I’ve always been told that boiling vegetables too long causes the vegetables to lose their nutrients. So I started baking my vegetables. So my question is, do the vegetables retain their nutrients when you bake them? – Tomeka O.

The main micronutrient (vitamin & mineral) losses from produce occur through boiling or exposure to light and heat over time.  Reducing cook time by microwaving for example, leaves more Vitamin C in broccoli compared to steaming.

You’re right that boiling does leach out some micronutrients into the water, which will be lost if you don’t consume that water.  Some people keep it for cooking rice or pasta. Another option is using it for soup. It can also be frozen for later use. You can retain a bit more micronutrients by ensuring the water is brought to the highest temperature (a rapid boil) for a shorter cook time, and vegetables removed while still firm, or al dente.

As far as macronutrients (carbohydrate, fat, and protein) go, vegetables are mostly carbohydrate with a little protein. Compared with baking them, boiling potatoes does reduce a type of complex carbohydrate called resistant starch.

Note that boiling is essential for preparation of dry beans and peas, and losing some of their resistant starch is necessary to reduce flatulence – so toss that boiled bean water!

The answer to your particular question is –YES, more vitamins and minerals are retained during baking.

But the moisture loss with this dry cook method may result in a less than favorable texture. Imagine a shriveled up broccoli stalk. If you end up eating less, then you are getting fewer nutrients, right? One way to lock in moisture is to coat the vegetables lightly in oil, particularly when broiling. This often produces a nice crisp outer finish that is sought after for broiled Brussels sprouts or baked potato wedges. Note that adding oil will increase calories to the tune of 40 calories per teaspoon of oil.  Another way to combat dryness from open heat is to wrap the vegetables tightly in foil and for corn, leave the husks on.

Using fresh picked vegetables will provide the most micronutrients no matter how they are prepared.

And on another note, frozen vegetables are known to lose more potassium than their fresh counterparts.

– Debbie J., MS, RD

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