thermolabile vitamins

thermolabile vitamins


Vitamins are essential molecules for human life; they can be classified according to various criteria; among the best known we mention:

  • In  water  ( water soluble vitamins )
  • In lipids ( fat soluble vitamins )

and heat stability:

  • Heat resistant (thermostable vitamins)
  • Non- or partially heat-resistant ( heat-labile vitamins )

    Which ones are they

    The group of thermolabile vitamins is essentially represented by ascorbic acid  (vitamin C) and by numerous  vitamins of the B group ; in particular:

    • Thiamine ( vitamin B1 )
    • Riboflavin ( vitamin B2 )
    • Pantothenic acid  ( vitamin B5 )
    • Folic acid  ( vitamin B9 )
    • Ascorbic acid  (vitamin C)
    • Retinol (or  vitamin A ) and  beta-carotene  (precursor of vitamin A)
    • Tocopherol ( Vitamin E )

    While the thermostables are all the others.

    How to preserve them

    In order to guarantee the right amount of vitamins in the diet, in addition to making sure that at least the minimum recommended ration is introduced with food  , it is essential to examine the entire food style to ensure that the efficiency of thermolabile vitamins is not completely compromised.

    Folic acid

    Evaluating the efficiency or otherwise of thermolabile vitamins might seem like overzealous behavior, but it is not. A perfectly fitting example concerns folic acid, otherwise called vitamin B9; folic acid is an essential molecule for the synthesis of  nucleic acids  and its deficiency can significantly affect the efficiency of  erythrocytes , causing  pernicious  or  megaloblastic anemia . Unfortunately, the most important side effect of vitamin B9 deficiency is the eventual fruit of  conception; the pregnant woman deficient in folic acid can cause irreversible neural damage to the unborn child. For hygienic reasons, the pregnant woman SHOULD limit the amount of raw foods , therefore, in order to avoid  vitamin deficiency , specialists usually administer some  food supplements … but it is not enough to supplement only during pregnancy  , it is advisable to guarantee the folic acid intake even before conception! In this regard, the advice of all nutrition professionals is to increase the intake of vitamin B9 through the frequent and systematic consumption of  vegetables RAW with green leaves. Unfortunately, it often happens that subjects “refractory to salad” are more oriented towards cooked side dishes; unfortunately, in this case the inactivation of folic acid as a thermolabile vitamin is quite relevant. It is therefore advisable to consume AT LEAST a portion of  raw vegetables  and a couple of portions of  fresh fruit  (in this case  oranges ) per day.

    Other Vitamins and Industrial Products

    The same argument is valid for all thermolabile vitamins and the seriousness of the risk of  hypovitaminosis  is directly proportional to:

    • Personal need
    • Quality of the selected foods (presence or absence of thermolabile vitamins)
    • Method of consumption (consumption of raw or cooked food)

    To be precise, the stability or otherwise of thermolabile vitamins is a greater obstacle for the home consumer than for the industries. In large-scale distribution, food technology has achieved excellent results and various experimental works (the most famous refer to the processing of  tomatoes ) have documented a preservation of thermolabile vitamins which sometimes abundantly exceeds 90%. That’s not all, in some cases (which have nothing to do with thermolabile vitamins), heat treatment FAVORS the nutritional enrichment of finished products by activating various antioxidant molecules (Maillard reaction in tomato cooking  )  or   by denaturing some  protein binding (protein  avidin  contained in egg white ).


    • Food chemistry  – P. Cabras, A. Martelli – Piccin – page 262
    • Lions 2002
    • Nicole et al, 1999


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