Validity of dietary patterns to assess nutrient intake adequacy.

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 alpha-carotene, beta-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 alpha-carotene, beta-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.