Santé de la tomate
La tomate donne saveur et couleur à une multitude de plats. Elle pourrait contribuer à la prévention des maladies cardiovasculaires et de certains cancers, notamment celui de la prostate.
Les bienfaits de la tomate
Cancer de la prostate. Le cancer de la prostate est l’un des cancers les plus souvent diagnostiqués chez les hommes au Canada23. Plusieurs études ont révélé que la consommation fréquente ou régulière de produits dérivés de la tomate pourrait avoir un effet protecteur contre cancer de la prostate24-26. Les composés présents dans les produits à base de tomate augmenteraient la résistance des cellules à l’oxydation et préviendraient ainsi le développement de ce type de cancer31. D’après les résultats d’une méta-analyse, les plus grands consommateurs de tomates et de ses dérivés diminueraient de 10 % à 20 % leur risque de développer le cancer de la prostate comparativement aux hommes qui en consomment peu27. D’autres études n’ont toutefois pas montré des résultats concluants28-30, la prévention du cancer de la prostate par la consommation de tomates s’observerait uniquement chez les personnes les plus à risque de ce type de cancer28.
Autres cancers. Selon une vingtaine d’études35, une consommation élevée de tomates ou d’un antioxydant prépondérant dans la tomate (le lycopène) serait reliée à une plus faible incidence de cancer du poumon36 et de l’estomac37. La consommation de tomates et de lycopène pourrait aussi avoir un effet protecteur sur l’incidence des cancers du pancréas, du côlon, du rectum, de l’oesophage, de la cavité orale, du sein et du col de l’utérus35. D’avantage d’études sont cependant requises pour bien définir le rôle du lycopène dans la prévention de différents types de cancer, de même que celui d’autres composés présents dans la tomate, tels que les caroténoïdes35,38,39.
Maladies cardiovasculaires. Une étude d’envergure menée chez des femmes a démontré que plus celles-ci consommaient de produits à base de tomates, plus elles réduiraient leurs risques de maladies cardiovasculaires40. Les dérivés de la tomate, consommés quotidiennement, diminueraient l’oxydation des lipides dans le sang41-43 (par exemple le cholestérol-LDL ou « mauvais » cholestérol) réduisant ainsi l’incidence de la maladie coronarienne44,45. Selon une autre étude, les extraits de tomates46 ainsi que différents produits à base de tomates43,47 diminueraient l’agrégation plaquettaire et, par conséquent, la formation de caillots sanguins pouvant obstruer les artères. De plus, des concentrations sanguines élevées de lycopène, un composé abondant dans la tomate, seraient associées à une plus faible incidence de maladie cardiovasculaire14. Les résultats de ces études démontrent que la protection cardiovasculaire de la tomate pourrait être assurée non seulement par le lycopène40,48, mais aussi par d’autres composés antioxydants et des vitamines, qui agiraient en synergie.
Que contient la tomate ?
Antioxydants
La tomate contient des antioxydants, principalement des caroténoïdes, dont le plus abondant est le lycopène4, un pigment qui lui donne sa couleur rouge vif11. L’activité antioxydante de la tomate est aussi assurée par différents composés phénoliques5-7. Les composés antioxydants contenus dans les fruits et les légumes protègeraient les cellules du corps des dommages causés par les radicaux libres et préviendraient le développement des maladies cardiovasculaires, de certains cancers et d’autres maladies liées au vieillissement3,51.
Le lycopène se trouve en concentration particulièrement élevée dans les tissus de la prostate. Selon plusieurs études, ce composé contribuerait à prévenir le cancer de la prostate4, d’autant plus que des concentrations élevées de lycopène dans le sang ont été associées à de plus faibles incidences de ce type de cancer15. Par contre, la prise de suppléments de lycopène n’a pas été associée aux mêmes effets dans l’organisme32,33. Les chercheurs supposent que le lycopène ne serait pas l’unique composé responsable de ces effets. Il agirait en synergie avec d’autres composés présents dans la tomate, dont d’autres caroténoïdes26,31.
