A recent study on turmeric yielded some fantastic results. Turmeric is a great food because of its antioxidant properties. However, it will degrade quickly if not cooked wisely; it is highly susceptible in terms of heat degradation. You will find turmeric in curry which is usually boiled, roasted or fried. Therefore, when you cook with turmeric boil it versus fry it. Roasting it will not be as good as boiling, but it’s better than frying.
Tomatoes are similarly impacted by cooking them. Fresh tomatoes are great, but so are cooked ones. I’m sure you’ve heard that cooked tomatoes help to make the lycopene more available. What happens when you cook tomatoes is you remove the water from them and everything else in them becomes more concentrated, including flavor and certain nutrients including lycopene. What happens with lycopene is that it binds to fiber, so softening the fiber by cooking it can make the lycopene more available to ingest. However, pureeing or juicing raw tomatoes also break up fiber, which also helps you ingest more the lycopene. However, dehydrating raw tomatoes reduces the water content, and it also concentrates the amount of lycopene which is similar to cooking them. In addition, fat helps to absorb lycopene, so next time you eat tomatoes use avocado or olive/avocado oils.
In sum, it’s important to understand how cooking impacts the nutritional value of the food we eat. Don’t overstress about it, just enjoy it!