Table 2.
The biological role and the reliable biomarkers or indicators of status of micronutrients of considerable public health significance
| Micronutrient | Function | Indicators of status | References |
|---|---|---|---|
| Folate | Involvement in the DNA cycle (cell replication); methylation cycle (aminoacids cysteine and methionine cycle) | Erythrocyte folate † ; serum/plasma folate † ; serum/plasma total homocysteine † | WHO/FAO 2004; McNulty & Scott 2008 |
| Vitamin B12 | Conversion of homocysteine to methionine as cofactor of the methionine synthase | Serum/plasma vitamin B12 † ; serum/plasma methylmalonic acid (MMA) † | Ryan‐Harshman & Aldoori 2008; Hoey et al. 2009 |
| Vitamin A | Growth and differentiation of a number of cells and tissues | Serum retinol † | Ross 2006 |
| Vitamin D | Bone resorption, intestinal calcium transport (calcium and bone homeostasis), modulation of transcription of cell cycle proteins, and cell‐differentiating, anti‐inflammatory and immunomodulatory properties | Plasma 25‐hydroxyvitamin‐D [25(OH)D] | WHO/FAO 2004 |
| Iodine | Synthesis of thyroid hormones | Urinary Iodine excretion in 24 h † ; serum thyroid‐stimulating hormone (TSH) † | WHO/FAO 2004; Zimmerman 2008; Ristic‐Medic et al. 2009 |
| Iron | Haematopoiesis; nucleic acid metabolism; carrier of oxygen to the tissues by red blood cell haemoglobin; transport medium for electrons within cells; integrated part of important enzyme systems | Haemoglobin † ; serum ferritin † ; serum transferrin receptor † | WHO/FAO 2004; Wood & Ronnenberg, 2006; Zimmerman 2008 |
| Zinc | Structural, regulatory and catalytic functions as cofactor for numerous metalloenzymes | Plasma/serum zinc † ; prevalence of inadequate intakes of dietary zinc † | McCall et al. 2000; Lowe et al. 2009 |
| Selenium | Protection of body tissues against oxidative stress, maintenance of defences against infection, and modulation of growth and development | Plasma/serum selenium † ; platelet or erythrocyte selenium † ; selenium‐related proteins † | WHO/FAO 2004; Sunde et al. 2008 |
Indicators of status were taken from a table compiled by the Biomarkers of Status Working Party, which comprised a group of international micronutrient experts and EURRECA partners (Fairweather‐Tait 2008), and successive updates†. Biomarkers reported here are those rated Excellent or Good according to a star rating used to classify the range of biomarkers available for each mineral/vitamin in relation to the limitations of the method.
Also reviewed in ‘Biomarkers of status/exposure. Minerals and vitamins’. RA1.2 Status Methods/IA3 Individuality, Vulnerability and Variability. July, 2008; ‘BIOMARKERS OF STATUS/EXPOSURE. Iron, Zinc, Vitamin A, Vitamin B12, Folate, Iodine & Selenium’. RA1.2 Status Methods/IA3 Individuality, Vulnerability and Variability. February, 2010 (http://www.eurreca.org).