There is something about the microwave that makes it seem less wholesome than a stove. Perhaps it is the speed, the strange humming sound or the long-running fear that radiation somehow gets into the food. But when scientists look at what actually happens inside a microwave, the story is considerably less alarming. Microwaving food does not make it radioactive or inherently unhealthy. In fact, research suggests that, for many foods, microwave cooking can preserve nutrients as well as, or sometimes better than, conventional cooking. Scroll down to read more….
Understanding Microwave Oven Safety
Microwave ovens operate using electromagnetic waves to generate heat by making food molecules move. This process involves non-ionising radiation, which lacks the energy to cause damage like ionising radiation, such as X-rays. According to the FDA, microwave ovens that comply with safety standards and are used properly pose no health risks. Notably, the heat produced during cooking is safe and does not render food radioactive. The main consideration is the amount of heat, water, and cooking time applied to the food, rather than the microwave radiation itself.
But this happens with conventional cooking too. A 1989 review published in National library of Medicine found that nutrient retention in microwave-cooked or reheated foods was generally equal to or better than conventional preparation. Microwaving with a small amount of water can reduce that loss. A 2022 review by researchers from the British Nutrition Foundation found that methods involving high temperatures and prolonged exposure to water, particularly boiling, can be more damaging to some nutrients. Not necessarily. Cooking can reduce certain nutrients, particularly heat-sensitive and water-soluble vitamins such as vitamin C and some B vitamins. Microwaving generally preserved more vitamin C, while boiling caused the greatest losses. However, the effects on other vitamins varied depending on the type of vegetable and cooking method used. That distinction matters. There is no universal rule saying that microwaving preserves every nutrient better. Cooking method, temperature, duration, amount of water and the food itself all make a difference. One reason microwaving can preserve nutrients is simple: it is fast and usually requires little water. When vegetables are boiled, water-soluble compounds can move from the food into the cooking water. If that water is discarded, some of those nutrients go with it. Microwaving and steaming may help retain certain water-soluble nutrients. The science is not saying that microwaving magically protects food from nutrient loss. Overheating can still degrade nutrients and change the texture and chemical composition of food. Research on broccoli , for example, has produced mixed results depending on the cooking conditions. A study published in Journal of Agricultural and Food Chemistry found that microwave cooking affected compounds such as glucosinolates, phenolics and vitamin C, with the extent of change depending on cooking time, power and added water. In other words, shorter cooking is generally your friend. Microwaving vegetables until they are just tender is very different from repeatedly overheating them until they are soft and dry.
An earlier review in Critical Reviews in Food Science and Nutrition similarly concluded that differences between microwave and conventional cooking were generally small. Another study published in the National Library of Medicine found that cooking methods affected vitamin retention differently depending on the vegetable.