DEAR DOCTOR, I tend to cook food and warm it up later in the microwave as it is fast and easy. My sister has warned me against this, saying it is not safe. Is this true? If it is unsafe, how so, and what are the safer ways to heat up food? GRACE DEAR GRACE, Microwave is a multipurpose kitchen appliance used widely world over for cooking, roasting, grilling, baking and reheating food. In it, food is cooked by exposing it to microwave radiation. Microwaves are a form of radiofrequency electromagnetic energy. When this energy comes in contact with food, absorbed energy rotates water molecules in food and cooks it. Cooking is much faster than other means of cooking like gas stoves. Flavour and texture of food is also retained. Because cooking time is minimised, nutrients of food are also supposed to be retained when cooked in microwave oven. Low fat food can be prepared, because it requires minimum oil for cooking. Thus, there are many advantages pointed out in using a microwave oven. However, overtime, many health hazards of using microwave cooked food have also been observed over the years by different studies. Since the food is cooked from outside to inside (in contrast to conventional stoves which cook beginning from outside), and that too by intense energy, cell membranes of food particles is disrupted, thus affecting nutrient value. Fats and proteins are more susceptible to this disruption. This process can lower immunity in a person using food continuously, cooked in microwave oven. Body is said to be unable to handle the breakdown products and metabolites of microwaved food, thus affecting elimination of toxins from body. Excess exposure to microwave radiation can potentially cause brain damage overtime, resulting in headache, memory loss and early fatigue. If plastic containers are used for cooking/reheating food in microwave oven, chemicals are released which are potentially carcinogenic, i.e. cancer producing. As such, food material put inside for cooking does not become radioactive. But in case of leaking doors, dirty doors, there is a risk of being exposed to radiation. This over time can cause health hazards of radiation like cancers, sterility, inflammation in food pipe, etc. Risk is enhanced when standing close to or directly in front of a microwave oven, when it is on. Microwaving can also cause some abnormal changes in blood profiles, as shown by some studies. Since the human body is made of 70% water, close proximity to microwave oven, can cause burns due to intense energy. Eyes and testicles of men are more vulnerable to it. Ideally, food prepared freshly, over low heat and consumed warm, is most healthy for the body, providing nutrition, as well as being suitable for human gut and metabolic process. Microwave can be used for its convenience, but one should be aware of its disadvantages as well. It should be ensured that the oven is cleaned regularly, as per instructions given in the product brochure. The door should close tightly without any effort. One should avoid standing very close to it when on. Dr. Rachna Pande, Specialist internal medicine rachna212002@yahoo.co.uk