Tomatoes
Tomatoes are sometimes called "the fruit of the vine," and were commonly thought to be poisonous. While many people refuse to believe tomatoes are actually a fruit instead of a vegetable, it is also difficult to comprehend that tomatoes are part of the nightshade family. Other members of this family are eggplants, peppers and potatoes.
Overview
Tomatoes are the diet mainstay of many cultures around the world. This is probably because tomatoes are so versatile - they can be consumed as juices or in soups, made into sauces and condiments or eaten alone or in salads.
One report from 1980 estimated that each American consumes 60 pounds of tomatoes per year, thought most of that number was in the form of sauces or ketchup.
Tomatoes come in varieties that can be red, orange, yellow, green or brown in color. This fruit comes in more than a thousand different types and ranges from the very small cherry tomatoes to the "normal" rounded version or the Italian pear-shaped tomato.
History
Tomatoes originated in South and Central America along with many other members of the nightshade family. The first tomatoes are thought to have been very small, not unlike the cherry tomatoes still found today. The Mexican Indians were the first to cultivate the tomato, supposedly because it resembled their own staple food, the tomatillo. Spanish conquistadors who travelled to Mexico after Columbus discovered the New World were introduced to tomatoes and brought their seeds back to Spain.
Even though tomatoes spread through Europe and had made their way to Italy by the start of the 16th Century, tomatoes were not very popular because many people thought they were poisonous. These doomsayers were not quite accurate - the leaves of the tomato plant contain toxic alkaloids that are poisonous, but the fruit itself is perfectly safe to consume.
The tomato made its way to North America with the colonists but did not gain in popularity until the latter part of the 19th Century. Tomatoes had become a dietary staple in Europe by that time as well.
New varieties are now in the marketplace. Thanks to efficient transportation, tomatoes are a top-selling food in many regions. The largest producers of tomatoes in the world today are the Russian Federation, the U.S., China, Turkey, Spain and Italy.
Nutritional Information
Many people love tomatoes because of their low calorie content. A fully ripened tomato has up to four times the beta-carotene of green tomatoes. This fruit is a great source of vitamin C, carotenes (lycopene in particular), vitamin K and biotin. They are also good sources of niacin, folic acid, pantothenic acid, vitamin B6 and dietary fiber.
Health Benefits
Perhaps the biggest attention-getter regarding tomatoes in recent years has been their lycopene content. Lycopene is a red carotene shown to be very protective against certain cancers, including colon, lung, skin, prostate and breast cancers. This carotene also helps to lower the risk of macular degeneration, cataracts, and heart disease. Lycopene accomplishes these acts by neutralizing free radicals before they can damage cellular structures.
Researchers at Harvard found that men who consumed high amounts of lycopene had a 21 percent decreased risk of prostate cancer than those who ingested much lower levels. Another study showed that men with prostate cancer who took lycopene supplements saw positive results - slower tumor growth, their tumors shrank in size and their prostate-specific antigen (PSA) levels were lowered by some 18 percent.
Depending on the variety of the tomato, the lycopene content can vary greatly. Lycopene concentration in red varieties of tomatoes is about 50 milligrams per kilogram, while the yellow strains contain only 5 milligrams per kilogram. Lycopene seems to be stable during cooking and food processing. Tomato paste or juice contains up to five times as much lycopene as raw tomatoes because the processing seems to liberate lycopene from the cells of the tomato. Eating a food containing lycopene along with an o3 such as olive improves its absorption. This helps to explain why Mediterranean diets are so healthy.
Safety
Tomatoes are commonly associated with allergic reactions. Some individuals claim to have improvements in their symptoms of arthritis when avoiding the foods in the nightshade family.
This fruit does contain moderate amounts of oxalate. People who have a history of oxalate-containing kidney stones should limit or avoid the consumption of tomatoes.
Tomatoes are known to have pesticide residues on their skins. Thoroughly wash tomatoes before consuming or cooking with them.
Selecting and Storing
Tomatoes should be plump and well-formed, of good color and free from bruises. Do not purchase tomatoes when they are soft or show any signs of decay. A puffy appearance is indicative of inferior flavor.
Store tomatoes at room temperature and out of direct sunlight. Cold will stop the ripening process if the tomatoes are not fully ripened. Tomato sauce, chopped tomatoes and whole tomatoes all freeze well. Cooked tomatoes generally stay good for about five to seven days if refrigerated.
Serving Ideas for Tomatoes
Most people use tomatoes in salads. They are also tasty using the following tips:
- Slice different colored tomatoes and top with olive oil and balsamic vinegar.
- Make a salsa by combining chopped tomatoes, onions and chili peppers.
- Add slices of tomatoes to sandwiches.
- Cold soup can be made from a puree of tomatoes, cucumbers, scallions and bell peppers. Add herbs or spices and chill.
References
- Holford, P.(2004). The optimum nutrition bible. London : Piatkus
- Holford, P & Lawson, S. (2008). Optimum Nutrition Made Easy How to achieve optimum health. London : Piatkus
- Murray, M.T. et al.(2005). Encyclopedia of healing foods. London : Piatkus
- Yeager, S. & Prevention Health Books. (1998). The doctors book of food remedies : the newest discoveries in the power of food to cure and prevent health problems from aging and diabetes to ulcers and yeast infections. [Emmaus, Pa.] : Rodale
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