Dietary recommendations / Nutritional requirements

Establishing human nutrient requirements for worldwide application

The Department of Nutrition for Health and Development, in collaboration with FAO, continually reviews new research and information from around the world on human nutrient requirements and recommended nutrient intakes. This is a vast and never-ending task, given the large number of essential human nutrients. These nutrients include protein, energy, carbohydrates, fats and lipids, a range of vitamins, and a host of minerals and trace elements.

Many countries rely on WHO and FAO to establish and disseminate this information, which they adopt as part of their national dietary allowances. Others use it as a base for their standards. The establishment of human nutrient requirements is the common foundation for all countries to develop food-based dietary guidelines for their populations.

Establishing requirements means that the public health and clinical significance of intake levels – both deficiency and excess – and associated disease patterns for each nutrient, need to be thoroughly reviewed for all age groups. Every ten to fifteen years, enough research is completed and new evidence accumulated to warrant WHO and FAO undertaking a revision of at least the major nutrient requirements and recommended intakes.

Activities and outputs

The following major revisions of nutrient requirements, including their role in health and disease, have been undertaken and published in the last four years:

• Trace elements in human nutrition and health (WHO/FAO/IAEA), WHO, Geneva 1996
• Fats and oils in human nutrition (FAO/WHO), FAO, Rome 1994
• Preparation and use of food-based dietary guidelines (WHO/FAO), WHO, Geneva 1996
• Carbohydrates in human nutrition (FAO/WHO), FAO, Rome 1998

Forthcoming outputs

During the 1980s WHO and FAO reviewed the requirements for protein, energy, vitamin A, folate, iron, and several other vitamins and minerals. With regard to vitamins and minerals, there is enough new research to once again justify updating our information on the subject. For example, there is a great deal of new evidence indicating that besides preventing deficiency diseases, some vitamins and minerals play an important role in preventing diet-related chronic diseases, one of modern society’s major causes of morbidity and mortality. Evidence is also mounting on the importance of micronutrients for immune function, physical work capacity, and cognitive development, including learning capacity in children.

Accordingly, WHO and FAO organized a joint expert consultation in Bangkok (September 1998). The principal purposes of this expert consultation were to:

• review new scientific information since the last FAO/WHO publication on specific nutrient requirements (1974) and prepare recommendations for daily nutrient intakes for infants, children, young and older adults, and pregnant and lactating women; and
• develop a report on human nutrition requirements to serve as an authoritative source of information for Member States in planning and procuring food supplies for population subgroups, interpreting food-consumption surveys, establishing standards for food-assistance programmes, and designing nutrition education programmes.

The scope of the expert consultation, and the subsequent recommended nutrient requirements, included over twenty essential nutrients. These nutrients comprise the basis of all human nutrition:

protein, energy, vitamin A and carotene, vitamin D, vitamin E, vitamin K, thiamine, riboflavin, niacin, vitamin B6, pantothenic acid, biotin, vitamin B12, folate, vitamin C, antioxidants, calcium, iron, zinc, selenium, magnesium and iodine.

For each nutrient, consideration was given to function, metabolism, dietary intake patterns, requirement levels, and toxicity. Basal requirements, safe intake levels, recommended dietary allowances, and tolerable upper intake levels are to be established for each. A detailed technical report of the Joint WHO/FAO Expert Consultation, in addition to a briefer handbook on human nutrient requirements, were published in 1999.

Source : WHO