Suck a lollipop to heal a sore throat. It is the dream of kids and the kid in us - medicine that tastes delicious.

Now comes functional food or food that more than meets your nutritional needs; it can also heal.

Such innovative food products can be expected in the next few years. Two months ago, Republic Polytechnic's School of Applied Science signed a Memorandum of Understanding with three food and beverage companies to develop foods like these.

"While functional foods are similar in appearance to our conventional foods, they also prevent some disease or demonstrate some form of physiological benefit like reducing cholesterol levels," said Dr Michelle Siow, Programme Chair of Pharmaceutical Science at Republic Polytechnic

In other words, while functional foods can be modified foods, they can also be naturally occurring foods. A tomato is considered a functional food since it contains lycopene, which studies suggest may have anti-cancer properties.

On the other hand, rice is not considered a functional food since it does not have any function beyond providing carbohydrates for basic bodily sustenance. Things change, however, if the rice were to be infused with something like lycopene.

And with increasing numbers of Singaporeans suffering from diet-related illnesses like heart disease, high blood pressure and some cancers, these illness-fighting foods can give our diets a boost.

Spring Singapore is growing the food industry, which it said generated $4.4 billion in sales in 2004, by supporting companies that develop functional foods.

Spring's Food Division Director, Ms Leung Wai Ling, said: "The global consumer market for food products is constantly changing. One of the major factors influencing consumer behaviour is the growing concern on health issues like high blood pressure, high cholesterol and other cardio-vascular diseases.

"This is especially prevalent in US, Europe and Japan where a wide range of functional food products has been introduced. The growing demand for such products also creates a potential market for our local food manufacturers," she added.

The potential appeal of functional foods to the consumer is clear. "There is a tendency for some people to buy supplements and then not eat them," said Dr Siow. "If I can take this bread that contains Omega-3 fatty acids and that tastes great, why not?

"Why not put healthy ingredients in food that you eat daily? It tastes better and you have one less thing to remember to take," added Dr Siow.

And while functional foods are not a new idea, the methods by which they can be produced have increased. According to Dr Siow, functional foods can be divided into three generations. We take a look at them here.

First generation - Health supplements

Health supplements refer to a wide range of products containing substances like minerals, vitamins and herbs, which can be found in natural sources. They come in forms like capsules, tablets and powders, and are usually not thought of as food.

They are useful when lifestyle conditions, like dieting and heavy drinking, as well as physical conditions, like pregnancy and illness, increase our needs and make it difficult to get sufficient amounts from food. This is where a supplement can plug the gaps in our diets.

While convenient to use, however, health supplements have an important drawback. As the name implies, they are meant to supplement your diet; they cannot replace whole foods. A vitamin C supplement gives you just that - vitamin C - while an orange would also give some vitamin A, calcium and dietary fibre, besides other nutrients.

Also, fruit and vegetables contain protective substances like antioxidants and phytochemicals - the latter usually occur as colour pigments in these foods and may protect against cancer and heart disease. And since scientists have yet to identify and isolate all the beneficial substances in food into supplements, whole foods are still the best bet against nutrient deficiencies in our diets.

Second generation - Food in food

Green tea ice cream, green tea soy milk, green tea cake, green tea everything. More than a tasty flavour, green tea has become a popular ingredient in many products because it is rich in antioxidants and is believed to have a wide range of benefits, from reducing the risk of cancer and heart attacks to treating skin damage caused by the sun.

Research frequently throws up findings suggesting that certain foods show promise in reducing the risk of various diseases and health conditions. Food manufacturers then quickly move to create products featuring these foods - examples include olive oil, tomatoes and oats - as ingredients.

Third generation - Enriched food

Since the body needs a wide range of vitamins and minerals only in small, daily amounts, getting them through food can be the most convenient and cheapest method.

As research advances, scientists are able to identify and isolate the substances in the functional foods that give them their health-promoting qualities. For example, it is the lycopene in tomatoes that shows promise in reducing the risk of prostate cancer.

What this does is to open up a whole new world of possibilities in creating health foods, since a tomato-hater can still get her dose of lycopene by eating other foods that have been enriched with this substance.