by Nick Rose, M.S., PCC Nutrition Educator
This article was originally published in September 2013
Fresh, sliced tomatoes are my very favorite summertime food, especially those colorful heirloom varieties. Raw tomatoes are 90 percent water, so they contribute to your daily fruit and vegetable intake (5 cups per day) and your daily water intake (8 cups per day). Tomatoes are an outstanding source of vitamins A, C, K and potassium and fiber.
Tomatoes also are among the few foods that provide lycopene, a red-colored nutrient also found in watermelon, pink grapefruit and guava. We often think that cooking reduces the nutrients in foods — but cooking tomatoes actually enhances their nutritional profile — and some cooked tomato products, such as canned tomato paste, provide up to 20 times more lycopene than raw, fresh tomatoes.
The cooking doesn’t actually create more lycopene; it reduces the tomato’s water content, creating a more concentrated source. Lycopene is a carotene (similar to vitamin A) and is a fat-soluble nutrient, meaning that in order to fully absorb the lycopene, we must also eat some type of dietary fats at the same meal (olive oil, avocado, salad dressing, hamburger). Carotenes also are better absorbed when chopped and/or pureed, making tomato paste, tomato sauce and ketchup excellent sources of lycopene (though keep in mind that these tomato products often have added salt and sugar).
Lycopene is not considered an “essential nutrient” like vitamin A or C, but its health benefits are well documented. This antioxidant protects against prostate cancer, bone loss and heart disease risk factors. Some lycopene is stored in our skin, and new research suggests that lycopene helps protect against UV radiation from sunlight.
Now that you think about it, it kind of makes sense that the produce kings of summertime — watermelon and tomatoes — are the best lycopene sources and available at the peak of summertime when UV exposure is highest.
While lycopene is associated with red foods such as tomatoes and watermelon, all tomatoes provide it, including the orange, yellow, black and even purple varieties.
Fruit or vegetable?
Tomatoes are fruits, based on their botanical classification as a seed-bearing structure growing from the flower of the plant. The U.S. Supreme Court classified tomatoes as a vegetable in the late 19th century to increase revenues because vegetables (but not fruits) required import taxes. Regardless, whether you trust the botanists or the politicians, we all need to eat 5 cups of fruits and/or vegetables every day.
Are organic tomatoes better?
Researchers have found that organic tomatoes are smaller but more nutrient dense than conventional tomatoes. More specifically, organic tomatoes contain more lycopene, vitamin C and total antioxidants than nonorganic tomatoes. Cherry tomatoes are one of the highest sources of pesticide residues when not organic. Choose organic ketchup for more lycopene.