The tomato (Solanum lycopersicum) is a fruit of the nightshade family, native to South America. Although botanically a fruit, it is generally eaten and prepared as a vegetable.
Tomatoes are the main dietary source of the antioxidant lycopene, which has been linked to numerous health benefits, including reduced risk of heart disease and cancer. They are also an excellent source of vitamin C, potassium, folate, and vitamin K. Typically red when ripe, tomatoes can also come in several colors, including yellow, orange, green, and purple. In addition, there are many subspecies of tomatoes with different shapes and flavors.
This article tells you everything you need to know about tomatoes.
Tomato Nutrition Facts
The water content of tomatoes is around 95%. The remaining 5% is mostly made up of carbohydrates and fiber. Here are the nutrients contained in a small raw tomato (100 grams):
Protein: 0.9 grams
Carbohydrates: 3.9 grams
Sugar: 2.6 grams
Fiber: 1.2 grams
Lipids: 0.2 grams
Carbohydrates represent 4% of raw tomatoes, or less than 5 grams of carbohydrates for an average specimen (123 grams). Simple sugars, such as glucose and fructose, make up almost 70% of carbohydrate content.
Tomatoes are a good source of fiber, with about 1.5 grams per medium-sized tomato. Most of the fiber (87%) in tomatoes is insoluble, in the form of hemicellulose, cellulose and lignin.
Tomato vitamins and minerals
Tomatoes are a good source of several vitamins and minerals:
Vitamin C. This vitamin is an essential nutrient and an antioxidant. A medium sized tomato can provide around 28% of the Reference Daily Intake (RDA).
Potassium. An essential mineral, potassium is beneficial for controlling blood pressure and preventing heart disease.
Vitamin K1. Also known as phylloquinone, vitamin K is important for blood clotting and bone health.
Folate (vitamin B9). One of the B vitamins, folate is important for normal tissue growth and cell function. It is especially important for pregnant women.
Other Plant Compounds
The vitamin and plant compound content of tomatoes can vary greatly depending on the variety and the sampling period.
The main plant compounds of the tomato are:
Lycopene. A red pigment and antioxidant, lycopene has been widely studied for its beneficial effects on health.
Beta-carotene. An antioxidant that often gives foods a yellow or orange tint, beta-carotene is converted into vitamin A in your body.
Naringenin. Found in the skin of tomatoes, this flavonoid has been shown to reduce inflammation and protect against various diseases in mice.
Chlorogenic acid. A powerful antioxidant compound, chlorogenic acid can reduce blood pressure in people with high levels.
Chlorophylls and carotenoids like lycopene are responsible for the rich color of tomatoes.
When the ripening process begins, chlorophyll (green) is degraded and carotenoids (red) are synthesized.
Lycopene, the most abundant carotenoid in ripe tomatoes, is particularly notable when it comes to plant compounds in the fruit. It is in the skin that it is found in greatest concentration.
In general, the redder the tomato, the more lycopene it contains.
Tomato products, such as ketchup, tomato juice, tomato paste and tomato sauces are the richest dietary sources of lycopene in the Western diet, providing over 80% of dietary lycopene in the West. Gram for gram, the amount of lycopene in processed tomato products is often much higher than in fresh tomatoes.
For example, ketchup contains 10 to 14 mg of lycopene per 100 grams, while a small fresh tomato (100 grams) contains only 1 to 8 mg.
However, remember that ketchup is often consumed in very small amounts. So it may be easier to increase your lycopene intake by eating unprocessed tomatoes, which also contain much less sugar than ketchup. Other foods in your diet can have a big effect on lycopene absorption. Consuming this plant compound with a fat source can increase absorption up to four times. However, not everyone absorbs lycopene at the same rate. Although processed tomato products are higher in lycopene, it is recommended to consume fresh, whole tomatoes whenever possible.
The health benefits of tomatoes
Eating tomatoes and tomato products has been linked to better skin health and a lower risk of heart disease and cancer.
Heart disease, including heart attacks and strokes, is the most common cause of death worldwide. A study in middle-aged men linked low blood levels of lycopene and beta-carotene to an increased risk of heart attack and stroke. Mounting evidence from clinical trials suggests that lycopene supplementation may help lower LDL (bad cholesterol) levels.
Cancer is the uncontrolled growth of abnormal cells that spread beyond their normal limits, often invading other parts of the body. Observational studies have noted links between tomatoes – and tomato products – and a decreased incidence of prostate, lung and stomach cancers. Although the high lycopene content is thought to be responsible, high-quality human research is needed to confirm the cause of these benefits. A study in women shows that high concentrations of carotenoids, found in large amounts in tomatoes, may protect against breast cancer.
Tomatoes are considered beneficial for skin health. Tomato-based foods high in lycopene and other plant compounds may protect against sunburn. According to one study, people who ingested 40 grams of tomato paste – providing 16 mg of lycopene, with olive oil every day for 10 weeks experienced 40% less sunburn.
Commercial ripening process
When tomatoes begin to ripen, they produce a gaseous hormone called ethylene. Commercially grown tomatoes are harvested and transported while still green and immature. To turn them red before selling them, food companies spray them with artificial ethylene gas. This process prevents the development of the natural flavor and can result in tasteless tomatoes.
Therefore, locally grown tomatoes may taste better because they are left to ripen naturally. If you buy unripe tomatoes, you can speed up the ripening process by wrapping them in a sheet of newspaper and keeping them on the kitchen counter for a few days. Just be sure to check daily that they are fully ripe.
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