Tomato Guide: Nutrition, Benefits, Side Effects, and More

Jul 27, 2023

Whether you’re in the mood for Latin, Mediterranean, or Italian food, a hamburger, pizza, or a salad, your meal is most likely going to include tomatoes. They are one of America’s most-consumed vegetables, according to the U.S. Department of Agriculture (USDA) — even if they are technically a fruit.

Yet as common as tomatoes are, the nutritional punch they pack is definitely not.

“Tomatoes are packed full of a variety of nutrients,” says Kristin Gillespie, RD, a certified nutritional support clinician in Virginia Beach. “As a result, tomatoes can help protect you against cancer and other chronic illnesses, improve blood pressure and overall heart health, and improve blood sugar levels in those with diabetes.”

Learn more about this widely popular fruit, including its benefits, potential side effects, and how to buy and cook it.

A staple in numerous cuisines, the tomato is arguably one of the most widely used produce items in the United States, and not just because of pizza. Americans also love to grow their own: Tomatoes are the most commonly planted home crop in the country, according to the University of Illinois Urbana-Champaign.

Tomatoes are often referred to as vegetables, but they are technically the fruit of a flowering plant called Solanum lycopersicum, according to Britannica. They belong to a family of fruits and vegetables known as nightshades, which includes potatoes and eggplants. While nightshades have gotten a bad reputation in recent years (Gisele Bündchen famously said she avoided them) because of possible issues with food sensitivities or allergies, the Cleveland Clinic explains that the heart of the issue is their alkaloid content, which is typically only harmful in large doses. The claim that nightshades create disease-causing inflammation has not been proved.

Tomatoes are thought to be indigenous to South America, but gained worldwide popularity after Spanish explorers introduced the fruit to Europe in the 16th century. Since then, tomatoes have been associated with Latin American, Italian, and Mediterranean dishes, but their versatility has made them a significant part of numerous cuisines.

While most of the tomatoes you may come across at supermarkets are various shades of red, orange, or yellow, green and purple tomatoes also exist. These are less common, but you may be able to find them at specialty stores or at farmers’ markets. Here is a breakdown of some of the most common tomato varieties, per Nature Fresh Farms.

No matter what type of tomato you prefer, know that each fruit is low in calories, with a high nutrient content, including antioxidants.

“Tomatoes are rich in various antioxidants, including lycopene, which gives them their red color and offers several health benefits,” says Trista Best, MPH, RD, a consultant with Balance One Supplements based in Georgia. She also notes that tomatoes contain some vitamin C, potassium, vitamin A, and folate.

Per the USDA, one medium tomato contains:

Tomatoes, like other antioxidant-rich fruits and vegetables, can offer a variety of health benefits when incorporated into a balanced diet. Here are some of the key benefits that both experts and researchers have identified.

Tomatoes’ potential anticancer effects are attributed to the powerful antioxidant lycopene. “It is known for its potential to reduce the risk of certain types of cancer, particularly prostate cancer,” says Best. According to the World Cancer Research Fund International, a study of men who consumed canned or cooked tomatoes five to six times per week were found to have a 28 percent lower risk of prostate cancer than men who ate no tomatoes. It’s important to note that the researchers found no effect on prostate cancer risk when they considered tomatoes in raw, juice, soup, or sauce form. It was found that cooking the tomatoes helped with lycopene absorption, particularly cooking them with olive oil. Also, per a 2022 review, lycopene has been widely studied for its ability to protect DNA in cells against the development of several other cancers, such as those of the colon, breast, and blood.

Lycopene is also thought to be responsible for a number of cardiovascular benefits associated with tomatoes. Lycopene “can contribute to cardiovascular health by reducing the risk of heart disease and lowering blood pressure,” says Best. One review published in February 2022 in the International Journal of Molecular Sciences found a growing body of evidence showing lycopene’s benefits, particularly for people with atherosclerosis and hypertension.

Michigan State University notes that other components of tomatoes may be heart protective as well. These include potassium and B vitamins, which may help reduce cholesterol and blood pressure, and thus decrease the overall risk of heart attack and stroke. Potassium has other essential benefits besides its role in your heart health, including body fluid balance, nerve function, and healthy muscle contractions, according to the National Institutes of Health (NIH).

Carrots and sweet potatoes shouldn’t be your only sources of vitamin A. USDA data shows that tomatoes are an important source of beta-carotene, which Best says is “a precursor to vitamin A,” and is essential for vision, immune function, and cell growth, according to the NIH. What’s more, vitamin A from tomatoes can help protect your night vision and cut the risk of age-related macular degeneration.

“Additionally, lycopene may have protective effects on the skin, helping to prevent sun damage and improve skin texture,” says Best. A systematic review and meta-analysis published in January 2023 in Critical Reviews in Food Science and Nutrition found that dietary supplements of tomato and lycopene helped prevent light-induced photodamage to the skin. Best also notes that the vitamin C content of tomatoes supports collagen synthesis, which is important in helping your skin maintain its elasticity and hydration. Moreover, Michigan State University points out that the beta-carotene in tomatoes may help protect your skin from UV damage.

