The way you cook your vegetables — or don’t — has a major impact on what nutrients you’re retaining when the food hits your fork. Some nutrients are water-soluble, some are fat-soluble, some degrade at high temperatures, and some are unavailable in raw form.
Take kale, held up as a superfood, as a case study: Boiled or braised kale loses much of its vitamin C, iron, and calcium. Frying it or baking it with oil diminishes its vitamin A. Because of the nutrient blocker oxalic acid, raw kale doesn’t afford you any of the iron and calcium it contains. Ultimately, the answer to the problem is that you should be eating kale in a variety of ways, because no one preparation is going to give you all the available nutrients.
Find out which vitamins and minerals you’re missing out on in these five vegetables with different ways of cooking them.
A study out of Zhejiang University has shown that out of the five most common ways of cooking broccoli — steaming, boiling, microwaving, stir-frying, and braising — the only one that didn’t account for major nutrient loss was steaming, followed next by pan-frying. Water-soluble nutrients like vitamin C are significantly decreased by wet cooking methods like braising and boiling. The results of the study showed that boiling and braising broccoli diminished the vitamin C content by 38% and 33%, respectively.
Glucosinolates are the cancer-fighting nutrients found in broccoli. This study also found that boiling reduces the compound by 41%; microwaving reduces it by a whopping 60%, while steaming had negligible effects on glucosinolates. If you’re going to be consuming the broth you’ve made by boiling the broccoli, you’ll regain some of the nutrients. Otherwise, you’re better off steaming your green, cruciferous vegetables. If you steam with a flavored liquid, it’ll even still taste good.
Other vegetables high in vitamin C affected by wet-cooking methods: bell peppers, kale, cauliflower, Brussels sprouts