5.7: WHO/FAO Nutrient Reference Values (8a.7)

When vitamin and mineral require­ments for a specific country are not available, the most recent NRVs in the WHO/FAO (2004) report are often used. In this report WHO/FAO defined three levels shown in Box 8a.7:

Box 8a.7 WHO/FAO Nutrient Reference Values

• Estimated Average Requirement
• Recom­mended Nutrient Intake
• Tolerable Upper Nutrient Intake Level

8a.7.1 WHO/FAO Requirement (R = AR) for Nutrients

The require­ment is defined by WHO/FAO as an average daily nutrient intake level that meets the needs of 50% of the “healthy” indi­viduals of a particular age and gender. It is based on a given criteria of ade­quacy which varies depending on the specified nutrient. Where necessary, an allowance for variations in nutrient bio­avail­ability has been included. However, a require­ment has been set by WHO/FAO for only a few nutrients. In the interim, Allen et al.(2006) have calculated the ARs from the RNIs for a limited range of vitamins and minerals for infants, children and adults. The conversion factors used were based on SDs derived by the U.S. Food and Nutrition Board of the Institute of Medicine (FNB/IOM) for calculating the U.S and Canadian RDAs. They are tabulated in Annex C of Allen et al. (2006). These calculated ARs are shown in Appendix 8a.9.

8a.7.2 WHO/FAO Recommended Nutrient Intake (RNI = RI))

The Recommended Nutrient intake require­ment is defined as a daily nutrient intake set at the require­ment (AR) plus 2SD. This meets the nutrient require­ments of almost all appar­ently healthy indi­viduals in an age and sex-specific pop­ula­tion group. Thus, it is equivalent to, and derived in the same way as indi­vidual require­ments set by COMA (1991) for the U.K., by IOM (2001) for the U.S. and Canada, and by EFSA (2017) in Europe. When the standard deviation for the nutrient require­ment is unknown, WHO/FAO (2004) has generally assumed a CV of 10%–12.5%, although there are exceptions for some nutrients (e.g., zinc, see below).

RNI values for dietary iron and zinc are based on estimates that meet the normative storage requirements, and are adapted from earlier reports (FAO/WHO, 1988; 1996). In these reports the normative require­ment was defined as the mean require­ment to maintain a level of tissue storage that is judged to be desirable. In Table 8a.9, the RNIs for zinc (mg/d) are given for diets with three levels of zinc bio­avail­ability. For these derivations, a CV for the dietary zinc require­ment of 25% is assumed. Appendix 8a.10 and Appendix 8a.11 summarize the mineral and vitamin Requirement Intakes (RNIs) of WHO/FAO (2004).

Table 8a.9: Recommended nutrient intakes for dietary zinc (mg/d) to meet the normative storage require­ments from diets differing in zinc bio­avail­ability. Unless otherwise specified, the within-subject variation of zinc require­ments is assumed to be 25%.
^a For infants receiving maternal milk only, assumed CV = 12.5%. The bio­avail­ability of zinc from human milk is assumed to be 80%.
^b Formula-fed infants; moderate bio­avail­ability for whey-adjusted milk formula and for partly breastfed infants or given low-phytate feeds supplemented with other milks; assumed CV = 12.5%.
^c Formula-fed infants; low bio­avail­ability applicable to phytate-rich vegetable-protein based formula with or without whole-grain cereal; assumed CV = 12.5%.
^d Not applicable to infants consuming human milk only. From WHO/FAO (2004).

Age group	Assumed weight (kg)	Bioavailability High Mod. Low
Infants & children
0–6mo	6	1.1^a	2.8^b	6.6^c
7–12mo	9	0.8^a	—	—
7–12mo	9	2.5^d	4.1	8.4
1–3y	12	2.4	4.1	8.3
4–6y	17	2.9	4.8	9.6
7–9y	25	3.3	5.6	11.2
Adolescents
F. 10–18y	47	4.3	7.2	14.4
M. 10–18y	49	5.1	8.6	17.1
Adults
F. 19–65y	55	3.0	4.9	9.8
M. 19–65y	65	4.2	7.0	14.0
F. > 65y	55	3.0	4.9	9.8
M. >65y	65	4.2	7.0	14.0
Pregnant women
1st trimester	—	3.4	5.5	11.0
2nd trimester	—	4.2	7.0	14.0
3rd trimester	—	6.0	10.0	20.0
Lactating women
0–3 mo	—	5.8	9.5	19.0
3–6 mo	—	5.3	8.8	17.5
6–12 mo	—	4.3	7.2	14.4

8a.7.3 WHO/FAO Upper Tolerable Intake Level (UL) of Nutrients

The WHO/FAO Upper Tolerable Nutrient Intake Levels are defined for a limited range of nutrients as the maximum intake from food (including fortified products), water and supplements of that nutrient that is unlikely to pose risk of adverse health effects from excess in almost all (97.5%) appar­ently healthy indi­viduals in an age and sex-specific pop­ula­tion group. The ULs were developed using the model outlined in (WHO/FAO, 2006).

In October, 2017, the WHO held a technical consultation entitled: “Risk of excessive intake of vitamins and minerals delivered through public health interventions — current practices and case studies”. The proceedings of this technical consultation are available in a special issue. The reader is advised to consult the following for further details: (Pike and Zlotkin, 2019).