While there’s no tomato-specific diet per se, the more fruits and vegetables in your diet, the easier it is to both lose and maintain your weight. As the Centers for Disease Control and Prevention (CDC) notes, produce like tomatoes create a calorie deficit while keeping you feeling full because of their naturally low calories but high nutrient content. Plus, tomatoes are rich in fiber and are more than 90 percent water, both of which aid satiety.

To create a calorie deficit, the CDC recommends swapping out high-calorie, high-fat items for tomatoes. For example, you can eat more sliced tomatoes with vegetables in place of pasta or rice, or add chopped tomatoes to omelets, wraps, and burritos instead of cheese.

The Keck School of Medicine at the University of Southern California says that tomatoes may help with appetite control because they contribute to leptin resistance. Leptin is a type of hormone that’s responsible for telling your brain that you’re full — when you’re leptin resistant, your brain erroneously tells you you’re hungry when you’re not. “In addition to increasing circulating leptin levels, tomatoes may help increase leptin sensitivity by reducing inflammation within the body, because inflammation is felt to be a primary cause of leptin resistance,” says Gillespie.

Still, Best cautions that not enough research has been done on this end. “More research is needed to fully understand the relationship between tomatoes, leptin resistance, and weight management,” she says.

Due to imports from other countries, you may be able to find tomatoes at grocery stores year-round. According to the USDA, local tomatoes are in season during the summer months.

Below are some important tips for selection and storage so you can get the most benefits and best taste out of your tomatoes.

No matter which tomatoes you choose, Produce for Better Health recommends looking for those that have bright, shiny skins and are firm to the touch. The University of California in San Diego notes that a ripe tomato ought to have a sweet smell. As a rule of thumb, avoid tomatoes that smell sour or bitter, or have mushy, bruised skins.

Canned tomatoes are another option for having tomatoes year-round or if you’re in a hurry. Ideally, you should look for cans labeled reduced-sodium or salt-free.

Ripe tomatoes last about one week and are best kept at room temperature. If, however, you cut or cook a tomato and don’t use it all at once, you can refrigerate leftovers for up to two days. You can also place raw or cooked tomatoes in your freezer for up to two months.

“For those who struggle to eat tomatoes regularly, there are some easy ways to sneak them into your diet,” says Gillespie. “Adding salsa or fresh tomato sauce to your favorite foods is an easy way to incorporate tomatoes naturally. They can also be added to salads, sandwiches, and soups, or made into a yummy caprese salad or bruschetta!” Be sure you wash the tomatoes before cutting them, and place the tomato on its side before thinly slicing with a serrated knife.

Best recommends cooking tomatoes in soups, stews, and stir-fries, as well as roasting them with your favorite herbs and olive oil to create a side dish. Previous research found that cooking tomatoes in olive oil increases lycopene absorption in the body.

To mix things up, consider drinking tomatoes. “Try tomato juice, gazpacho, or tomato smoothies for a refreshing twist,” says Best. The Florida Tomato Committee lists other recipe ideas, such as black bean cakes topped with tomatoes, tomatoes stuffed with artichokes or couscous, and tomato sandwiches.

Finally, don’t forget that your tomatoes don't have to be fresh. Best recommends using canned tomatoes in your favorite pasta or chili dishes, as well as to create a healthier pizza sauce.

While considered generally safe, tomatoes may pose the risk of side effects, allergic reactions, and other health concerns in some people. If you have a history of acid reflux, take certain medications, or have symptoms of an allergic reaction, talk with your doctor about whether tomatoes are a safe component in your diet.

Consider reducing your intake or avoiding tomatoes altogether and talking with a healthcare provider if any of the following applies to you.

If you experience an adverse reaction to tomatoes, the thought of a tomato allergy may have crossed your mind. While Best says tomato allergies are rare, but they are possible. “Symptoms can range from mild itching or swelling to more severe reactions,” she says. According to Allergy Link, problems associated with tomato allergies may include anaphylactic shock, oral allergy syndrome, and gastrointestinal issues. Some people with mild tomato allergies may be able to tolerate the fruit when it's cooked, rather than raw. But if you do have a known tomato allergy, it’s best to talk with a doctor before adding them to your diet.

Also, if you experience itchiness, rashes, or other side effects after eating tomatoes, consider seeing a doctor for possible allergy testing.

With prices rising because of inflation, as well as the potential exposure to harmful chemicals in non-organically grown produce, some individuals are opting to grow their own fruits and vegetables at home. You may be able to grow your own tomatoes either directly in the ground or in pots, depending on how much space you have.

To grow tomatoes from seeds, Minneopa Orchards recommends planting them outdoors during the spring months, or once the last hard freeze has passed in your area. Start with a few seeds in a small container, and once they've germinated, transfer the small plant into the ground after four to six weeks.

If you don’t have the ground space, you can transplant the tomatoes to larger pots instead. According to the Spruce, 5-gallon buckets are ideal; make sure there are holes in the bottom of the container so water can drain through the soil. Also, if you decide to plant tomatoes in containers, make sure they get between six and eight hours of sun per day.

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