The nutrient modeling R project

Gerald C. Nelson December 14, 2018

The goal of this project is to provide estimates of the nutritional consequences of changes arising in scenarios that combine socioeconomic and climate futures to 2050. It integrates data from

• FAO’s Food Balance Sheets,
• the Shared Socioeconomic Profiles used in the IPCC’s Fifth Assessment Report and many other studies,
• quantitative scenario modeling results from IFPRI’s IMPACT model,
• a lookup table that is used to convert food consumption by a representative consumer in a country (including optionally a measure of nutrient loss during food preparation) to it macro and micro constituents, and
• age- and gender-adjusted nutrient requirements from the Institute of Medicine of the US National Academy of Sciences 1 using a U.S. diet to correct for dietary effects on bioavailability.

The results from this project are published in the following paper

Paper reference: Nelson, Gerald, Jessica Bogard, Keith Lividini, Joanne Arsenault, Malcolm Riley, Timothy B. Sulser, Daniel Mason-D’Croz, Brendan Power, David Gustafson, Mario Herrero, Keith Wiebe, Karen Cooper, Roseline Remans, Mark Rosegrant, 2018. “Income Growth and Climate Change Effects on Global Nutrition Security to Mid-Century.” Nature Sustainability 1 (12). doi:10.1038/s41893-018-0192-z.

The automate.R script executes each script in the order needed to generate output used in the Nature Sustainability paper. Each script can also be run standalone. It assumes that file generated in scripts earlier in the automate script are available.

Directory structure

The directory hierarchy of the project is as follows. Second level directories are in parentheses:

• data (IMPACTData) — contains .xlsx and .rds files generated by the dataPrep and dataManagement R scripts
• data-raw (FBSData, IMPACTData, NutrientData, SSPData) — data files from FAO, SSP, IMPACT, the nutrient lookup table
• graphics — graphic outputs from the analysis
• R — R scripts
• Results — results from the analysis, contains .xlsx and .rds files

R code file naming conventions

All R code is in the R directory. File naming conventions are:

• dataPrep.xxx.R — reads in the raw data from the data—raw directory and processes it into .rds (and sometimes .xlsx) files and writes these to the data or IMPACTData directory
• dataManagement.xxx.R — reads in .rds data files from the data or IMPACTData directory, does more processing and writes writes these to the data or IMPACTData directory.
• xxxFunctions.R — has generic functions used in the xxx R scripts. A special functions script is nutrientModFunctions.R. In addition to R functions it holds the names of key variables such as file names and directory paths. All other scripts read this information in with functions from this script.
• nutrientCalcs.R — all final calculations are done in this script.

Results files

All file names have a standard format — substantive name, creation date, suffix. An example is metaData.2018-04-17.xlsx.

• suffix — .rds (a compressed file format used in R) in all cases, .xlsx and .csv as options

substantive name examples

• General — metaData, nut.requirements, food.group, staples
• requirements — req.EARxxx, req.RDA.vitsxxx, req.RDA.minrls, req.RDA.macroxxx, req.UL.vitsxxx,req.UL.minrlsxxx
• type of results — ratio of nutrient consumption by commodity/staple/food group to total consumption, ratio of nutrient consumption by commodity/staple/food group to requirement

Variable naming conventions

• scenario — name of the IMPACT scenario, currently SSP2-GFDL, SSP2-MIROC, SSP2-NoCC
• region — the aggregation from individual countries to larger regions. Currently region_code.IMPACT3
• year — 4 digit year with an X to start with so it is a character value. Example - X2020
• IMPACT_code — a 4 or 5 digit code for each of the IMPACT commodities. Example - cwhea - the quantity of wheat consumed by a representative consumer
• food.group.code — the code for a food group. Example - cereals.
• staple.code — the code for a food group. Example - staple
• foodAvailpDay — the per capita quantity of an IMPACT commodity available for consumption by a representative consumer. Units - kg/day
• nutrient.code — a nutrient code combines the common name of the nutrient and the units it is in. Example - folate_µg (folate in micrograms)
• nutrient.Q — the quantity of a nutrient available from an IMPACT commodity per day
• nutrient.sum [.all, .staple, .foodGroup] — The sum of nutrient.Q for all commodities, for each staple group, for each food group.
• nutrient.ratio [.all, .staple, .foodGroup] — The ratio of a nutrient to the total consumed
• nutrient.req.ratio [.all, .staple, .foodGroup] — The ratio of a nutrient to the daily requirement for a representative consumer (i., population weighted by age and gender requirements)