Are we taking a risk by exposing food (and ourselves) to microwave radiation? What about the danger of heating plastic packaging with semi-finished products to high temperatures? Let’s find out all these questions.
Despite the fact that the microwave has been the workhorse of our kitchens for decades, rarely has a household appliance generated so many conflicting opinions about itself. The microwave has been called a true salvation for those who do not know how and do not want to cook, while some chefs have claimed that this invention kills the art of cooking.
But there is another perennial question that never ceases to provoke heated debate, and it has nothing to do with the finer points of cooking: is it dangerous to have a microwave in the kitchen? According to the World Health Organization, there is no cause for concern when the device is used properly. Maybe so. But the jury is still out on another cause for concern: Can microwaved food be harmful? Does food lose its nutritional value when heated in a microwave? Does reheating food in plastic packaging lead to disruptions in the human endocrine system?
Some studies have shown that vegetables lose some of their nutritional value when cooked in the microwave. For example, broccoli can lose up to 97% of its flavonoids – phytochemicals with antimicrobial and antioxidant properties. This is one-third more than after cooking in boiling water. However, a 2019 study points out that previous experiments with broccoli were conducted at different temperatures and cooking times, and did not take into account whether the product was submerged in water. It has been found that short cooking times (one minute in the microwave) do not destroy the nutrients. Steaming or microwaving may even increase the amount of flavonoids. “Under the cooking conditions used in this study, microwave cooking was found to be the best way to preserve flavonoids compared to steaming,” the scientists wrote. At the same time, they found that when broccoli is microwaved with too much water (about the amount we use to boil it in a pot), the amount of flavonoids decreases.
Some items, such as green peas, lose nutrients when steamed or microwaved, while others, such as beans, do not. Xian Li Wu of the United States Department of Agriculture’s Beltsville Research Center says there is no single explanation for the fact that microwave cooking increases flavonoid levels. Maybe they are just easier to detect, easier to distinguish after microwaving, and there is no increase in quantity here. There is no clear answer to the question of whether vegetables retain more nutrients after microwaving than after other cooking methods, according to Sian Li Wu. “Although microwaving is generally preferable, the optimal cooking time varies for different vegetables,” he says. So even though the microwave is a preferred method, it’s by no means suitable for all plant-based foods.
Another study found that “moderate heating may be a tool to enhance the health benefits of certain vegetables.
We often heat food by placing it in a plastic container or wrapper and microwaving it. Some scientists warn about the risk of inhaling phthalates (esters of phthalic acid, especially those used in the manufacture of plastic utensils and packaging). These toxic additives can break down and leach into food during high-temperature processing.
When food is reheated in plastic containers, toxic phthalates can break down and leach into the food. We explain quickly, simply, and clearly what happened, why it matters, and what happens next. The number of episodes should remain the same. End of story Podcast advertising
“Some types of plastic are not meant to be used in microwaves because they are made of polymers that melt when heated, and if the temperature exceeds 100 degrees Celsius, they can get into food,” says Jumin Tan, a professor at Washington State University.
In a 2011 study, scientists purchased over 400 plastic food containers and found that the majority of them emit chemicals that disrupt hormone function in the human body. Phthalates are the most common additives used to make plastic products more flexible. They are commonly found in food containers, plastic packaging, and water bottles. It turns out that phthalates disrupt the functioning of hormones and our metabolic system. In children, phthalates can cause increased blood pressure and insulin resistance, increasing the risk of metabolic diseases such as diabetes and hypertension. Phthalates have also been linked to infertility, asthma and attention deficit disorder. Phthalates can potentially disrupt the function of thyroid hormones, notes Professor Leonardo Trasande of New York University’s School of Medicine.
Bisphenol is also a common component of plastic products, and studies suggest that it may also disrupt hormone function in humans. However, there are fewer studies on this than on the effects of phthalates. Phthalates are everywhere, from toys to body lotion, and it is still not entirely clear how harmful they are. However, most experts agree that heating food in a plastic container containing phthalates can increase their impact on the human body.
Scientists have discovered that phthalates interfere with the functioning of hormones and our metabolic system.
“Microwave heating activates contaminants,” says Professor Rolf Halden, director of the Biodesign Center at Arizona State University. “This process is used in laboratories to extract contaminants from samples before analyzing their chemical composition.”
