First of all, let’s clarify something. Generally speaking, when cooking vegetables, vitamins are not destroyed – but the nutritional value may be diminished, depending on the way you decide to cook them. The healthiest way to cook vegetables can depend on a number of factors, including the variety of vegetable, how you’re planning to store them and the type of vitamins they contain. For some vegetables, cooking may even help to release vitamins - this is true for carrots and courgettes.
The effects of cooking on vitamins differs. Whilst some vegetable could be more nutritious when cooked, there are types of vegetables whose vitamins may decrease during cooking or heating. This is because some vitamins are heat-sensitive, whilst others are heat-resistant. Here’s a quick and easy guide to each type of vitamin.
A list of heat-sensitive vitamins and foods that contain them includes:
- Vitamin C: This can be found in peppers, chives, coriander, broccoli, green peppers, tomatoes, dark green vegetables, and potatoes.
- Vitamin B1 (thiamin): This can be found in pulses, potatoes, asparagus, and spinach.
- Vitamin B5 (pantothenic acid): This can be found in lentils, chickpeas, and potatoes.
- Vitamin B9 (folic acid): This can be found in salad, tomatoes, asparagus, cabbage, and pulses.
- Vitamin B6: This can be found in potatoes, pulses, cabbage, and avocados.
- Vitamin B12: This can be found in eggs and dairy products.
In contrast, heat-resistant vitamins do not get lost when cooked or heated. These include:
- Vitamin A: This can be found in carrots, peppers, and spinach.
- Vitamin D: This can be found in mushrooms and milk.
- Vitamin E: This can be found in vegetable oils, peppers, asparagus, and margarine.
- Vitamin B2 (riboflavin): This can be found in milk and dairy products, broccoli, and kale.
- Vitamin B3 (niacin): This can be found in minor parts in plants and grains.