A tomato is a berry in botany and a vegetable in United States law. In 1893 the Supreme Court ruled in Nix v. Hedden that tomatoes are vegetables for tariff purposes.
Its reason was that in everyday speech they are served with the main meal, not as dessert. The court still accepted that botanically they are fruit.
Tomatoes are the best-known source of lycopene, the red pigment, and how you eat them changes how much of it you absorb. Raw tomatoes have about 2.6 mg of lycopene per 100 g.
In one trial, lycopene was absorbed 3.8 times better from tomato paste than from fresh tomatoes. In another, cooking diced tomatoes with olive oil raised blood trans-lycopene by 82%, against no clear change without oil.
Tomatoes have an approved EU health claim, but it covers a lycopene-free, water-soluble tomato extract, not the fruit. The claim is about normal platelet aggregation, the clumping of blood cells called platelets. For eating tomatoes against prostate cancer, the FDA (the US Food and Drug Administration) reviewed the evidence and found it very limited.
Health benefits of tomatoes
The top findings from 30 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★★Less platelet clumping with a tomato extractA water-soluble tomato extract, not whole tomatoes, lowered platelet clumping by 8 to 25% against placebo 3 hours after a dose. The EU approved a health claim for the extract, which covers platelet function, not heart attacks.
- ★★Mixed results for cholesterol and artery functionA review of 21 trials (foods and supplements mixed) found LDL cholesterol 0.22 mmol/L lower and better artery function. A larger review of 34 trials of tomato and lycopene found no clear change in cholesterol or blood pressure.
- ★★No clear effect on PSA, a prostate markerIn 6 trials of lycopene supplements or tomato extracts, PSA, a blood marker used to check the prostate, did not clearly change.
- ★More lycopene absorbed from cooked tomatoes with oilTomatoes cooked in olive oil raised blood trans-lycopene by 82%, while oil-free tomatoes did not clearly change it. In another study, tomato paste gave higher lycopene absorption than fresh tomatoes.
- ★Less UV skin redness in small trialsTomato paste with olive oil cut UV-induced skin redness by 40% after 10 weeks in 19 volunteers, compared with olive oil alone. In 20 women, paste raised the UV dose needed for redness (36.6 mJ/cm² against 23 on oil alone), but sunburn testing did not clearly differ.
All 30 studies, strongest evidence first
Lycopene-free tomato extract earned an EU health claim on platelet aggregation
The European Food Safety Authority’s panel reviewed eight human studies, seven of them the applicant’s own, and judged that cause and effect was established. In a double-blind trial, aggregation fell 8 to 25% against placebo (a dummy product) 3 hours after 3 g or 9 g of the concentrate. The approved amount is 3 g of one form or 150 mg of another a day, studied in healthy adults aged 35 to 70. The European Commission authorized it in December 2009; it covers the extract, not eating tomatoes, and platelet function, not heart attacks.
Tomato extract lowered platelet aggregation up to 21% after a single dose
This randomized, double-blind, placebo-controlled crossover trial included 90 healthy adults, using doses equal to the extract of 2 or 6 tomatoes. Three hours after the dose, with a low dose of the ADP trigger, aggregation fell 12.7% and 21.3%, and with collagen 14.6% and 17.5%. The effect was largest in people with high homocysteine or CRP (an inflammation marker). It tested a water-soluble extract, not whole tomatoes.
Tomato trials lowered LDL by 0.22 mmol/L and improved artery function
This meta-analysis pooled 21 intervention trials in adults. Interleukin-6, an inflammation marker, fell, and flow-mediated dilation, a test of artery function, rose 2.53%. Lycopene supplements lowered systolic blood pressure by 5.66 mm Hg. Other outcomes, including HDL and CRP, did not clearly change, and the pooled trials mix foods with supplements.
Larger review: tomato and lycopene left cholesterol, blood pressure, sugar unchanged
This 2023 meta-analysis pooled 34 randomized trials of lycopene and tomato intake. Only malondialdehyde, a marker of oxidative stress, fell, and that was with lycopene supplements. LDL, HDL, triglycerides, blood pressure, CRP and body weight showed no clear change. It disagrees with the 2017 analysis above, and the authors call for longer trials at different doses.
Lycopene or tomato extract did not change PSA in 6 randomized trials
This meta-analysis pooled 6 randomized trials (9 were in the full review) of lycopene supplements or tomato extracts. PSA is a blood marker used to check the prostate. The pooled difference was −0.12 ng/mL, which could be chance. The authors say larger, more consistent trials are needed.