8a.7.4 WHO/FAO Additional Levels

WHO/FAO (2004) adopted additional terms for certain nutrients. For vitamin A, for example, they adopted the term “Recom­mended Safe Intake,” as was used in their earlier report (FAO / WHO, 1988),because of the lack of data for deriving a true mean require­ment and variance for any group. The Recom­mended Safe Intake level is set to prevent clinical signs of deficiency and allow normal growth, but it does not allow for prolonged periods of infection or other stresses. As such, it represents the normative storage require­ment plus 2SDs.

8a.7.5 WHO/FAO Human Energy Requirements

Energy require­ments set by FAO/WHO (2004) are presented by gender and selected age groups and are expressed as energy (as kJ or kcal) per day and energy per kilogram of body weight. Requirements are also expressed as multiples of Basal Metabolic Rate (BMR). The recom­men­dations for dietary energy intake are also accompanied by guidelines for desirable physical activity levels: see FAO/WHO(2004) for more details.

Note that, like the U.K and EFSA, the FAO/WHO energy require­ments are specifically “prescriptive” in relation to body weights, defining suitable reference ranges consistent with long-term good health, amd should be applied to pop­ula­tion groups and not to indi­viduals.

The FAO/WHO (2004). energy require­ments are based on estimates of TEE in free-living persons measured by DLW or other methods (e.g., indi­vidually calibrated heart rate monitoring) that give comparable results. They also modified their earlier factorial estimates of energy require­ments which used occupational-related mean values of physical activity levels (PALs). Instead FAO/WHO (2004).used a range of life-style PAL values for each of the three lifestyles — sedentary, active, vigorously active, and shown in Table 8a.10.

Table 8a.10: FA0/WHO (2004) Class­ification of lifestyles in relation to the intensity of habitual physical activity, or PAL.
* PAL values > 2.40 are difficult to maintain over long periods

Category	PAL value
Sedentary or light-activity lifestyle	1.40–1.69
Active or moderately active lifestyle	1.70 –1.99
Vigorous or vigorously active lifestyle	2.00–2.40*

The PAL values were calculated from the measurement of TEE and measurements or estimates of BMR (i.e., PAL = TEE/BMR). Both men and women are assigned to a PAL category using th same PAL values. The estimates of BMR were derived from the age and sex-specific predictive equations of Schofield (1985) using body weight alone.

The additional energy needs for pregnancy and lactation were also calculated using factorial estimates for the growth of maternal and fetal tissues, the metabolic changes associated with pregnancy, and the synthesis and secretion of milk during lactation.

For infants 1–12mos, the energy require­ments were estimated from equations for TEE, adding the energy needs for growth. Separate energy require­ments (as kJ/kg/d) are available for breastfed and formula fed infants with the same body weight up to 12mos of age because TEE is lower among breastfed than formula-fed infants during the first year of life.

For children and adolescents, measurements of TEE were derived using both DLW and heart rate monitoring, from which predictive quadratic polynomial regression equations for boys and girls were derived; equations are available in FAO/WHO (2004). The sum of TEE and the additional energy deposited in growing tissue and laid down during normal growth, represents the mean daily energy requirement (kcal or MJ/day). For more details, see FAO/WHO (2004).

8a.7.6 WHO/FAO Pop­ula­tion Average Intake Goals for Macronutrients

The WHO ranges of pop­ula­tion nutrient intake goals for preventing diet-related chronic diseases are shown in Table 8a.3. The recom­men­dations are expressed as a proportion of the daily total energy intake rather than the absolute amount, with the exception of cholesterol and sodium, which are given in mg/d and g/d, respectively. This approach was adopted because the desirable up or down change will depend on the existing intakes in a given pop­ula­tion (Nishida et al., 2004). The recom­men­dations represent the pop­ula­tion average intake that is judged to be consistent with the maintenance of health (i.e., low prevalence of diet-related diseases) in a pop­ula­tion (IOM, 2002). Hence these focus on the maintenance of low pop­ula­tion risk rather than low indi­vidual risk. In general, most of the ranges set are comparable to those of the U.K and the U.S. and Canada, although the meaning and application of the ranges differ. Exceptions are the recom­men­dations by WHO/FAO for total fat intake which take into account countries with usual fat intake (as % energy) > 30% and < 15%. Total fat (as % energy) of at least 20% is consistent with good health.

The recom­men­dation to restrict the intake of free sugars to less than 10% energy was made in view of the recognition that higher intakes of free sugars provide significant energy without supplying specific nutrients, and hence can have a negative impact on diet quality. In addition, increasing or decreasing intake of free sugars is associated with parallel changes in body weight, a relationship that exists irrespective of the level of the intake of free sugars. The excess body weight associated with intake of free sugars arises from excess energy intake. Free sugars include monosaccharides and disaccharides added to foods and beverages by the manufacturer, cook, or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrations.

WHO emphasize that whole grain cereals, fruits and vegetables are the preferred sources of non-starch polysaccharides (NSP) (See Table 8a.3). They state that whole grain foods should together provide > 20g per day of NSP and > 25g/d of total dietary fiber. Note that fruits and vegetables do not include tubers (i.e., potatoes, cassava).

In addition to the pop­ula­tion nutrient intake goals presented in Table 8a.3, WHO also emphasize the importance of maintaining at the pop­ula­tion level an adult median BMI of 21–23kg/m², and for indi­viduals a BMI in the range 18.5–24.9kg/m², with the avoidance of a weight gain greater than 5kg during adult life. Physical activity is also highlighted with a recom­men­dation for a total of one hour per day on most days of the week of moderate- intensity activity , such as walking.