How to choose foods that improve your health

Cancer develops when mutant cells escape the body's im­mune system. Plants are also susceptible to cellular damage and have developed their own protective mechanisms. Beta-carotene and vitamins C and E are natural antioxidants that hinder cell damage by scavenging and inactivating free radicals, the unstable molecules that are released when the body uses oxygen. Here are some tips to help you choose foods that help prevent cancer.

Some phytochemicals in vegetables block the growth of blood vessels that feed tumours, others inactivate the enzyme systems that allow cancer cells to spread. Still others suppress the hormones that promote cancer growth.

• Indoles, found in cruciferous vegetables such as broccoli, cauliflower, turnip and cabbage, appear to stimulate enzymes that offer some cancer protection.
• Lutein, found in corn, dark leafy greens and peppers, is an antioxidant that helps prevent the age-related eye disease called macular degeneration.
• Lycopene, found in tomato products, watermelon and pink grapefruit, has been shown to lower the risk of prostate cancer as well as provide protection from heart ­disease.
• Onions and garlic contain sulphur compounds, many of which also offer disease protection. For example, in Vidalia, Georgia, where large amounts of onions are consumed, the death rate from stomach cancer is significantly lower.

Studies have found that people who eat lots of vegetables and fruits enjoy a reduced incidence of many cancers. By contrast, researchers have found that people who eat few vegetables are more prone to develop colon cancer. Vegetables have a protective effect that goes far beyond what vitamin pills can offer. Most vegetables have more than one benefit. Broccoli, for example, contains beta-carotene, vitamin C, fibre, folic acid and the phytochemical sulforaphane. It is this variety of protective nutrients, plant chemicals and as-yet-unidentified compounds in vegetables that helps keep cancer at bay.

Brilliant-coloured vegetables look beautiful on the plate. But there's another reason to eat them: the plant pigments they contain are rich sources of disease-fighting antioxidants. These compounds help protect cells from damage that can lead to cancer and heart disease.