Dietary Carotenoids and Vitamin C Inversely Correlate to Lung Cancer Risk, Study Suggests

29 Jun 2017 --- A new study has revealed the protective effects of selected carotenoids and vitamin C against lung cancer risks and growth of a different type of carcinoma cells, with the results showing that when compared to low intake of beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene and vitamin C, subjects with highest intake of aforementioned carotenoids and vitamin C demonstrated reduced risk of lung cancer.

Additionally, high consumption of carotenoids (i.e., beta-carotene, alpha-carotene, beta-cryptoxanthin and lycopene) and vitamin C show statistical lower risk of lung cancer in male heavy smokers and female heavy smokers respectively. Moreover, high intakes of selected carotenoids and vitamin C were shown to associate with decreased development of different carcinoma cells. Carotenoids such as beta-carotene, alpha-carotene, beta-cryptoxanthin, lycopene and vitamin C were linked with decreased progression of squamous cell carcinoma. Alpha-carotene and beta-carotene reduced adenocarcinoma cells development while beta-cryptoxanthin and lycopene show an inverse correlation with small cells carcinoma growth. 

In this study, data from a case-control study of lung cancer in Montreal Canada was used to examine the roles of dietary beta-carotene, alpha-carotene, beta-cryptoxanthin, lutein/zeaxanthin, lycopene and vitamin C in lung cancer risks. Dietary information was generated from interviews among 1,105 lung cancer cases and 1,449 population control with subjects’ age 35 to 75-year-old. The consumption frequency of 49 fruits and vegetables for two years before diagnosis or interviews was collected. The estimation of lung cancer risks and dietary intakes of carotenoids and vitamin C, after adjusting for confounding factors was assessed by odd ratios (ORs) and 95% confidence intervals (CIs) using logistic and polytomous regression models. 

“Beta-carotene was once thought to be the most potent carotenoid when it was first discovered. However and unfortunately, large human clinical such as the CARET and ATBC studies showed that supplementation with beta-carotene alone could increase the risk of lung cancer, especially among smokers. These unexpected results caused turmoil in the research and market of beta-carotene as well as the dietary supplement industry. A number of reasons were put forth to explain the results and one of the most compelling reason was that the beta-carotene used in these studies was of synthetic origin and consisted of one single-isoform only (100% trans form) – which is different from the natural mixed carotenes (in both cis- and trans- forms) in carrot, palm fruits and other fruits and vegetables.”

“In this current study, it is worthwhile to note that high consumption of dietary natural carotenoids and vitamin C from fruits and vegetables, with a multitude of carotenoid isoforms - do not correlate with lung cancer risk. Hence it is believed that dietary supplement of natural mixed-carotenes may help to lower the risk of lung cancer and progression of carcinoma cells, as these carotenoids work synergistically to confer optimum protection and benefits,” says CheeYen Lau, Nutritionist at ExcelVite.

“The bottom line is to take natural carotenoids derived from fruits and vegetable (as found in nature) – which are “natural and wholesome” antioxidant and carotenoids, Lau says.