Tomatoes cooked in olive oil raised blood trans-lycopene 82%, unlike oil-free
In this study, 23 healthy adults ate one meal a day of 470 g of diced tomatoes for 5 days. The tomatoes were cooked with 25 mL of extra virgin olive oil (11 people) or without it (12 people). Without oil, trans-lycopene did not clearly change; cis-lycopene rose 40% with oil and 15% without. It was small and short, and it measured blood levels, not health effects.
Tomato paste gave 3.8 times better lycopene absorption than fresh tomatoes
In this single-dose study, people ate fresh tomatoes or tomato paste, each giving 23 mg of lycopene, with 15 g of corn oil. Peak lycopene in chylomicrons, the particles that carry fat from a meal into the blood, was 2.5 times higher after paste. Alpha- and beta-carotene showed no difference. The abstract does not give the number of volunteers.
Finely crushing canned tomatoes raised lycopene absorption by breaking the cell structure
In this trial, 33 men and women ate canned tomatoes for 4 days, at about 22 mg of lycopene a day. The tomatoes had minimal or extra heating (1 hour at 100°C) and were not, mildly or severely homogenized (crushed). The absorption curve measured 54.9, 72.0 and 88.7 nmol·h/L for the three crushing levels. Extra heating tended to help but could be chance, and it measured absorption, not health.
Oil in tomato juice raised all blood lycopene forms and lowered LDL
In this randomized crossover trial, 11 healthy volunteers drank unheated tomato juice with 10% refined olive oil, or without oil, on two days. Lycopene peaked at 24 hours. LDL and total cholesterol fell 6 hours after the juice with oil, and the drops tracked the rise in two lycopene forms. It was a single dose in a small group.
Fat-free dressing gave almost no carotenoid absorption from cherry tomato salad
In this crossover study, 7 people ate salads of spinach, romaine, cherry tomatoes and carrots. The dressings held 0, 6 or 28 g of canola oil. Carotenoids, lycopene included, appeared in the blood fat fraction only negligibly with fat-free dressing, more with reduced-fat and most with full-fat. It was a small group, and the salad held four vegetables, not tomato alone.
Avocado in tomato salsa raised lycopene absorption 4.4 times
In this crossover study, 11 healthy adults ate tomato salsa with or without 150 g of avocado; beta-carotene absorption also rose 2.6 times. In a second 11-person study of salad, 24 g of avocado oil worked as well as the fruit. That points to the fat as the active part. Absorption was followed for 9.5 hours after one meal.
Tomato paste protected skin from UV better than olive oil alone
In this randomized trial, 20 fair-skinned healthy women ate 55 g of tomato paste (16 mg of lycopene) in olive oil daily for 12 weeks. The UV dose needed for a set level of redness rose to 36.6 mJ/cm² with paste, against 23 with oil alone. The standard sunburn test (minimal erythema dose) did not clearly differ. Skin samples showed less UV-induced MMP-1, an enzyme that breaks down collagen, and less mitochondrial DNA damage.
Tomato paste with olive oil cut UV-induced skin redness by 40%
In this controlled study of 19 volunteers, 9 ate 40 g of tomato paste with 10 g of olive oil for 10 weeks. The paste gave about 16 mg of lycopene a day, and the other 10 ate olive oil alone. The difference showed clearly at week 10 but not at week 4. It was small, and redness was measured after a solar simulator.
Tomato extract suppressed platelets about one-third as much as daily aspirin
This double-blind crossover trial in 47 healthy adults compared Fruitflow, a water-soluble tomato extract, with 75 mg of aspirin. A single aspirin dose roughly matched one extract dose, but daily aspirin was about three times as effective after 7 days. Clotting times did not change, and the extract and aspirin together were not clearly additive. Several authors worked for Provexis, which sponsored the trial.
Lycopene-rich tomato juice improved artery function in adults with borderline readings
In this randomized, double-blind, placebo-controlled trial, 75 healthy adults whose flow-mediated dilation was 4 to 7% drank the juice for 12 weeks. Juice with 15.0 or 26.7 mg of lycopene brought it to 6.1% and 7.0%, against 5.4% on placebo juice. Oxidative stress markers did not differ, and the authors say the mechanism is unclear.
Tomato products did not lower PSA overall before prostate cancer treatment
This randomized trial in 79 men lasted three weeks. It compared tomato products with 30 mg of lycopene a day, tomato products plus selenium, omega-3, soy, juices and tea, and a control diet. In an exploratory analysis of 41 intermediate-risk men, median PSA fell 2.9% on tomato and rose 6.5% on control. This was a post-hoc finding, looked for after the fact, that needs its own trial.
