if you can't stand the heat... cooking lesson #1

Cooking (heating) does a lot for us in terms of food: It improves palatability of food; makes it easier to digest; adds a variety of flavors; and it kills some harmful pathogens.  Cooking can make food gorgeous- bringing out color of fruits and vegetables, but it can also help bring out some vitamins and and other phytochemicals!!  However, you must be careful with cooking because you can quickly and unknowingly lose nutrients and flavor.

Andrew Scrivani for The New York Times

Lesson #1: water soluble v. fat soluble vitamins



There are 13 essential vitamins needed for normal body function:

Andrew Scrivani for The New York Times

• Vitamin A
• Vitamin C
• Vitamin D
• Vitamin E
• Vitamin K
• Vitamin B1 (thiamine)
• Vitamin B2 (riboflavin)
• Vitamin B3 (niacin)
• Pantothenic acid
• Biotin
• Vitamin B6
• Vitamin B12
• Folate (folic acid)
• 
  

They are divided into 2 categories:

1) Fat-soluble vitamins

• These are stored in the body's fatty tissues and in the liver
• Vitamins A, D, E, and K
• Generally, these are more stable and less sensitive to environment

2) Water-soluble vitamins

• These must be used immediately because they are not stored!  Whatever is not used at the time is excreted from the body through urine
• These include B-complex Vitamins and Vitamin C
• These are very sensitive to cooking environment!

What does this have to do with my cooking?

In theory, it makes sense that something that is water soluble means that the vitamins in that product can leach into water if you leave it too long (...they are soluble in water).  Same for fat soluble and fats.  In reality, you have to pay attention to the method that you cook your fruits and vegetables.  If you leave a carrot in water to soak overnight- no problem! Vitamin A is fat-soluble and will not leach out in water; but, if you leave a peeled potato to soak overnight in water, you lose all the Vitamin C because it is a water soluble vitamin.  

Tips:

• Pay attention to the method that you use to cook.  Steaming, stir-fry, or microwave vegetables is better than boiling (unless you want to drink the water that you boiled your veggies in... eww)
• Use as little water as possible for all cooking methods
• Be careful about leaving vegetables in water or oil for too long (fat soluble vitamins will leach into oils!)
• If you must boil- add food items to already boiling water instead of adding to cooler water and allowing the temperature to rise and boil
• Cut fruit or vegetables just before cooking or serving.  Exposing them to air increases the degradation of vitamins and causes dehydration and wilting.
• Also, cut after washing
• Avoid soaking fruits and vegetables, in general
• Limit cooking time and avoid high temperatures for all foods.

Andrew Scrivani for The New York Times

Cool side-note fact: Some vitamins are degraded by light.  This is why you see orange juice (vitamin C) and milk (riboflavin) in opaque containers!! (Marion Nestle makes some interesting points in her blog about this!)

Also- vitamins come from more places than just fruits and vegetables.  here's were you can find them.  remember- to still pay attention to cooking times and methods when cooking anything that you want to retain the nutrient value!

Source: Utah LessonPlans. "Basic Vitamins: Water-Soluble and Fat-Soluble." 09 July 1997. Web. 21 Sept. 2011. <http://www.uen.org/Lessonplan/preview.cgi?LPid=1261>.