Quality of diet still poor for SNAP participants

New study identifies continuing disparities in diet quality for participants on SNAP

BOSTON (June 15, 2018, 11:00 a.m. ET)—A new Food-PRICE study finds persistent nutritional disparities within the food choices of those receiving assistance under the Supplemental Nutrition Assistance Program (SNAP) compared to those not receiving SNAP assistance. The study is published today in JAMA Network Open.

Led by researchers from the Friedman School of Nutrition Science and Policy at Tufts, the study examined the dietary patterns of SNAP recipients with two comparison groups, those whose income qualifies them for SNAP but choose not to participate, and those whose income is higher than the SNAP guidelines. 

The study represents the characteristics of 25.5 million adult SNAP participants, 26.9 million income-eligible nonparticipants, and 158.7 million higher-income U.S. adults. The team used data for U.S. adults aged 20 years and older who had completed at least one valid 24-hour diet recall during eight two-year cycles of National Health and Examination Survey (NHANES), through 2014. 

Based on the American Heart Association (AHA) 2020 Strategic Impact Goals for diet, the research team created a summary score reflecting a diet quality of poor, intermediate, or ideal. A ‘poor diet’ corresponded to less than 40 percent adherence to the AHA 2020 goals; an ‘intermediate diet’ to 40 to 79.9 percent adherence and an ‘ideal diet’ to 80 percent or greater adherence.

Greater consumption of fruits/vegetables, fish/shellfish, whole grains, and nuts/seeds/legumes and lower consumption of sugary-sweetened beverages, sodium, processed meat, and saturated fat contributed to a better diet score.

For the 2003-2004 to 2013-2014 survey group, the average diet score among SNAP participants did not significantly improve. During the same period, however, the average AHA diet score significantly improved in both income-eligible nonparticipants and higher-income individuals. 

Dietary disparities worsened for several key food groups.  Compared to both income-eligible nonparticipants and higher-income individuals SNAP participants experienced smaller reductions in added sugar intake, experienced no appreciable increases in intakes of nuts/seeds or fish/shellfish, and actually increased their intake of processed meats like hot dogs, deli meats, sausages.

“Over time, there were some improvements for certain food groups and nutrients among SNAP participants, such as increased consumption of whole grains, whole fruits, and dark green vegetables and decreased consumption of sugary-sweetened beverages,” said first author Fang Fang Zhang, M.D., Ph.D., epidemiologist and associate professor at the Friedman School at Tufts. “However, SNAP participants still had the lowest diet quality compared to income-eligible nonparticipants and higher-income individuals by 2013-2014. SNAP participants also had the lowest consumption of fruits and vegetables, whole grains, fish and shellfish, and nuts, seeds, and legumes, and the highest consumption of sugary-sweetened beverages.”

“Disparities persisted for most food groups and nutrients. Even after adjusting for differences in age, sex, race/ethnicity, education, and income over time, diet-related disparities by SNAP participation status were not materially altered for most dietary components,” said co-first author Junxiu Liu, Ph.D, postdoctoral scholar at the Friedman School at Tufts.

“These poor diets should not be interpreted as a cause-and-effect of participating in SNAP. It is possible that dietary trends of these low-income Americans could have been even worse without participation in SNAP. With the 2018 Farm Bill being debated in Congress, our findings underscore the need for robust new strategies for healthier eating and reduced dietary disparities for all Americans,” said Dariush Mozaffarian, M.D., Dr.P.H., dean of the Friedman School at Tufts.

The authors also found that the proportion of SNAP participants among US adults increased from 9 percent in 1999-2000 to 17 percent in 2013-2014, which could reflect changes in economic factors – in particular the economic recession during this period -- and to a lesser extent changes in SNAP policies in the 2002 and 2008 Farm Bills that improved accessibility and expanded eligibility. These economic and policy changes moved individuals with greater education and previously higher-income onto SNAP. Because such individuals would generally have better diet quality than participants in SNAP with less education, such population shifts likely make the observed dietary disparities by SNAP participation among U.S. adults even smaller than they would be otherwise.

In the limitations portion of the study, the researchers noted that self-reported dietary intake is subject to measurement error, although they also note that it is an excellent method for estimating the mean intake of groups like in this study. They also note that SNAP participants may have different benefit levels over time, producing partial misclassification of SNAP participation.

This study is part of the Food Policy Review and Intervention Cost-Effectiveness (Food-PRICE) research initiative, which focuses on population-level nutrition strategies and their relation to cardiovascular and cancer health outcomes.

SNAP (formerly called the Food Stamp Program) served 42.1 million people in 2017 with an annual budget of $70 billion, exceeding the budgets of the National Institutes of Health, Center for Disease Prevention and Control, Food and Drug Administration, Health Resources and Services Administration, and Agency for Healthcare Research and Quality combined. The average benefit per person in 2017 was $125.80 per month or approximately $4.19 per day. SNAP is the foremost U.S. program that provides food support for low-wage working families, low-income seniors, and people with disabilities. SNAP is reauthorized every five years as part of the omnibus Farm Bill.  The 2018 Farm Bill is currently being debated in Congress. 

Additional authors on this study are Colin D. Rehm at Albert Einstein College of Medicine and Parke Wilde and Jerold R. Mande, both at the Friedman School of Nutrition Science and Policy at Tufts University.

This work was supported by awards from the following institutes of the National Institutes of Health: National Institute on Minority Health and Health Disparities (R01MD011501) and National Heart, Lung, and Blood Institute (R01HL115189). Additional support was provided by the American Heart Association postdoctoral fellowship. The content of this announcement is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or other funders. For conflicts of interest please see the study.

Zhang, F. F., Liu, J., Rehm, C. D., Wilde, P., Mande, J. R., and Mozaffarian, D. (2018). Trends and disparities in diet quality among US adults by Supplemental Nutrition Assistance Program participation status. JAMA Network Open. doi:10.1001/jamanetworkopen.2018.0237


About the Friedman School of Nutrition Science and Policy at Tufts University

The Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy at Tufts University is the only independent school of nutrition in the United States. The school’s eight degree programs – which focus on questions relating to nutrition and chronic diseases, molecular nutrition, agriculture and sustainability, food security, humanitarian assistance, public health nutrition, and food policy and economics – are renowned for the application of scientific research to national and international policy.

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