Raw foods are a very trendy concept right now. But when it comes to serving veggies, raw is not always the most nutritious.
While water soluble nutrients such as Vitamin C, the B vitamins and some antioxidants get lost in cooking, others actually need the heat to bring out their nutritional best.
A great example of this is the lycopene in tomatoes, which gets released by cooking. This also applies to other compounds in the carotenoid family, such as sweet potatoes, carrots and spinach.
Cooking vegetables can also improve their digestibility, helps break down proteins and loosens or removes the protective coatings that might keep them from being fully digested.
What are the best cooking methods?
Not all cooking methods are created equal – water is the enemy. According to the Journal of Food Science, March 2009, microwave cooking without water and only until tender maintains the highest antioxidant levels. Baking, steaming and grilling also preserved antioxidants.
Boiling and pressure cooking however cause the greatest losses in nutrients because Vitamin C, folate and thiamin leach out into the water which is usually discarded. If you must boil vegetables, be sure to use the water in a sauce.
Nutrient loss is also dependent upon the type of vegetable. Carrots, celery and green beans all have increase antioxidants released from cooking. Cooking spinach and carrots produces higher levels of beta-carotene which may have preventative factors in certain types of cancer.
What about Minerals?
Spinach, beat greens and chard are all high in calcium. In their raw state, these greens contain calcium binding oxalic acid which binds to calcium, preventing absorption. Cooking these greens causes the acid to break down and more calcium is absorbed.
The following vegetables are best eaten raw because they contain high concentrations of glucosinolates. These compounds are converted to anti-cancer chemicals called isothiocyanates:
- Bok Choy
Always use gentle cooking methods such as grilling or steaming until vegetables are just crisp or tender!
Frozen veggies go directly from the field to the freezer, locking in more nutrients as compared to “out of season” produce that has been transported across the country, losing many nutrients along the way.
Your best bet is to purchase produce directly from the farm or at your local farmer’s market. Prepare vegetables right before consuming. The more they are exposed to light and air, the more nutrients they lose.
The bottom line is to balance raw and lightly cooked vegetables to get the best nutrition bang for your buck.