Tomatoes

What's New and Beneficial About Tomatoes

WHFoods Recommendations

Tomatoes are available in a variety of colors—including not only red but also yellow, orange/tangerine, green, purple, brown, and black. However, since most people consume this vegetable in its vibrant shades of red, our recommendation for tomatoes in your meal plan starts with our red/purple vegetable subgroup. Most of the 38 vegetables that we profile on our website fit naturally into subgroups based on their color or food family, and you can find detailed information about these subgroups in our  Vegetable Advisor. Our minimum recommended intake level for vegetables from the red/purple subgroup is 1/2 cup per day. Our more optimal recommended intake is one cup. Along with red tomatoes, red and purple carrots, red onions, and eggplant would be examples of other vegetables in this red/purple subgroup. Since there are 90–100 grams of fresh tomato in every 1/2 cup, and since a 200-gram, 3-inch tomato is considered "large" in most food databases, we think about this 1/2 cup serving size as approximately the same as 1/2 large tomato.

Our 7-Day Menu is a great example of how to bring tomatoes into your meal plan in a balanced way. Although we do not include tomato on an everyday basis in our 7-Day Menu, for the week as a whole we still average 3/4 cup of tomato per day. This average intake level for tomatoes alone exceeds our minimum recommended intake level for all red/purple vegetables!

Two other most commonly consumed tomato varieties in the U.S. are green and yellow tomatoes. If you choose yellow tomatoes, we recommend that you treat them as part of our yellow/orange vegetable subgroup. For this subgroup, our recommended minimal intake level is also 1/2 cup per day, and our optimal intake level is 1 cup. Of course, alongside of yellow tomatoes, vegetables like sweet potato, yellow summer squash, and carrots can contribute to your daily yellow-orange total.

And finally, if you choose green tomatoes, we recommend that you approach them as part of our green vegetable subgroup. Here our minimal recommended intake level is 4 cups per day, and our outstanding level of intake is 8 servings of green vegetables per day. Of course, there are many different types of green vegetables that can provide you with exceptional nourishment!

Tomatoes, sliced, raw
1.00 cup
(180.00 grams)
Calories: 32
GI: very low

NutrientDRI/DV

 vitamin C33%

 biotin24%

 molybdenum20%

 vitamin K16%

 potassium12%

 copper12%

 manganese11%

 fiber9%

 vitamin A8%

 vitamin B68%

 vitamin B37%

 folate7%

 phosphorus6%

 vitamin B16%

 vitamin E6%

 magnesium5%

 chromium4%

 iron3%

 zinc3%

 choline3%

 pantothenic acid3%

 protein3%

Health Benefits

Outstanding Antioxidant and Anti-Inflammatory Benefits from Tomatoes

We realize that it is easy to find websites that describe tomatoes as a cause of inflammation and a food that can increase risk of unwanted inflammation rather than reducing it. Research studies on tomatoes consistently show a very different relationship in which tomato intake is associated with decreased risk of unwanted inflammation and decreased risk of oxidative stress as well. These research studies should not be surprising, given the wealth of antioxidant and anti-inflammatory phytonutrients provided to us by tomatoes. While carotenoids have been key area of research focus in this regard, tomatoes actually offer an extensive list of health-supportive phytonutrients. This list includes flavonoids, carotenoids, saponins, and fatty acid derivatives. Some of the best-studied phytonutrients in tomatoes are listed below.

While not typically considered phytonutrients, one unusual category of compounds found in tomatoes may also provide us with health benefits. Members of this category are called alkaloids (and in tomatoes, they are also sometimes called solanaceous alkaloids, since they are found almost exclusively among plants in the nightshade or Solanaceae family). Tomato alkaloids include tomatine and tomatidine. The reason that these alkaloids are not currently considered to be phytonutrients involves the risk that they can pose when consumed in large amounts or by individuals with a special sensitivity to them. (And to be fair, we should note that some observers believe tomato alkaloids can pose a certain level of risk even when consumed in smaller amounts, despite lack of evidence for this conclusion in large-scale research studies.) Another piece of information that is helpful to know in this regard involves the way that alkaloids are distributed within the tomato plant. Tomato alkaloids are far more concentrated in the leaves and stems of the plant than in the fruit portion that we commonly enjoy.

