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Nutrient requirements

Key points

  • Dietary Reference Values (DRVs) comprise a series of estimates of the amount of energy and nutrients needed by different groups of healthy people in the UK population.
  • Included within this definition are three types of estimates: Reference Nutrient Intakes (RNIs), Estimated Average Requirements (EARs) and Lower Reference Nutrient Intakes (LRNIs).
  • RNIs are used for protein, vitamins and minerals, and are an estimate of the amount that should meet the needs of most of the group to which they apply. They are not minimum targets.
  • The EAR is used in particular for energy.
  • Intakes below the LRNI are almost certainly not enough for most people.

What are nutritional requirements?

Today, nutritionists have a wide knowledge of the role of nutrients in health and disease. We know that people need many different nutrients if they are to maintain health and reduce the risk of diet-related diseases. The amount of each nutrient needed is called the nutritional requirement. These are different for each nutrient and also vary between individuals and life stages, e.g. women of childbearing age need more iron than men.

Why do nutritional requirements vary?

Each nutrient has a particular series of functions in the body and some nutrients are needed in larger quantities than others. For example, protein is needed in gram (g) quantities. Vitamin C is needed in milligram (mg) quantities (1/1000 gram) and vitamin B12 is needed in microgram (µg) quantities (1/1000000 gram). Individual requirements of each nutrient are related to a person’s age, gender, level of physical activity and state of health. Also, some people absorb or utilise nutrients less efficiently than others and so will have higher than average nutritional requirements, e.g. among older people, vitamin B12 absorption can be relatively poor.



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