Heat Treatment Destroys Vitamins In Vegetables: Truth Or Myth

Fruits and vegetables undergo compositional changes when heated, but this is not always a bad thing. Several studies have shown that heat breaks down some nutrients but releases others. Let us find out more.

It's all about the type of nutrient

Many people think that raw vegetables contain more nutrients than cooked ones, but this depends on the type of nutrient.

Heat treatment breaks down the thick cell walls of many plants, releasing the nutrients they store.

A German study on 200 raw foodists showed higher plasma beta-carotene levels but lower than average lycopene levels. One of the factors that influenced the result was the lower content of lycopene in raw tomatoes than thermally processed ones.

Read also: How To Clean And Cut Vegetables And Fruits

What Happens to Vitamin C and Other Water-Soluble Substances

Researchers at the University of California at Davis have published a paper that claims that the loss of vitamin C, depending on the cooking method, can range from 15% to 55%. Fresh spinach loses about ⅔ during cooking, and peas and carrots - 85–95% of vitamin C.

Water-soluble nutrients such as vitamin C, vitamin B, and polyphenols are most susceptible to degradation during processing and cooking.

Interestingly, frozen foods frequently have higher levels of vitamin C than fresh ones because they decrease during the storage and transportation of raw crops. Another study found that cherries lost 50% of anthocyanins after six months of freezing, nutrients found in fruits and vegetables' dark pigments. So, vitamins are not always stored in frozen foods.

Heat Treatment Destroys Vitamins In Vegetables: Truth Or Myth
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What Happens to Vitamin A and Other Fat-Soluble Substances

According to a report published in The Journal of Agriculture and Food Chemistry, to preserve vitamins in carrots, zucchini, and broccoli, it is better to boil them than steam, fry, or eat them raw. Frying has proven to be the worst way to preserve nutrients.

Fat-soluble substances such as vitamins A, D, E, and K, and antioxidant compounds called carotenoids, are better retained during cooking and heat processing.

But when it comes to cooking vegetables, you always have to compromise. The same method can increase the availability of some nutrients while degrading others. For example, boiled carrots have higher carotenoid levels compared to raw carrots. However, unprocessed carrots have many more polyphenols, which disappear as soon as you start cooking them.

What happens to vitamins in the microwave

Although many people think that cooking in the microwave is harmful, vegetables cooked in the microwave can have higher concentrations of certain vitamins.

Also read: How To Choose Fruits And Berries

In March 2007, an experiment was carried out in which scientists observed how boiling, steaming, microwave cooking, and pressure cooking affect the nutrients in broccoli. Steaming and boiling resulted in a loss of 22 to 34% of vitamin C. The vegetables cooked in the microwave and under pressure retained 90% of the vitamin C.


1. No cooking method, serving, and storing food will retain all the nutrients in vegetables.

2. If scientists have decided that boiled zucchini is useful, it is not a fact that it is right for you. If it doesn't go down your throat, it won't do you any good. Therefore, when choosing a cooking method, also rely on your taste.

3. The most effective method to get the most out of your vegetables is to enjoy them in different varieties: raw, stewed, boiled, baked, and grilled.

4. If you regularly eat various fruits and vegetables, you do not need to worry about cooking.

Adapted and translated by The Cop Cart Staff

Sources: Life hacker