Immune-boosting Foods: Broccoli

Cancer institutes around the world value broccoli as the number-one anticancer food, and with good reasons. As well as being rich in disease-fighting vitamin C, it also contains sulforaphane, a phyto-chemical that occurs naturally in broccoli and other vegetables of the cruciferous family — kale, cabbage, cauliflower, bok choy, brussels sprouts and many salad greens. Sulforaphane stimulates the body's production of substances called Phase II detoxification enzymes. These enzymes destroy carcinogens (cancer-causing substances) and free radicals before they can attack healthy cells. Second, cruciferous vegetables are loaded with indole-3-carbinol (I3C), a phytochemical shown to inhibit the growth of the type of cancer cells in the breast that are responsive to estrogen. In fact, researchers are now examining the feasibility of putting I3C in a pill to combat breast cancer.

The proof: When scientists fed rats hearty servings of broccoli for a few days, then exposed them to a potent compound that induces breast cancer, the broccoli eaters were half as likely to develop tumors as animals on the standard feed. And the broccoli eaters that did develop cancer ended up with fewer and smaller tumors.

Put broccoli to work: Regardless of how you prepare cruciferous vegetables, eating them is good for you. But if you want to rev up your body's disease-fighting abilities fast, look a little further down the family tree to broccoli sprouts. Scientists at Johns Hopkins University have found that, gram for gram, these tender shoots can contain up to 20 times more sulforaphane than mature broccoli. In other words, 30 g of sprouts yields as much protective power as about 625 g of cooked broccoli!

Ask for broccoli sprouts at your local greengrocer or supermarket, but if you can't find them, why not grow your own? Sprouts of all kinds are powerhouses of health and are very quick and easy to grow. Health food shops will supply you with special sprouting seeds that have not been treated with pesticides and recommend a sprouter that suits the size of your household. Simply follow the manufacturer's instructions. Refrigerate your fat-free, low-kilojoule broccoli sprouts and rinse in fresh, clean water before using. Serve generously in sandwiches and salads before the use-by date.

Immune-boosting Food: Blueberry

Anthocyanins, the pigments that give blueberries their stunning deep colour, have potent immune-stimulating properties. Because they are antioxidants, anthocyanins protect capillaries (tiny blood vessels) from oxidative damage. In doing so, they promote brisk blood flow through the circulatory channels through which many immune cells travel to reach parts of the body that need their help. Protection against oxidation also helps ensure good circulation of lymph, the fluid that carries immune cells through its own system of channels.

Moreover, blueberries are rich in concentrated tannins, astringent substances also found in tea. According to US research, these tannins prevent E. coli bacteria from sticking to the cells that line the urinary tract, where they can cause infection. Scientists think that tannins block the growth of the part of the bacteria that gives the bugs their adhesive property. Tannins also contain compounds called catechins. Several studies suggest that catechins shield us against some types of cancer.

The proof: When US researchers measured the levels of antioxidants in 40 different fruits and vegetables, blueberries came out near the top. In fact, a 12S g serving of fresh blueberries supplies enough antioxidants to almost double our average daily intake. The study suggests that eating a fistful of blueberries (or their cousins, cranberries) daily will go a long way towards preventing urinary tract infections and promoting good overall health. Blueberries are at their peak in January and February, but canned and frozen are available year-round.

Put blueberries to work: Use fresh berries to add texture to your breakfast cereal and in fruit salads. Or add fresh, frozen, or dried blueberries to pancake or muffin batters. Don't like blueberries? Other berries, including raspberries, blackberries and strawberries, deliver many of the same cancer-fighting phytochemicals. Like blueberries, they're loaded with fibre (all those tiny seeds) and ellagic acid, shown in early studies to inhibit the development of cancer. This may explain, in part, why research at the Harvard School of Public Health, involving 1271 people, found that strawberry lovers were less likely to develop cancer than those who rarely ate the fruit.