|MadSci Network: General Biology|
Hello, Brittany. Microwave cooking has unjustifiably received a "bad rap." Many people popularly believe that microwaves are radioactive and that eating food from microwave ovens will make them "glow in the dark." To top it off, some of the science behind microwaves have been misinterpreted or misunderstood by the general population, due to false data, unfounded rumours and fears, spread by questionable websites, and even the popular press. Case in point, Spanish researchers microwaved 1-1/2 stalks of broccoli in 2/3rds cup of water, on high for 5 minutes, and then compared its nutrient content to other forms of cooking. They found a significant loss of nutrients in microwaved broccoli compared to boiling or steaming. Well sure, they overcooked it! To preserve nutrients in microwaved vegetables the idea is to use just a little water, (i.e. a couple of tablespoons), for as short a time as possible, just enough to tenderize it. It's well known that because microwave ovens cook so fast, they end up preserving more nutrients than other forms of cooking, provided of course, that they're not overcooked. Furthermore, microwave cooking does not produce cancer-causing substances called (HAA's) - heterocyclic aromatic amines, which are commonly produced by frying, grilling, or broiling. Perhaps your question was prompted by a recent story going round of a woman who died, after receiving a blood transfusion that was heated up in a microwave oven. Yes, this is true, but the culprit here was not that the microwave somehow changed the blood by breaking its DNA, or creating some kind of poison. Once again, it was due to overheating. Simply put, when blood is overheated, it causes the blood cells to break apart. Red blood cells are unstable at temperatures over 49°C. This can lead to serious side effects and can even be fatal when undergoing blood transfusions. Safer methods of heating blood for transfusions are usually employed by technicians, that enable better temperature control than with microwaves. However, any type of heating method that results in overheated blood could be dangerous, not merely because they're from microwave ovens. Finally, can microwaves or its cooking break apart DNA, and also, does microwave cooking cause cancer? The short answer is no. Simply put, microwaves are a nonionizing form of radiation, which means they cannot break apart the nucleus of a cell, they cannot break DNA apart, and there is no credible evidence to suggest that it could cause cancer. This is in contrast to ionizing radiation, which can indeed beak apart DNA and cause cellular damage. Examples of these are: x-rays, ultraviolet rays, gamma radiaition, and cosmic radiation. For this reason we are told to minimize x-rays, wear protective spacesuits in space, and slather on sunscreen on earth. Microwaves are very efficient for satellite and electronic communications, as well as cooking. So don't believe the various scaremongers and microwave alarmists you may hear from or come across on the net. As far as I know, they still have not succeeded in changing the laws of physics. Hope that helps, Peter Bosani. References & Further Reading: Science Matters - R.M. Hazen & J. Trefil - Doubleday publishers. Let Them Eat Flax - J. Schwarcz- ECW Press
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