Does microwaving destroy nutrients in food


After answering this article, I did some research on microwaving killing vitamins and nutrients in food.

I very quickly learned that this is a touchy subject, even among nutritionists, and nobody (at least, nobody I saw) seems to have a "this is the science behind it and here is a definite answer" answer. Some articles claim "there is no hard evidence" while others point to studies from Stanford and other respected institutions that back the "yes" answer.

Some quick articles with conflicting information, if you're only going to read one please read the first and last as they seem the most reputable to me:

  1. The Straight Dope: Scientists are not sure yet, but it's likely in some cases
  2. Microwaving can be like boiling, which kills nutrients
  3. Microwaving is the best way of cooking for preserving nutrients
  4. Microwaving hurts broccoli, but is good for potatoes
  5. Harvard: Microwaving may preserve nutrients, like Vitamin C

As an interesting note, the "use less water" idea, which most of us take as common sense when cooking vegetables, may also be under scrutiny. From the Harvard article above:

But this is nutrition, and nothing in
nutrition is simple. Italian
researchers published results in 2008
of an experiment comparing three
cooking methods — boiling, steaming,
and frying — and the effect they had
on the nutritional content of
broccoli, carrots, and zucchini.
Boiling carrots actually increased
their carotenoid content, while
steaming and frying reduced it.
Carotenoids are compounds like lutein,
which may be good for the eyes, and
beta carotene. One possible
explanation is that it takes longer
for vegetables to get tender when
they’re steamed, so the extra cooking
time results in more degradation of
some nutrients and longer exposure to
oxygen and light.

So, my questions are: Is microwaving known to kill nutrients in foods? Is there a way to minimize this effect? Can any nutritionists weigh in here with their experience, and ideally, the science behind their answers? This has been a very confusing research path full of conflicting information, so all answers are appreciated.

Best Answer

Anything that breaks down due to heat is going to break down no matter HOW you cook it. Boiling only "destroys" nutrients by leaching them away into the water, which is the same reason that other people say that steaming/microwaving is better.

Thiamine, for example, is highly water soluble, so boiling is out. But it also breaks down at 100C, so you can't really cook it either. Niacin, on the other hand, leeches into water, but it's not heat-sensitive, so you can cook the hell out of it, as long as you don't get it wet. Folate is so fragile you can't leave your leafy greens in the sun without it breaking down (common with acids).

Basically, almost everything is better uncooked, but a lot of things are impossible to eat if you don't cook them enough to break down the cellulose. So eat a balanced diet, and stop worrying about the microwave.