A Call to Action: Measuring and Monitoring Nutrient Status
The International Life Sciences Institute (ILSI) is holding its annual meeting. ILSI North America President Liz Westring opened the meeting calling for transparency and increased focus on integrity and excellence in nutrition science. One of the many global health challenges is an increasing prevalence of overweight and obesity. Unfortunately, social media seems to favor venomous exchanges which undermine meaningful dialogue among stakeholders in government, industry, non-government agencies and academics.
New technologies, wearable devices and smart phones, are enabling people (and researchers) to monitor individual physical activity but tools to measure nutrient exposure are lacking. Scientists continue to rely upon dietary intake questionnaires and food databases. As scientists, we need more effort elucidating biological associations between nutrient status and health outcomes. As individuals, we want to know our nutritional status.
Within China, differences between rural and urban diets are disappearing. And for 25 years, some nutrient intakes, namely retinol, calcium and dietary fiber, continue to be low. This trend of increasing urbanization is happening globally. With increasing urbanization, we change our dietary choices. The observation that most restaurants serve oversized meals, regardless of whether they are part of a branded chain or not, does not help us estimate and manage our calorie intake.
In the Women’s Health Initiative, obesity was associated with increased risk of invasive breast cancer among postmenopausal women. But it isn’t known if this relationship reflects excessive calorie intake or suboptimal essential nutrient status. Why? Because self-reported data is too crude and too often erroneous for meaningful interpretations. In a nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort, higher concentrations of plasma β-carotene and α-carotene were associated with lower breast risk of ER-tumors. Longitudinal measures find blood concentrations of carotenoids (α-carotene, β-carotene, β-cryptoxanthin, lutein+zeaxanthin, α-tocopherol, γ-tocopherol and retinol) are inversely correlated with adiposity. In short, subjective measures of nutrient exposure are needed. We cannot understand nutrient-disease relationships using dietary intake data.
Our best hope, nationally and as individuals, is to monitor nutrient exposure using biological status indicators. Most of us know our body weight. Maybe our blood pressure. Why don’t more people know their vitamin D status? Why aren’t more females assessed for iron anemia? Do you eat enough vegetables, fruit and whole grains to maintain healthy circulating carotenoid concentrations?
The omega-3 index is a measure of DHA and eicosapentaenoic acid (EPA) concentrations in blood. While studies measuring fish intake and blood pressure are inconsistent, circulating docosahexaenoic acid (DHA) concentrations are inversely associated with elevated blood pressure. Do you know your omega-3 index or are you trying to estimate serving size and count number of fish meals consumed this week?
Wang X, Wu Y, Zhang Z, Zhang M, Huang G. Dietary changes over 25 years in Tianjin residents: Findings from the 1986-1988, 200-2004, and 2008-2011 nutrition surveys. 2016 Nutrients doi: 10.3390/nu8020062
Yang B, Shi M-Q, Yang J-J, Li D. Fish, long-chain n-3 PUFA and incidence of elevated blood pressure: A meta-analysis of prospective cohort studies. 2016 Nutrients doi: 10.3390/n8010058
Neuhouser ML, Aragaki AK, Prentice RL, Manson JE, Chiebowski R, Carty CL, Ochs-Balcom HM, Thomson CA, Caan BJ, Tinker LF, Peragallo Urrutia, Knudtson J, Anderson GL. Overweight, obesity and postmenopausal invasive breast cancer risk: A secondary analysis of the Women’s Health Initiative randomized clinical trials. 2015 JAMA Oncol doi: 10.1001/jamaoncol.2015.1546
Bakker MF, Peeters PHM, Klaasen VM, Bueno-de-Mesquita HB, Jansen EHJM, Ros MM, Travier N, Olsen A, Tjonneland A, Overvad K, Rinaldi S, Romieu I, Brennan P, Boutron-Ruault M-C, Perquier F, Cadeau C, Boeing H, Aleksandrova K, Kaaks R, Kuhn T, Trichopoulou A, Lagiou P, Trichopoulos D, Vineis P, Krogh V, Panico S, Masala G, Tumino R, Weiderpass E, Skeie G, Lund E, Quiros JR, Ardanaz E, Navarro C, Amiano P, Sanchez M-J, Buckland G, Ericson U, Sonestedt E, Johansson M, Sund M, Travis RC, Key TJ, Khaw K-T, Wareham N, Riboli E, van Gils CH. Plasma carotenoids, vitamin C, tocopherols, and retinol and the risk of breast cancer in the European Prospective Investigation into Cancer and Nutrition cohort. 2016 Am J Clin Nutr doi: 10.3945/ajcn.114.101659