Carbohydrate

Functions

Carbohydrate is a key macronutrient required to provide fuel for our body cells. In particular, our brains require glucose (a form of carbohydrate) for fuel. Carbohydrates take a range of different forms; sugars are simple carbohydrates whereas starch is a complex carbohydrate.

Other fuel sources for our body are fats, protein and alcohol - however an oversupply of these nutrients can cause problems, hence carbohydrate is a singularly important fuel source.

Food Sources

The best natural sources of carbohydrates are whole grains, fruits, beans and vegetables. In addition to providing a rich source of carbohydrate for energy these foods also provide a rich source of vitamins, minerals, fibre and other phytonutrients. In contrast, white breads, white rice and many processed foods do provide a source of carbohydrate but relatively less positive health benefits.

Typical Contributions from Food

Food	Carbohydrate (g)
Bread, multigrain (1 slice)	10.3
Muffin, bran (medium size)	42.7
Pasta, fresh (1 cup)	36.3
Rice, brown (1/2 cup)	30.1
Oats, rolled, raw (1/2 cup)	25.3
Porridge, prepared with milk (1/2 cup)	16.5
Beans, red kidney, (1/2 cup)	14.9
Sweetcorn, cob, boiled (one)	26.8
Banana (one)	30.8
Kiwifruit (one)	9.3
Nectarine (one)	11.2
Apple (one)	13.9
Pear (one)	17.2
Orange (one)	9.9
Peach (one)	10.1

Source: The Concise New Zealand Food Composition Tables 5th Edition.

Adequate Intake (AI) Levels

There is currently insufficient data available to set a 'recommended dietary intake' level for carbohydrate, or indeed an adequate intake level for adults. Following are the adequate intake (AI) levels for infants only.

Carbohydrate AIs – New Zealand and Australia

Life Stage	Age	Males (g/day)	Females (g/day)
Infants	0-6 months	60	60
	7-12 months	95	95

Acceptable Macronutrient Distribution Ranges to Reduce Chronic Disease Risk

The New Zealand and Australian governments recommend that between 45% and 65% of the energy in our diet comes from carbohydrates, with the majority of this from low energy density and/or low glycaemic foods.

For a moderately active young man (height 1.8m) a daily energy intake of 12,000kJ would be normal. Hence, between 5,400 and 7,800kJ of energy should ideally come from carbohydrates for this man. This equates to around 340-500g of carbohydrate each day for a man. For a  moderately active young woman (1.6m tall) energy requirements are typically lower at around 8700kJ/day. At this energy intake level, carbohydrates contribution would ideally be between 250-360g.

Deficiency and Toxicity

The percentage range of 45-65% was originally set as it was thought that an intake of carbohydrate above 65% increased the risk of coronary heart disease, whereas an intake of carbohydrate below 45% would result in an excessive fat intake thereby increasing the risk of obesity. It has since been argued that the nature of the carbohydrate is a more important factor in the causation of these diseases than the proportion of energy from carbohydrate. That is, it is more important to consume carbohydrates of low energy density or low glycaemic foods.

References

Ministry of Health. (2006). Nutrient reference values for Australia and New Zealand. Canberra: Commonwealth of Australia.

Last Updated: 16 October 2008

The material provided by Thinking Nutrition Ltd on this website is for information purposes only. It is not a substitute for appropriate health advice from a qualified medical practitioner.