Monday, April 12, 2010

We don't know the micro nutrient levels in cooked food

Yet another disturbing revelation about how little we know about the micro nutrient levels in the food we eat. Here are some juciey quotes from a 2000 paper.
The majority of nutrient databases provide information mainly on the nutrient composition of raw foods
So at the year 2000 nutrition information was still unavailable for cooked foods. I find this very bizarre cause most food is cooked before eating in places like hospitals were ones nutrition is very important. The article goes to say that due to costs in analyzing foods one is forced to estimate the nutrient levels in foods. How good is this estimation? Well its pretty bad...... In the study they looked at vitamin B1 and B6 in rice, broccoli , chicken and pork comparing estimation to actual level. They found that B1 if was overestimated by 23% in rice and 16% in broccoli. For B6 overestimated by 80% in rice and underestimated by 11% in chicken and 28% in pork.

So the two vitamins looked at had a error of >10% for 5 of the 8 tests. This is shocking. The paper goes onto say these errors are erratic. What this means is that they are random and uncontrollable, so we really have no idea about why the are so difference.    

Then the paper looked at the effects of food method for nutrient levels of chicken. The table had white area, for things well known and grey areas for nutrients that we estimated as there was not enough data to firmly conclude anything. The following nutrients were grey
  • Zinc
  • Trace elements
  • Retional
  • Carotene
  • Vitamins D, E, K
  • Vitamin B12, folate, pantothenate, vitamin C  
This is like nearly all the vitamins...and don't even get started on other phyto-nutrients. There was no data at all for vitamin C levels for boiled, steamed, braised, pan fried roasted or deep fried chicken. That is right folks no studies have looked at how vitamin C changes when you cook chicken. Now granted that chicken is hopefully not your major source of vitamin C! But the point remains that we now very little about how nutrients change in cooking.

Yet we allow "experts" to say that extra vitamins are not needed?! Not even the researches know what is in cooked food. The only reason they can say this is that people don't get scurvy..... so all must be well. 

Clearly good food eg fruit, vege, high nutrient animal products, are still going to be good for you no mater what you do. Bad food like sugar, processed foods are still going to be bad for you. However any processed food that has micro nutrients listed are likely to be no better than a random money. 

Reference: Guidelines for recipe information and calculation of nutrient composition of prepared foods (dishes). Jounral of food composition and analysis vol 13 pg 391, 2000. Picture link

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