Les tomates et les produits à base de tomates sont les principales sources de lycopène dans l’alimentation nord-américaine4, fournissant 85 % de ce caroténoïde12. En plus de son importante action antioxydante13, la tomate aurait des effets hypocholestérolémiants et anti-inflammatoires, ainsi que la capacité d’empêcher la prolifération de certains types de cellules cancéreuses13. Même si les données actuelles ne sont pas suffisantes pour recommander un apport quotidien en lycopène, les études indiquent que la consommation de plus de 6 mg de lycopène par jour (environ 2 tomates crues ou ½ verre de jus de tomate) pourrait entraîner des effets bénéfiques16.
Les tomates et les produits dérivés de la tomate contiennent différentes quantités de lycopène selon le processus de transformation qu’ils ont subit (cuisson, broyage, homogénéisation, etc.). La biodisponibilité du lycopène, c’est-à-dire son absorption dans l’organisme, augmente lorsque le lycopène change de structure ou lorsqu’il est libéré des cellules qui le contiennent17,18. La consommation de produits à base de tomates augmente significativement la concentration de lycopène dans le sang19,20. À titre d’exemple, il faudrait consommer de 3 à 13 fois plus de tomates fraîches que de jus ou de pâte de tomates pour augmenter de façon équivalente les concentrations sanguines de lycopène21. Le fait de couper les tomates fraîches en petits morceaux21 et de les consommer avec une source de gras21,22 aurait pour effet d’améliorer l’absorption de ce caroténoïde dans le sang. Il est à noter que la capacité d’absorption du lycopène dans l’organisme diffère d’un individu à l’autre16.
Plus d’antioxydants dans la sauce et la pâte de tomate.
La pelure de la tomate contient davantage d’antioxydants (composés phénoliques, vitamine C et lycopène) que sa chair et ses graines8,9. Comme les produits dérivés de la tomate (telles la pâte ou la sauce tomate) sont plus concentrés, ils contiennent généralement plus de nutriments et de composés antioxydants, tel le lycopène. Par exemple, à poids équivalent, le contenu en antioxydants de la pâte de tomate serait de 3 à 6 fois plus élevé que celui de la tomate fraîche4,10.
Aux États-Unis, la Food and Drug Administration (FDA) a autorisé l’utilisation d’une allégation évoquant les effets potentiels de la consommation de tomates et de la sauce tomate afin de prévenir le cancer de la prostate34. Cette allégation, inscrite sur les étiquettes de certains produits alimentaires, indique que la consommation d’1/2 à 1 tasse (125 à 250 ml) de tomates ou de sauce tomate par semaine pourrait diminuer les risques de cancer de la prostate. Elle doit par contre être accompagnée de la mention suivante : « La FDA conclut qu’il y a peu de preuves scientifiques pour appuyer cette allégation. » Une telle allégation n’est actuellement pas permise au Canada
1. Bazzano LA, Serdula MK, Liu S. Dietary intake of fruits and vegetables and risk of cardiovascular disease. Curr Atheroscler Rep 2003 November;5(6):492-9.
2. Lampe JW. Health effects of vegetables and fruit: assessing mechanisms of action in human experimental studies. Am J Clin Nutr 1999 September;70(3 Suppl):475S-90S.
3. Willcox JK, Ash SL, Catignani GL. Antioxidants and prevention of chronic disease. Crit Rev Food Sci Nutr 2004;44(4):275-95.
4. Khachik F, Carvalho L, et al. Chemistry, distribution, and metabolism of tomato carotenoids and their impact on human health. Exp Biol Med (Maywood ) 2002 November;227(10):845-51.
5. Vinson JA, Hao Y, et al. Phenol antioxidant quantity and quality in foods: vegetables. J Agric Food Chem 1998;46:3630-4.
6. Raffo A, La Malfa G, et al. Seasonal variations in antioxidant components of cherry tomatoes (Lycopersicon esculentum cv. Naomi F1). Journal of food composition and analysis 2006;19:11-9.
7. Takeoka GR, Dao L, et al. Processing effects on lycopene content and antioxidant activity of tomatoes. J Agric Food Chem 2001 August;49(8):3713-7.
8. George B, Kaur C, et al. Antioxidants in tomato (Lycopersium esculentum) as a function of genotype. Food Chemistry 2004;84:45-51.
