanthin to the AREDS formulation did not further reduce the risk of progression to advanced age-related macular degeneration, but may be a suitable substitute for beta-carotene in the formulation 4.