However you prepare your food, the loss of vitamins is inevitable. Food technologist Matthijs Dekker at Wageningen University & Research explains how to keep this under control.
All kinds of factors influence the retention of vitamins when preparing food. Think of the cooking time, the temperature during preparation, the amount of water, how the food has been stored and the freshness of the products.
The consumer therefore does have influence on the final amount of vitamins in a dish, the Nutrition Center concludes in a fact sheet about preparing food.
According to Dekker, who contributed to the document, there are two sides to the story: "On the one hand, vitamins are indeed lost, but the body is better able to absorb the vitamins."
“When cooking vegetables, water-soluble vitamins dissolve in the cooking water. Half of the vitamin C can be lost in this way. ”
Different types of vitamins
There are water-soluble and fat-soluble vitamins and they behave differently during baking and cooking. "When cooking vegetables, water-soluble vitamins dissolve in the cooking water," explains Dekker. "As a result, for example, half of the vitamin C can be lost. This is not the case with stir-frying."
Fat-soluble vitamins suffer less during preparation. However, the high temperature during cooking or baking causes the breakdown of both types of vitamins. "Vitamin C and some of the vitamins B are especially sensitive to this," says the food technologist.
Tips to minimize vitamin loss:
- Vary between cooking, (stir) baking, roasting, stewing and steaming
- Cut vegetables as short as possible before cooking
- Coarsely cut vegetables so that the contact area with the water is smaller
- Cook in little water and as short as possible
- Cook vegetables directly in boiling water
- Use cooking liquid for a soup or sauce
A small part of the vitamins is also lost when cutting vegetables. This is especially true for vitamin C. "You can limit this by cutting the vegetables as short as possible before cooking, so that exposure to oxygen is minimal," says Dekker.
Incidentally, this does not apply to pre-cut vegetables from the supermarket, the air in the packaging is adapted and contains little oxygen.
However, as said, preparing food also has a positive effect on our vitamin intake: because the cells of vegetables break down during cooking, steaming or baking, the contents of the cells are released more easily during digestion and vitamins are also absorbed more quickly.
"This is especially the case with fat-soluble vitamins that dissolve in the fat used during baking or roasting. Think of carotenoids, precursors of vitamin A, for example in sweet potato, tomato and carrot."
Cooking, steaming or stir-frying?
How can we best prepare our food? "In terms of preserving vitamins, stir-frying is better than boiling in water," says Dekker. "You do have to add some fat or oil, which means more calories. Even with stewing and steaming, the loss of vitamins is limited. It is therefore best to vary."
In any case, there is a lot of variation in the amount of vitamins in fruit and vegetables. Dekker: "Unfortunately, as a consumer you have little influence on that."