Publications

2020
Moore ERH, Smith MR, Humphries D, Dubrow R, Myers SS. The Mismatch between Anthropogenic CO2 Emissions and Their Consequences for Human Zinc and Protein Sufficiency Highlights Important Environmental Justice Issues. Challenges [Internet]. 2020;11 (1). Publisher's VersionAbstract
The impacts of climate change are not equally distributed globally. We examined the global distribution of CO2 emissions and the ensuing distribution of increases in the risk of zinc and protein deficiency resulting from elevated atmospheric CO2 concentrations. We estimated cumulative per capita (2011–2050) CO2 emissions for 146 countries using existing measurement data and by apportioning regional emissions projections. We tested the relationship between cumulative per capita CO2 emissions and the risk of additional zinc and protein deficiency at the population-level and country-level. At the population-level (i.e., population-weighted), we observed a significant inverse association between CO2 emissions and the percentage of the population placed at additional risk of zinc (p-value: <0.001) and protein (p-value: <0.01) deficiencies. Country-level (i.e., unweighted) analyses produced significant but less strong associations. Populations with lower per capita CO2 emissions between 2011 and 2050 will experience a disproportionately high nutritional burden, highlighting socioeconomic, geospatial, and intergenerational injustices.
challenges-11-00004.pdf
2019
Beach RH, Sulser TB, Crimmins A, Cenacchi N, Cole J, Fukagawa NK, Mason-D'Croz D, Myers S, Sarofim MC, Smith M, et al. Combining the effects of increased atmospheric carbon dioxide on protein, iron, and zinc availability and projected climate change on global diets: a modelling study. The Lancet Planetary Health. 2019;3 (7) :e307–e317. beach_et_al._2019_-_combined_effects_of_co2_and_climate_change.pdf
Smith MR, Myers SS. Global Health Implications of Nutrient Changes in Rice under High Atmospheric Carbon Dioxide. GeoHealth. 2019. smith_et_al-2019-geohealth.pdf
Golden CD, Shapero A, Vaitla B, Smith MR, Myers SS, Stebbins EA, Gephart JA. Impacts of Hydropower Development on Fisheries and Human Nutrition in the Lower Mekong. Frontiers in Sustainable Food Systems. 2019;3 :93.
Smith MR, DeFries R, Chhatre A, Ghosh-Jerath S, Myers SS. Inadequate Zinc Intake in India: Past, Present, and Future. Food and nutrition bulletin. 2019;40 (1) :26–40.
2018
Vaitla B, Collar D, Smith MR, Myers SS, Rice BL, Golden CD. Predicting nutrient content of ray-finned fishes using phylogenetic information. Nature communications. 2018;9 (1) :3742.
DeFries R, Chhatre A, Davis KF, Dutta A, Fanzo J, Ghosh-Jerath S, Myers S, Rao ND, Smith MR. Impact of historical changes in coarse cereals consumption in India on micronutrient intake and anemia prevalence. Food and Nutrition Bulletin. 2018;39 (3) :377–392. defries_et_al._2018
Smith MR, Thornton PK, Myers SS. The impact of rising carbon dioxide levels on crop nutrients and human health. IFPRI GCAN Policy Note [Internet]. 2018;10. Publisher's Version smith_thornton_and_myers_2018_-_impact_of_rising_co2_on_human_health_-_ifpri_policy_note.pdf
Wood SA, Smith MR, Fanzo J, Remans R, DeFries RS. Trade and the equitability of global food nutrient distribution. Nature Sustainability. 2018;1 (1) :34.
Smith MR, Myers SS. Impact of anthropogenic CO 2 emissions on global human nutrition. Nature Climate Change. 2018;8 (9) :834.
2017
Myers SS, Smith MR, Guth S, Golden CD, Vaitla B, Mueller ND, Dangour AD, Huybers P. Climate change and global food systems: potential impacts on food security and undernutrition. Annual review of public health. 2017;38 :259–277.
Beal T, Massiot E, Arsenault JE, Smith MR, Hijmans RJ. Global trends in dietary micronutrient supplies and estimated prevalence of inadequate intakes. PloS one. 2017;12 (4) :e0175554.
Golden CD, Seto KL, Dey MM, Chen OL, Gephart JA, Myers SS, Smith M, Vaitla B, Allison EH. Does aquaculture support the needs of nutritionally vulnerable nations?. Frontiers in Marine Science. 2017;4 :159.
Smith MR, Golden CD, Myers SS. Potential rise in iron deficiency due to future anthropogenic carbon dioxide emissions. GeoHealth. 2017;1 (6) :248–257.
2016
Golden C, Allison EH, Cheung WWL, Dey MM, Halpern BS, McCauley DJ, Smith M, Vaitla B, Zeller D, Myers SS, et al. Fall in fish catch threatens human health. Nature. 2016;534 (7607) :317–320.
Smith MR, Micha R, Golden CD, Mozaffarian D, Myers SS. Global Expanded Nutrient Supply (GENuS) Model: A new method for estimating the global dietary supply of nutrients. PLoS ONE [Internet]. 2016;11 (1) :e0146976. Publisher's VersionAbstract

