Red, White and Blue? Try Red, Orange and Yellow in your Diet
On Independence Day today, many of our American readers will be celebrating the occasion today with family and friends, perhaps by holding a barbecue and serving some patriotic treats. When thinking about the significance of red, white and blue, think also about how important colors in the diet are. Many of the most colorful parts of the diet come from carotenoids, which are naturally-occurring pigments that make carrots orange, corn yellow, and grapefruit juice pink. Cooney and colleagues in the latest issue of the journal Cancer Epidemiology looked at the effect of the colorful dietary components the carotenoids as biomarkers for survival in cancer patients.
The study used data from the Multiethnic Cohort study, conducted in ethnically diverse group of 215,000 men and women in Hawaii and California by the National Cancer Institute. Blood samples of people with a colorectal cancer diagnosis were analyzed; people who survived at least 8 years after diagnosis were compared with non-survivors to determine whether any biomarkers existed that could potentially identify people at a lower risk of mortality from any cause. Perhaps these biomarkers could themselves be protective of health, or otherwise help to direct attention to the people most at risk.
Survival was associated with lower concentrations of the inflammation marker C-reactive protein. Inflammation occurs as an immune reaction to a various conditions, and it seems likely that higher levels could be a result of ongoing cancer or illness related to the disease. It seems likely that higher C-reactive protein levels result from active cancer or other infection that could reduce survival. Measuring C-reactive protein could identify people that need increased medical intervention to stay healthy.
To get back to the link between a colorful diet and health, the authors also found that levels of serum carotenoids were protective against mortality. Specifically, levels of total carotenoids and alpha-carotene were protective. This relationship could be just an association. For example, higher carotenoid levels are found in people meeting dietary recommendations according to analysis by Murphy et al., and may have a healthier lifestyle in general that may be protecting them. And since carotenoids have a long half-life in the body according to Burri, Neidlinger and Clifford, total carotenoid levels are indicative of long-term intakes. It is also possible that individuals with more severe disease or uncomfortable complications may have difficulty consuming a varied diet. On the other hand, as Sommer and Vyas write, carotenoids have many biologically important properties and are antioxidants. While it seems unlikely given the long-term etiology of cancer that carotenoids can have a protective effect in the short term, they could prevent the oxidation damage that is implicated in cancer formation, or also prevent other diseases related to oxidative stress such as cardiovascular disease. A good reason to eat a balanced diet, whether red, white and blue, or red, orange and yellow.
Robert V. Cooney, Weiwen Chai, Adrian A. Franke, Lynne R. Wilkens, Laurence N. Kolonel, and Loïc Le Marchand. C-Reactive Protein, Lipid-soluble Micronutrients, and Survival in Colorectal Cancer Patients. Cancer Epidemiol Biomarkers Prev July 2013 22:7 1278-1288; Published OnlineFirst May 15, 2013.http://dx.doi.org/10.1158/1055-9965.EPI-13-0199