Nutritional epidemiology studies require objective biomarkers as an unbiased and reliable means of measuring nutrient uptake. Although urine is the most common source of dietary intake biomarkers, it has yielded few relevant micronutrient biomarkers to date. Blood, however, has the potential for additional nutrient biomarker discovery, but its use in nutritional epidemiology studies has not been verified. Ross Prentice and Johanna Lampe of the Public Health Sciences Division, along with Mary Pettinger, Marian Neuhouser, Lesley Tinker, Ying Huang, and Garnet Anderson, used serum and demographic information from participants in a controlled feeding study through the Women’s Health Initiative (WHI) to interrogate the methodology and applications of blood nutritional biomarkers and to determine their association with the incidence of cardiovascular diseases, cancer, and diabetes. They recently published their findings in the American Journal of Clinical Nutrition.
The authors took advantage of serum that was collected and analyzed from over 5,000 fasting WHI participants between 1993 and 1998, as well as a human feeding study among 153 WHI participants in the Seattle area to examine the association between their recently proposed micronutrient biomarkers and chronic disease risk during WHI follow-up. Because Prentice and colleagues had measured compounds including a- and b-carotene, lutein plus zeaxanthin (L+Z), and a-tocopherol from the serum of WHI study participants early in the WHI program, they focused their analysis on these potential nutrient biomarkers for the current research. Using high-performance liquid chromatography, a technique that separates and identifies chemicals within a solution, the initial WHI studies had measured these micronutrients in the baseline serum samples and collected participant demographic data such as age, body mass index, and race. These participants were also followed for biannual or annual disease outcome reporting. The authors of the current study were then able to statistically correlate serum nutrient concentrations with eventual diagnoses of various cardiovascular diseases, cancer, or diabetes.
When Prentice and colleagues compared individuals with higher blood micronutrient concentrations compared to concentrations in other study participant blood, they found that the hazard ratios, or the ratio of chance of disease, was decreased for cardiovascular diseases, breast cancer, and diabetes in those with increased a- and b-carotene exposure. Likewise, increases in L + Z was associated with a decrease in several cardiovascular diseases as well as diabetes. Interestingly, an increase in a-tocopherol was associated with a slight increase in a specific cardiovascular disease. Together these results show that relevant micronutrients can be identified and measured from blood and that these compounds can serve as biomarkers to predict various future disease outcomes. Prentice explained the importance of these findings: “this work is the first to develop intake biomarkers based on blood nutrient concentrations (in conjunction with study subject characteristics such a body mass index, age and ethnicity). This work has potential to relieve the 'bottleneck' of dietary variables having an objective intake assessment (as compared to possibly unreliable self-reported diet), and to move intake biomarkers into the mainstream of the important nutritional epidemiology research area.”
In addition to validating a potentially superior source for nutrient biomarkers, this study also expands the possibilities for investigating the associations between nutrient intake and disease outcome. “The analyses reported are based on a modest sub-cohort of WHI participants where blood levels of these nutrients were routinely measured,” Prentice said. “Further work will examine these associations in the entire WHI, with its 161,808 participants, all post-menopausal and in the age range 50-59 when enrolled in 1993 to 1998), either in an inexpensive fashion exploiting the relationship between the novel intake biomarkers and available self-reported dietary data, or better through an approach involving intake biomarker comparisons between participant who developed one or more of the study diseases during WHI follow-up (the cases) and those who did not (controls).” Their lab is also interested in identifying and using other nutrient biomarkers, “including efforts based on the interrogation of both blood and 24-hour urine specimens using metabolomics profiling, in collaboration with Dr Dan Raftery (UW Medicine),” Prentice explained. “This is much needed research, with substantial potential to augment and to strengthen nutritional epidemiology findings.”
This work was supported by the National Cancer Institute and the National Heart, Lung, and Blood Institute.
UW/Fred Hutch Cancer Consortium members Ross Prentice, Marian Neuhouser, Yinh Huang, Garnet Anderson, and Johanna Lampe contributed to this work.
Prentice RL, Pettinger M, Neuhouser ML, Tinker LF, Huang Y, Zheng C, Manson JE, Mossavar-Rahmani Y, Anderson GL, Lampe, JW. 2019. Application of blood concentration biomarkers in nutritional epidemiology: example of carotenoid and tocopherol intake in relation to chronic disease risk. American Journal of Clinical Nutrition. 109(4):1189-1196. doi: 10.1093/ajcn/nqy360.