Researchers are only just beginning to realise the value of chemicals found naturally in fruit and vegetables which have remarkable potential as cancer-fighting agents. The emerging importance of "phytonutrients" was discussed yesterday by Mr Peter Berry Ottaway, a scientific and legal food consultant with Berry Ottaway & Associates Ltd.
Little research has been done on these substances yet the fruit and vegetables we eat contain phytonutrients that make a significant contribution to our health, according to Mr Ottaway. Scientists were only beginning to to understand their benefits, he said. "A lot of the research is really on the starting blocks." There were perhaps 500 to 600 such substances of value to health, he said.
An understanding of vitamin B12 only went back to the 1950s, he said, and selenium, now regarded as an essential trace mineral, was ranked as a dangerous toxin 25 years ago. Beta carotene was perhaps the most widely-known phytonutrient, but it was one of a whole range of carotenoids, including lycopene and lutein, which were known to have beneficial properties.
Lycopene occurs as the red pigment in tomatoes and lutein is the pigment in yellow-green vegetables. The genes responsible for them could probably be genetically engineered either to increase their amounts in vegetables or transfer them into other foods, he said. He cautioned, however, against any rush to take supplements of these and other phytonutrients such as anthacyanins (found in blackcurrent and bilberry), phytoestrogens (found in soya) or catechins (found in green tea). While they were thought to be of value at the levels found naturally in these sources, increasing their dose might cause harm, not benefit.
Something similar had happened when beta carotene was suggested as being of benefit to smokers' health, he said. Yet taking too much had the opposite effect, enhancing the harm of tobacco use.