Does microwaving fresh food and vegetables, actually make them healthier?
We live in a world where so many people are terrified of microwaves. I worked as a private tutor for the wealthy elite, and one family refused to have a microwave in the house, seeing it as a recipe for DNA damage (there is as much evidence for this as there is that phones cause cancer and yet we are on our phones all the time), cancer and poor health. They raised their noses at those who microwaved food, believing it destroyed their food's nutritional benefit and quality. However, as microwaving potatoes, fresh fish, eggs and vegetables is similar to steaming or poaching food and can help retrogradation, could it actually maintain or enhance the nutritional value of fresh food?
When I was working as a science writer and teacher and had a busy schedule, I microwaved my sweet potatoes, baked potatoes and new potatoes and packs of parboiled wholegrain quinoa or basmati rice, as it was a quick way of getting cheap complex carbs into me without having to wait hours for them to roast or boil. I was time and money poor, so as I used less electricity and fuel, it saved me time and money. When I was anorexic, I loved how it allowed me to cook without butter or oil (less fat) and when I was recovered and a food connoisseur, I loved the flavour of it, as a microwaved sweet or new potato goes all crinkly and tastes nuttier and more chestnutty and a jacket potatoes peel does not get tough like when you roast or bake it.
I microwaved eggs for a quick poached egg to go in my sandwich for work the next day with wholegrain mustard. I microwaved salmon fillets and peppered mackerel fillets or prawns and I bought those quick parboiled healthy wholegrain basmati rice packets (not the ones full of additives, just the simple wholegrain rice ones) and had rice with prawns or fish and vegetables. I microwaved wholegrain rolled porridge oats with cinnamon and hot water in the morning for a quick breakfast, and I microwaved milk and put it over wholegrain bran flakes on cold mornings, to give me a warming nutritious breakfast.
I used it as a way of steaming vegetables quickly, putting cauliflower, courgette, broccoli, kale, cut-up tomatoes, Brussel sprouts, aubergine, pak choy, red and white cabbage, frozen green beans and peas or carrots or sweetcorn and many more in the microwave and then adding spices like paprika and salt to bring out the flavour. I added cinnamon or nutmeg to my microwaved sweet potatoes for cracking flavour.
I made microwaved popcorn (from the corn kernels not some highly processed and sugared or buttered popcorn pack) and put paprika or cinnamon or peanut or almond or fennel dried power on it for flavour as a snack and I microwaved leftover rice or pasta for quick dinners. Microwaving saved me so much time and (food snobs be dammed) produced some really quite delicious food.
What are the health benefits of microwaving food?
I cooked with microwaves for cost and convenience. However, there are I have learnt (I am an academic biomedical, neuroscience and nutrition scientist), many health benefits.
- You can cook with no oil or butter (add this later if you want it- frying or heating oil or butter to high temperatures changes its health benefits- it increases hydrogenation making it worse for your health, heart and waistline).
- Cooking food to 100 degrees destroys some vitamins, but microwaves never get this hot and heating actually opens up plant cells, increasing the bioavailability of the water-soluble nutrients in the plant, so you get more Vitamin C, Thiamine (B1), Pantothenic Acid (B5) and Folate (B9) from your food. B vitamins help enhance the energy-giving properties of food and lower the glycaemic index, so you have more vitality and feel more satiated for longer.
- Microwaved aubergine, parsnips, carrot and potato peels and cauliflower stems are softer and so easier to eat, so you easily eat more fibre from the veg. Fibre is a great prebiotic for your gut microbiota, feeding the gut and helping the microbiota produce more small chain fatty acids, boosting their immune-boosting (regulating Treg cells so they are more anti-inflammatory) and brain-gut-axis (helping enhance Serotonin) benefits of the veg. Fibre also is more satiating (it fills you up) and helps decrease the glycaemic index of the food you eat, so it helps balance your energy levels and give you more energy for longer. It also makes you less likely to reach for a sugary snack as it high glycaemic index foods cause high blood sugar spikes, Insulin hormone (which lowers blood sugar) spikes, and energy lows. When on an energy low you are more likely to reach for a simple carbohydrate sugar as it provides a quick, short-lasting, energy supply. Energy lows make you crave sugar things. The more Fibre you get the fewer energy lows you have.
- It changes the structure of the food. There is scientific evidence (see below) that cooking, cooling and reheating starches such as potatoes, rice and pasta causes a process called starch retrogradation. As the glycaemic index is a measure of how readily available and digestible food is for use to make energy (the more processed, more simple sugars like white flour in bread, white rice and couscous, can be quickly broken down to energy), retrogradation makes the starch (it changes its structure from a more linear to more branched structure) less quickly metabolised (used for energy) and so causes less sharp peaks and troughs in blood sugar and Insulin levels, keeping you satiated, full of vitality for longer and less likely to experience the low moods and irritability that come with low blood sugar.
Microwaves are also cheaper to run than ovens (good in the current economic climate) and better for the environment as they use fewer fossil fuels to run. Microwaves also soften vegetable peels, so you are more likely to eat them and this decreases food waste and increases fibre intake for people. Perhaps people need to stop the anti-microwave snobbery and see microwaves in a more positive light. They save money and time and could help not hinder your health.
- Cross, G.A., Fung, D.Y. and Decareau, R.V., 1982. The effect of microwaves on the nutrient value of foods. Critical Reviews in Food Science & Nutrition, 16(4), pp.355–381.
- Jufă, A., Pascu, A., Floroian, L., Calaver, D., Nunes, G. and Badea, M., 2016. Microwaves-our ally in cooking?. Journal of EcoAgriTourism, 12(2), pp.15–20.
- Klein, B.P., 2019. Effect of processing on nutritive value of food: microwave cooking. In Handbook of nutritive value of processed food (pp. 209–236). CRC Press.
- Hegarty, P.V.J., 1982. Influence of Food Processing on Nutritive Value. Food Proteins, p.145.
- Wang, S., Li, C., Copeland, L., Niu, Q. and Wang, S., 2015. Starch retrogradation: A comprehensive review. Comprehensive Reviews in Food Science and Food Safety, 14(5), pp.568–585.
- Sethi, S., Choudhary, P., Nath, P. and Chauhan, O.P., 2022. Starch Gelatinization and Modification. In Advances in Food Chemistry (pp. 65–116). Springer, Singapore.