30 mg of lycopene daily did not change markers of oxidative damage
This double-blind, placebo-controlled trial ran for 21 days in 105 African American veterans due for a prostate biopsy. Of them, 47 had cancer and 58 benign enlargement. Lycopene rose in blood from 0.74 to 1.43 µmol/L and in prostate tissue from 0.45 to 0.59 pmol/mg. It used a tomato oleoresin supplement, not tomatoes.
Tomato supplement brought a PSA response in only 1 of 46 men
This phase II study, an early test of whether a treatment works, had no control group. The men had advanced prostate cancer that kept growing despite hormone treatment, and took 15 mg of lycopene twice a day. It was well tolerated, with mild diarrhea in 18 men and nausea in 12. The authors conclude it did not appear effective in this setting.
Top tomato eaters had 19% lower prostate cancer risk; not raw alone
This meta-analysis pooled 30 studies with 24,222 cases among 260,461 people. Cooked tomatoes and sauces went with a 16% lower risk, while raw tomatoes did not (risk ratio 0.96, which could be chance). The studies are observational, and the authors say the reasons are still unknown.
Frequent tomato sauce went with 23% lower prostate cancer risk
The Health Professionals Follow-up Study tracked 47,365 men, of whom 2,481 developed prostate cancer between 1986 and 1998. Frequent meant tomato sauce twice a week or more, against less than once a month. The highest fifth of lycopene intake had a 16% lower risk. The links held after adjusting for fruit and vegetable intake and olive oil use.
Lycopene and tomato products were not linked to prostate cancer risk
This large US screening trial (Prostate, Lung, Colorectal and Ovarian) followed 29,361 men for about 4.2 years, with 1,338 cases. Pizza and spaghetti sauce showed lower risks that could be chance. Among men with a family history of prostate cancer, higher lycopene went with lower risk, which the authors say needs confirmation.
FDA: only very limited evidence tomatoes may lower prostate cancer risk
This is the FDA’s account of its review of two 2004 petitions. It found no credible evidence that lycopene lowers the risk of prostate, lung, colorectal, gastric, breast, ovarian, endometrial or pancreatic cancer. For tomatoes, it found very limited evidence against prostate, ovarian, gastric and pancreatic cancers. In a November 8, 2005 letter, the FDA would consider not objecting only to a heavily qualified tomato or tomato sauce claim on prostate cancer.
Higher lycopene went with 5% lower overall cancer risk; blood levels, 11%
This meta-analysis of prospective cohorts had 121 studies in the review and 119 in the analysis, with 108,574 cancer cases over 2 to 32 years. Total tomato intake went with 11% lower cancer mortality. For prostate cancer, dietary lycopene showed only a borderline link (risk ratio 0.99).
Mostly weak evidence links tomatoes to less death, prostate and stomach cancer
This umbrella review, a review of reviews, covered 17 meta-analyses and systematic reviews and 20 health outcomes. Lycopene intake or blood levels were also linked to lower risk of stroke, cardiovascular disease, metabolic syndrome and male infertility. By GRADE, a standard rating system, most of the evidence was low or very low quality, with moderate quality for six links. The authors also flag allergy as a caution.
Finnish men with most blood lycopene had 55% lower stroke risk
This cohort followed 1,031 Finnish men aged 46 to 65 for a median 12.1 years, with 67 strokes. The highest blood lycopene group was compared with the lowest, and its risk of ischemic stroke (from a blocked artery) was 59% lower. Alpha-carotene, beta-carotene, alpha-tocopherol and retinol were not linked. Blood lycopene is a marker of tomato intake, the number of strokes was small, and a link is not proof of cause.
Frequent tomato products went with 32% lower cardiovascular risk in women
The Women’s Health Study followed 39,876 women for 7.2 years, with 719 cardiovascular events. Frequent here means 7 to under 10 servings a week of tomato products. Lycopene intake groups showed no clear trend, and tomato sauce and pizza twice a week or more showed lower risks that could be chance. The authors suggest oil-based tomato products may matter.
Most raw tomatoes or ketchup: 5 to 7% lower death risk
This analysis used data from the US PLCO screening trial: 24,141 deaths over about 1.67 million person-years of follow-up. Cardiovascular deaths were also lower with ketchup (0.92 times the risk). Raw tomato and ketchup were not linked to cancer deaths. The authors call the results preliminary.
After diagnosis, lycopene and tomatoes were not linked to prostate cancer death
Cancer Prevention Study II included 8,898 men with nonmetastatic (not yet spread) cancer and diet data from before diagnosis (526 prostate cancer deaths). Another 5,643 had diet data from after diagnosis (363 deaths). The highest against the lowest quarter of lycopene gave 1.00 times the risk before and 1.22 times after diagnosis. A lower risk in high-risk cancers rested on ten deaths, and the authors ask for confirmation.
