Nutrition - Diet and the big 'C'

Prostate cancer is the most common type of cancer among men, but what you eat can play a part in the prevention of the disease. Chris Fenn takes a look at the evidence...

Think of the 'C' word and a vision of cycling - and being out on your bike - may come to mind. For others, it's the shorthand for cancer. For Lance Armstrong, it meant both. It seems incredible that an elite athlete, with a level of fitness that most of us can only aspire to or dream of, could join the cancer statistics.

These statistics are disturbing. They reveal that prostate cancer is the most common form of cancer in men. Currently, there are 30,000 new cases of prostate cancer each year in the UK and around 10,000 men a year die from the disease.

The exact cause is still unknown but, as with Lance Armstrong, being a fit, lean cyclist doesn't offer any immunity. Ironically, some of the by-products of metabolism, which are produced during exercise, may contribute to cancer.

It seems that when the body cranks up to a higher gear during exercise, and there's a huge increase in metabolism to provide enough energy to power the pedals, more damaging free radical molecules are produced. These are a normal by-product of energy metabolism and can be neutralised by the body's own defence mechanisms and by eating enough of the right type of foods. However, if the free radical molecules are left unchecked, they disrupt cell membranes and generally wreck havoc on cell functions.

This disturbance may trigger the cancer process and the prostate gland seems to be the most vulnerable area in men.

The prostate gland is small, sits underneath a man's bladder and is shaped like a doughnut. It fits around the urethra - the tube that carries urine out of the bladder. Its purpose is to produce the fluid that mixes with sperm when a man ejaculates. Any sort of disruption to urine flow, pain when passing urine, passing urine often (especially at night) and pain in the lower back, hips and upper thighs are all possible early signs of the disease.

The latter might easily be confused with the effects of a long ride or strenuous time trial. In many cases, prostate cancer isn't discovered until it's moved out from the prostate gland and, in some cases, resulted in secondary growths in other parts of the body. Unfortunately, Lance's body became riddled with cancers, which required chemotherapy and radiotherapy rather than simply removing the diseased gland.

Although there's no known way of preventing prostate cancer, there are plenty of studies that suggest that specific nutrients can greatly reduce the risk.

Lycopene, the red pigment that gives tomatoes their colour, has been shown to be particularly effective. It seems to reduce the risk of pre-cancerous prostate tissue turning into full blown cancer. Doctors at the VM Medical College in India treated 40 men with high grade prostate intraepithelial neoplasia (HGPIN), a precancerous condition.

Half of the group were given a small 4mg dose of natural lycopene twice a day for a year and the other half weren't given any of the supplements. At the end of the study, men taking lycopene had an average 42% decrease in their prostate-specific antigen (PSA) level - a marker of prostate cancer risk. In contrast, the PSA levels rose by an average of 23% in the men not given lycopene supplements.

Nevertheless, two of the men taking lycopene developed cancer during the study. However, six of the men in the untreated group developed cancer in the course of the year-long study.

Rather unsurprisingly, the latest advice for cancer prevention is to eat foods rich in lycopene as regularly as possible. Fresh tomatoes, tomato soup, ketchup and tomato puree are all good sources. Tesco are now stocking a new British-grown tomato that has high levels of lycopene.

But cancer is a complex disease and there are several other nutrients that have been linked to the prevention of cancer.

Other research from the Erasmus Medical Centre in Rotterdam found that low doses of both lycopene and vitamin E were particularly effective in slowing the growth of human prostate tumours, which had been transplanted into mice. Vitamin E was first discovered in 1922 and found to be an important factor in fertility in rats. At that time, vitamin E was easy to produce and, being associated with fertility, it was initially marketed as an aphrodisiac - a reputation which has since proven to be a complete myth. Recent research shows that it has slightly less romantic, but no less important, functions in helping to improve blood circulation and preventing dry skin.

To keep up with Lance Armstrong in terms of cycling, rather than cancer, the best plan would be to follow medical advice and increase your intake of lycopene and vitamin E. The best sources of vitamin E are whole almonds, peanuts, sunflower seeds, olive oil, egg yolks, spinach, kale and broccoli, muesli and wheatgerm.

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