A team of researchers at Almeria University (UAL) has demonstrated the health benefits of olive oil combined with tomato in combating the development of colorectal cancer, and has praised the many recipes from the Mediterranean diet which use both of these ingredients together, such as gazpacho, salmorejo, salads, tomato juice, etc.
The study, which was published recently in the Journal of the Science of Food and Agriculture, has shown that some components of tomato, for example lycopene, "act against the development of original tumoral cells in the colon" and stop them spreading.
"All tomatoes provide bioactive compounds for the body, but this research has shown the difference between the varieties of tomato and how olive oil intensifies their benefits," says José Luis Guil Guerrero, co-author of the study and a member of the biomolecular chemistry and food processes group at the university.
"We have confirmed that certain dishes in the Mediterranean diet can be excellent in helping to prevent some types of cancer," he adds, referring to a report with the title 'Phytochemical composition and in vitro anti-tumoral activities of selected tomato varieties'.
The Spanish research team has also carried out previous studies to analyse the beneficial effects attributed to tomato extracts and this type of diet, which is very typical in southern Europe. The scientists have ascertained that some varieties of tomato act more intensively than others in tackling the proliferation of cancer cells.
In new trials, explained in the article, "the researchers worked with HT-29 cellular lines, a human colo-rectal line of cancer. All the varieties of tomato were analysed to ascertain their content of bioactive compounds, such as carotenoids, sterols, phenolic acids and fatty acids. They were able to see the way different concentrations of these extracts acted against cancer cells, and compare these cells when extracts were not added with other non-tumoral cells from the colon," according to the Fundación Descubre, an Andalusian research group which has the backing of the CSIC.
"The results showed that while the tomato compounds act against tumoral cells, the healthy cells are not affected by them. On the other hand, it has been confirmed that some types of tomato are more effective in this sense than others. Specifically, those which are most red and round produce a more active response against the tumoral cells in vitro," the group added in a press release.
The research also included analysis of the combined action of tomato carotenoids and olive oil on cell cultivations, and corroborated "inhibiting effects which are significantly higher than those obtained from each of them separately."
José Luis Guil Guerrero and his colleagues found that there are many different compounds in olive oil which act against tumours, such as polyphenols, which enhance the action of the bioactive substances in tomatoes. In their research, they were able to see that any type of tomato impedes the proliferation of colorectal cancer cells at very low concentrations.
The more colourful varieties have an even greater anti-cancer capacity "because they contain more lycopene and fatty acids," says José Luis. Along the same lines, another test was carried out on vegetables such as rocket and watercress, which also have anti-tumoral actions on colorectal cancer cells.
According to the article in the Journal of the Science of Food and Agriculture, in the latter case the scientists were able to show "that the extracts of rocket not only inhibit the proliferation, but also affect the integrity of the tumour cells, producing notable damage to their membranes."