The objective of the present paper is to review the methods of measuring micronutrient intake adequacy for individuals and for populations in order to ascertain best practice. A systematic review was conducted to locate studies on the methodological aspects of measuring nutrient adequacy. The results showed that for individuals, qualitative methods (to find probability of adequacy) and quantitative methods (to find confidence of adequacy) have been proposed for micronutrients where there is enough data to set an average nutrient requirement (ANR). If micronutrients do not have ANR, an adequate intake (AI) is often defined and can be used to assess adequacy, provided the distribution of daily intake over a number of days is known. The probability of an individual's intake being excessive can also be compared with the upper level of safe intake and the confidence of this estimate determined in a similar way. At the population level, adequacy can be judged from the ANR using the probability approach or its short cut – the estimated average requirement cut-point method. If the micronutrient does not have an ANR, adequacy cannot be determined from the average intake and must be expressed differently. The upper level of safe intake can be used for populations in a similar way to that of individuals. All of the methodological studies reviewed were from the American continent and all used the methodology described in the Institute of Medicine publications. The present methodology should now be adapted for use in Europe.

EURopean micronutrient RECommendations Aligned is a network of excellence funded by the European commission, and established to address the problem of differences between countries in micronutrient recommendations as well as to understand how nutritional information including requirements and adequacy of intake is processed among different population groups. The aims of the present paper were to review the methods used for the adequacy assessment of the intake of six micronutrients of public health concern (vitamin A, folate, vitamin B12, Fe, Zn and iodine) in non-European and European nutrition surveys carried out on the apparently healthy population and to compare in particular the adequacy across surveys for folate intake. A systematic literature review was conducted to identify nutrition surveys that assessed micronutrient intake adequacy. The search yielded 9049 records, out of which 337 were eligible for the selected micronutrients. The majority (83·9 %) of the European surveys compared the adequacy of the nutrient intake against the Recommended Dietary Allowances (RDA); only a few surveys (8·0 %) used the estimated average requirement cut-point method, while none of them used the probability approach. The comparison of folate inadequacy across eight countries revealed that about 25 % of the adult female population had inadequate intakes when judged against the different recommendations used by the respective investigators, but nearly 75 % had inadequate intakes when compared against the estimated average requirement cut-point value of 320 μg/d. The present review showed that different methods were applied across Europe to estimate the adequacy of micronutrient intake, which led to different prevalence estimates of micronutrient inadequacy.

The purpose of the present study was to conduct a systematic review of the literature on the value of the methods used to assess dietary patterns for measuring nutrient intake adequacy in the population. Systematic review on Pubmed database up to April 2008. The search included specific key words and MeSH terms. No language limit was set. Only studies that compared food patterns with nutrient intake adequacy or nutrient biomarkers were included in the analysis. The search resulted in 1504 articles. The inclusion and exclusion criteria limited the selection to thirty articles. Nineteen studies evaluated the usefulness of the dietary patterns, either a priori defined (thirteen studies), or defined by factor analysis (four studies) or by cluster analysis (two studies), but only nine of them tested their validity (four a priori defined and four a posteriori defined). Diet indices showed moderate to good validity results for measuring the adequacy of intakes for α-carotene, β-carotene, vitamin C, vitamin B6, Ca, folic acid, Fe and Mg. The factor analysis approach showed moderate to good validity correlations with the adequacy of intake of α-carotene, β-carotene, lutein, lycopene, vitamin C, vitamin B6 and folic acid. Vitamin B12 and vitamin E are the micronutrients with less probability of being adequately assessed with dietary patterns a priori or a posteriori defined. Diet indices are tools with fair to moderate validity to assess micronutrient intake adequacy.