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Nutrigenomics explains why smokers may have higher risk of lung cancer after consuming β-carotene

Nutrigenomics is a study of the genetic variants in human body in response to the nutrients in food and the interactions between genes and nutrients at a molecular level.1 Researchers use this molecular information to investigate the food components that may affect the expression of genes towards health and diseases. This is where the term of ‘personalised nutrition’ is being introduced with the aim of improving or maintaining an optimum health.

What are the benefits of taking β-carotene?

In human studies, carotenoids including β-carotene, lycopene and β-cryptoxanthin are known to lower the risk of lung cancer and improve vision. It’s also a good source of antioxidant to neutralise free radicals in order to prevent diseases. Carrots, sweet potatoes, spinach, kale, apricots, pumpkin and peas are examples of β-carotene sources. Other than food source, β-carotene can also be found in over the counter supplements.

It seems like β-carotene has a lot of benefits and people tend to buy β-carotene supplements since no prescription is needed. Surprisingly, many studies found that high dosage of β-carotene supplements is associated with lung cancer.2,3 The research is contrast with the previous studies on β-carotene which generally report a decreased risk of lung cancer. The meta-analysis studies show that smokers or second-hand smokers who have genetic predisposition to lung cancer and consume high dosage of β-carotene tend to have higher risk of developing lung cancer.2 Without knowing their genetic variants, their lives are in jeopardy!

How β-carotene is associated with lung cancer?

Naturally, CYP (cytochrome P450) involves in metabolising carcinogens to inactive derivatives.4 Due to dysfunctions of cytochrome P450, that person cannot excrete the carcinogens properly resulting in increase the risk of cancers. In addition, smokers with GSTT1 gene have higher risk of lung cancer compared to non-smokers due to the impaired ability to eliminate carcinogens.5

The DNA mutations can be inherited from parents. Additional factors such as consuming unnecessary dosage of β-carotene and practising unhealthy lifestyle such as smoking may increase the risk of lung cancer.

References:

  1. Sales, N. M., Pelegrini, P. B., & Goersch, M. C. (2014). Nutrigenomics: definitions and advances of this new science. Journal of nutrition and metabolism, 2014, 202759. https://doi.org/10.1155/2014/202759
  2. Diet, nutrition, physical activity and lung cancer. (2018). World Cancer Research Fund (WRCF), American Institute for Cancer Research.
  3. Abar, L., Vieira, A. R., Aune, D., Stevens, C., Vingeliene, S., Navarro Rosenblatt, D. A., Chan, D., Greenwood, D. C., & Norat, T. (2016). Blood concentrations of carotenoids and retinol and lung cancer risk: an update of the WCRF-AICR systematic review of published prospective studies. Cancer medicine, 5(8), 2069–2083. https://doi.org/10.1002/cam4.676
  4. Oyama, T., Uramoto, H., Kagawa, N., Yoshimatsu, T., Osaki, T., Nakanishi, R., Nagaya, H., Kaneko, K., Muto, M., Kawamoto, T., Tanaka, F., & Gotoh, A. (2012). Cytochrome P450 in non-

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