At what temperatures do different kinds of vitamins are destroyed or lose their nutritional value?

Imagine you went to the store and bought vitamin enriched cacao powder. Then you made yourself a hot drink by pouring boiling water. How much in general(approximately) vitamins were destroyed by that heat.

"How to prepare/cook" usually doesn't have this kind of information. Thus any benefits of vitamins are lost(?).

  • $\begingroup$ There is already a lot of information on this topic (also for non-biochemists). Did you try googling "heat sensitivity of vitamins"? $\endgroup$ – WYSIWYG Sep 30 '19 at 11:49
  • $\begingroup$ @WYSIWYG yes, I have googled it. Bottom line every article or page that I have found just says - "yes vitamins lose their value when heated" (I am not very good at googling or finding this kind of data when it comes to biology). Not very informative, I understand that they lose their value. I wanted to know how serious those effects can be. $\endgroup$ – Candid Moon _Max_ Sep 30 '19 at 18:06
  • $\begingroup$ This question is not about biology in terms of SE Biology but domestic science, unless it is a personal medical question, which would be off-topic. It might fit Chemistry SE if it were not so broad/imprecise. $\endgroup$ – David Oct 1 '19 at 7:30
  • 2
    $\begingroup$ @David I see. I thought that since it's about vitamins and they have biochemical functions that occur in our bodies - it would be fit for biology. But since the question is more outside of terms of biology and closer to chemistry and reactions, I agree with you that it may better fit Chemistry. Although, it would be incorrect moving it after Jan's answer. Biology, chemistry and physics are tightly coupled together, so I guess it's not that big of an issue, is it? $\endgroup$ – Candid Moon _Max_ Oct 1 '19 at 11:54
  • $\begingroup$ I understand that the question is not of a nearly perfect quality. But due to my incompetence in this topic that is naturally what I could do. $\endgroup$ – Candid Moon _Max_ Oct 1 '19 at 12:41

Here's one estimation about how much vitamins or minerals can get lost due to various "food processing" (cooking, drying, freezing) methods:

According to NutritionData, cooking can result in a loss of vitamins:

  • Vitamin A: 25%
  • Vitamin C: 50 %
  • Vitamin B complex vitamins: 25-70%
  • Minerals: 25-70%; most important: potassium loss in cooking water. In this study with potatoes:

Leaching alone did not significantly reduce levels of potassium or other minerals in tubers. Boiling tuber cubes and shredded tubers decreased potassium levels by 50% and 75%, respectively.

According to USDA retention factors, the following vitamins are most affected by food processing:

  • Vitamin C
  • Vitamin B1, B6, B12 and folate

Vitamin and mineral loss is related to both the temperature and time of cooking.

Mineral loss can be prevented by cooking in vapour (steaming) instead of cooking in water.

According to this source, the following can be loses after heat treatment at 70 °C and (90 °C):

  • Vitamin A: 10% (30-40%)
  • Vitamin D: 15% (35%)
  • Vitamin B1: 15% (50%)
  • Folic acid: 5-20% (45%)
  • Vitamin C: 40% (85%)
  • 1
    $\begingroup$ But the minerals won't be truly lost if the cooking water is not thrown away. $\endgroup$ – WYSIWYG Sep 30 '19 at 18:10
  • $\begingroup$ @WYSIWYG, most people throw away cooking water after boiling potatoes. Since potatoes are rich in potassium, a lot of it can be lost that way. If the water is consumed, of course no minerals are lost. I added one study about potatoes. $\endgroup$ – Jan Oct 1 '19 at 6:48

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