Vegetables: To Cook or Not To Cook

January 10, 2012 in Categories: , , , by

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There are many people out there who will tell you that cooking vegetables destroys the nutrients and beneficial enzymes within.  This is partially true.  It is also true that cooking vegetables makes many of the nutrients and enzymes within more easily absorbed and used by your body.  So, which is better?  Eating vegetables raw or cooked?

Prehistoric man mastered the art of fire and cooking perhaps as early as 1.5 million years ago.  This means that for the majority of human evolution, our ancestors have been eating cooked food.  In fact, some believe that the advent of cooking may be one of the most important factors in our success as a species because it greatly increased the nutrition that could be digested out of our food for a lower energy expenditure (this is true for meat and plant matter). 

But, some vitamins are very volatile in heat.  Vitamin C for example, degrades with heat, dehydration and prolonged storage.  Polyphenols are antioxidants known to reduce the risk of cardiovascular disease and cancer which are destroyed by the cooking process.  There are some beneficial enzymes that are destroyed by the cooking process; for example: the enzyme myrosinase, whose activity forms sulforaphane, known to prevent cancer, is found in raw broccoli but destroyed in cooking.  The allicin in garlic (the compound in garlic responsible for its anti-biotic and anti-microbial effects, also shown to reduce the risk of cancer and cardiovascular disease) is destroyed by heat.  There is some very convincing evidence supporting the case for eating raw vegetables.

While some nutrients are lost in cooking, we are compensated by the many other nutrients that are increased during cooking.  Heat breaks down the thick walls of a plant’s cells, which makes any nutrients bound to the cell wall or locked inside the cells available to our body for digestion.  Typically, anti-oxidants are dramatically increased by cooking.  For example, many carotenoids increase in bioavailability when vegetables that contain them are cooked.  Lycopene increases when tomatoes are cooked or sun-dried.  And some compounds require heat to be formed, such as indole, thought to prevent cancer, which is formed when cruciferous vegetables (like broccoli, cabbage, Brussels sprouts and kale) are cooked.

So I advise mixing it up.  Cook some of your vegetables and eat some others raw.  Sometimes cook your carrots; sometimes eat them straight out of the bag.  Out of sheer convenience, I typically eat raw vegetables at breakfast and lunch and cooked vegetables at supper.  Do whatever works for you.  Eat your vegetables however they taste the best to you.  The most important thing is that you eat them! (See more posts about vegetables here)


Which is the best way to cook the vegetables?
I prefer roasting in the oven or grill. I heard steaming is good. What about microwaving?

Both roasting and steaming are great, I’d mix it up. Definitely avoid the microwave as it can be toxic and destroy important nutrients in vegetables that are preserved during roasting and steaming.

They don’t call it “nuking” for nothing. Microwaving changes the molecular structure of the food, and when you eat it, your body has a hard time digesting it as it does not recognize the altered state. Just start cooking your veges on top of the stove or in the oven like people did prior to the advent of microwave ovens.

That’s *ridiculous*, from the very first sentence. You clearly do not understand what a molecule is, or how basic physics, or a microwave work. Please read this:
And consider educating yourself about basic scientific principles, before you make a statement with a word like “molecule” in it.

At my job, there is a toaster oven next to the microwave. I use the toaster oven. If it is a frozen meal, I defrost it first then slip it into a glass dish and cook it in the toaster oven.

What about storing veggies? Does freezing fresh green, leafy vegetables (like kale) deplete nutritents? My local farmstand sells kale in GINORMOUS bunches. Am I still getting a good set of health benefits if I wash, dry, and freeze what I won’t use before it spoils? Then use those portions either to cook and/or in smoothies?

Great. Thank you! I’ve been doing that, but was wondering if the nutrition value left after freezing was worth the time of doing it. 🙂 Thanks again.

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