Do microwaved foods lose their nutrients?

The myth that microwaved food loses more nutrients is one of the most popular nowadays.

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Many people avoid its use due to this urban legend that has little scientific proof. Many claim that this is because food loses vitamins and nutrients when cooked in the microwave.
However, this idea that microwaves are worse than other forms of cooking does not have a scientific basis, explains on its website the program of the BBC Trust Me, I'm a Doctor ("Trust me, I'm a doctor").

Microwaves cook food using energy waves that are similar to radio waves, but shorter. These waves are very selective and affect mainly water and other molecules that are electrically asymmetrical: positively charged at one end and negatively charged at the other.

Microwaves cause these molecules to vibrate and generate heat that then spreads to nearby molecules to heat, and cook food.

This process can affect the vitamins and nutrients of the food, but these changes are not unique to microwaves, but are a result of the heating process. When the food is heated, some vitamins, such as vitamin C, break down, explains Harvard University, in the United States, on its information website on medicine and health.

But this happens regardless of whether the food is heated in a conventional oven, in a stove or in a microwave. Proteins are also "denatured" (that is, they decompose and sometimes lose their properties), when heated, by whatever means.

But because preparation times are shorter, cooking with microwaves actually helps preserve vitamin C and other nutrients.

Cooking with water

Nutrients in food are also lost when cooking food with water. Several scientific studies have concluded that when boiling vegetables, much of their nutrients are released into the water.

Vitamin C and many of the B vitamins, such as B6 and B12, are more vulnerable because they are soluble in water. And normally that water is not used, but is discarded when finished cooking, so the nutrients in it are also lost.

The loss of nutrients is greater when boiling than with other cooking techniques, such as microwave use, frying or steaming. So the best way to retain vitamins and nutrients from food when cooking is to use short times that limit heat exposure, and a cooking method that uses as little liquid as possible.

An article published in 2009 in the Journal of Food Science concluded, for example, that cooking with microwaves helps maintain antioxidant levels in foods such as beans, asparagus or onion that if boiled, cooked under pressure or baked .

To recap: the best way to use the microwave is by minimizing the amount of water and without cooking too much the vegetables. Although, if you are most concerned about maintaining the nutritional value of food, it is best to steam it. In addition, there are other things that can be done to preserve the nutritional value of the food as much as possible.


Useful tips to prevent the loss of nutrients when cooking

-Peel and chop the food just before preparing it or consuming it
-Use short times to wash it before cooking
-Use methods of cooking in which water and food come into contact as little as possible
-Wait for the water to boil completely to submerge the food, as this will reduce the cooking time required
-Cook the vegetables al dente and chill them after cooking to preserve their vitamins
-Take advantage of water from cooked vegetables to make other foods, such as soups or stews
-Avoid storing fruits and vegetables in the refrigerator for a long time
-Adding vinegar or lemon juice contributes to the preservation of vitamins and the absorption of some minerals, such as iron (although it can also change the flavor).