Fisiológicamente, las uñas pueden registrar la historia de los desequilibrios recientes. Como señala la Academia Americana de Dermatología en su web, las uñas se han utilizado como herramienta de diagnóstico desde los tiempos antiguos. Por medio del análisis de las uñas, pueden detectarse deficiencias nutricionales, reacciones a los fármacos o intoxicaciones. El análisis de los minerales en las uñas revela las exposiciones tóxicas sucedidas durante el periodo de crecimiento.
Análisis de los minerales en las uñas
Las uñas están formadas principalmente por una proteína resistente llamada queratina. Al igual que el cabello y los dientes, son un apéndice de la piel. Estos tejidos acumulan metales que circulan por la corriente sanguínea. Debido a sus pautas de crecimiento, tanto el cabello como las uñas revelan la exposición pasada o crónica a minerales.
Diversos autores han establecido que el crecimiento medio de las uñas oscila entre 2 y 3 milímetros al mes, lo que equivale a alrededor de un tercio del ritmo de crecimiento del cabello. Las uñas de la mano tardan entre 3 y 6 meses en renovarse completamente, mientras que las uñas de los pies necesitan entre 12 y 18 meses. El ritmo de crecimiento depende de la edad, el sexo, la estación, el ejercicio, la dieta y factores hereditarios. El embarazo modifica el crecimiento de las uñas, como también el del cabello.
Arsenic and other elements in hair, nails, and skin-scales of arsenic victims in West Bengal, India.
Samanta G., Sharma R., Roychowdhury T., Chakraborti D. Department of Civil and Environmental Engineering, University of Houston, N 107 Engineering Bldg 1, Houston, TX 77204-4003, USA. gsamanta@mail.uh.edu. Sci Total Environ. 2004 Jun 29;326(1-3):33-47.
For the first time, biological tissues (hair, nails, and skin-scales) of arsenic victims from an arsenic affected area of West Bengal (WB), India were analyzed for trace elements. Analysis was carried out by inductively coupled plasma-mass spectrometry (ICP-MS) for 10 elements (As, Se, Hg, Zn, Pb, Ni, Cd, Mn, Cu, and Fe). A microwave digester was used for digestion of the tissue samples. This study reveals the higher levels of toxic elements As, Mn, Pb, and Ni in the tissue samples compared with available values in the literature. The elevated levels of these toxic metals in the tissues may be due to exposure of these elements through drinking water and food. This study reveals that in the arsenic-affected areas of WB, the concentrations of other toxic elements in drinking water and foodstuff should be monitored to evaluate the arsenic poisoning.
HAIR and NAILS are similar body tissues. They do have a different growth rate and thus reflect a different period of metal storage in tissue. For this reason, we recommend that you send either hair or nails, not both.
The sample can be placed in a plain envelope for shipping. Download and fill out the submission sheet (see submission forms) and send both to our laboratory.
Reports are released within one week (per post or e-mail) after sample and submission sheet have arrived at our laboratory.
Biological materials are widely used as a bio-indicator for environmental Pollution with heavy metals. Among These are hair and nails, which are also recommended by the World Health Organization (WHO) for worldwide environmental Monitoring. Heavy metals Cd, Cu, Pb and Zn were determined in fingernails and scalp hair from different sexes and ages of school children, adults and workers from polluted and unpolluted Areas of Aswan, Egypt. The results reveal that people living in polluted Areas show higher concentration of metals in nails and hair. The study proves that nails and hair can be used successfully as biological indicators for the assessment of heavy metal Pollution.
The above excerpt is from the research paper by Rashed MN and Hossam F: HEAVY METALS IN FINGERNAILS AND SCALP HAIR OF CHILDREN, ADULTS AND WORKERS FROM ENVIRONMENTALLY EXPOSED AREAS AT ASWAN, EGYPT