Home » Consumer Information » Diet And Health » Nutritional Requirements

Nutritional Requirements

Today nutritionists have a wide knowledge of the role of nutrients in health and disease. The amount of each nutrient needed is called the nutritional requirement.

How are nutritional requirements estimated? The Committee on Medical Aspects of Food and Nutrition Policy (COMA) reviews the scientific evidence and makes proposals that are used by government to formulate policy.

Meaningful estimates of nutritional requirements must take account of the distribution of requirements within a population or group. To achieve this the COMA panel use four dietary reference values (DRVs). DRVs are estimates of the requirements for groups of people and are not recommendations or goals for individuals.

Estimated Average Requirement (EAR): an estimate of the average requirement for energy or a nutrient "approximately 50% of a group of people will require less and 50% will require more. For a group of people receiving adequate amounts, the range of intakes will vary around the EAR.

Reference Nutrient Intake (RNI): the amount of a nutrient that is enough to ensure that the needs of nearly all the group (97.5%) are being met.

Lower Reference Nutrient Intake: the amount of a nutrient that is enough for only the small number of people that have low requirements (2.5%).

Safe Intake: This is used where there is insufficient evidence to set an EAR, RNI or LRNI. The safe intake is the amount judged to be sufficient for everyone. There is no evidence that intakes above this level have any benefits ? and in some instances they could have toxic effects.

The COMA panel set EARs for energy, dietary fibre and desirable population average intakes for fat and carbohydrate. EARs and RNIs were set for protein, whilst LRNIs EARs and RNIs were set for 9 vitamins and 11 minerals. Safe intakes were set for a further four vitamins and minerals.

How should DRVs be used?

For practical purposes the RNI should be used when assessing the dietary intake of a group. The nearer the average intake of the group to the RNI, the less likely it is that any individual will have a deficient intake. The nearer the average to the LRNI, the greater the probability that some individuals are not achieving adequate intake. When planning a diet for a group the aim should be to provide the RNI.

Energy Requirements:

Energy requirements are related to age, gender, body size, and level of activity. Requirements tend to increase up to the age of 15?18 years after which there is a decline. Due to a reduction in the basal metabolic rate (BMR), a further decline occurs after 50 years. BMR is the energy required to maintain basic body functions and is measured when the body is at rest.

The table shows the EARs for various groups. These were calculated by multiplying the BMR by a factor to reflect the physical activity level (PAL) which reflects current levels of physical activity.

Energy EAR = BMR x PAL

"CAN YOU CALCULATE YOUR OWN ESTIMATED AVERAGE REQUIREMENT (EAR)?'

A factor, or multiple of BMR, of 1.4 reflects the lifestyle of most adults in the UK. For those who are more active a higher factor would be more appropriate e.g. 1.9 for very active adults.

It should be noted that the EAR for pregnant women increases by 200kcal/day in the final three months. Breast feeding mothers also have increased requirements depending on the amount of milk produced, the fat stores that have accumulated during pregnancy and the duration of breastfeeding.

People who take more energy than they require gain weight and if this continues they will become obese. People who are obese have a shorter life expectancy and are at a greater risk of developing diseases such as coronary heart disease (CHD) and diabetes.

One way of gauging if your weight is within a 'healthy' range is to measure your Body Mass Index (BMI). Use our BMI Calculator to check how you shape up.

Changes which should be made to meet with nutritional recommendations:

• Eat more starchy foods such as bread, potatoes, rice and pasta
• Eat more fruit and vegetables
• Choose leaner cuts of meat and lower fat versions of dairy products
• Reduce total fat intake? e.g. eat less fried foods
• Reduce consumption of sugary foods such as biscuits, cakes and sweets.
• Reduce salt intake.