The health philosophy that prevention is better than cure holds true particularly for cancer when the treatments can nearly be as distressing as the disease itself.
On a brighter note there is increasing recognition that substances in the diet have real potential to prevent cancer and this body of evidence continues to grow. There are now more than 200 studies demonstrating the disease-fighting ability of phytochemicals which are found in fruits, vegetables and grains. Scientists continue to identify and explore these powerful phytochemicals and antioxidants which mop up free radicals that cause tissue damage and disease. So far it remains unclear whether it’s an individual phytochemical, or a combination of these plant chemicals that lowers the risk of cancer.
Take prostate cancer as an example. The risk of prostate cancer drops for men who eat tomato products (tomato based pasta sauces, tomato juice, tomato purees and ketchups). Lycopene, a carotenoid found in tomatoes was thought to be the protective phytochemical. However the November 2003 issue of the Journal of the National Cancer Institute reported that while tomato products had a significant impact on reducing the risk of cancer, they didn't see a significant benefit from lycopene alone. It appears that tomato based foods are the key to cancer prevention, not a lycopene supplement. This isn’t all that surprising as past experience has taught us that single nutrients or a few nutrients in a supplement does not give the same effect as eating whole foods.
Remember beta-carotene? For years, scientists noted that diets rich in foods containing beta-carotene (carrots and other brightly coloured fruit and veg) reduced the risk of many types of cancer, including lung cancer in smokers.
But when researchers tested beta-carotene supplements in people who smoked, two major independent studies showed that supplements actually increased the risk of cancer – substantially! Beta-carotene supplements also increased the risk of heart attacks and strokes.
The chances are it’s something else in carrots and tomato that protects us. It could be the effect of hundreds of these phytochemicals and antioxidants working together. But the bottom line is - think ‘foods first’. Supplement only when there is enough evidence to convince the experts that it is worthwhile and safe to do so.
A recent paper published in the American journal of Clinical Nutrition explored the role of functional foods in the prevention of chronic diseases such as cancer. Could foods containing significant amounts of synthetic phytochemicals provide desirable health benefits beyond basic nutrition? The study found that the vitamin C in apples with skin accounts for only 0.4% of the total antioxidant activity, suggesting that the antioxidant activity may come from phenolics and flavonoids in apples and other fruits and vegetables. The authors proposed that the synergistic effects of phytochemicals in fruit and vegetables are responsible for their potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruit and vegetables is attributed to the complex mixture of phytochemicals present in whole foods.
There’s no doubt that we will see novel nutritional approaches to reducing the risk of cancer in the future - scientists are already genetically modifying garlic to increase its selenium content. People with a family history or a genetic predisposition to cancer will eventually be able to take supplements that are tailor-made to fight the disease. But until then – we are what we eat!
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| Eat at least five servings of fruit and vegetables a day. | Many studies report that vegetarians have less cancer that other people. This doesn't mean we should avoid meat - small amounts of lean meat can be part of a healthy diet. But it’s probable that vegetarians' high intake of vegetables and fruit helps protect them from disease. | | Eat tomato based products daily. | Men can help to lower their risk of prostate cancer by consuming tomato based products regularly. | | Use garlic, rosemary and turmeric to season food. Cut down on salt. | A recent study found that men who ate garlic at least twice a week have 50% lower risk of prostate cancer than men who never ate garlic. People who eat too much salt double their risk of stomach cancer. | | Drink Green Tea | Green tea contains epigallocatechin-3-gallate which is thought to cut off the supply of blood to cancer cells. | | Include soya based foods in your diet but avoid Genistein supplements. | Genistein, a major phytoestrogen in the soya bean, is a weak estrogen that can bind to estrogen receptors on cells. This blocks human estrogen’s ability to bind to cells and promote breast tissue growth. However, there is some concern that in postmenopausal women, who have little of their own estrogen, genistein may act like estrogen and increase the risk of breast cancer in some women. | | Drink alcohol in moderation | Your risk of cancer increases with the amount of alcohol you drink and the length of time you've been drinking too much. | | Eat fibre rich foods: wholegrain breakfast cereals and bread, oats, wild rice, beans, fruits and vegetables. | Diets low in fibre intakes are linked with colon cancer. The more fibre people eat the less risk they face. | | Eat less saturates and more of the protective fats found in oily fish. | Breast cancer has been linked with large intakes of saturated fats. People who eat oily fish such as salmon, sardines, tuna and trout twice a week have a significantly reduced risk of colon cancer. | | Maintain a healthy weight. | Being the correct weight for your height is important. Being even slightly too heavy increases your risk of a range of cancers. |
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