Increased Consumption of Subsidized Foods Ups Cardiometabolic Risk


More than half of the calories consumed by US adults in recent years were from major subsidized food commodities, and greater consumption of calories from these sources is linked with a higher likelihood of cardiometabolic risk, according to the results of a study published online July 5 in JAMA Internal Medicine.

“The US Department of Agriculture and US Department of Health and Human Services Dietary Guidelines for Americans emphasize consumption of fruits, vegetables, whole grains, protein, and moderate amounts of dairy, while recommending limited consumption of saturated fats, sugars, salt, and refined grains,” write Karen R. Siegel, PhD (Centers for Disease Control and Prevention [CDC], Atlanta, GA), and coauthors. “At the same time, current federal agricultural subsidies focus on financing the production of corn, soybeans, wheat, rice, sorghum, dairy, and livestock, the two latter of which are in part via subsidies on feed grains.”

“A large proportion of these subsidized commodities are converted into high-fat meat and dairy products, refined grains, high-calorie juices and soft drinks (sweetened with corn sweeteners), and processed and packaged foods,” they note.

According to Siegel and colleagues, these results show that there is currently a lack of alignment between agricultural policies and nutritional policies in the United States.

Nutrition Survey

Siegel et al analyzed data from a single day of 24-hour dietary recall taken by 10,308 participants from the National Health and Nutrition Examination Survey between 2001 and 2006. For each participant, they calculated a subsidy score that estimated the consumption of subsidized food commodities as a percentage of total caloric intake.

Overall, 56.2% of the calories consumed by participants were derived from subsidized foods. Compared with people eating the lowest proportion of subsidized foods, those eating the most tended be poorer, less educated, and less food secure (P < 0.001 for all).

Additionally, a higher intake of subsidized foods was linked to an increase between 14% and 41% in the probability of having certain cardiometabolic risk factors. Compared with those eating the least amount of subsidized foods, those eating the greatest amount had a higher likelihood of:

  • Obesity (prevalence ratio [PR] 1.37; 95% CI 1.23-1.52),
  • Abdominal adiposity (PR 1.41; 95% CI 1.25-1.59)
  • Elevated C-reactive protein level (PR 1.34; 95% CI 1.19-1.51)
  • Dyslipidemia (PR 1.14; 95% CI 1.05-1.25)
  • Dysglycemia (PR 1.21; 95% CI 1.04-1.40)

The only cardiometabolic outcome examined that did not turn out to be linked with subsidized food intake was blood pressure.

Impacting the Poor

“Although subsidized foods are intended to ensure adequate availability of storable, staple foods, studies at the population level have noted links between agricultural policies and rising obesity and chronic disease prevalence,” Ed Gregg, PhD, who was not directly involved in the study but serves as chief of the CDC’s Epidemiology and Statistics Branch in the Division of Diabetes Translation, told TCTMD in an email. “This study is the first of its kind to examine these relationships at the individual level—specifically, the relationship between diets made up of more subsidized foods, and an individual’s personal risks for developing cardiovascular disease and type 2 diabetes.”

Although the data by Siegel et al drew a connection between subsidized foods and cardiometabolic risk, Raj Patel, PhD (University of Texas at Austin, TX), who wrote an accompanying editorial, noted to TCTMD via email that there is actually a web of causes and effects that associate these variables, one of which is poverty.

As Siegel and colleagues write in their paper, “The present finding that higher subsidy scores are associated with adverse cardiometabolic risk highlights the effect that agricultural subsidies may be having on health disparities in the United States, in part due to the lower cost per calorie of unhealthier food and the higher cost per calorie of healthier food.

“This observation,” they continue, “has implications for food security because these same population groups may also be restricted by the amount of money they have available to meet their nutritional requirements.”

Indeed, the majority of the Farm Bill—passed in 1973 to provide consumers with food at reasonable prices—is spent on the Supplemental Nutrition Assistance Program (SNAP), with agricultural commodity supports and insurance providing a share of the remainder, Patel said.

This may already come as a surprise to those who thought the Farm Bill was about farmers. Mostly, it’s about families on low incomes who can barely afford to eat—there are around 50 million food insecure people in the US—and a little less about farmers,” Patel told TCTMD. “The greatest beneficiaries of subsidized commodities are the processors and distributors, who turn these cheap inputs into much higher-priced and more profitable processed foods which, compared to fresh fruits and vegetables, are likely more significant contributors to cardiometabolic risks.

“None of this is designed either to support farmers growing healthy food, or eaters being able to afford it,” he said. “SNAP benefits are too low, running out for 80% of recipients by the end of the second week of every month. And federal support for fresh fruit and vegetables is negligible compared to the abundant support for processed food.”

Looking at the Whole System

In their conclusion, Siegel et al comment that “although eating fewer subsidized foods will not eradicate obesity, our results suggest that individuals whose diets consist of a lower proportion of subsidized foods have a lower probability of being obese. Nutritional guidelines are focused on the population’s needs for healthier foods, but to date food and agricultural policies that influence food production and availability have not yet done the same.”

According to Gregg, additional research is needed to more fully elucidate how agricultural and nutritional policies could be better aligned. For example, it would be valuable to examine how changes to the current subsidy structures would alter the production and consumption of various foods.

Patel agreed, adding that food subsidies artificially lower the price of certain foods despite high social costs associated with the agricultural arena. A more systemic view of population health is needed, he said, one that examines the system in which food is produced, not just the food itself.


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Sources
  • Siegel KR, McKeever Bullard K, Imperatore G, et al. Association of higher consumption of foods derived from subsidized commodities with adverse cardiometabolic risk among US adults. JAMA Intern Med. 2016;Epub ahead of print.

  • Patel R. How society subsidizes big food and poor health. JAMA Intern Med. 2016;Epub ahead of print.

Disclosures
  • Siegel and Patel report no relevant conflicts of interest.

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