I hear this question frequently from my patients, and I found all these great examples on a newsletter from a dietitian site, and thought it answered it quite nicely. I did not write all of these, but they give permission to share it.
Question: Does cooking deplete vitamins and minerals? Should I only eat raw vegetables if I want to absorb all of the nutrients?
Steamed broccoli - pic from here
Answer: While some foods become less nutritious with cooking, other nutrients actually will become easier to absorb.Look at these examples:
• Heating garlic increases its potential to decrease the risk of cancer
• Heating increases the availability of lycopene, an important antioxidant that helps prevent several forms of cancer (the richest source of lycopene is cooked tomatoes)
• Steaming broccoli increases its glucosinolates, which may help to prevent cancer
• Vitamin A and potassium are not lost during canning; in fact in some foods, such as canned pumpkin, the vitamin A content actually is higher than it is in fresh foods
Here are some other tips for cooking vegetables:
• Steaming, boiling, or baking are always better than frying vegetables
• As Dr Joel Fuhrman says: "Water-based cooking as in soups, steaming, and cooking in a pressure cooker results in very little loss of nutrients and a significant increase in the absorption of phytochemicals. To fear eating a steamed vegetable or vegetable/bean soup is entirely unfounded and without scientific support."
• Always slice, chop, or crush onions to increase the formation of sulfur compounds, which helps to lower blood cholesterol and prevent heart disease (it’s best to allow cut onions to sit for 10 minutes before using them)
Hope you got your daily dose of nutrition today, and thanks for reading! If you enjoy the blog, please share using the buttons below, or in the box to the right. Also, we would love to have you join us! Join this site in the "followers" box to the right. "Like" the blog on facebook, and follow me on twitter (@jennasteprd), tumblr, and pinterest using the the boxes on the right. Thanks, and have a great day! ~jenna