One of the simplest and most overlooked ways to stay healthy is to treat food as your medicine.

Every day you should eat food from as many colour groups as possible.

Taking a good lunch with you to work every day should be as important to you as getting a good night’s sleep, or going for a regular health check-up.

It is not something you should skip – even if it means getting up 15 minutes earlier so you have time to make a decent lunch.

But rather than just throwing together a ham and cheese sandwich, nutritional experts are urging people to ‘think colour’ when preparing their meals.

So try a multicoloured ham and cheese salad instead. Grate in some vivid purple raw beetroot and bright orange carrot. Lightly steam some green broccoli, snow peas and beans and white cauliflower, and throw them in, too. Add some yellow capsicum, red tomatoes and red onion for good measure.

Now – that’s a vitamin and mineral-packed healthy salad!

Leading world nutrition experts like Dr Mark Hyman have been telling people for many years that what you put at the end of your fork is more powerful medicine than anything you will find in a pill bottle.

Dr Hyman believes food is the most powerful medicine available to heal chronic disease.

At a recent lecture he spoke about prevention of ill-health, wellness, nutrition and the new field of nutrigenomics, the science of how molecules in food interact with our genes to support or interfere with our health.

Dr Hyman said new research has proven that beyond simply being a mechanism for conveying calories, food is a source of special ingredients than can prevent and treat disease and transform your health.

These special ingredients are called phytonutrients – plant chemicals that are not calories, protein, fat, carbohydrates, vitamins or minerals, but special molecules that interact with your biology. These special molecules act like switches on your DNA to heal your body.

Phytonutrients have medicinal properties and enhance health through improving the function of genes and metabolism.

Dr Hyman said that the notion that food is anything other than calories for energy and sustaining life is foreign to most Westerners, while in Asia, ordinary people have applied this knowledge of ‘food as medicine’ for thousands of years.

“What people in the West are yet to realise is that food contains information that speaks to our genes, not just provides calories for energy,” he said writing in his weekly newsletter (available at www.drhyman.com). “We are learning from research in the field of nutrigenomics, that good food ‘talks’ to our DNA switching on or off genes that lead to health or disease. What you eat programs your body with messages for health or illness.”

Dr Hyman says to improve our health we need to ‘think colour’ when we choose our foods.

“Plants use colours as their protective mechanisms. Those colours are the sources of the phytonutrients which act like medicine in our bodies. We use their defence mechanisms to help our bodies function better – these are the anti-inflammatory, detoxifying, anti-oxidant and hormone-balancing compounds that we should eat every day to prevent disease and create optimal health,” he said.

“The vast array of colours in vegetables represents over 25,000 chemicals that are beneficial. There is evidence that interaction between the colours provides additional benefits, so it’s important to have a diverse diet and eat different foods.

“Fruits and vegetables are historically and biologically important. Our ancestors, the hunter-gatherers, ate over 800 varieties of plant foods.

“Each colour represents a different family of healing compounds. Though we have selectively bred the colours we eat into very narrow ranges, in nature, vegetables comes in a painter’s palate of colour. Just one example is that there are red carrots in India; we only eat orange ones. There are 150 varieties of sweet peas, but only a few are available to us. We need to make an extra effort to eat many different foods to get the full range of benefits.”

Here are a few tips from Dr Hyman to put healing medicines into your diet without swallowing a pill. Remember  - eat the rainbow!

Red Group (tomato, pink grapefruit, watermelon)

These contain the carotenoid lycopene, which helps rid the body of free radicals that damage genes. Lycopene seems to protect against prostate cancer as well as heart and lung disease. Juices contain a lot of the beneficial ingredients. One glass of tomato juice gives you 50 percent of the recommended daily intake of lycopene.

Yellow/Green Group (spinach greens, collard greens, mustard greens, turnip greens, green peas, yellow corn, avocado, honeydew melon)

These are sources of the carotenoids lutein and zeaxanthin. These are believed to reduce the risk of cataracts and age-related macular degeneration. Lutein is a yellow-green substance that concentrates in the back of your eye. It may also reduce atherosclerosis.

Orange Group (carrot, pumpkin, yellow squash, sweet potato, mango, apricot, rockmelon)

These contain alpha carotene, which protects against cancer. They also contain beta-carotene, which the body converts to vitamin A. It protects the skin against free-radical damage and helps repair damaged DNA. Beta-carotene is also good for night vision. It’s important to note that these beneficial nutrients can be received from other foods, too. For instance, vitamins found in dairy products and meat. But it’s not as beneficial because you get high calories and fat along with it.

Orange/Yellow Group (pineapple, orange, mandarin, tangelo, peach, pawpaw, nectarine)

These contain beta cryptothanxin, which helps cells in the body communicate and may help prevent heart disease. In addition, a single orange contains 170 percent of the recommended daily vitamin C. It’s interesting to note that the skin of an orange is high in a protective fat that has been found to kill cancer cells in humans and animals, which highlights the fact that two-thirds of all drugs come from the plant world.

Red/Purple Group (beetroot, eggplant, purple grapes, red wine, grape juice, prunes, cranberries, blueberries, blackberries, strawberries, mulberries, red apples)

These are loaded with powerful antioxidants called anthocyanins believed to protect against heart disease by preventing blood clots. They may also delay the aging of cells in the body. There is some evidence they may help delay the onset of Alzheimer’s disease.

Green Group (broccoli, Brussel’s sprouts, cabbage, Chinese cabbage or bok choi, kale)

These contain the chemicals sulforaphane and isocyanate and they also contain indoles, all of which help ward off cancer by inhibiting carcinogens. If you don’t like broccoli, try it very lightly steamed and still bright green and crunchy. You can hide it in an omelette or on a pizza, too.

White/Green Group (leeks, shallots, garlic, onions, celery, pears, white wine, endive, chives)

The onion family contains allicin, which has anti-tumour properties. Other foods in this group contain antioxidant flavonoids like quercetin and kaempferol.