Apples can keep the doctor away (BBC article)

There may be more reasons than simply vitamin C to eat an apple a day, according to researchers.

Scientists have examined the cancer-fighting potential of various chemicals found in the flesh and skin of the fruit. And they have found that together, these chemicals have an effect which far outweighs that of taking only vitamin C.

The chemicals involved are called flavanoids and polyphenols, and the research study, published in Nature magazine, look at their combined "anti-oxidant" ability. Anti-oxidants are thought to possibly protect from cancer by "mopping up" molecules responsible for cell damage, which can trigger the disease. The researchers, from Cornell University in New York, found that eating just 100g of apple gave an anti-oxidant effect equivalent to taking some 1,500mg of vitamin C.

'Keeps the doctor away'

Professor Chong Yong Lee, one of the study authors, said: "Some of the chemicals are known to be anti-allergenic, some are anti-carcinogenic, anti-inflammatory, anti-viral. Now I have a reason to say an apple a day keeps the doctor away."

To test the cancer fighting qualities of the "phytochemicals" in apples, the researchers used colon cancer cells grown in the laboratory. They found that 50mg of the phytochemicals - extracted from the apple skin, inhibited the reproduction of the cells by 43%. An extract of the apple flesh inhibited the cells by 29%. An even more pronounced effect was found when the same chemicals were tested on human liver cancer cells.

A spokesman for the Imperial Cancer Research Fund said: "This research suggests that fresh apples have an anti-oxidant activity greater than can be expected through its vitamin C content. "The mechanism for the protective effect of fruit and vegetables has not been identified nor has it been established that apples are more beneficial than other fruits." He advised that people should eat a balanced diet with plenty of fruit and vegetables.

Anyone wanting to ward off cancer should eat plenty of garlic and tapioca pudding, if recent headlines are anything to go by.

They are just the latest two foods to be hailed by scientists as potentially safeguarding against cancer.

Diet has the most impact on the development of bowel cancer, but has also been shown to influence others including lung, breast and head cancer.

Another recent study would have us eating grain, fish, meat and Brazil nuts - because they contain the trace element selenium.

Fruit and salad

For salads, turn to cherry tomatoes, red onions and red-coloured Lollo Rosso lettuce because they are rich in particles known as flavanols. Citrus fruit skins can help - they contain a cancer-beating substance known as citrus limonoids. For those on hormone replacement therapy, soya products can fend off the disease.

Most cancer specialists recommend fibre, as does the government, although a 16-year study involving nearly 90,000 people recently found no evidence that natural fibre had an impact on cancer.

Certain red wines - such as Cabernet and Merlot - are also high in flavanols and another substance called resveratrol, although if bladder cancer is a fear, constant drinking - water is best - is recommended by one study. An after dinner cup of green tea could also be helpful. Off the menu are red meat, processed meat, excessive alcohol and, according to one study, sweeteners.

But while studies indicating that eating more of one type of food can beat cancer is guaranteed to catch the headlines, there is often very little to back them up.

Laboratory conditions

They can be based on a laboratory experiment using a compound found in the food rather than the food itself. Such experiments may not even look at the compound's effect on cancer, but at how a rat's immune system reacts. If the immune system appears stronger, the researchers might then suggest that the rat would be better placed to fight off cancer. Other studies will look at how the compound reacts with human cancer cells in a test tube. Scientists can never be sure that the original food will have the same effect in the human body.

'Bizarre diets'

Dr Lesley Walker, head of science information at the cancer research campaign, said plenty of unsubstantiated research made the headlines. "If we ate everything the newspapers told us to eat, we'd have pretty bizarre diets," she said.

She said there was "unlimited potential" for researchers to find anti-cancerous properties in fruit and vegetables as most of them will contain substances that can beat cancer in a test tube. "What is important, though, is to see the relevance of that to a population," she said.

One example was that of garlic - substances found in garlic have been shown to fight cancer in a test tube, but, as yet, there is no significant evidence that it can do the same in humans.

Long-term studies

Only long-term, large-scale studies could give a definite indication of which foods could help combat cancer, she said.

One such ongoing trial was the European Prospective Investigation into Cancer - EPIC - which involves more than 400,000 people in nine countries across Europe. The UK base for the study is in Cambridge, and involves more than 25,000 middle-aged and elderly people in the East Anglia region. Participants keep "extremely detailed" records of what they eat, Dr Walker said.

She said that the study would compare the habits of those who developed cancer with those who did not.

'Eat fibre, avoid red meat'

The results would be particularly useful as they would cover a range of different diets. The findings would help scientists determine not just whether, say, fats played a role in cancer, but also what sorts of fat.

"They'll be comparing people in Norfolk with people in Germany with people in the Mediterranean. The power of the study is in that huge variation," she said. In the meantime, the advice was simple - eat a healthy well-balanced diet and take exercise

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