Diet Quality, Nutrient Biomarkers and American Thanksgiving
Food consumption data is valuable for many reasons. As the CDC notes, the data is used nutrition monitoring and surveillance and a variety of policy making and research purposes, including dietary guidance, food fortification, environmental exposure assessment, and nutrition assistance and education program planning and evaluation. The USDA has invested in the collection of national food consumption data for >70 years. The National Health and Nutrition Examination Survey (NHANES) is the primary instrument used to nationally assess the health and nutritional status of Americans.
Using cross-sectional data, Deierlein and colleagues assessed nutrient intakes and Healthy Eating Index (HEI) scores of 1,306 New York City adults living independently (60-99y) who were participating in the Cardiovascular Health of Seniors and the Built Environment Study. They report dietary relationships with ethnicity, eating patterns (home vs restaurant), and shopping preferences.
Others may disagree with their conclusions. Archer and colleagues argue that nutrition surveys do not accurately reflect dietary consumption. They give several reasons: underreporting, errors in nutrient composition database because of continual changes in the types of foods available for purchase, and accuracy of self-reported reports on portions and composition of meals ‘eaten away from home’. Kim and Ferraro make a strong case that people who volunteer for studies are not representative of the general populace. Volunteering is strongly associated with many healthful activities and socioeconomic resources which may protect them from hypertension and cardiovascular disease. How can researchers overcome these shortfalls?
The CDC’s Second Nutrition Report is a nationally representative assessment of 58 biochemical indicators. It reports ‘what the levels of nutrition indicators are actually in people’. Using validated biomarkers, researchers do not have to guestimate nutrient composition, portion size, or the degree of underreporting. Validated biomarkers using standardized procedures are the BEST way to assess the nutritional status of individuals and the health of populations. For example, red blood cells are considered the most robust marker of omega-3 fatty polyunsaturated fat intake. Hodson and colleagues report that plasma fatty acid composition also reflects dietary fatty acid intakes, even of saturated and omega-6 fatty acids, over the preceding 2 weeks. This means that researchers don’t have to rely on nutrient databases or self-reported food intakes.
In other words, as Americans enter the Thanksgiving holidays, it isn’t necessary to keep track of everything one eats. The most accurate health assessment will be a blood lipid analysis in the following week (or two).
Deierlein AL, Morland KB, Scanlin K, Wong S, Spark A. Diet quality of urban older adults aged 60 to 99 years: The Cardiovascular Health of Seniors and Built Environment Study. 2013 J Acad Nutr Diet doi:10.1016/j.jand.2013.09.002
Archer E, Hand GA, Blair SN. Validity of US National Surveillance: National Health and Nutrition Examination Survey caloric energy intake data, 1971-2010. 2013 PloSOne doi:10.1371/journal.pone.0076632
Kim S, Ferraro KF. Do productive activities reduce inflammation in later life? Multiple roles, frequency of activities, and C-reactive protein. 2013 The Gerontolog doi:10.1093/geront/gnt090
Hodson L, Eyles HC, McLachlan KJ, Bell ML, Green TJ, Skeaff CM. Plasma and erythrocyte fatty acids reflect intakes of saturated and n-6 PUFA within a similar time frame. 2013 J Nutr doi:10.3945/jn.113.183749