Scientific Evidence

This is a study that has just been published. I thought it was interesting if you hadn’t seen it yet.

Microwaving Zaps Nutrition

(The Epoch Times) – Healthy eating is not just about choosing healthy foods to eat, but also relates to how they are prepared prior to eating. Vegetables, for instance, can suffer nutritional losses during cooking.

Microwaving broccoli destroys a whopping 97 percent of its disease-protective nutrients know as flavonoids. A study this week has found, for instance, that boiling broccoli in water for just 10 minutes reduced the content of plant chemicals known as glucosinolates by 40 percent. Within the body, glucosinolates are converted into other compounds called isothiocyanates that are believed to have cancer-protective properties.

This research, conducted at Warwick Medical School, found that shorter cooking times, as expected, led to less degradation of glucosinolates: Just five minutes of boiling led to losses of only 15 percent.

This recent research reminded me of a previous piece I wrote which summarized some of the research of the nutrient losses that can occur with different methods of cooking.

Microwaving is often recommended as a preferred cooking method because it can shorten the cooking time. However, the evidence suggests that this form of cooking can lead to considerable nutrient losses. In a study published in the Journal of the Science of Food and Agriculture, researchers assessed the effects of a variety of cooking methods on nutrient levels in broccoli.

While boiled broccoli was found to lose two-thirds of its original content of disease-protective nutrients known as flavonoids, this actually compared quite favorably with the whopping 97 percent loss induced by microwave cooking. Analysis of other nutrients revealed similarly dire depreciations. Contrary to what may be expected, it seems we can microwave goodbye to a good deal of the nutritional goodness vegetables have to offer.

In this study, steaming induced only 11 percent degradation in this type of flavonoids. In another study, boiling was found to reduce the level of folate (believed to protect against both heart disease and cancer) in spinach and broccoli by more than half. In comparison, steaming had minimal effects on the level of this vitamin.

What the research shows is that when it comes to cooking vegetables, steaming is generally best. And the shorter the cooking time, the better. For the best of health, it can help to develop a taste for vegetables done al dente.


  • There is a lot more to it than that. It is not the amount of a nutrient that is found in a vegetable or anything else for that matter but the amount of nutrient that gets absorbed and assimilated into our body after digested. If you want a nutrient you can go out and buy a supplement of 100% of that nutrient. Will you get 100% absorbtion and assimilation? I doubt it, in fact you might actually lose that nutrient as your body probably will use nutrients to eliminate the toxic supplement that it doesn’t recognize as a food. Nature created fruits and vegetables and also the bodies that we have to consume them. Making any overt changes to these foods will change the balances of nutrients and co-factors and will make the food far less valuable in all cases.

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