Nutrient Reference Value (NRV) (previously known as RDA)

The purpose of developing NRV’s (nutrient reference values; previously recommended daily allowances) was to develop standards for acquiring and supplying specific vulnerable population demographics with enough food and nutrients in order that they could maintain functional health. Thus, NRV’s are representative of ensuring that the nutritional requirements of the most vulnerable demographic groups are achieved. Companies are required to display NRV’s on packaging, so that consumers can monitor their intake of macro- and micronutrients.

Method of Establishing NRV’s

NRV’s cannot be established for all nutrients, as there is limited information available. However work is ongoing. The method used to establish NRV’s, is to estimate the average requirement of the demographic group most likely to fall deficient, followed by increasing the average by twice the coefficient, to account for individual variability, and then counterweight according to potential for low biological availability in the food supply. NRV’s are then established according to age and gender, in consideration of changes caused by different requirements from internal and environmental pressures. In practice, it is suggested that anyone meeting the NRV for nutrients, based on this series of complicated calculations, is unlikely to suffer from disorders relating to nutritional deficits.

Limitations of NRV’s

NRV’s are also used to assess the adequacy of nutrient intakes according to frequency of consumption and preferential food types amongst different categories of people within the population. However, the major flaw with NRV is that it wasn’t designed for this purpose and as such, lacks any real validity, Therefore the question is whether they are the most appropriate scale of assessment. The major issue is that NRV’s fail to establish a numerical point where nutrient consumption becomes inadequate. Evidence has shown that the nutrient requirements vary according to several factors not limited to age, gender, race etc.  Consequently variation is set to an approximate two fold range, meaning average scales of assessment for requirements are severely limited.

Moreover individual differences in requirements have equal consistency across all nutrients within the scales. Therefore the need to establish normal scales is necessary across each nutrient. For example, the NRV for vitamin C is 60mg per day. If an individual consumed one third of this amount, it has been shown that they would be unlikely to develop any type of disorder. However, evidence suggests that if an individual was unable to consume sufficient thiamine, beri-beri would likely occur. Therefore average requirements and ranges of requirements for each nutrient are necessary in order to establish potential for malnourishment risk.

Vitamin and Mineral Supplements

If you refer to the majority of multivitamin, and/or single ingredient vitamin and mineral supplements, they often contain enormous percentages of active ingredients in excess of NRV values. However, the ideal intake of a vitamin or mineral is not consistent with NRV but the intake which supports the best possible health outcome, without any indicators of deficiency, and promotes optimal physiological function. These levels are often far in excess of NRV’s. Not only do basic NRV values levels vary substantially amongst individuals according to age, gender, race and several other factors, but ideal levels do as well. If vitamin and mineral supplements are used in the long-term, they are safe if recommended intakes are followed, and in practical terms, the use of vitamin and mineral supplements may confer specific health benefits to support the diet.