Does cooking food significantly decrease its nutritional content?

  Tags: health   diet   cooking   raw foods   vegetarian   vitamins


There are some nutritionists and advocates of "raw foods" who believe that cooking food decreases its nutritional content. To what degree is this true? To what extent is nutritional content decreased? Is there a loss that is significant enough to cause health concern?

Here is one online paper of raw vs cooked foods that may be worth reviewing.

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Arguments For

Yes, cooking food does decrease nutritional value.


Cooking and draining food can reduce vitamin A by 35%, vitamin C by 75%, thiamin by 70%, folate by 75%, potassium by 70%, and similarly across all nutrients found in food.[3] A complete table can be found at nutritiondata.com for reference.

Boiling food can reduce water-soluble vitamins such as B and C.[1] It is better to microwave or steam them.

A study done on faba beans showed that cooking significantly decreased protein digestibility.[2]


An excerpt from cancer.org: "...some research suggests that frying, broiling, or grilling meats at very high temperatures forms chemicals that might increase cancer risk. Although these chemicals can damage DNA and cause cancer in animals, it is not clear how much they (as opposed to other substances in meat) may contribute to the increased colorectal cancer risk seen in people who eat large amounts of meat in some studies. Techniques such as braising, steaming, poaching, stewing, and microwaving meats produce fewer of these chemicals".[1]

Arguments Against

No, cooking food does not change the nutritional value.


In fact, cooking tomatoes will break down cell walls that actually increase their nutritional value.

As long as you cook vegetables and consume the broth as well rather than draining, you will get most of the nutrients. There is little anecdotal evidence that shows cooking food is a serious health risk.


Many meats should be thoroughly cooked to kill harmful bacteria such as salmonella and E. coli.


 1  Common Questions about Diet and Cancer Fetched Sept 16, 2009 Unknown Author (Cancer.org)
 2  Effect of cooking on anti-nutritional factors and in vitro protein digestibility (IVPD) of faba bean grown with different nutritional regimes Feb 9, 1999 E. A. E. Elsheikh, I. A. Fadul and A. H. El Tinay (ScienceDirect.com)
 3  Nutritional Effects of Food Processing Fetched Sept 16, 2009 Unknown Author (NutritonData.com)

User Comments & Opinion


1 Voted Yes

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Yes it does decrease the nutritional value in the item but the nutrients do not just evaporate into thin air. So yes it does if you measure one thing but not very much if you count the whole dish. - _fraz_ (twitter) 0

1 Voted No

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I don't think it's significant and cooking food reduces harmful bacteria. Also I think it tastes better sometimes. I just remember to drink the broth too. - jennyhooah (twitter) vote up image vote down image 0
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