Kamis, 12 November 2009

benefit of tomato

Benefits of tomato

Tomato, Solanum lycopersicum L, Solanacea family, originally from South America, is one of the most important plants in human alimentation, which can be consumed fresh or as an ingredient in various dishes and is considered the most consumed vegetable after the potato . Tasty and almost indispensable in the kitchen, the tomato has many beneficial health characteristics.

The tomato is considered the "queen" of garden crops, both for its beneficial effects on health, and for its color, improving all the gastronomy. Although we can eat tomatoes all year round because of the greenhouse crops, their nutritional value is much higher and has a more intense
flavor when grown in gardens, in the sun, from June to September.

Chemical composition of tomatoes

There are known different varieties of tomato, round, oval, "cherry", but all have the same nutritional characteristics, being an important source of:

- potassium, phosphorus, magnesium, iron, so necessary to the normal activity of nerves and muscles;
- vitamins as A, B and C - tomatoes is the third source of vitamin C in our diet and the fourth for vitamin A, through its content in beta-carotene or pro vitamin A;
- phytosterols, compounds that help to keep cholesterol under control;
- folic acid, which helps eliminate homocysteine, an amino acid whose metabolism is dependent on the metabolism of vitamins from B complex, especially that of folic acid.

Lycopene, a compound with exceptional properties

The tomato is a food very rich in lycopene, a vegetal pigment from carotenoid family, a compound discovered in 1873, which gives color to the vegetable, but also has exceptional properties as lycopene is a powerful antioxidant. Numerous studies have shown that by regular consumption of tomatoes, the resistance to cancer of the prostate, lung, digestive, but also heart disease is increased. Also, tomatoes help to fight against atherosclerosis syndrome and muscle degeneration, the main causes of discomfort in people over 65 years.

Studies on the health beneficial effects of tomatoes and their derivatives have focused mainly on lycopene, however, the administration only of lycopene for 12 weeks had no effect on the damaged DNA in human lymphocytes. These observations show that is more efficient the combination of:

- carotenoids (a class of natural liposoluble pigments found especially in plants, interfering in the photosynthesis);
- tocopherol (vitamin E, soluble);
- phenolic acid and flavonoids (natural compounds found in plants).

This combination of different carotenoids or the association of carotenoids with tocopherol (vitamin E) or phenolic acid has simultaneous effects on blocking the pathological reactions, which generates free radicals, able to affect the DNA. It was also found that the supplementation of a diet containing a small quantity of carotenoids with tomato juice can increase cellular immunity, involved in reducing the risk of cancer

Lycopene, a compound with exceptional properties

The tomato is a food very rich in lycopene, a vegetal pigment from carotenoid family, a compound discovered in 1873, which gives color to the vegetable, but also has exceptional properties as lycopene is a powerful antioxidant. Numerous studies have shown that by regular consumption of tomatoes, the resistance to cancer of the prostate, lung, digestive, but also heart disease is increased. Also, tomatoes help to fight against atherosclerosis syndrome and muscle degeneration, the main causes of discomfort in people over 65 years.

Studies on the health beneficial effects of tomatoes and their derivatives have focused mainly on lycopene, however, the administration only of lycopene for 12 weeks had no effect on the damaged DNA in human lymphocytes. These observations show that is more efficient the combination of:

- carotenoids (a class of natural liposoluble pigments found especially in plants, interfering in the photosynthesis);
- tocopherol (vitamin E, soluble);
- phenolic acid and flavonoids (natural compounds found in plants).

This combination of different carotenoids or the association of carotenoids with tocopherol (vitamin E) or phenolic acid has simultaneous effects on blocking the pathological reactions, which generates free radicals, able to affect the DNA. It was also found that the supplementation of a diet containing a small quantity of carotenoids with tomato juice can increase cellular immunity, involved in reducing the risk of cancer.


Thermally treated tomatoes are more efficient

Unlike fruits and vegetables which reduce their nutritional content when are thermally treated, such as vitamin C, thermally treated tomatoes increase the concentration of lycopene and the antioxidant properties are not lost. Moreover, studies have confirmed that the body absorbs better the lycopene from tomatoes when they are thermally treated.

Fresh tomato provides 4 times less the amount of bioavailable lycopene to the while the juice or sauce of a tomato is a source of lycopene easier to use. Besides tomatoes, there are other red fruits and vegetables rich in lycopene, such as watermelon, but the content is lower Over 80 percent of the lycopene in our diet comes from tomatoes and tomato-derived products, and combination with olive oil increases its absorption.

Antioxidants

Antioxidants are substances (vitamins, minerals, natural coloring) that protect body cells from the harmful effects of free radicals, molecules that form in the body through contact with oxygen. Free radicals are partly responsible for the processes of aging, cardiovascular diseases and cancer and act by attacking the cell membranes and the cellular DNA.

Cellular oxidation is a normal process that affects all tissues, is inevitable, but some factors such as environmental contamination, smoking, diets high in saturated fats, excessive sun exposure and excess physical activity contribute to increased production of free radicals . Most antioxidants are found in plants, which is why it is so necessary to eat more fruits and vegetables as they protect us from free radicals naturally.

The three main representatives of antioxidants are vitamins C, E and pro vitamin A. Citrus, nuts, peanuts, almonds, spinach, onion, especially the red one, berries, cabbage, carrots , grapes, pumpkins, melon, kiwi and of course, tomatoes have the highest antioxidant power. It is recommended a weekly consumption of 7 servings of tomato derivatives, (one serving = one glass of tomato juice of 250 ml or 125 ml of tomato sauce for other dishes). Tomatoes are mostly used in the Mediterranean diet, and in Spanish cuisine is the main component of a typical preparation called gazpacho.

Contraindications for tomatoes

It should also be remembered the moderately content in oxalic acid of tomatoes (5.3 mg / 100 g), substances which form insoluble calcium salts (calcium oxalate) which can precipitate in the form of kidney stones. Also, due to its acidity, a moderate consumption is encourage and in the case of gastro duodenal diseases, the consumption should be stopped.

When buying tomatoes, you have to choose the freshest ones, with smooth, soft skin, of medium consistency (neither too strong nor too soft) or too green, but not too mature. Tomatoes can be stored for longer periods in their natural state by placing them on their tail or the green area corresponding to the tail and separated between them. The fridge can maintain them in good condition between 6 to 8 days, if kept whole and no more than 2 days if they are preserved in the form of fresh juice.
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