9. Toor RK, Savage GP. Antioxidant activity in different fractions of tomatoes. Food Research International 2005;38:487-94.
10. Renfroe MH, Brevard PB, Montgomery JR. Antioxidant content varies in fresh and processed tomato products. Journal of the American Dietetic Association 2004;104(suppl.2):A-49.
11. Shi J, Le MM. Lycopene in tomatoes: chemical and physical properties affected by food processing. Crit Rev Biotechnol 2000;20(4):293-334.
12. Barber NJ, Barber J. Lycopene and prostate cancer. Prostate Cancer Prostatic Dis2002;5(1):6-12.
13. Heber D, Lu QY. Overview of mechanisms of action of lycopene. Exp Biol Med (Maywood ) 2002 November;227(10):920-3.
14. Arab L, Steck S. Lycopene and cardiovascular disease. Am J Clin Nutr 2000 June;71(6 Suppl):1691S-5S.
15. Giovannucci E. A review of epidemiologic studies of tomatoes, lycopene, and prostate cancer.Exp Biol Med (Maywood ) 2002 November;227(10):852-9.
16. Porrini M, Riso P. What are typical lycopene intakes?J Nutr 2005 August;135(8):2042S-5S.
17. Gartner C, Stahl W, Sies H. Lycopene is more bioavailable from tomato paste than from fresh tomatoes. Am J Clin Nutr 1997 July;66(1):116-22.
18. Willcox JK, Catignani GL, Lazarus S. Tomatoes and cardiovascular health. Crit Rev Food Sci Nutr 2003;43(1):1-18.
19. Rao AV. Processed tomato products as a source of dietary lycopene: bioavailability and antioxidant properties. Can J Diet Pract Res 2004;65(4):161-5.
20. Rao AV, Agarwal S. Bioavailability and in vivo antioxidant properties of lycopene from tomato products and their possible role in the prevention of cancer. Nutr Cancer 1998;31(3):199-203.
21. Frohlich K, Kaufmann K, et al. Effects of ingestion of tomatoes, tomato juice and tomato puree on contents of lycopene isomers, tocopherols and ascorbic acid in human plasma as well as on lycopene isomer pattern. Br J Nutr 2006 April;95(4):734-41.
22. Unlu NZ, Bohn T, et al. Carotenoid absorption from salad and salsa by humans is enhanced by the addition of avocado or avocado oil. J Nutr 2005 March;135(3):431-6.
23. Centre de prévention et de contrôle des maladies chroniques (CPCMC), Agence de santé publique du Canada. Cancer de la prostate. 2010.
24. Ansari MS, Ansari S. Lycopene and prostate cancer. Future Oncol 2005 June;1(3):425-30.
25. Giovannucci E, Rimm EB, et al. A prospective study of tomato products, lycopene, and prostate cancer risk. J Natl Cancer Inst 2002 March 6;94(5):391-8.
26. Stacewicz-Sapuntzakis M, Bowen PE. Role of lycopene and tomato products in prostate health. Biochim Biophys Acta 2005 May 30;1740(2):202-5.
27. Etminan M, Takkouche B, Caamano-Isorna F. The role of tomato products and lycopene in the prevention of prostate cancer: a meta-analysis of observational studies. Cancer Epidemiol Biomarkers Prev 2004 March;13(3):340-5.
28. Kirsh VA, Mayne ST, et al. A prospective study of lycopene and tomato product intake and risk of prostate cancer. Cancer Epidemiol Biomarkers Prev 2006 January;15(1):92-8.
29. Cohen JH, Kristal AR, Stanford JL. Fruit and vegetable intakes and prostate cancer risk. J Natl Cancer Inst 2000 January 5;92(1):61-8.
30. Hayes RB, Ziegler RG, et al. Dietary factors and risks for prostate cancer among blacks and whites in the United States. Cancer Epidemiol Biomarkers Prev 1999 January;8(1):25-34.
31.Ellinger S, Ellinger J, Stehle P. Tomatoes, tomato products and lycopene in the prevention and treatment of prostate cancer: do we have the evidence from intervention studies?Curr Opin Clin Nutr Metab Care 2006 November;9(6):722-7.
32. Collins AR, Olmedilla B, et al. Serum carotenoids and oxidative DNA damage in human lymphocytes. Carcinogenesis 1998 December;19(12):2159-62.
33. Torbergsen AC, Collins AR. Recovery of human lymphocytes from oxidative DNA damage; the apparent enhancement of DNA repair by carotenoids is probably simply an antioxidant effect. Eur J Nutr 2000 April;39(2):80-5.
34. U.S.Food and Drug Administration. Qualified Health Claims: Letter Regarding Tomatoes and Prostate Cancer (Lycopene Heath Claim Coalition). (Docket No. 2004Q-0201) 2005.
35. Giovannucci E. Tomatoes, tomato-based products, lycopene, and cancer: review of the epidemiologic literature. J Natl Cancer Inst 1999 February 17;91(4):317-31.
36. Arab L, Steck-Scott S, Fleishauer AT. Lycopene and the lung. Exp Biol Med (Maywood ) 2002 November;227(10):894-9.
37. Nouraie M, Pietinen P, et al. Fruits, vegetables, and antioxidants and risk of gastric cancer among male smokers. Cancer Epidemiol Biomarkers Prev 2005 September;14(9):2087-92.
38. Agarwal S, Rao AV. Tomato lycopene and its role in human health and chronic diseases. CMAJ2000 September 19;163(6):739-44.
39. Blum A, Monir M, et al. The beneficial effects of tomatoes. Eur J Intern Med 2005 October;16(6):402-4.
40. Sesso HD, Liu S, et al. Dietary lycopene, tomato-based food products and cardiovascular disease in women. J Nutr 2003 July;133(7):2336-41.
41. Agarwal S, Rao AV. Tomato lycopene and low density lipoprotein oxidation: a human dietary intervention study. Lipids 1998 October;33(10):981-4.
42. Bub A, Watzl B, et al. Moderate intervention with carotenoid-rich vegetable products reduces lipid peroxidation in men. J Nutr 2000 September;130(9):2200-6.
43. Visioli F, Riso P, et al. Protective activity of tomato products on in vivo markers of lipid oxidation.Eur J Nutr 2003 August;42(4):201-6.
44. Witztum JL. The oxidation hypothesis of atherosclerosis. Lancet 1994 September 17;344(8925):793-5.
45. Heller FR, Descamps O, Hondekijn JC. . LDL oxidation: therapeutic perspectives.Atherosclerosis 1998 April;137 Suppl:S25-S31.
46. O'Kennedy N, Crosbie L, et al. Effects of tomato extract on platelet function: a double-blinded crossover study in healthy humans. Am J Clin Nutr 2006 September;84(3):561-9.
47. Lazarus SA, Bowen K, Garg ML. Tomato juice and platelet aggregation in type 2 diabetes.JAMA 2004 August 18;292(7):805-6.
48. Hak AE, Stampfer MJ, et al. Plasma carotenoids and tocopherols and risk of myocardial infarction in a low-risk population of US male physicians. Circulation 2003 August 19;108(7):802-7.
49. Wagner S, Breiteneder H. The latex-fruit syndrome. Biochem Soc Trans 2002 November;30(Pt 6):935-40.
50. Basu A, Imrhan V. Tomatoes versus lycopene in oxidative stress and carcinogenesis: conclusions from clinical trials. Eur J Clin Nutr 2006 August 16.
51. Wojcik M, Burzynska-Pedziwiatr I, Wozniak LA. A Review of Natural and Synthetic Antioxidants Important for Health and Longevity. Curr Med Chem. 2010;17(28):3262-88.
52. He FJ, Nowson CA, et al. Increased consumption of fruit and vegetables is related to a reduced risk of coronary heart disease: meta-analysis of cohort studies. J Hum Hypertens 2007;21:717-28.
53. Soerjomataram I, Oomen D, et al. Increased consumption of fruit and vegetables and future cancer incidence in selected European countries. Eur J Cancer 2010;46:2563-80.
54. Harding AH, Wareham NJ, et al. Plasma vitamin C level, fruit and vegetable consumption, and the risk of new-onset type 2 diabetes mellitus: the European prospective investigation of cancer--Norfolk prospective study. Arch Intern Med 2008;168:1493-9.
Lycopersicon esculentum / Tomato
The tomato is the fruit of the plant Lycopersicon esculentum. (Botanically speaking, tomato is not only a fruit, but also a berry since it is formed from a single ovary.) Originally, tomato was named after the food family to which it belongs - the Solanaceae (sometimes called "solanoid" or "nightshade") family. The botanical name Solanum lycopersicum for tomatoes has now largely been replaced by the name Lycopersicon esculentum. (The genus/species name Lycopersicon esculentum is also sometimes used to refer to tomatoes.)
The French sometimes refer to the tomato as pomme d'amour, meaning "love apple," and in Italy, tomato is sometimes referred to as "pomodoro" or "golden apple," probably referring to tomato varieties that were yellow/orange/tangerine in color.
Regardless of its name, the tomato is a wonderfully popular and versatile food that comes in over a thousand different varieties that vary in shape, size, and color. There are small cherry tomatoes, bright yellow tomatoes, Italian pear-shaped tomatoes, and the green tomato, famous for its fried preparation in Southern American cuisine.
Only the fruits of this plant are eaten since the leaves often contain potentially problematic concentrations of certain alkaloids (see Individual Concerns section below). Tomatoes have fleshy internal segments filled with slippery seeds surrounded by a watery matrix. They can be red, pink, yellow, orange/tangerine, green, purple, brown, or black in color.
Beefsteak and beef master tomatoes are among the largest-sized varieties. Roma tomatoes are more of an intermediate size, while cherry and grape tomatoes are small and rounded. The term "heirloom tomatoes" has become somewhat confusing as it can have a variety of different meanings. In the most traditional sense, "heirloom" refers to seeds from tomato cultivars that get handed down over time from family to family. Obviously, seeds handed down in this way do not make it possible for tomato production on a very large commercial scale. Yet there are definitely "commercial heirloom" tomatoes in the marketplace (sometimes produced from cross-breeding and sometimes produced through open pollination.)
Although tomatoes are fruits in a botanical sense, they don't have the dessert quality sweetness of other fruits. Instead they have a subtle sweetness that is complemented by a slightly bitter and acidic taste. They are prepared and served like other vegetables, which is why they are often categorized as such, including in our A-Z List of the World's Healthiest Foods. Cooking tempers the acid and bitter qualities in tomatoes and brings out their warm, rich sweetness.
History
Although tomatoes are often closely associated with Italian 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." It wasn't until the 1500's that Spanish explorers and colonizers brought tomato seeds from Mexico back to Spain and introduced this food to European populations.
Although the use of tomatoes spread throughout Europe (including Italy) over the course of the 1500's, tomatoes did not enjoy full popularity then and were seen by many people as unfit to eat. Part of this "food inappropriateness" was associated with the status of the tomato plant as a nightshade plant and its potential poisonousness in this regard. (It's true, of course, that tomatoes belong to the Solanaceae or nightshade family of plants, along with potatoes, sweet and hot peppers, eggplant, tomatillos, tamarios, pepinos, pimentos, paprika, and cayenne. It's also true that tomatoes contain alkaloids —substances that even in small doses can be associated with adverse reactions in sensitive individuals. But it's also true that the levels of alkaloids found in nightshade foods are well-tolerated by many individuals in diets worldwide. For more on nightshades, please see our article "What are nightshades and in which foods are they found?")
Today tomatoes are enjoyed worldwide—to the tune of about 130 million tons per year. The largest tomato-producing country is China (with approximately 34 million tons of production), followed by the United States, Turkey, India, and Italy.
In the U.S., cultivation of tomato varieties is usually determined by their final destination: (1) consumption in fresh form by consumers or (2) use in processing by manufacturers of tomato products. Tomato processors need varieties that have a greater proportion of soluble solids in order to make products like tomato paste more efficiently. Between 80-90% of all commercial tomato cultivation in the U.S. is cultivation for eventual use in processing. (Processing tomatoes are needed for the manufacturing of pasta sauces, pizza sauces, and tomato pastes. Both processing and fresh market tomatoes may be used in the production of salsa—although fresh market tomato salsas or homemade salsas—like our Fresh Tomato Salsa—are the salsas that we like best on account of their minimal processing.) California and Florida produce about two-thirds of all commercially grown fresh market tomatoes in the U.S. During the winter months, because Florida tomatoes are generally shipped to other states along the east coast of the U.S., imported Mexican tomatoes make up a high percentage of commercially grown fresh tomatoes along the west coast.
Health Benefits
Tomatoes are a treasure of riches when it comes to their antioxidant benefits. In terms of conventional antioxidants, tomatoes provide an excellent amount of vitamin C and beta-carotene; a very good amount of the mineral manganese; and a good amount of vitamin E. In terms of phytonutrients, tomatoes are basically off the chart, and include:
Flavonones: naringenin,chalconaringenin
Flavonols: rutin, kaempferol, quercetin
Hydroxycinnamic acids: caffeic acidferulic acidcoumaric acid
Carotenoids: lycopeneluteinzeaxanthinbeta-carotene
Glycosides: esculeoside A
Fatty acid derivatives; 9-oxo-octadecadienoic acid
Specific antioxidant nutrients found in tomatoes, whole tomato extracts, and overall dietary intake of tomatoes have all been associated with antioxidant protection. Sometimes this protection comes in the form of reduced lipid peroxidation (oxygen damage to fats in cell membranes or in the bloodstream). Sometimes this protection comes in the form of better antioxidant enzyme function (for example, better function of the enzymes catalase or superoxide dismustase). Better antioxidant protection has also been shown using broad measurements of oxidative stress in different body systems. We've seen studies involving tomato and specific antioxidant protection of the bones, liver, kidneys, and bloodstream.
Cardiovascular Support
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 (and a related group of nutrients) has the ability to help lower the risk of lipid peroxidation in the 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 leads to trouble. Overly damaged fat components sound an alarm to the body's immune and inflammatory systems, and the result is a series of processes 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 and the other called 9-oxo-octadecadienoic acid—are currently under active investigation by researchers as tomato phytonutrients especially important in blood fat regulation.
Yet 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 "antiaggregatory effect.") In combination with the other heart benefits described above, this platelet-regulating impact of tomatoes puts them in a unique position to help us optimize our cardiovascular health.
Supports Bone Health
Bone health is another area of growing interest in tomato research. Interestingly, the connection of tomato intake to bone health involves the rich supply of antioxidant in tomatoes. We don't always think about antioxidant protection as being important for bone health, but it is; and tomato lycopene (and other tomato antioxidants) may have a special role to play in this area. In a recent study, tomato and other dietary sources of lycopene were removed from the diets of postmenopausal women for a period of 4 weeks to see what effect lycopene restriction would have on bone health. At the end of 4 weeks, women in the study started to show increased signs of oxidative stress in their bones and unwanted changes in their bone tissue. We expect to see follow-up studies in this area that will hopefully determine exactly what levels of tomato intake are most helpful in protecting bone tissue.
Anti-Cancer
While not well researched for all cancer types, tomatoes have repeatedly been show to provide us with anti-cancer benefits. The track record for tomatoes as a cancer-protective food should not be surprising, since there is a very large amount of research on tomato antioxidants and a more limited but still important amount of research on tomato anti-inflammatory nutrients. Risk for many cancer types starts out with chronic oxidative stress and chronic unwanted inflammation. For this reason, foods that provide us with strong antioxidant and anti-inflammatory support are often foods that show cancer prevention properties.
Prostate cancer is by far the best-researched type of cancer in relationship to tomato intake. The jury verdict here is clear: tomatoes can definitely help lower risk of prostate cancer in men. One key tomato nutrient that has received special focus in prostate cancer prevention is alpha-tomatine. Alpha-tomatine is a saponin phytonutrient and it's shown the ability to alter metabolic activity in developing prostate cancer cells. It's 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 are the two best-studied areas involving tomatoes and cancer risk. Research on tomatoes and breast cancer risk has largely focused on the carotenoid lycopene, and there is fairly well documented risk reduction for breast cancer in association with lycopene intake.
Other Health Benefits
While not as thoroughly researched as these other areas of antioxidant support, cardiovascular support, and anti-cancer benefits, several other health benefit areas are important to mention with respect to tomatoes. Diets that include tomatoes have been linked with reduced risk of some neurological diseases (including Alzheimer's disease) in multiple studies. Tomato-containing diets have also been linked in a few studies with reduced risk of obesity.
References
Aldrich HT, Salandanan K, Kendall P et al. Cultivar choice provides options for local production of organic and conventionally produced tomatoes with higher quality and antioxidant content. J Sci Food Agric. 2010 Dec;90(15):2548-55. 2010.
Anthon GE, LeStrange M, and Barrett DM. Changes in pH, acids, sugars and other quality parameters during extended vine holding of ripe processing tomatoes. J Sci Food Agric. 2011 May;91(7):1175-81. 2011.
Bai Y and Lindhout P. Domestication and Breeding of Tomatoes: What have We Gained and What Can We Gain in the Future? . Ann Bot. 2007 October; 100(5): 1085-1094. Published online 2007 August 23. 2007.
Borguini RG and Torres EAFDS. Tomatoes and Tomato Products as Dietary Sources of Antioxidants. Food Reviews International. Philadelphia: 2009. Vol. 25, Iss. 4; p. 313-325. 2009.
Cao XL, Corriveau J, and Popovic S. Bisphenol A in Canned Food Products from Canadian Markets. Journal of Food Protection. Des Moines: Jun 2010. Vol. 73, Iss. 6; p. 1085-1089. 2010.
Dilis B and Trichopoulou A. Antioxidant Intakes and Food Sources in Greek Adults. The Journal of Nutrition. Bethesda: Jul 2010. Vol. 140, Iss. 7; p. 1274-1279. 2010.
Dogukan A, Tuzcu M, Agca CA et al. A tomato lycopene complex protects the kidney from cisplatin-induced injury via affecting oxidative stress as well as Bax, Bcl-2, and HSPs expression. Nutr Cancer. 2011;63(3):427-34. 2011.
Etminan M, Takkouche B, and Caamano-Isorna F. The role of tomato products and lycopene in the prevention of prostate cancer: a meta-analysis of observational studies. Cancer Epidemiol Biomarkers Prev. 2004 Mar;13(3):340-5. 2004. 2004.
Friedman M, Levin CE, Lee SU et al. Tomatine-containing green tomato extracts inhibit growth of human breast, colon, liver, and stomach cancer cells. J Agric Food Chem. 2009 Jul 8;57(13):5727-33. 2009.
Gonzali S, Mazzucato A, and Perata P. Purple as a tomato: towards high anthocyanin tomatoes. Trends Plant Sci. 2009 May;14(5):237-41. Epub 2009 Apr 8. 2009.
Herbette S, de Labrouhe DT, Drevet JR et al. Transgenic tomatoes showing higher glutathione peroxydase antioxidant activity are more resistant to an abiotic stress but more susceptible to biotic stresses. lant Sci. 2011 Mar;180(3):548-53. Epub 2010 Dec 14. 2011.
Ishida BK, Chapman MH. A comparison of carotenoid content and total antioxidant activity in catsup from several commercial sources in the United States. J Agric Food Chem. 2004 Dec 29;52(26):8017-20. 2004. PMID:15612790.
Jacob K, Garcia-Alonso FJ, Ros G et al. Stability of carotenoids, phenolic compounds, ascorbic acid and antioxidant capacity of tomatoes during thermal processing. Arch Latinoam Nutr. 2010 Jun;60(2):192-8. 2010.
Kim YI, Takahashi H, Goto T et al. 9-oxo-10(E),12(E)-octadecadienoic acid derived from tomato is a potent PPAR agonist to decrease triglyceride accumulation in mouse primary hepatocytes. Molecular Nutrition & Food Research, 2010; DOI: 10.1002/mnfr.201000264. 2010.
Lazarus SA, Bowen K, Garg ML. Tomato juice and platelet aggregation in type 2 diabetes. JAMA. 2004 Aug 18;292(7):805-6. 2004. PMID:15315994.
Lee ST, Wong PF, Cheah SC et al. Alpha-tomatine induces apoptosis and inhibits nuclear factor-kappa B activation on human prostatic adenocarcinoma PC-3 cells. PLoS One. 2011 Apr 26;6(4):e18915. 2011.