Heating tomatoes raised measured lycopene and antioxidant activity; vitamin C fell
This lab study heated tomatoes at 88°C for 2, 15 and 30 minutes. After 30 minutes, trans-lycopene was 5.32 mg/g against 2.01 raw, and antioxidant activity 6.70 against 4.13 µmol vitamin C equivalents per gram. Vitamin C was 0.54 against 0.76 µmol/g, and phenolics and flavonoids did not change. This is lab chemistry, not a study in people.
Chilling below 12°C cut tomato flavor compounds; some did not recover
This lab study chilled tomatoes. Lower levels of specific aroma compounds tracked lower activity of the genes that make them. Some genes stayed low after the fruit returned to 20°C. It concerns taste, not nutrition.
Who should be careful with tomatoes
Most people can eat tomatoes freely. Take a little care if one of these applies:
- Grass pollen allergy. People with grass pollen allergy can get an itchy mouth and throat from raw tomatoes, a pollen-related food allergy. A review notes that the reaction usually comes with the raw food, not the cooked one. It also notes that 1 to 2% of people with this syndrome have severe reactions.
- Kidney disease. The National Kidney Foundation lists tomatoes and tomato products among the higher-potassium vegetables. A medium tomato (123 g) has 292 mg. If your potassium runs high, ask your care team how much fits.
- Acid reflux. The NIDDK, a US government health institute, lists tomatoes among acidic foods commonly linked to reflux symptoms. The link is individual, so if tomato sauce triggers your heartburn, talk with your doctor about cutting back. No study here tested it.
How to choose, store and eat tomatoes
- Cooked with oil: in 23 healthy adults, diced tomatoes cooked with olive oil raised blood trans-lycopene 82%, with no clear change without oil.
- Paste and sauce: lycopene was absorbed 3.8 times better from paste than from fresh tomatoes. In a lab test, heating tomatoes at 88°C for 30 minutes cut vitamin C from 0.76 to 0.54 µmol/g.
- Raw with some fat: with fat-free dressing, 7 people absorbed almost no carotenoids from a salad with cherry tomatoes. Adding 150 g of avocado raised salsa lycopene absorption 4.4 times.
Choose tomatoes with smooth skin and no blemishes that feel firm and give slightly when pressed. Keep ripe ones at room temperature, out of direct sun, for up to a week. Keep them out of the cold: in lab tests, chilling below 12°C (54°F) cut flavor compounds and some did not recover. So refrigerate only cut or overripe tomatoes.
Residues are no reason to skip tomatoes. In USDA (US Department of Agriculture) tests of 708 samples in 2023, only 4 had a residue above the legal limit.
Sources
- Muluk NB, Cingi C. Oral allergy syndrome. Am J Rhinol Allergy. 2018.
- Potassium and your CKD diet. National Kidney Foundation.
- Eating, diet, and nutrition for GER and GERD. National Institute of Diabetes and Digestive and Kidney Diseases.
- Tomatoes. University of Nebraska–Lincoln Extension.
- Fielding JM, Rowley KG, Cooper P, O’Dea K. Increases in plasma lycopene concentration after consumption of tomatoes cooked with olive oil. Asia Pac J Clin Nutr. 2005.
- Gärtner C, Stahl W, Sies H. Lycopene is more bioavailable from tomato paste than from fresh tomatoes. Am J Clin Nutr. 1997.
- Dewanto V, Wu X, Adom KK, Liu RH. Thermal processing enhances the nutritional value of tomatoes by increasing total antioxidant activity. J Agric Food Chem. 2002.
- Brown MJ, Ferruzzi MG, Nguyen ML, et al. Carotenoid bioavailability is higher from salads ingested with full-fat than with fat-reduced salad dressings as measured with electrochemical detection. Am J Clin Nutr. 2004.
- Unlu NZ, Bohn T, Clinton SK, Schwartz SJ. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil. J Nutr. 2005.
- Zhang B, Tieman DM, Jiao C, et al. Chilling-induced tomato flavor loss is associated with altered volatile synthesis and transient changes in DNA methylation. Proc Natl Acad Sci U S A. 2016.
- Pesticide Data Program annual summary, calendar year 2023. USDA Agricultural Marketing Service.
History of tomatoes
The tomato began in western South America. Its likely wild ancestor, Solanum pimpinellifolium, grows in Chile, Peru and Ecuador. By 500 BCE, tomatoes were already cultivated in southern Mexico.
A 2020 genome study found the story was more tangled than a single move north. Partly domesticated tomatoes in South America lost some typical traits as they spread, and these were selected again later. The English word comes from the Spanish tomate, from the Nahuatl tomatl.
