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Carotenoids and cancer: prevention and potential therapy
1Department of Nuclear Medicine, Royal Marsden NHS Trust, England, UK.
Abstract:
Epidemiological studies suggest that cancer risk is related to dietary intake of carotenoid-rich fruit and vegetables. Whether or not carotenoids are the active component has yet to be definitively proven, although some of these studies have shown that after elimination of obvious factors, such as fibre content, these foods still possess anticancer properties. On the other hand, two large intervention studies have shown that beta-carotene supplementation increases the risk of lung cancer in smokers. However, high doses of beta-carotene were used in these studies. Experimental work on animals and cells has shown that treatment with carotenoids can inhibit the development of cancer. Such studies have revealed a variety of mechanisms, in addition to antioxidant and conversion to vitamin A, including up-regulation of gap junctional communication, induction of detoxifying enzymes and inhibition of proliferation. Studies on tumour cells indicate that carotenoids can interfere with the growth of transformed cells, suggesting that they may be effective in the treatment of some cancers.
Insights
Carotenoids from fruits and vegetables may offer cancer protection. However, high-dose beta-carotene supplements increased lung cancer risk in smokers, warranting further research into carotenoid mechanisms and cancer treatment potential.
Area of Science:
- Nutritional Science
- Oncology
- Biochemistry
Background:
- Epidemiological studies link carotenoid-rich diets to reduced cancer risk.
- Anticancer properties of fruits and vegetables persist even after accounting for fiber content.
- Beta-carotene supplementation studies yielded conflicting results, with some showing increased lung cancer risk in smokers.
Purpose of the Study:
- To investigate the role of carotenoids in cancer prevention and treatment.
- To explore the mechanisms by which carotenoids may exert anticancer effects.
- To reconcile conflicting findings regarding beta-carotene supplementation and cancer risk.
Main Methods:
- Review of epidemiological studies on diet and cancer.
- Analysis of intervention studies on beta-carotene supplementation.
- Examination of experimental data from animal and cell-based cancer models.
Main Results:
- Carotenoids exhibit anticancer properties through various mechanisms, including antioxidant activity, vitamin A conversion, enhanced gap junction communication, induced detoxification, and proliferation inhibition.
- Experimental studies demonstrate carotenoid efficacy in inhibiting cancer development in animals and cells.
- High-dose beta-carotene supplementation was associated with increased lung cancer risk in smokers.
Conclusions:
- Carotenoids play a complex role in cancer, with potential benefits from dietary sources but risks associated with high-dose supplementation.
- Further research is needed to elucidate optimal carotenoid intake for cancer prevention and their therapeutic potential in cancer treatment.