I have heard that the production of soy is actually quite bad from a sustainability point of view. As a vegetarian, what are my best options in terms of soy products (if indeed there are good options), or if not soy products, what are other good alternatives that provide the protein that soy does.
Asked by Marc Evans, ’10, MA ’11, Stanford, Calif.
The question of whether soy has a place in a sustainable diet raises another question: what is the most sustainable diet? What is the best way to be an environmentally conscious eater? There are quite a few different ways to measure the sustainability of food, but three criteria are particularly important: The effects of production on the surrounding ecosystem; the effects of the food on human health; and the amount of climate-warming gasses emitted during production and transportation.
In the Essential Answer, we explored the destructive effects of genetically modified soy on ecosystems, and the devastating land conversion associated with soy production. Soy gets an especially bad rap in the “harmfulness to ecosystems” category. But poor production techniques also affect other forms of produce. Conventional farms that use pesticides, herbicides, and synthetic fertilizers also wreck havoc on the environments surrounding their farms. Nitrogen-based fertilizers contaminate water systems, and trace elements of pesticides and herbicides that remain on our food can make us sick. Studies have increasingly touted the benefits of organic farming on health and the environment – meaning that any protein sources that we might substitute for soy should also be evaluated carefully. The Environmental Working Group has developed a list of foods that are particularly prone to contamination by pesticides, including apples, celery and strawberries. Buying organic is the safest bet.
Let’s look back at soy. Why does soy exhibit these environmentally hazardous tendencies on a larger scale than many other vegetarian sources of protein? It has to do with the scale of soy production. It is BIG. Soy is used for much more than the edible soy-based products that we pick up at the grocery store. Demand for this rich protein source is driven by its usefulness as an animal feed and for biofuels production.
Human consumption is only a drop in the bucket. The increasing global demand for meat and fuel ensures that soy will continue to be a coveted commodity, produced at a large scale.
The United States, Brazil, and Argentina are leading the world in producing to meet this insatiable demand for soy. The United States, Brazil and Argentina produce more than eighty percent of the world’s soy annually, the United States being the world’s largest producer. The environmental impacts of this production appear especially grievous when we consider that ninety-three percent of US soy, one-hundred percent of soy from Argentina, and seventy-five percent of soy produced in Brazil was genetically modified soy in 2010. The graph below displays the increase of GM soy in each of these places.
There are some good reasons for farmers to consider using GM crops, especially in light of the high demand for soy. Engineering crops to produce larger and more reliable quantities of food can provide a more secure food source for our growing global population. Vitamin-infused GM crops hold the potential to make nutrient-rich diets accessible to communities in the developing world who would otherwise remain nutrient deficient. But the health and environmental hazards of GM crops present a considerable risk, as we outlined to some extent in the Essential Answer. The most prevalent strain of soy in the United States has been genetically engineered to resist herbicides: It is agricultural biotechnology giant Monsanto’s Round-up Ready Soybean. In 2007, the Monsanto-generated, Roundup-Ready Herbicide-Resistant soybean variety accounted for more than 70 percent of the soy produced in the United States. This crop specifically allows for the increased application of an herbicide called Roundup, causing further harm to the native environments in the form of nutrient depletion of the soil and damage to other native species.
In addition to the environmental impacts that we have outlined, there is serious debate over whether GM crops also pose human health risks. Genetically modified crops are created by introducing a new gene into a plant. While this is intended to introduce some beneficial characteristic to the plant, the effects of consuming these modified species remain ambiguous. The three most discussed health risks of eating GM crops are:
(1) Allergies – Transferring genes from foods, like soy, that are commonly allergenic can result in a product that also produces an allergic reaction.
(2) Gene transfer – The stability of the gene being introduced must also be closely monitored. There is also a risk of an antibiotic resistant gene from a crop transferring to bacteria or a person’s intestinal tract and posing health risks.
(3) Outcrossing - GM crops have been linked to harmful cross-pollination between non-GM plants and the GM crops planted nearby, which can create crossbreeds that have not been certified for human consumption. This occurred in the United States when a strain of corn, approved only for cattle feed, appeared in corn meant for human consumption.
There is considerable disagreement about the likelihood of these dangers occurring, and scientists are continuing to research the impacts of GM soy on human health. Genetically modified crops clearly present more unknowns and risk factors into one’s diet, and they take a severe toll on the environment. Avoiding GM crops when possible is the safest and healthiest alternative for you and the planet.
Speaking of health risks, the health benefits and risks of consuming soy at all have been hotly debated. There has been considerable speculation on the risks of eating soy, especially because soy contains high concentrations of organic compounds called isoflavones. These compounds are a kind of phytoestrogen – chemicals found in plants that mimic the effects of the female hormone, estrogen. While this has been linked in some studies to reduced risk of breast cancer, prostate cancer, and heart disease, other studies have concluded that soy is linked to cancer, menopausal symptoms in women, and decreased sperm counts in men. The conclusion of the Fourth International Symposium on the Role of Soy in Preventing and Treating Chronic Disease can shed some light on these findings. Evidence fails to support the idea that soy could be a danger to cognitive health or linked to breast cancer, but research did show that eating 10 grams of soy per day can be beneficial to your health. More research needs to be done, but it is likely that soy is neither poison nor the miracle food that the media has made it out to be.
In the context of developing an overall, sustainable diet, we have seen that human health and environmental health are two of the most important concerns. Another measure of environmental sustainability is the carbon footprint of your diet. In the effort to mitigate our individual impacts on the climate, the most environmentally conscious diet would avoid foods that emit high levels of greenhouse gases over their lifetimes. The chart below was used in a report by the Environmental Working Group called “The Meat-Eater’s Guide to Climate Change and Health.”
It is clear enough from the diagram that meat is the most carbon-intensive option with cheese also at the top of the pack, emitting 13.5kg of CO2 per kilo of cheese eaten. Soy fares much better in this analysis at only 2.0 kg of CO2 emitted per kilo of tofu eaten. To minimize the greenhouse gas emissions associated with your food, buy locally to minimize transportation emissions and eat less lamb, beef, and cheese.
It is important to remember that soy is not intrinsically worse than these other vegetarian protein sources. However, it is also important to be aware of irresponsible food production methods that can occur in the process of delivering soy products to your local grocery store. As members of a global, interconnected society, we must always be conscious of what we are eating, and where it comes from. Eat soy and other foods that are local and labeled organic—products certified organic cannot be GM crops, and won’t leave pesticide residues behind where they were grown. Ultimately, the most environmentally friendly diet is different depending on where you live and what season it is—so take the time to read the label on your soy products at the grocery store and purchase responsibly when you can. Knowing where your food comes from and how food production practices impact the planet is the key to constructing a sustainable diet.
Judee Burr, ’12, is majoring in earth systems and philosophy.