Insufficient data exist for accurate estimation of global nutrient supplies.  Commonly used global datasets contain key weaknesses:  1) data with global coverage, such as the FAO food balance sheets, lack specific information about many individual foods and no information on micronutrient supplies nor heterogeneity among subnational populations, while 2) household surveys provide a closer approximation of consumption, but are often not nationally representative, do not commonly capture many foods consumed outside of the home, and only provide adequate information for a few select populations.  Here, we attempt to improve upon these datasets by constructing a new model — the Global Expanded Nutrient Supply (GENuS) model — to estimate nutrient availabilities for 23 individual nutrients across 225 food categories for thirty-four age-sex groups in nearly all countries.  Furthermore, the model provides historical trends in dietary nutritional supplies at the national level using data from 1961-2011.  We determine supplies of edible food by expanding the food balance sheet data using FAO production and trade data to increase food supply estimates from 98 to 221 food groups, then estimate the proportion of major cereals being processed to flours to increase to 225.  Next, we estimate intake among twenty-six demographic groups (ages 20+, both sexes) in each country by using data taken from the Global Dietary Database, which uses nationally representative surveys to relate national averages of food consumption to individual age and sex-groups; for age children and adolescents where GDD data does not yet exist, average calorie-adjusted amounts are assumed.  Finally, we match food supplies with nutrient densities from regional food composition tables to estimate nutrient supplies, running Monte Carlo simulations to find the range of potential nutrient supplies provided by the diet.  To validate our new method, we compare the GENuS estimates of nutrient supplies against independent estimates by the USDA for historical US nutrition and find very good agreement for 21 of 23 nutrients, though sodium and dietary fiber will require further improvement.

journal.pone_.0146976.pdf
2015
Gobbo LCD, Khatibzadeh S, Imamura F, Micha R, Shi P, Smith MR, Myers SS, Mozaffarian D. Assessing global dietary habits: a comparison of national estimates from the FAO and the Global Dietary Database. American Journal of Clinical Nutrition [Internet]. 2015;101 (5) :1038-1046. Publisher's VersionAbstract

Background: Accurate data on dietary habits are crucial for understanding impacts on disease and informing policy priorities. Nation-specific food balance sheets from the United Nations FAO provided the only available global dietary estimates but with uncertain validity.

Objectives: We investigated how FAO estimates compared with nationally representative, individual-based dietary surveys from the Global Dietary Database (GDD) and developed calibration equations to improve the validity of FAO data to estimate dietary intakes.

Design: FAO estimates were matched to GDD data for 113 countries across the following 9 major dietary metrics for 30 y of data (1980–2009): fruit, vegetables, beans and legumes, nuts and seeds, whole grains, red and processed meats, fish and seafood, milk, and total energy . Both absolute and percentage differences in FAO and GDD mean estimates were evaluated. Linear regression was used to evaluate whether FAO estimates predicted GDD dietary intakes and whether this prediction varied according to age, sex, region, and time. Calibration equations were developed to adjust FAO estimates to approximate national dietary surveys validated by using randomly split data sets.

Results: For most food groups, FAO estimates substantially overestimated individual-based dietary intakes by 74.5% (vegetables) and 270% (whole grains) while underestimating beans and legumes (−50%) and nuts and seeds (−29%) (P < 0.05 for each). In multivariate regressions, these overestimations and underestimations for each dietary factor further varied by age, sex, region, and time (P < 0.001 for each). Split–data set calibration models, which accounted for country-level covariates and other sources of heterogeneity, effectively adjusted FAO estimates to approximate estimates from national survey data (r = 0.47–0.80) with small SEs of prediction (generally 1–5 g/d).

Conclusions: For all food groups and total energy, FAO estimates substantially exceeded or underestimated individual-based national surveys of individual intakes with significant variation depending on age, sex, region, and time. Calibration models effectively adjusted the comprehensive, widely accessible FAO data to facilitate a more-accurate estimation of individual-level dietary intakes nationally and by age and sex.

am_j_clin_nutr-2015-del_gobbo-ajcn.114.087403.pdf
Smith MR, Singh GM, Mozaffarian D, Myers SS. Effects of decreases of animal pollinators on human nutrition and global health: a modelling analysis. The Lancet [Internet]. 2015;386 (10007) :1964-1972. Publisher's VersionAbstract

Background

Anthropogenic declines of animal pollinators and the associated effects on human nutrition are of growing concern. We quantified the nutritional and health outcomes associated with decreased intake of pollinator-dependent foods for populations around the world.

Methods

We assembled a database of supplies of 224 types of food in 156 countries. We quantified nutrient composition and pollinator dependence of foods to estimate the size of possible reductions in micronutrient and food intakes for different national populations, while keeping calorie intake constant with replacement by staple foods. We estimated pollinator-decline-dependent changes in micronutrient-deficient populations using population-weighted estimated average requirements and the cutpoint method. We estimated disease burdens of non-communicable, communicable, and malnutrition-related diseases with the Global Burden of Disease 2010 comparative risk assessment framework.

Findings

Assuming complete removal of pollinators, 71 million (95% uncertainty interval 41–262) people in low-income countries could become newly deficient in vitamin A, and an additional 2·2 billion (1·2–2·5) already consuming below the average requirement would have further declines in vitamin A supplies. Corresponding estimates for folate were 173 million (134–225) and 1·23 billion (1·12–1·33). A 100% decline in pollinator services could reduce global fruit supplies by 22·9% (19·5–26·1), vegetables by 16·3% (15·1–17·7), and nuts and seeds by 22·1% (17·7–26·4), with significant heterogeneity by country. In sum, these dietary changes could increase global deaths yearly from non-communicable and malnutrition-related diseases by 1·42 million (1·38–1·48) and disability-adjusted life-years (DALYs) by 27·0 million (25·8–29·1), an increase of 2·7% for deaths and 1·1% for DALYs. A 50% loss of pollination services would be associated with 700 000 additional annual deaths and 13·2 million DALYs.

Interpretation

Declines in animal pollinators could cause significant global health burdens from both non-communicable diseases and micronutrient deficiencies.

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