Does cooking vegetables in the microwave kill all the nutrients?
A question from a reader today, Melanie emailed me to ask:
I microwave a bowl of raw broccoli, cauliflower and Brussels sprouts almost everyday for dinner, will the ’waves from the microwave destroy all the nutrients in the veggies?
There are three main factors which affect the nutrient content of cooked vegetables – time, temperature and the amount of water used. The greater the quantity of each of these, the greater the nutrient loss. Which means that boiling vegetables until they’re grey and mushy in a big saucepan of water will knock out more nutrients than steaming something for a few minutes.
Therefore microwaving vegetables is a good cooking option, because it’s fast and minimal water is needed. Some studies find microwaving to be on par with, if not better than steaming vegetables, when it comes to retaining some nutrients.
But it’s not as simple as that
However, as Harvard Medical School says “this is nutrition, and nothing in nutrition is simple”. What I’ve written above applies to the water soluble nutrients, like Vitamin C, folate, together with some phytocompounds, like the glucosinolates found in broccoli.
However longer cooking times actually benefit other nutrients. Carotenoids, like lycopene (after which this site is partially named) become more useful to us after longer cooking times.
Take home message
All of which means it’s better not to get too hung up on _how) you’re cooking your veg. The most important thing is that you eat vegetables and plenty of them. In fact, I’ve written these before, but I think they’re worth repeating – my top 5 guidelines on how to eat vegetables are:
- The number one priority is to eat vegetables, no matter how they are prepared. Without at least five daily serves of vegetables your diet is deficient.
- Eat a variety of vegetables. They all contain different vitamins and antioxidants. By eating a variety you are ensuring your diet is the best it can be.
- As well as eating a variety of veg, prepare them in a variety of different ways. Eat some raw, but also have some cooked and cook them in different ways.
- Most of the time try not to over-cook vegetables. Lightly steam, stir fry or microwave them.
- Cook and eat vegetables with a small amount of oil, as this helps you absorb the fat-soluble vitamins and antioxidants.
Thanks for your question Melanie.