DEAR DR. BLONZ: What is the comparison between the vitamin, mineral and lycopene content of sun-dried tomatoes versus cooked and fresh tomatoes? -- F.F., San Jose, California
DEAR F.F.: Sun-drying will reduce vitamins C and A, and, to a lesser degree, some of the other vitamins, but the mineral content is comparable. As for lycopene -- a reddish phytochemical that contributes to the tomato's characteristic color -- there isn't any significant difference between the levels in cooked, fresh or dried tomatoes. Lycopene is chemically bound inside the plant-cell matrix of the tomato. The cooking process breaks apart the intact cells and actually makes the lycopene more bioavailable, which means it gets absorbed with greater efficiency.
Sun-drying isn't the same as cooking. In the drying process, the cells shrivel and break as the water is removed, especially if heat is used. If lycopene absorption is your only consideration, the bioavailability of the lycopene will be greater with sun-dried than with fresh tomatoes.
Eating sun-dried tomatoes requires a bit of a chew; this not only helps release the flavors, but it helps mix the nutrients in the meal to facilitate absorption. All the better if there is a little olive oil (or any other oil) in the meal: Lycopene, like other carotenoids, is fat-soluble, so oil present at the same meal will help with absorption. And any lycopene that does not get absorbed still helps our bodies by contributing to the healthful environment in our intestines.
But we miss the point of healthful eating when we get overly focused on the individual substances in the whole foods we eat. The point is that you should enjoy healthful foods like tomatoes in whatever form you like best.
DEAR DR. BLONZ: Please tell me what is so bad about bananas. I have seen online ads saying things like "The 5 Foods to Avoid," and they always show a banana. I clicked on one of these and listened to a long spiel that never mentioned bananas, but had a pitch for a "bargain" $49 offer. I start my day with a banana. Most of my mother-in-law's diet was bananas. I had a dietitian once who didn't want to allow me bananas at all, but reluctantly let me cut one in half! I'm puzzled. -- R.P.
DEAR R.P.: What's bad about bananas? Perhaps bad PR, in that their commodity group does not pursue those who characterize the banana as less than "appealing" (pun intended). There is no science (or logic) behind the banana being touted as a poster child for "foods to avoid." One rare exception might be a person taking medication to control their potassium levels. Concern about the sweet taste in a ripe banana is also misplaced; it is the sugar added to processed foods that should be our concern, not that which is naturally present in a healthful whole food.
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