In addition to the phytonutrient antioxidants listed above, tomatoes also provide us with a good number of conventional antioxidants, including excellent amounts of vitamin C; very good amounts of vitamin E, vitamin A (in the form of carotenoids), and manganese; and good amounts of zinc and chromium.

If you combine all studies on the antioxidant and anti-inflammatory benefits of tomatoes, you will find these benefits extending to many different body systems, including the cardiovascular system, musculoskeletal system, renal system (kidneys), hepatic system (liver), and integumentary system (skin).

It's also worth noting the level of detail that has come into play with research studies on the anti-inflammatory benefits of tomatoes. Multiple studies have documented these anti-inflammatory benefits at the level of cell signaling in our body. This research has centered on biomarkers of inflammation including interleukin-6 (IL-6), vascular cell adhesion molecule-1 (VCAM-1), and lymphocyte function-associated antigen-1 (LFA-1).

Cardiovascular Benefits from Tomatoes

Reduced risk of heart disease is an area of health benefits in which tomatoes truly excel. There are two basic lines of research that have repeatedly linked tomatoes to heart health. The first line of research involves antioxidant support, and the second line of research involves regulation of fats in the bloodstream.

No body system has a greater need for antioxidant protection than the cardiovascular system. The heart and bloodstream are responsible for taking oxygen breathed in through the lungs and circulating it around throughout the body. In order to keep this oxygen in check, antioxidant nutrients are needed in an ample supply. Earlier in this Health Benefits section, we gave you a close-up look at some of the best-researched antioxidants in tomatoes. It's worth noting here that conventional vitamin antioxidants like vitamin E and vitamin C are sometimes overlooked in tomatoes because of their unique phytonutrient composition. Yet vitamin E and vitamin C provide critical antioxidant support in the cardiovascular system, and they are an important part of the contribution made by tomatoes to our heart health. It's the carotenoid lycopene, however, that has gotten the most attention as tomatoes' premier antioxidant and heart-supportive nutrient. Lycopene has the ability to help lower the risk of lipid peroxidation in our bloodstream. Lipid peroxidation is a process in which fats that are located in the membranes of cells lining the bloodstream, or fats that are being carried around in the blood, get damaged by oxygen. This damage can be repaired if it is kept at manageable levels. However, chronic and/or excessive lipid peroxidation in the bloodstream can lead to trouble. Overly damaged fat components can sound an alarm to the body's immune and inflammatory systems, and the result is a series of events that can lead to a gradual blocking of blood vessels (atherosclerosis) or other problems.

The second line of research linking tomatoes with heart health involves regulation of fats in the blood. Dietary intake of tomatoes, consumption of tomato extracts, and supplementation with tomato phytonutrients (like lycopene) have all been shown to improve the profile of fats in our bloodstream. Specifically, tomato intake has been shown to result in decreased total cholesterol, decreased LDL cholesterol, and decreased triglyceride levels. It's also been shown to decrease accumulation of cholesterol molecules inside of macrophage cells. (Macrophage cells are a type of white blood cell that gets called into action when oxidative stress in the bloodstream gets too high, and the activity of macrophages—including their accumulation of cholesterol—is a prerequisite for development of atherosclerosis.) Many phytonutrients in tomatoes are likely to be involved with the improvement of our blood fat levels. Two little-known phytonutrients—one called esculeoside A (a saponin) and the other called 9-oxo-octadecadienoic acid (a fatty acid derivative)—are currently under active investigation by researchers as tomato phytonutrients that can provide us with special benefits for regulation of fats in our bloodstream.

Another area of increasing interest in tomatoes and heart health involves blood cells called platelets. The excessive clumping together of platelet cells can cause problems for our bloodstream in terms of blockage and unwanted clotting, and prevention of this excessive clumping is important for maintaining heart health. Numerous phytonutrients in tomatoes have been shown to help prevent excessive clumping of our platelet cells. (This ability is usually referred to as an "anti-aggregatory effect.") In combination with the other heart benefits described above, this platelet-regulating impact of tomatoes puts them in a great position to help us optimize our cardiovascular health.

