Carbohydrates add taste, texture and variety to our food. They are the single most important source of food energy in the diet. Carbohydrates in the form of sugars, starches, oligo- and polysaccharides and fibres form one of the three major macro-nutrients that supply the human body with energy. A landmark report recommends that at least 55 percent of daily energy intake should come from a variety of carbohydrate sources - cereals, sugars, fruits, vegetables and legumes.

Good news for carbohydrates. The Food and Agriculture Organisation of the United Nations and the World Health Organisation (FAO/WHO)(1) recently published a report on Carbohydrates in Human Nutrition. It reviews, for the first time in nearly 20 years, the role of all forms of carbohydrates in health and disease. The way carbohydrates enhance nutrition and influence health is now more fully understood. This is due to better awareness of carbohydrate digestion, absorption and metabolism.

Carbohydrates and Health

Whereas it is important to maintain an appropriate balance between energy intake and expenditure, research suggests that people who eat a high carbohydrate diet are less likely to accumulate body fat compared to those on a low-carbohydrate/high-fat diet. The reasons for these observations include:

• The lower energy density of high-carbohydrate diets, as carbohydrates have less calories weight for weight than fat. Fibre-rich foods also tend to be bulky and therefore physically filling.
• Studies have found that carbohydrates work quickly to aid satiety, therefore those consuming high carbohydrate diets are less likely to overeat.
• It has also been suggested(2) that very little dietary carbohydrate is converted to body fat mainly because it is a very inefficient process for the body. Instead, carbohydrate tends to be preferentially used by the body for energy.

With regards to dental health, research from recent years allows a more rational approach to the role of sugars and other carbohydrates in dental caries. It is now recommended that programmes to prevent dental caries focus on fluoridation, adequate oral hygiene and a varied diet, and not on sugar intake alone(1).

Carbohydrate Recommendations

In promoting the benefits of carbohydrates, the report makes many recommendations for health professionals and research scientists, but the most important messages for the public are:

• The many health benefits of dietary carbohydrates should be recognised and promoted. Carbohydrates provide more than energy alone.
• An optimum diet contains at least 55% of energy from carbohydrates for all those over two years of age.
• A wide range of carbohydrate-containing foods should be consumed so that the diet is sufficient in essential nutrients and dietary fibre.

Carbohydrates in all shapes and forms are good for one's health. For those who want to stay active and fit, a well-balanced, high carbohydrate diet is recommended.

Major Dietary Carbohydrates

Class	Sub-Group	Components	Foods
Sugars	Monosaccharides Disaccharides	Glucose, galactose, fructose Sucrose, lactose	Honey, Fruit Table Sugar, Milk
Oligosaccharides	Malto-oligosaccharides Other oligosaccharides	Maltodextrins Raffinose, stachyose fructo-oligosaccharides	Soya, Artichokes, Onions
Polysaccharides	Starch   Non-starch polysaccharides	Amylose, amylopectin   Cellulose, hemicelluloses pectins, hydrocolloids	Rice, Bread, Potatoes, Pasta All Vegetables and Fruits

1. WHO/FAO (1998) Carbohydrates in human nutrition. FAO food and nutrition paper no. 66. FAO, Rome.
2. Hellerstein, M.K., Christiansen, M., Kaempfer, S. et al (1991). Measurement of de novo hepatic lipogenesis in humans using stable isotopes. J. Clin. Invest. 87: 1841-1852.

FOOD TODAY 02/1999