|Nutrition labels on fresh blueberries - do we really need them?|
That's probably 2 months ago and the reason I do remember this event now is the publication of a paper that examines the effect a change in the "daily values" (i.e. the references), the figures in the obiquitous black and white table are based on, would have on the average US citizen's nutritional intake of the vitamins A, D, E, C, B-12 and folate, and the minerals calcium and iron.
"Daily Values" (DV), fortified foods and nutrient adequacy: Before I dig deeper into the actual study results, it's probably wise to point out that fortified foods are the link between the DV's and micro-nutrient intake of the average American. If manufacturers continue to fortify foods to the same %DV for each nutrient, the extent to which potential changes in DVs would affect nutrient intake adequacy depends on the proportion of nutrient intakes derived from fortified foods and the magnitude and direction of change in the DV.According to the data Mary M. Murphy and her colleagues from the National Institutes of Health/Office of Dietary Supplements present in their latest paper, there is still a large gap between the current DV values, which represent the RDAs (recommended daily allowances) from 1968 and have been matched to
"the highest level of intake judged to be adequate to meet the known nutrient needs of practically all healthy persons in a specific age-gender group" (Murphy. 2013)on the one hand, and supposedly "improved" candidates that could replace them: The population weighed and the population coverage varieties of the RDA & EAR.
- RDA = the average daily dietary nutrient intake level that is sufficient to meet the nutrient requirements of nearly all (97–98%) healthy individuals in a particular life-stage and gender group
- EAR = the average daily nutrient intake level that is estimated to meet the requirements of half of the healthy individuals in a particular life-stage and gender group
more about vitamin C).
Not an improvement by any means
In a more thorough sub-analysis, the scientists observed that the differences in the proportion of the total population with usual intakes less than the EAR would be <2% of 5 out of 8 nutrients (vitamins D, E, and B-12; folate; iron), regardless of whether the policy makers sued the population weighted EARs or the population-coverage RDAs as a basis for the revision of the DVs.
To put it plainy: This means that the micronutrient intake of more then 3 million individuals would still fall below the EAR in the total population (U.S. Census Bureau. 2005).
Even worse, if someone in the upper echolons was bribed.... ah, I mean convinced by the conclusive evidence we have that using the population-weighted EARs instead of the population coverage RDA would be the best thing to do, this would increase the risks of inadequate iron and folate intake in women of childbearing age. Both, iron and folate deficiency, can result in irreversible damage to the unborn child (Scholl. 2000; McArdle. 2013). The same is true for vitamin A (Wallingford. 1986) of which Murphy et al. write that it "was identified as a shortfall nutrient (although intakes are not currently in the category ‘‘of concern’’) for the U.S. population" (Murphy. 2013).
- McArdle, Harry J., Lorraine Gambling, and Christine Kennedy. "Iron deficiency during pregnancy: the consequences for placental function and fetal outcome." The Proceedings of the Nutrition Society (2013): 1-7.
- Murphy, Mary M., et al. "Revising the Daily Values May Affect Food Fortification and in Turn Nutrient Intake Adequacy." The Journal of nutrition 143.12 (2013): 1999-2006.
- U.S. Census Bureau. 2005 Middle series data from annual projections of the resident population by age, sex, race, and Hispanic origin: lowest, middle, highest, and zero international migration series, 1999 to 2100 (NP-D1-A). Washington: Department of Commerce; 2000 [cited 2012 Jun 16]. Available from: http://www.census.gov/population/www/projections/natdet-D1A.htm
- Scholl, Theresa O., and William G. Johnson. "Folic acid: influence on the outcome of pregnancy." The American journal of clinical nutrition 71.5 (2000): 1295s-1303s.
- Wallingford, J. C., and B. A. Underwood. "Vitamin A deficiency in pregnancy, lactation, and the nursing child." In: Bauernfeind JC, ed. "Vitamin A deficiency and its control." New York: Academic Press, 1986:101–52.