Tomatoes reached Europe in the 16th century, after the Spanish took Tenochtitlan in 1521. Pietro Andrea Mattioli’s 1544 herbal is the earliest mention in European writing. About ten years later he called the fruit pomi d’oro, golden apples.
Europeans grew them for show at first. Tomatoes belong to the nightshade family, and people assumed they were poisonous. John Gerard’s 1597 Herbal helped spread that view, though he knew they were eaten in Spain and Italy.
In Florence they were table decoration until the late 17th or early 18th century. The earliest known cookbook with tomato recipes was published in Naples in 1692.
In British North America the first mention dates from 1710, in South Carolina. Breeding for the market followed, with Alexander Livingston introducing the Paragon in 1870 and the Acme in 1875.
The fruit-or-vegetable question reached court because of a tax. Under the Tariff Act of 1883, imported vegetables were taxed and fruit was not. The Nix family imported tomatoes from the West Indies in 1886, paid the duty under protest and sued the New York customs collector, Edward Hedden. On May 10, 1893, the Supreme Court sided with Hedden.
A century later tomatoes made food history again. After the FDA finished its review on May 18, 1994, the Flavr Savr became the first commercially available genetically modified food. The company Calgene had made it to resist softening. It stayed on the market only until 1997.
Sources
- Bergougnoux V. The history of tomato: from domestication to biopharming. Biotechnol Adv. 2014.
- Razifard H, Ramos A, Della Valle AL, et al. Genomic evidence for complex domestication history of the cultivated tomato in Latin America. Mol Biol Evol. 2020.
- Tomato. Wikipedia.
- Flavr Savr. Wikipedia.
- Nix v. Hedden, 149 U.S. 304 (1893). Legal Information Institute, Cornell Law School.
- Nix v. Hedden. Wikipedia.
Frequently asked questions about tomatoes
Are tomatoes good for you?
For most people, yes. Raw tomatoes have 18 calories, 13.7 mg of vitamin C (15% of the Daily Value) and 237 mg of potassium per 100 g.
In a large US cohort, people who ate the most raw tomatoes had a 5% lower risk of dying. That is a link, not proof, and trials of tomato and lycopene on heart risk factors disagree.
Are cooked tomatoes healthier than raw?
Neither is simply better. In a lab test, heating tomatoes at 88°C for 30 minutes raised measured lycopene from 2.01 to 5.32 mg/g. It also cut vitamin C from 0.76 to 0.54 µmol/g.
Lycopene was absorbed 3.8 times better from paste than from fresh tomatoes, and olive oil raised blood trans-lycopene 82%. For prostate cancer, cooked tomatoes and sauces went with a 16% lower risk and raw tomatoes with no link.
Is a tomato a fruit or a vegetable?
Both: botanically it is a fruit, the berry of the plant. In 1893 the US Supreme Court ruled in Nix v. Hedden that it is a vegetable for tariff purposes. The reason: in everyday speech it is served with the main meal, not as dessert.
Do tomatoes help prevent prostate cancer?
Nobody has shown that. Cooked tomatoes and sauces went with a 16% lower risk in a meta-analysis of 30 studies. But a US study of 29,361 men found no link.
The FDA found only very limited evidence for tomatoes and none for lycopene itself. In 6 randomized trials, lycopene or tomato extract did not change PSA.
How many calories and carbs are in a tomato?
A medium tomato (123 g) has 22 calories, 4.8 g of carbohydrate with 1.5 g of fiber (3.3 g net), and 1.1 g of protein. It also gives 16.9 mg of vitamin C, 19% of the Daily Value. Per 100 g it is 18 calories and 94.5 g of water.
Should you keep tomatoes in the fridge?
Not while they ripen. University of Nebraska–Lincoln Extension advises keeping ripe tomatoes at room temperature, out of direct sun, for up to a week. It advises refrigerating only overripe or cut ones. In lab tests, chilling below 12°C cut flavor compounds, and some did not recover after rewarming.
Do tomatoes cause acid reflux?
They can for some people, and no study here tested it. The NIDDK lists tomatoes among acidic foods commonly linked to reflux symptoms. It says to talk with your doctor about foods that seem to make yours worse. If tomato sauce is your trigger, try smaller portions.
Do tomatoes protect your skin from the sun?
A little, in two small trials, and they do not replace sunscreen. Eating 40 g of tomato paste with olive oil for 10 weeks cut UV-induced redness by 40% in 19 volunteers.
In 20 women, 55 g for 12 weeks raised the UV dose needed to redden skin. The standard sunburn test did not clearly differ in that second trial.