Is Stress Edible?
By Joon Yun, M.D.
Photos by Carole Topalian
The connection between food and stress may be stronger than you think.
The notion that food can affect our health has been around since antiquity, but fears about food have increased dramatically in recent times. The word “diet” means the sum of food eaten, but today that word is associated with not eating. Pejorative phrases like “junk food” entered our vocabulary in the 1970s. Since then, a new culprit—the latest food that we should blame and avoid—is identified every year. Many of the foods that have long been part of the human diet have suddenly become implicated in disease.
What’s going on?
The diseases most commonly attributed to food—heart disease, hypertension, diabetes, depression, inflammation and obesity start the list—are without exception stress-related diseases. “Stress eating” is commonly understood to mean “eating during times of emotional stress.” But what if the food we eat contains a chemical echo of the stressful experience it recently suffered? In that case, we might be putting stress on a plate and calling it lunch.
Food writers and activists such as Michael Pollan, Alice Waters and others have drawn attention to the many harmful aspects of modern food production. Industrial cultivation and distribution put extreme stress on plants and animals that we eat. It seems that the stresses placed on food ingredients are coming back to us full circle in a perverse rendition of “you are what you eat.”
Take cholesterol, for example. Eating foods high in cholesterol increases the risk of heart disease and other stress-mediated diseases. Stress increases cholesterol levels in both humans and industrially raised animals. When we consume a stressed animal’s high cholesterol, our cholesterol levels go up, and we may develop stress-related diseases, as if we had been the ones stressed in the first place.
Now examine salt. A high-salt diet increases the risk of hypertension and other stress-related diseases. Environmental stress causes both humans and food-source animals to retain salt. When we consume animal products that are high in salt, our salt levels go up and we may develop stress-related diseases, as if we had been the ones stressed in the first place.
Next, think about sugar. Too much sugar can increase the risk of diabetes and other stress-related diseases. We also know that stress tends to elevate blood sugar levels in the human body, which, again, contributes to diabetes. Stress also makes fruits sweeter through the plant’s natural stress hormone, ethylene. Ethylene helps fruit ripen, but ethylene is also triggered when the fruit is plucked, bruised during transport, or cut during processing. Furthermore, ethylene is often sprayed onto produce by grocers in order to ripen immature produce and to make it look more luscious. The net effect is that we put stress on fruits, and in turn their sugar levels go up. When we consume those sugars, our own sugar levels go up and we may develop stress-related diseases, as if we had been the ones stressed in the first place.
Consider omega-6 fatty acids. They increase the risk of obesity and other stress-related diseases. (By contrast, omega-3 fatty acids found in products such as extra-virgin olive oil and wild salmon generally decrease the risk of stress-related diseases.) When stressed plants release ethylene, the process also drives up their levels of omega-6 fatty acids. Heavily processed plants, such as refined corn, have higher levels of omega-6 fatty acids as a result. Animals don’t make omega-6 fatty acids and only acquire them through their diet. But when farmed animals and farmed fish are fed refined corn, which is high in omega-6 fatty acids, the animals’ own omega-6 fatty acid levels go up. The net effect is that when we put stress on corn, the biochemical markers of that stress (omega-6 fatty acids) flow through the industrial food chain and end up our plate. Eating such foods contributes to stress-related diseases, as if we had been the ones stressed in the first place.
The use of a biochemical from one species as a hormone by another species is called “xenohormesis.” The ability to detect ecosystem stress through biochemical messengers in the food chain was a favored trait during evolution. If our prehistoric ancestors were eating foods that were high in sugar and fat, it was probably a sign that winter—a season with high stress—was coming. Storing reserves of fat for winter months was important for survival. Evolution favored animal species that were able to respond to the increasing availability of fat and sugar in their diet by converting calories to fat.
Thanks to the modern industrial food complex, however, excessively salty, sweet and fatty foods are available year-round today, and people eat such “stressed foods” all year long. As a result, the typical human body now looks like it is fattening up for an imaginary year-long, stressful winter—an earlier tool for survival has become a Darwinian maladaptation.
While the potential health risks of salt, cholesterol, sugar and omega-6 fatty acids are well publicized, other biochemical messengers of stress may also be lurking in our foods. For example, stressed hens tend to lay eggs with higher levels of corticosterone, a stress hormone that’s part of the same family as cortisol. Ingested corticosterone carries forward the hormonal effects within the animal that consumes it. Research has shown that humans who consume cortisol analogues for medical use over a long period of time will develop stress-related diseases.
Similarly, human consumption of the plant stress hormone ethylene warrants further investigation. Scientific data from the 1920s, when ethylene was used as an anesthetic agent, suggest that it has many biologic effects on humans, including hypertension, pain relief and water retention, which also happen to be some of the effects of cortisol. Factories make more than 100 million metric tons of ethylene each year for various industries, including the food industry—making it the most commercially-synthesized chemical on the planet.
The Low Stress Food Diet
A low-stress food (LSF) diet involves focusing on the quality or character of the food, regardless of what type of food you eat. Specifically, the food’s origin matters. When was it harvested? How was it treated? What was done to it? Eating an LSF diet means minimizing your exposure to foods that have been put through heavy stress—during cultivation to distribution to preparation—before arriving on your plate.
Think about what is least likely to cause stress to your food. Whole foods would be better than processed foods. Choose plants that were grown in the season and soil in which they evolved. Choose food animals that were raised in cage-free, free-range conditions. Animals raised on natural feed, such as grass instead of corn, would be preferred. Wild meats and fish would be better than farmed. Since freezing or cooking in high heat can cause oxidative stress on foods, raw foods might be better, too. Long transport times and distances also induce oxidative stress on foods.
Ideally, a LSF diet means eating thoughtfully raised, local products as close as possible to the vine or farm. Undeniably, that’s an ideal and there are challenges of geography, seasonality, expense and convenience. The foundations of our contemporary, factory-produced diet did not appear overnight. It will take time to replace the sources of harmful, high-stress foods with healthier, fresher alternatives. The good news is that healthy grocery stores and farmers markets are starting to spring up nationwide.
Consider making some of these dietary improvements: