Fruits and vegetables are generally associated with a reduced risk of cancer, but tomatoes appear to be especially good at fighting the disease.
In one of the biggest studies so far, Harvard researchers found that men who ate lots of tomatoes and tomato products (such as tomato sauce and pizza) reduced their risk of prostate cancer by 35 per cent. As for aggressive forms of prostate cancer, high tomato intakes cut the risk by more than half (J Natl Cancer Inst, 1995; 87: 1767-76).
Other studies have had similar findings (Int J Cancer, 2005; 113: 1010-4; Exp Biol Med [Maywood], 2002; 227: 852-9), with benefits for women, too. In one study of Brazilian women, those who regularly ate these fruit were significantly less likely to have breast cancer (Nutr Hosp, 2007; 22: 565-72). In the US, women who consumed lots of cooked tomatoes reduced their risk of multiple myeloma (bone-marrow cancer)(Cancer Causes Control, 2007; 18: 1065-76), while both male and female tomato eaters can slash their risk of renal cell carcinoma (a type of kidney cancer) by up to
50 per cent (J Am Diet Assoc, 2009; 109: 656-67).
Although these findings don't prove that tomatoes prevent cancer, scientists suspect that lycopene, a potent antioxidant found in the fruit, is responsible for the anti-cancer effect. Indeed, a Finnish study found a strong link between blood lycopene levels and overall cancer rates in men (Ann Epidemiol, 2009; 19: 512-8). Lycopene has proved able to reduce the risk of prostate, lung, blood and gastrointestinal tract cancers (Molecules, 2010; 15: 959-87).
As a cancer treatment, lycopene could be a comple-mentary therapy for high-grade tumours (gliomas) of the brain or spine (Neurol India, 2010; 58: 20-3). Most research, however, is on prostate cancer-and the evidence is mixed. Still, one review found that six out of eight studies showed that the higher the lycopene intake, the lower the levels of prostate-specific antigen (PSA), a diagnostic marker of prostate cancer. The evidence also suggested that lycopene can delay prostate cancer progression, and reduce symptoms such as pain and urinary tract problems (Prostate Cancer Prostatic Dis, 2009; 12: 325-32).
Animal studies show that lycopene on its own may not be as effective as eating the tomatoes whole, suggesting that these fruit contain other anti-cancer compounds besides lycopene (J Natl Cancer Inst, 2003; 95: 1578-86).
Prevent heart disease
Tomatoes may also help to prevent heart disease, the world's number-one killer disease. In a study of nearly 40,000 women, those who ate the most tomato-based products had a 30-per-cent lower risk of heart disease and a 60-per-cent reduced risk of heart attack (J Nutr, 2003; 133: 2336-41). Another study in women showed a link between blood lycopene and heart disease risk: the higher the levels, the lower the risk (Arch Latinoam Nutr, 2009; 59: 120-7). In men, Finnish researchers found an inverse relationship between blood lycopene and atherosclerosis (plaque buildup in the arteries) (Am J Clin Nutr, 2003; 77: 133-8).
There's even evidence that tomatoes might be thera-peutic against heart disease, as short-term treatment with lycopene-rich tomato extract was found to reduce blood pressure in patients with hypertension (Cardiovasc Drugs Ther, 2009; 23: 145-51; Am Heart J, 2006; 151: 100).
Also, a study in Taiwan gave participants either fresh tomatoes, tomato juice or a lycopene drink (all delivering around 40 mg of lycopene/day) for six weeks. On measur-ing the subjects' blood lipids, they found that triglyceride levels and LDL ('bad') cholesterol were both decreased, whereas HDL ('good') cholesterol levels increased in those who consumed the fresh tomatoes and tomato juice. Surprisingly, no significant differences were observed in those who consumed the lycopene drink, again suggesting the importance of eating the whole fruit rather than taking lycopene as a dietary supplement (J Agric Food Chem, 2007; 55: 6475-81).
Other possible benefits
Another benefit of eating tomatoes is that they appear to offer natural protection against skin damage from the sun. In one German study, nine healthy volunteers consumed 40 g of tomato paste (containing about 16 mg of lycopene) with 10 g of olive oil every day for 10 weeks, while a control group consumed the olive oil alone. The researchers then analyzed the subjects' skin before and after exposing them to artificial ultraviolet (UV) light. The results showed that the tomato-paste group had a 40-per-cent reduction in skin redness (erythema) compared with the controls (J Nutr, 2001; 131: 1449-51).
In another study by the same research team, supple-mentation with tomato extract, tomato paste and lycopene each had a protective effect against UV-induced sunburn-although lycopene alone was the least effective. Those consuming the tomato extract and the tomato drink saw skin redness reduce by 38 per cent and 48 per cent, respectively, compared with only 25 per cent in the lycopene-only group. Again, this suggests that we're better off eating the whole fruit rather than only taking an isolated compound from it (Int J Vitam Nutr Res, 2005; 75: 54-60).
In addition to sunburn, tomatoes could also be useful for a range of other health problems. Although such research is still in its early stages, the findings already hint at a beneficial role of these fruit for asthma, gum disease, age-related macular degeneration, neurodegenerative disorders and even osteoporosis (Annu Rev Food Sci Technol, 2010; 1: 189-210; Exp Biol Med [Maywood], 2002; 227: 845-51).
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