Please verify your email address to receive email notifications.

Enter your email address

We have sent you a verification email. Please check your inbox and spam folder.

Unable to send verification, please refresh and try again later.

  • Q&A with Australian Health Practitioners

    How much does cooking damage the quality of most foods?

    Related Topic
  • Find a professional to answer your question

  • Mel Haynes


    Chef, Scientist and Nutritionist. I specialise culinary nutrition and disease prevention with plant based diets. View Profile

    Any food processing can damage foods, reducing the quantities of active vitamins and minerals it contains.  Some vitamins are damaged more easily, like vitamin c and folate for example break down quickly with cooking, storing, freezing, drying etc.  Evidence shows that eating RAW salad vegetables over cooked vegetables is more beneficial to heart health and diabetes.  Nuts are another thing that are best consumed raw due to the heat lablility of the essential oils they contain. here is a good guide you can look at:

    here is a lot of hype lately regarding raw vegan diets.  I do belive that increasing raw nuts, fruit and vegetables is beneficial but by limiting foods only to raw products you are missing out on great foods like rice, cereals, lentils etc that are extremely beneficial for health even in their cooked state.  Some foods like tomatoes can benefit from cooking as this releases the lycopene which is great for cancer prevention.

    My advice is eat a nice balanced diet rich in fruit and vegetables - some of which being raw.

    happy cooking xx

  • Arlene is a registered practising dietitian, with a private practice in the Eastern Suburbs of Sydney, and has built a strong business over the last … View Profile

    The nutrient value of food is almost always altered by the kind of processing it undergoes. The water-soluble vitamins are the most vulnerable to processing and cooking. Careful cooking and storage will help retain the nutrients in your food.

    Almost all food is processed in some way before it is eaten. Commercially, the main reasons to process food are to eliminate micro-organisms (which may cause disease) and to extend shelf life. Simply cooking or combining a food with other foodstuffs to create a recipe is also considered a form of food processing. Whatever the case, the nutrient value of any food is often altered by the processing.

    Some vitamins are more stable (less affected by processing) than others. Water-soluble vitamins (B-group and C) are more unstable than fat-soluble vitamins (K, A, D and E) during food processing and storage. The most unstable vitamins include:

    • folate
    • thiamine
    • vitamin C.

    More stable vitamins include:

    • niacin (vitamin B3)
    • vitamin K
    • vitamin D
    • biotin (vitamin B7)
    • pantothenic acid (vitamin B5).

    Most vegetables are peeled or trimmed before cooking to remove the tough skin or outer leaves. But most nutrients, such as vitamins, tend to lie close to the skin surface, so excessive trimming can mean a huge reduction in a vegetable’s nutrient value.

    Some vitamins dissolve in water, so you lose your vitamins to the cooking water if you prefer to boil your vegetables. For example, boiling a potato can cause much of the potato’s B and C vitamins to migrate into the boiling water. It is still possible to benefit from these nutrients if you consume the liquid, for example, by turning the potato and the liquid into a soup. Alternative cooking methods such as grilling, roasting, steaming, stir-frying or microwaving generally preserve a greater amount of vitamins and other nutrients.


    It would be inaccurate to say that cooking food always lessens the nutrient value. Cooking can be advantageous in many ways, including:

    • making the food tastier
    • breaking down parts of vegetables that would otherwise be indigestible
    • destroying bacteria or other harmful micro-organisms
    • making phytochemicals more available, for instance, phytochemicals are more available in cooked tomatoes than in raw tomatoes. (Phytochemicals are chemicals produced by plants).



answer this question

You must be a Health Professional to answer this question. Log in or Sign up .

You may also like these related questions

Ask a health question

Empowering Australians to make better health choices