Sometimes too much of a good thing is bad -- and that seems to be the case when it comes to dietary supplements and the risk of lung cancer.
While higher blood levels of carotenoids such as beta-carotene, and retinol have been associated with a lower risk of developing lung cancer, getting these nutrients through dietary supplements may do the opposite.
A recent study found that individuals who took individual supplements of beta-carotene, retinol, and lutein, had a significantly elevated risk of developing lung cancer. This isn’t the first time that beta-carotene supplements were linked with more lung cancer, nor the only supplements that have been studied. Last year a study showed an increase in lung cancer with vitamin E supplements.
So why should getting these nutrients through diet help prevent lung cancer and consuming them through supplements increase the risk? The researchers in this study speculated that too much of a good thing may have an opposite effect -- perhaps a high dose of one nutrient interferes with the absorption of another -- but we don’t really know.
Wouldn’t it be easier if we could just take a pill? I guess my mom was right ages ago, when she interrupted our Saturday morning cartoons to make us eat a good breakfast. Our pleas for the magic food tablets equivalent to a meal (that one of our favorite characters was handed by his mom), didn’t cut it for her. Decades later, it seems she is still right. We simply don’t have a substitute for eating a healthy diet, and moderation still reigns. Too much of a good thing can be bad.
Oh – Since I prefer the glass-half-full approach, a few good dietary sources of these nutrients are:
- beta-carotene – carrots, sweet potatoes, spinach, and kale
- retinol – low-fat dairy products
- lutein – spinach, kale, and winter squash
Sources:
Albaines, D. et al. Alpha-Tocopheral and beta-carotene supplements and lung cancer incidence in the alpha-tocopherol, beta-carotene cancer prevention study: effects of baseline characteristics and study compliance. Journal of the National Cancer Institute. 1996. 88(21):1560-70.
Satia, J. et al. Long-term Use of B-Carotene, Retinol, Lycopene, and Lutein Supplements and Lung Cancer Risk: Results From the VITamins And Lifestyle (VITAL) Study. American Journal of Epidemiology. 2009. 164(7):815-828.
Yuan, J. et al. Prediagnostic levels of serum beta-cryptoxanthin and retinol predict smoking-related lung cancer risk in Shanghai, China. Cancer Epidemiology Biomarkers and Prevention. 2001. 10(7):767-73.
