Estimating long term intake patterns from short term assessments is necessary in order to properly conduct research or to address public health goals.  However, doing so leads to many types of errors, which led to the creation of the National Cancer Institute method that relies on macros implemented within SAS.  Although beneficial, these tools require considerable understanding of programming with SAS, thus limiting its usefulness for many potential users.  To address the need of expanding its usefulness, Luo and colleagues developed a new tool, which is described in the May 2021 issue of The Journal of Nutrition.

A new macro (SIMPLE) was developed that connects the statistical code written for the NCI method, and allows estimations of usual intake distributions, and enables advanced analyses including predictive modeling.  In addition to the base SIMPLE macro, other macros were developed to estimate iron intake (SIMPLE-Iron) and to conduct descriptive or modeling analyses using data for a single 24-hour period (SIMPLE-1D).  To test effectiveness of the programs, results from NHANES and the Cameroon National Micronutrient Surveys were compared to the SIMPLE macro outputs. 

Output from the SIMPLE macro generated identical results to those generated by the NCI method.  Estimates of inadequate iron intake from the SIMPLE-Iron macro were similar to those generated by IMAPP software.  Because of the ability of the SIMPLE macros to provide usable data for nutrient intake from food and supplements, and to estimate intake derived from breast milk, the authors concluded that the SIMPLE macro may facilitate diet analyses by those wishing to conduct nutrition research and develop/implement nutrition programs and policies.

In a commentary on this article, Bailey and Jun discuss the need for better tools that reduce sources of error produced when estimating long term intake patterns so as to be more effective when addressing those at risk of inadequate or excess intakes. 

FIGURE 1 Hypothetical distributions of dietary intakes highlighting the impact of measurement error at the tails of the distribution. Reproduced with permission from Bailey et al. (7). EAR, Estimated Average Requirement; UL, Tolerable Upper Intake Level.

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They state the benefits of the SIMPLE macro but also describe some limitations, including the fact that some knowledge of SAS programming is still required.  Yet, they see the SIMPLE tool as being a great advancement for the field that will facilitate the efforts of many who wish to conduct this type of work.


Luo H, Dodd KW, Arnold CD, Engle-Stone R.  Introduction to the SIMPLE macro, a tool to increase the accessibility of 24-hour dietary recall analysis and modeling.  Journal of Nutrition, Volume 151, Issue 5, May 2021, Pages 1329–1340,

Bailey RL, Jun S. Public health decisions are made at the tails of the distribution:  A novel tool to estimate usual intake distributions from short-term dietary assessment methods.  Journal of Nutrition, Volume 151, Issue 5, May 2021, Pages 1059–1060,

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