Eat A Rainbow

 

Colour your world with a plateful of disease-fighting foods by discovering a full spectrum of good-for-you hues.

Apples aren't red by accident. And they're not made that way just to look pretty, either. In nature, beauty always has a reason, and coloured foods can encourage us to eat them (and spread their seeds).

Plant-eating animals can use colour to identify edible materials, and the intensity of the colour signifies ripeness. But scientists have also found that those pigments are created by a group of highly beneficial anti-oxidants called carotenoids, which mop up harmful free radicals in the body. Red and yellow hues signifying the presence of carotenoids are nature's advertisement for immune-boosting, cancer-fighting properties.

The Dieticians' Association of Australia (DAA) recommends five servings of vegetables and two of fruit each day, while the Australian Department of Health's Guide To Healthy Eating advises that 40 per cent of your daily diet should consist of fruit and vegetables.

You also need variety, including each of these colour groups daily: red, orange, green, yellow, blue/purple and white. Mix as many hues as possible with every meal. The deeper the colour, the higher the nutrient value. "The most crucial colours of all are green and orange," says Katherine Warth, dietician and spokeswoman for DAA. "Never go without either ... and try a new food each week to boost variety even more."

RED
Signal for: Lycopene
Find it in: Tomatoes, persimmon, watermelon, pink grapefruit

This carotenoid is a fierce cancer-fighter and can also help prevent heart disease by inhibiting the formation of harmful LDL cholesterol. The deeper the red or pink colour, the higher the lycopene content. Says Warth, "Studies have shown that a high intake of tomatoes, which are rich in lycopene, can reduce the risk of prostate cancer quite significantly."

Lycopene can also protect against cancers of the digestive tract, stomach and lungs. It's a fat-soluble substance, and is more readily available from cooked tomato products and juices than raw ones. "It's better to cook your tomatoes with a little olive oil, or at least mix them into a salad with some oil on it so that your body can best absorb the lycopene," says Warth.

ORANGE
Signal for: Beta-carotene
Find it in: Oranges, carrots, mangoes, pumpkin, sweet potato, apricots, squash, rockmelon, pawpaw

Beta-carotene is a major anti-oxidant which lowers cholesterol and converts it to vitamin A, an immune booster that helps fight off colds, flu, cystitis and skin problems. "A study of smokers showed that those who ate more beta-carotene had a lower incidence of lung cancer," says Warth. She adds that this was true only when the beta-carotene was acquired from food, not a supplement.

Vegetables containing beta-carotene benefit from being cooked lightly to release maximum amounts. Like lycopene, it's fat soluble, so using a little oil will help your body absorb it. These orange fruits and vegies are also high in that other great immune-booster, vitamin C.

GREEN
Signal for: Isothiocyanates, folic acid
Find them in: Cruciferous vegetables (the cabbage family), spinach, bok choy, kale, peas, artichokes, asparagus

Sulphur-based sinigrin, a substance unique to the cabbage family (which includes brussels sprouts, broccoli, cabbage, cauliflower), converts into anti-oxidant isothiocyanates, which cause pre-cancerous cells to destroy themselves.

Isothiocyanates give broccoli and brussels sprouts their distinctive smell, but the more pungent and strongly flavoured they are, the better, says Warth. Also present is folic acid, which is in its highest quantity in chlorophyll-rich dark-green leafy vegetables.

Folate works to prevent birth defects, such as spina bifida, and is a dietary essential for women who are (or are trying to become) pregnant.

YELLOW
Signal for: Lutein, zeaxanthin
Find them in: Yellow corn, bananas, yellow capsicum, honeydew melon

These two carotenoids work together to help maintain sharp, healthy eyesight. They are used in the area of the retina called the macula, which is the centre for sharp, focused vision. They protect the eyes from long-term light damage. We need to eat about 5mg of lutein and 1mg of zeaxanthin every day for adequate eyesight protection, so it's vital to include a large splash of yellow.

Bananas are worth a special mention for their high potassium content. They can help decrease the risk of stroke, lower blood pressure, relieve heartburn, prevent stomach ulcers and even aid in abating diarrhoea.

PURPLE/BLUE
Signal for: Anthocyanins
Find them in: Blueberries, dark cherries, prunes, blackcurrants, cranberries, red wine, red apples, black grape juice, blackberries, strawberries, beetroot, figs

The blueberry is a tiny hero. It contains more anti-oxidants than any other fruit or vegetable. Anthocyanins have remarkable anti-bacterial powers, useful for tackling E coli, urinary tract infections and gastrointestinal upsets. They're also anti-inflammatory, which is why blackcurrant syrups are used in cold and throat medicine.

The anti-oxidants in purple or blue fruits help prevent nerve cells in the brain from deteriorating, and possibly help guard against the effects of ageing in general. Anthocyanins may also have a beneficial effect on heart disease by inhibiting blood clots.

WHITE
Signal for: Flavonoids, allicin
Find them in: Onions, garlic, celery, leeks, pears, shallots, white wine, endive, chives

Allicin has been shown to inhibit abnormal cell growth, and flavonoids are important anti-oxidants. The sulphur compounds in these types of produce can help raise levels of beneficial HDL cholesterol and lower dangerous levels of blood fats called triglycerides, as well as easing the inflammatory response of asthma and breaking up catarrh secretions caused by colds and flu.

Pears stand out because, although they have white flesh, they are covered by green skin. Just beneath the skin lies a soluble fibre called pectin, says Anne Egan, dietician and co-author of Meals That Heal (Rodale Press, $55). Pectin can help prevent haemorrhoids, lower cholesterol and reduce the risk of colon cancer.