Study shows diet impacts environment

by Allison Kronberg

Agricultural education senior Jared Luhman uses a number of different methods to control the amount of nutrients in his organic farm’s soil.
Efforts to manage nutrients in farms’ soil often involve soil testing or using different amounts of chemical or manure fertilizers. But a new study done in part by a University of Minnesota researcher found that everyone — not only farmers — can have an impact on the amount of nutrients in their soil.
An international research team published a study earlier this month that found both human diets and waste management technology influence the amount of nutrients found in agricultural soil. And an imbalance of nutrients can pollute surrounding bodies of water through runoff.
“You’ve heard the phrase, ‘You are what you eat,’ but what you eat also affects your environment,” said University postdoctoral researcher Daniel Nidzgorski, one of the five researchers from the United States and Sweden who worked on the study.
Nutrient pollution occurs when excess nutrients in waterways cause plants like algae to grow too much, which can starve fish and other organisms of oxygen.
The study aimed to answer how what people eat, along with waste management or recycling practices, interacts and affects soil nutrients, Nidzgorski said.
The idea for the study came up last year in Sydney, Australia, during a conference on ecological stoichiometry, or the study of the balance of energy and elements in ecological interactions, said Arianne Cease, the study’s lead author and an Arizona State University sustainability scientist.
“After our first conversation as a group, this topic quickly rose to the top as an important area for us to pursue,” she said.
The team studied six diet patterns for nitrogen and phosphorous consumption and waste, along with six urban waste management methods. The models represented both diets for people in the U.S. and in developing nations.
Many of the nutrients come from additives in processed foods, Nidzgorski said. Omnivore diets in the U.S. had the highest amounts of nutrients.
Phosphorous was usually stored or recycled in U.S. waste management processes, but nitrogen was often released as pollution.  In developing nations, both nitrogen and phosphorous were sometimes released as pollutants because of a lack of sanitation infrastructure.
There are efforts to try combating nutrient pollution from human waste, Cease said.
The Environmental Protection Agency is working to incorporate nitrogen and phosphorus management criteria into its policies, she said, which would mean less nitrogen pollution. 
But Nidzgorski, who is now working to research new waste management strategies in Minnesota, said waste management is only part of the problem.
“Changing something as integral to people’s lives as their diets or as big as waste management infrastructure also requires looking at the other environmental, economic, social and behavioral factors,” he said.
In the meantime, Luhman said his farm will continue trying to manage nutrients in their soil the best way possible.
“Any research to find a way to reduce erosion or control nutrients is extremely beneficial,” he said.