At the same time, as Trasande notes, the level of potential risk does not necessarily depend on how often a person reheats food in a plastic container. The relationship is nonlinear. “We now know from numerous studies that a low level of exposure can actually be the most dangerous. And there is no level that can be considered safe,” he says. It is important to remember that when a plastic container is heated, the danger comes from the surfaces that do not come into contact with the food. For example, moisture can condense on the lid, which contains harmful substances that then enter the food in the form of droplets,” emphasizes Halden.
To minimize the risk of overheating food in the microwave, use ceramic dishes instead of plastic containers.
The most reliable way to minimize risk is to use non-plastic containers, such as ceramic dishes. However, if you must use plastic, avoid situations where the container is deformed, as old and damaged containers are more likely to release chemicals. It is also necessary to check the label on the container itself: those with the number 3 and the letters “V” or “PVC” contain phthalates. But even if you avoid plastic utensils, there are other potential health hazards, such as uneven heating of food and high temperatures in the microwave.
First of all, try not to use the microwave for cooking (as the food may heat up unevenly – and some parts of the dish will be less cooked), but for reheating food that has already been prepared. “Depending on the size of the portion, certain parts of the dish may be heated more than others,” says Francisco Dies-Gonzalez, professor at the University of Georgia (USA). “In cross-section, the temperature of different layers of the product can vary. Achieving completely uniform heating is difficult, especially when it comes to dishes made from raw ingredients.”
However, it is important to note that there are risks associated with reheating. Food should be reheated to a temperature of 82 degrees Celsius, which kills all harmful bacteria. But each time the food cools, these bacteria multiply more actively, and it will be harder to get rid of them the next time you heat it up. This is why it is not recommended to reheat food more than once.
However, it is not advisable to reheat certain foods more than once, especially rice. High temperatures in the microwave can be dangerous in and of themselves. In general, the temperature itself is not the problem. Some studies have shown that there is some risk in microwaving starchy foods, including root vegetables and grains.
When Betty Schwartz, a professor at the Hebrew University in Jerusalem, saw her students microwaving potatoes in their uniforms during a break in class, she noticed the small crystals that had formed in the potatoes. After studying them, she discovered that these crystals contain a large amount of acrylamide, a chemical substance used in the production of polymers and considered toxic. In this case, acrylamide was a byproduct of potato processing. Schwarz asked the students to boil potatoes and discovered that no acrylamide was formed after boiling. She concluded that the high temperature of the microwave was to blame.
This is alarming because animal studies have shown that acrylamide acts as a carcinogen by disrupting the functioning of DNA in cells. There is little evidence that it works the same way in humans. Some studies suggest that microwave cooking contributes more to the formation of acrylamide than other methods. “At 100 degrees Celsius, enough energy is released to change the bonds between molecules and create a molecule that reacts with changes in the DNA, resulting in mutations,” Schwartz says. “If there are a lot of mutations, oncology can occur.”
One way to avoid this is to soak the potatoes in water before putting them in the microwave.
As for the radiation in microwaves, it is completely harmless. These devices use low-frequency electromagnetic radiation, similar to that used in light bulbs and radios. Food placed in a microwave absorbs these microwaves, causing water molecules in the food to vibrate, creating friction and heating the food.
“Radiation from microwave ovens is completely harmless.” Humans are also capable of absorbing electromagnetic waves. However, microwave ovens produce relatively low-frequency waves that do not extend beyond the limits of the appliance. Even if they did exist, these waves are safe, Professor Tan claims. (But of course, high temperatures in the microwave are not safe at all, so you should never try to put a living creature in there!)
“We are exposed to waves like those in a microwave every day. People even share this radiation with each other,” says Jumin Tan. “If you eat products made from grains grown in the sun, you don’t have to worry about food from the microwave.” Unlike X-rays, microwaves do not use ionizing radiation, which means they do not have enough energy to remove electrons from atoms.
Microwaves do not use ionizing radiation, so there is no danger in using them to heat food. “To damage DNA, you have to break chemical bonds. This is the main way radiation kills: cells begin to mutate, and oncology develops,” explains Associate Professor of Radiation Medicine Timothy Jorgensen of Georgetown University Medical Center (USA). According to him, all concerns about microwave radiation were allayed in the early years after the invention of the microwave oven.
The microwave has long been considered a safe kitchen appliance, but as modern research shows, there are some concerns. There are certain things you need to be aware of if you want to use it. In particular, experts continue to worry about how the plastic packaging we use when we microwave food can affect the way our hormones work.
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