Other Potential Health Benefits from Tomatoes

In addition to the areas of health support described above, the single largest area of potential health benefits from tomatoes involves cancer risk. Prostate cancer is the best-researched type of cancer in relationship to tomato intake, and here the verdict is pretty clear: tomato intake helps lower risk of prostate cancer in men. One key tomato nutrient that has received special attention in this regard is alpha-tomatine. Alpha-tomatine is a saponin phytonutrient and it has demonstrated an ability to alter metabolic activity in developing prostate cancer cells. It has also been shown to trigger programmed cell death (apoptosis) in prostate cancer cells that have already been fully formed. Research on alpha-tomatine has also been conducted for non-small cell lung cancer, with similar findings.

Along with prostate cancer and non-small cell lung cancer, pancreatic cancer and breast cancer have been examined in relationship to tomato intake. Research on tomatoes and breast cancer has largely focused on the carotenoid lycopene, however, rather than tomato intake per se. In association with lycopene intake (in supplemental form), there is reasonably consistent research showing risk reduction for breast cancer. However, we have not seen a large-scale study that expanded this risk reduction to intake of fresh tomatoes in a weekly meal plan.

The area of skin health has also sparked the interest of tomato researchers. Tomato and tomato products—especially tomato paste—have been shown to provide health benefits following unprotected sun exposure in humans. Specifically, researchers have found tomato consumption to result in less skin redness after UV exposure from sunlight. In addition, they have found that food forms of tomato (like tomato paste ) do a better job of lessening the impact of sunburn than purified tomato-based nutrients like lycopene (which are taken in the form of dietary supplements).

The ability of tomato intake to help protect our skin comes as no surprise since carotenoids like beta-carotene have long been known for their ability to get deposited in our skin cells. And we know that they can play a protective role there in fending off the unwanted consequences of excessive UW light. Animal studies have extended the skin-support role of tomato intake to risk reduction for certain types of skin cancer. In one recent study, mice were given whole tomato powder from two different varieties of tomato—one red-colored variety and one tangerine-colored variety. Consumption of both tomato powders was determined to affect skin cell metabolism and to lower risk of skin cancer development. Specifically, the researchers measured a form of skin cancer called keratinocyte carcinoma (sometimes more loosely referred to as nonmelanoma skin cancer) and found the occurrence to be reduced in the mice consuming the tomato powder. It's only the carotenoids in tomato that were likely associated with this reduced risk, but also certain tomato alkaloids, including tomatine and tomatidine. We expect to see follow-up studies on tomato intake and reduced risk of skin cancer in humans that analyze routine intake of fresh tomatoes in an everyday meal plan.

Description

Tomatoes rank fourth on the list of most-consumed vegetables in the U.S. (The first three are potatoes, lettuce, and onion.) We use the word "vegetables" here, even though tomatoes are technically classified as a fruit. (And like all fruits, they develop from the fertilized ovary of the plant.) However, from a practical standpoint, most people are accustomed to thinking about tomatoes as vegetables. In addition, tomatoes also have more in common with the vegetable group of foods in terms of their nutrient and calorie content. So you'll find us referring to them as vegetables throughout this profile and throughout our website as a whole.

Among their many delightful varieties, consumers are probably most familiar with the larger red slicing varieties often just called "slicers." However, tomatoes come in a wealth of shapes and a rainbow of colors.

In terms of shape, what might first come to mind are the round tomatoes that are commonly referred to as "classic" or "globe" tomatoes. These varieties are usually between 2–3 inches in diameter, and their overall round shape can also appear somewhat flattened. There are a very large number of varieties in this category. Noticeably larger but similarly shaped are beefsteak tomatoes, with examples including Brandywine and Beefmaster. Also round but much smaller in size are cherry tomatoes. These varieties are only about an inch or so in diameter. Popular varieties of cherry tomatoes include Mountain Belle, Red Pearl, and Cherry Grande. Round tomatoes that fall somewhere in between classic tomatoes and cherry tomatoes in size are often referred to as "cocktail" tomatoes.

Oval or plum tomatoes are somewhat elongated in shape. Their shape is also often referred to as "egg-like" or "pear-like." The term "roma" is typically used interchangeably with "oval" and "plum", although you may also find some descriptions in which "roma" is treated as a subgroup of plum tomatoes.

