native to: western South America and possibly the Galapagos Islands
in season here: late summer-fall
The specific nutrients in tomatoes vary by variety and also by season, but one of the big ones is lycopene, an antioxidant that has been linked to bone health. Surprisingly, it's actually the orange tomatoes that are best in this case, because they proved to have a more readily absorbed kind of lycopene than red tomatoes, but they're all good sources. Tomatoes, especially fresh ones, have also been linked to heart health, lower cholestrol levels, and decreased risk of various cancers and neurological diseases such as Alzheimer's. They're excellent sources of vitamins C and E, beta-carotene, and manganese, as well as some important phytonutrients. As with cucumbers, the seeds of the tomato are particularly nutritious.
All this healthiness is rather ironic, because the tomato is a member of the solanaceae family and a close relative of the nightshade or belladonna, a popular source of the poison atropine. According to popular legend, the tomato was once shunned for this connection, although there doesn't seem to be much evidence to support the idea rather than, say, a general disinclination to grow and eat unfamiliar foods. Other members of this family are potatoes, eggplants, and chili peppers, so it's not a generally dangerous group of plants. However, the leaves of the tomato contain high concentrations of dangerous alkaloids, so for once you really should stick to just the fruit (or, technically, berries). There is even some anecdotal evidence that avoiding tomatoes may lessen symptoms of arthritis, although this hasn't been confirmed by any scientific studies.
Although tomatoes originated in South America, they were probably first cultivated in Mexico by the Aztecs, in the form of yellow cherry tomatoes (the name may come from the Aztec word tomatl, meaning "swelling fruit"). They hit Europe in the 1500s and spread pretty quickly for the time. Today China grows the most tomatoes. When you buy canned tomatoes, it's a good idea to look for ones produced in the US, since the high acid content of tomatoes makes the metals in the cans more likely to be picked up by the contents (this is also why it is generally recommended to avoid cooking tomatoes in aluminum) and some countries aren't as strict about the lead content of their containers. There has been some concern about BPA in the vinyl linings we often see in tomato cans, but recent studies have found that while there is some, the levels are very low, about 1/600 of the maximum safe level -- so low, in fact, that organic tomatoes are allowed to keep that description even after being canned in a vinyl-lined container (you have to look for a "BPA-free" label to avoid it entirely).
When I was a child in Spokane, my mother always watched the fall weather forecasts closely and when the first killing frost was predicted she would strip all the tomato plants in the garden. The tomatoes that were nearly ripe would go on a sunny windowsill to ripen (more recent advice is to put them in a paper bag with a banana or apple to provide maturation-encouraging ethylene gas) and the not-a-chance green ones would be made into green tomato relish in a row of pint or jelly jars in the pantry (except for the couple of jars that didn't seal, and there were always one or two, that had to go into the refrigerator until we used them up). She would make the relish after lunch and then we'd spend the rest of the afternoon and evening counting the pings and pops as the jars sealed, each one a tiny victory.
Read more:
label-style nutrition information for raw tomatoes
Tomato Dirt has facts, recipes, and even costumes
a long and thorough article at whfoods
WebMD
Versión en español: this post is also available in Spanish.
Esperanta traduko: this post is also available in Esperanto, because Dana is a language geek.