Lippi G and Targher G. Tomatoes, lycopene-containing foods and cancer risk. Br J Cancer. 2011 Mar 29;104(7):1234-5. Epub 2011 Feb 22. 2011.
Mackinnon ES, Rao AV, and Rao LG. Dietary restriction of lycopene for a period of one month resulted in significantly increased biomarkers of oxidative stress and bone resorption in postmenopausal women. J Nutr Health Aging. 2011 Feb;15(2):133-8. 2011.
Mathieu S, Dal Cin V, Fei Z et al. Flavour compounds in tomato fruits: identification of loci and potential pathways affecting volatile composition. J Exp Bot. 2009 January; 60(1): 325–337. Published online 2008 December 16. 2009.
Moneruzzaman KM, Hossain ABMS, Sani W et al. Effect of Stages of Maturity and Ripening Conditions on the Biochemical Characteristics of Tomato. American Journal of Biochemistry and Biotechnology Year: 2008 Vol: 4 Issue: 4 Pages/record No.: 336-344. 2008.
Nohara T, Ono M, Ikeda T et al. The Tomato Saponin, Esculeoside A. J Nat Prod. 2010 Sep 20. [Epub ahead of print]. 2010.
Palozza P, Parrone N, Catalano A et al. Tomato lycopene and inflammatory cascade: basic interactions and clinical implications. Curr Med Chem. 2010;17(23):2547-63. 2010.
Reboul E, Borel P, Mikail C et al. Enrichment of Tomato Paste with 6% Tomato Peel Increases Lycopene and {beta}-Carotene Bioavailability in Men. J Nutr. 2005 Apr;135(4):790-4 2005. 2005.
Salem S, Salahi M, Mohseni M et al. Major dietary factors and prostate cancer risk: a prospective multicenter case-control study. Nutr Cancer. 2011;63(1):21-7. 2011.
Sesso HD, Liu S, Gaziano JM et al. Dietary lycopene, tomato-based food products and cardiovascular disease in women. J Nutr Jul;133(7): 2336-41. 2003. 2003.
Shieh JM, Cheng TH, Shi MD et al. a-Tomatine suppresses invasion and migration of human non-small cell lung cancer NCI-H460 cells through inactivating FAK/PI3K/Akt signaling pathway and reducing binding activity of NF-kB. Cell Biochem Biophys. 2011 Jul;60(3):297-310. 2011.
Silaste ML, Alfthan G, Aro A, et al. Tomato juice decreases LDL cholesterol levels and increases LDL resistance to oxidation. Br J Nutr. 2007 Dec;98(6):1251-8. 2007. PMID:17617941.
Slimestad R and Verheul M. Properties of chalconaringenin and rutin isolated from cherry tomatoes. J Agric Food Chem. 2011 Apr 13;59(7):3180-5. Epub 2011 Mar 4. 2011.
Talvas J, Caris-Veyrat C, Guy L et al. Differential effects of lycopene consumed in tomato paste and lycopene in the form of a purified extract on target genes of cancer prostatic cells. Am J Clin Nutr. 2010 Jun;91(6):1716-24. Epub 2010 Apr 14. 2010.
Tan HL, Thomas-Ahner JM, Grainger EM et al. Tomato-based food products for prostate cancer prevention: what have we learned? . Cancer Metastasis Rev. 2010 Sep;29(3):553-68. 2010.
Torres-Urrutia C, Guzman L, Schmeda-Hirschmann G et al. Antiplatelet, anticoagulant, and fibrinolytic activity in vitro of extracts from selected fruits and vegetables. Blood Coagul Fibrinolysis. 2011 Apr;22(3):197-205. 2011.
Visioli F, Riso P, Grande S et al. Protective activity of tomato products on in vivo markers of lipid oxidation. Eur J Nutr. 2003;42(4):201-6. 2003.
Willcox JK, Catignani GL, Lazarus S. Tomatoes and cardiovascular health. Crit Rev Food Sci Nutr 2003;43(1):1-18. 2003.
Wood M. Tangerine Tomatoes Top Reds in Preliminary Lycopene Study. Agricultural Research. Washington: Feb 2011. Vol. 59, Iss. 2; p. 15. 2011.