Very similar to cherry tomatoes but more oval in shape are grape tomatoes. As evidenced by their oval shape, grape tomatoes are smaller variations of oval/plum tomatoes.

In terms of color, most of us are accustomed to seeing the vivid red colors of this popular vegetable. However, yellow, orange/tangerine, green, pink, purple, brown, and black are also widely-enjoyed colors of tomatoes. You can also find varieties that feature different color blends. It is important to note that you can take any of the tomato shapes described above, match it up with any color, and find a specific tomato variety that features that exact shape and that exact color in combination.

"Determinate" and "indeterminate" are two categories that you might hear to describe tomatoes. Determinate refers to varieties that grow on a bush-like plant and produce tomatoes during one particular time of year. Indeterminate refers to varieties that grow on the vine and typically produce tomatoes throughout the year. While we are on the topic of vines, we suspect that you have already come across the term "vine-ripened" in some descriptions of tomatoes. Unfortunately, this term has no legal description in terms of food labeling and is used in a variety of ways (with some of these ways being misleading). Many growers consider "vine-ripened" to have only one legitimate meaning: allowed to ripen prior to harvest. This interpretation of "vine-ripened" could refer to either bush tomatoes (determinate) or vine tomatoes (indeterminate). However, commercial producers often harvest "vine-ripened" tomatoes at what is called the "breaker" stage of development. "Breakers" are tomatoes that display an initial change in color from green to either yellowish-tan, pink, or red on approximately 10% of their outer surface (skin). Later on in the ripening process, when this color change goes on to exceed 10% of the skin, the tomatoes are said to have moved past the breaker stage and on to the "turning" stage. With further ripening, they move on from this turning stage to the "pink" stage and then further still to a fully ripened red stage. So you can see how tomatoes that have been harvested at the breaker stage have been harvested at a very early stage in the ripening process that hardly seems to meet the spirit of the term "vine-ripened."

One final set of terms that you will come across in descriptions of tomatoes involve the conditions under which they were grown. Within the U.S., the majority of tomatoes are grown in the outdoors in soil. These tomatoes are typically called "field tomatoes." The quality of field tomatoes naturally depends upon the quality of the soil and a long list of other environmental factors. However, U.S. consumers also enjoy an increasing number of "greenhouse" tomatoes that are grown in a greenhouse rather than in a field. At present, over 70% of all greenhouse tomatoes purchased in the U.S. are imported from Mexico due to the relatively small number of U.S. producers and the year-round demand for tomatoes (that greenhouse production can help to meet). Within a greenhouse, tomatoes can be grown either in soil or in water. Water-based production systems—called hydroponic systems—provide the tomatoes with nutrients by adding them to the water. We have not seen enough indexed journal studies to provide you with any reliable information about possible patterns in nutrient quality related to these different growing methods.

All tomatoes belong to the solanoid family of plants called the Solanaceae. (This family is also called the nightshade family.) Based on membership in this plant family, scientists initially gave tomatoes the genus/species name Solanum lycopersicum. However, during the history of tomato research, a second genus/species name was given to this vegetable: Lycopersicon esculentum. And further down the road, yet other scientists tried to bridge the gap between these two names with creation of a third name: Lycopersicon lycopersicum. When we look in the science journals, we find approximately equal mentions for Lycopersicon esculentum and Solanum lycopersicum, but relatively few mentions for Lycopersicon lycopersicum.

Before leaving this Description section, we want to make one final note about tomato measurements and their use in recipes: this topic can be confusing! Since many recipes talk about tomatoes in terms of size, you may find it helpful to know that what counts as a "large" tomato in the minds of many people is not all that large in terms of the US Standards for Grades of Fresh Tomatoes as set by the U.S. Department of Agriculture (USDA). The chart below shows the USDA standards for sizing fresh tomatoes.

Tomato SizeMinimum Diameter
Small2-1/8 inches
Medium2-1/4 inches
Medium2-1/2 inches
Medium2-3/4 inches

Since a tennis ball is approximately 2.6-2.7 inches in diameter, we're talking about a "large" tomato being slightly smaller than a tennis ball, and an "extra-large tomato" being slightly bigger—but not by much.

