Many health-and-wellness professionals believe that your immune system is the key to good health and long life. When it's in good shape, you're better protected against illness; when it's not, you're more likely to get sick. While a healthy lifestyle in general is important, studies have shown that diet plays a special role in keeping the immune system strong.

All-star lineup
For a healthy immune system, be sure to regularly include these star defence players in your diet.

• Citrus fruits, tomatoes and sweet potatoes are rich in the antioxidants beta-carotene and vitamin C.

• Chicken soup helps flush out cold and flu viruses (by getting the mucus moving out of your system) so you feel better faster. Scientists aren't exactly sure why but suggest that it's the heat or a special unidentified compound in the broth.

• Garlic scores big for its medicinal properties and ability to boost the production of illness-fighting antibodies. It has antifungal, antibacterial and antiviral properties.

• Fluids help flush out bad bugs, such as bacteria. Normally, eight glasses of fluid a day is recommended for good health. When you're sick, try to get double that.

• Cranberries are rich in antioxidants and are a natural guard against bladder infections. They may also protect against ulcers, heart disease and cancer.

• Healthy fats in olive oil, fatty fish, avocados and nuts help the immune system work optimally.

• You can count on wheat germ to deliver vitamin E and a little zinc for healthy skin, healing and resistance to infection.

• Brazil nuts are tops in selenium, but tuna, halibut and cod are also winners. Selenium keeps your defences in great shape.

• Honey has been a natural healer for thousands of years. It provides antioxidants; kills bacteria that cause coughs, sore throats and ear infections; helps heal wounds; keeps skin healthy; and aids digestion.

• Grains provide carbohydrates, which provide energy and calories to fuel your body.