We all know vegetables are a great source of vitamins and minerals, but how we cook and store them can have a marked effect on their nutrient levels.
Nutrients can be destroyed by light, heat, oxygen and microwave cooking, as well being lost in cooking water. Water soluble vitamins are lost when we cook them in liquid – which makes sense! If you’re going to be eating the fluids they come in, such as in a soup or a casserole, it’s not a big deal, but if you’re boiling your vegetables then water soluble vitamins like folate are lost when you pour that water down the sink.
Easily destroyed by heat: Vitamin C, Vitamin B6, Vitamin E, Thiamine, Folate, Omega 3 fats
Easily destroyed by light: Vitamin A, Vitamin B2 (riboflavin), Omega-3 fats
Easily destroyed by microwave cooking: Vitamin B 12
Easily destroyed by oxygen (from cutting and storing food) :Vitamin C, folate, Vitamin E, Omega-3
Easily lost in water: the water soluble vitamins (includes B vitamins and vitamin C)
Tips to preserve nutritional value of food
- Cook oily fish over a medium temperature until just cooked to help preserve the integrity of the omega 3 fats. Oven bake rather than fry.
- No soft soggy vegetables! Cook so they’re just cooked and still a little firm to bite.
- Stir fry or steam vegetables rather than boil
- Aim to buy local produce – if you’ve got a local farmers market, make the most of it. Veges from the supermarket have had to come from the farm, to storage, through transport then they sit on the supermarket shelves until they’re purchased. This means they could have lost significant amounts of nutrients before they reach you. Growing your own is also an excellent way of maximising nutrient value – and you can get organic vegetables at a fraction of the cost of store bought too. There’s nothing like going to the garden and picking some fresh produce to use in cooking.
- Cut your veges up just before cooking/eating to avoid nutrient losses by oxygen.
- Store nuts and seeds in the fridge to prevent the good fats being destroyed.
- Put milk back in the fridge as soon as you’ve used it to stop light degradation of it’s riboflavin and vitamin A.
References: Louise Fulton Keats, Nutritionist