The following chart estimates the weight of tomatoes according to their size.

Tomato SizeApproximate Weight (grams)Approximate Weight (ounces)
Small90–100 grams3–4 ounces
Medium125–135 grams4–5 ounces
Large180–200 grams6–7 ounces
Extra-Large280–340 grams10–12 ounces

What you are seeing here is a little less than 1/2 pound for a large tomato, and a little more than 1/2 pound for an extra-large one.

And finally, in terms of weight-per-cup, you can treat one cup's worth of tomato as weighing approximately 1/2 to 3/4 pounds. Of course, this weight will vary according to the shape and size of the slices and the starting weight of the tomato.

History

Although tomatoes are often closely associated with Italian and Mediterranean cuisine, they are actually originally native to the western side of South America, in the region occupied by Columbia, Ecuador, Peru, Chile, and the western half of Bolivia. The Galapagos Islands off the coast of Ecuador are also believed to be part of tomatoes' native area. The first type of tomato grown is thought to have more resembled the smaller-sized cherry tomato than the larger varieties.

The tomato does not appear to have been first cultivated in South America, however, but rather in Mexico, most likely in Aztec civilizations and probably in the form of small yellow fruits. The word "tomato" may actually originate from the Nahautl (Aztecan) word "tomatl " meaning "the swelling fruit." From a historical standpoint, it wasn't until much later that tomatoes eventually made their way on European vessels from Mexico back to Europe, resulting in the introduction of this vegetable to that continent.

On a commercial basis, most tomatoes are grown for processing into food products including tomato sauce, tomato paste, tomato juice, and canned tomatoes. Worldwide, about one-third of all tomatoes end up in processed form (approximately 40 million tons' worth out of 130 million tons total). Within the U.S., however, a much higher percentage of the total tomato crop finds its way into processed foods. For reasons involving taste, texture, and nutrition, we recommend consumption of tomatoes—and all of our WHFoods vegetables—in their fresh versus processed forms.

Within the U.S., California leads all states in tomato production. It produces about 95% of all processing tomatoes grown in the U.S., and about 30-35% of all fresh tomatoes. Florida essentially matches California in terms of fresh tomato production, and these two states alone produce about 65-75% of all fresh U.S. tomatoes. Sizeable amounts of acreage are planted with tomatoes in Ohio, Virginia, Georgia, and Tennessee, North Carolina, New Jersey, and Michigan. About one-third of all fresh tomatoes consumed in the U.S. are imported from other countries, most notably Mexico. At present, far more greenhouse tomatoes are imported into the U.S. than are produced domestically.

On a worldwide basis and including tomatoes grown for both processing and fresh use, this vegetable ranks first in terms of total global production (as measured in tons). China, the countries of the European Union, India, the United States, and Turkey are the top tomato producers worldwide. Also, on a global basis, Mexico is the world's largest exporter of tomatoes.

How to Select and Store

Choose tomatoes that have rich colors. Deep reds are a great choice, but so are vibrant oranges/tangerines, brilliant yellows, and rich purples. Tomatoes of all colors provide outstanding nutrient benefits. Tomatoes should be well shaped and smooth skinned with no wrinkles, cracks, bruises, or soft spots. They should not have a puffy appearance since that characteristic is often associated with inferior flavor and may also result in excess waste during preparation. Ripe tomatoes will yield to slight pressure and often have a noticeably sweet fragrance.

At WHFoods, we encourage the purchase of certified organically grown foods, and tomatoes are no exception. Repeated research studies on organic foods as a group show that your likelihood of exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchased of certified organic foods, including tomatoes. In many cases, you may be able to find a local organic grower who sells tomatoes but has not applied for formal organic certification either through the U.S. Department of Agriculture (USDA) or through a state agency. (Examples of states offering state-certified organic foods include California, New York, Oregon, Vermont, and Washington.) However, if you are shopping in a large supermarket, your most reliable source of organically grown tomatoes is very likely to be tomatoes that display the USDA organic logo.

One area of longstanding debate about tomatoes involves their best place of storage. Unfortunately, there is no "one size fits all" answer about the optimal place because the optimal place depends on the degree of ripeness when you bring the tomatoes home.

Let's start at one end of the spectrum, with tomatoes that have been purchased before they are sufficiently ripe to fully enjoy. In this situation, it does not make sense to store the tomatoes in your refrigerator because the cold temperature will impede the ripening process that need to occur. Instead, you will want to store the tomatoes at room temperature and out of direct exposure to sunlight. They may be left there to continue ripening will for as long as a week, depending upon their degree of ripeness when you brought them home. If you want to speed up the ripening process, one thing that you can do is place the tomatoes in a paper bag with a banana or apple. The ethylene gas emitted by these fruits emit can help speed up the ripening of the tomatoes.

At the other end of the spectrum, if you bring home tomatoes that already seem a bit overripe—yet you are not ready to eat them&mdash we recommend placing them in the refrigerator. Since they are likely to do better at the higher side of the temperature range inside your refrigerator, one good storage spot would be a door compartment with a plastic cover, like an egg or butter compartment. That spot is usually a bit warmer than the rest of the fridge. Your tomatoes will usually keep for one or two more days when stored in this way. Removing them from the refrigerator about 30 minutes before using will help them to regain their maximum flavor and juiciness. Whole tomatoes, chopped tomatoes and tomato sauce freeze well for future use in cooked dishes. Sun-dried tomatoes should be stored in an airtight container, with or without olive oil, in a cool dry place (and not in the refrigerator).

Ketchup can be a surprisingly good source of tomato nutrients, including lycopene. If you are going to purchase tomatoes in the form of ketchup, we recommend that you choose organic ketchup. We make this recommendation not only because you're likely to avoid some unwanted pesticide residues and other potential contaminants by purchasing organic, but also because some studies show higher lycopene content in organic versus non-organic ketchup.

How to Enjoy

A Few Quick Serving Ideas

WHFoods Recipes That Include Tomatoes

If you'd like even more recipes and ways to prepare tomatoes the Nutrient-Rich Way, you may want to explore The World's Healthiest Foods book.

Safety

Tomatoes Belong to the Nightshade Family

Tomatoes are one of the vegetables that belong to the nightshade (Solanaceae) family. For helpful information about nightshade vegetables—including our WHFoods Recommendations—please see our article, Which foods are classified as "nightshades," and is it true that foods from this group can potentially contain problematic substances?

Nutritional Profile

Introduction to Food Rating System Chart

The following chart shows the nutrients for which this food is either an excellent, very good or good source. Next to the nutrient name you will find the following information: the amount of the nutrient that is included in the noted serving of this food; the %Daily Value (DV) that that amount represents (similar to other information presented in the website, this DV is calculated for 25-50 year old healthy woman); the nutrient density rating; and, the food's World's Healthiest Foods Rating. Underneath the chart is a table that summarizes how the ratings were devised. Read detailed information on our
Food and Recipe Rating System.

Tomatoes, sliced, raw
1.00 cup
180.00 grams
Calories: 32
GI: very low
NutrientAmountDRI/DV
(%)
Nutrient
Density
World's Healthiest
Foods Rating
vitamin C24.66 mg3318.3excellent
biotin7.20 mcg2413.3excellent
molybdenum9.00 mcg2011.1excellent
vitamin K14.22 mcg168.8excellent
copper0.11 mg126.8very good
potassium426.60 mg126.8very good
manganese0.21 mg115.8very good
fiber2.16 g94.8very good
vitamin A74.97 mcg RAE84.6very good
vitamin B60.14 mg84.6very good
folate27.00 mcg73.8very good
vitamin B31.07 mg73.7very good
vitamin E0.97 mg (ATE)63.6very good
phosphorus43.20 mg63.4very good
vitamin B10.07 mg63.2good
magnesium19.80 mg52.8good
chromium1.26 mcg42.0good
pantothenic acid0.16 mg31.8good
protein1.58 g31.8good
choline12.06 mg31.6good
zinc0.31 mg31.6good
iron0.49 mg31.5good
World's Healthiest
Foods Rating
Rule
excellent DRI/DV>=75% OR
Density>=7.6 AND DRI/DV>=10%
very good DRI/DV>=50% OR
Density>=3.4 AND DRI/DV>=5%
good DRI/DV>=25% OR
Density>=1.5 AND DRI/DV>=2.5%

References

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