Science of HTMA

Koc, ER, et al. A comparison of hair and serum trace elements in patients with Alzheimer disease and healthy participants. Turk. J. Med. Sci. 45, 2015.

Some elements may change in Alzheimer disease. Analysis of these elements in hair may be superior to blood analysis.

Asano R, Suzuki K, Otsuka T, Otsuka M, Sakurai H., Concentrations of toxic metals and essential minerals in the mane hair of healthy racing horses and their relation to age., J Vet Med Sci. 2002 Jul;64(7):607-10.

This reference range of trace elements in the mane hair of racing horses should be used to assess disease and the nutritional status in equine practice.

Frick A ,Tolen A, Hair tissue mineral analysis patterns in 564 dogs, HVMA Journal Volume 48 Fall 2017

The majority (94%) of the 564 dogs studied were found to have a high Na/K ratio with low Ca and Mg. According to mineral analysis research, both results (the levels and the ratio) are indicative of inflammatory processes and stress. This correlates well with the clinical signs (general, physiological, and psychological) reported in the cases studied.

Priya, L, Geetha, A. Level of Trace Elements (Copper, Zinc, Magnesium and Selenium) and Toxic Elements (Lead and Mercury) in the Hair and Nail of Children with Autism. Biol.Trace Elem.Res. 2010.

Results showed that hair copper concentrations could be correlated with the degree of severity, in that the higher the copper burdens, the more severe the autism. Levels of lead and mercury were also found higher in the affected group and increased with the degree of severity. Whereas, selenium and magnesium were significantly different in the low functioning group of children compared to others in the affected group as well as controls.

Eleonor Blaurock-busch E.,Omnia R. Amin, Hani H. Sessoki, Thanaa Rabahd. Toxic Metals and Essential Elements in Hair and Severity of Symptoms among Children with Autism. Maedica (Bucur). 2012 Jan; 7(1): 38–48.

The potentially toxic elements chromium, copper, mercury, nickel, and lead are more prevalent in the hair of children with autism as compared to age and sex matched healthy controls. Nutritive elements, including calcium, iron, iodine, magnesium, manganese, zinc, and selenium are more deficient among autistic children. Hair analysis is of potential usefulness for the determination of toxic and essential elements in ADS children, offering an early chance for intervention and treatment.

Hair toxic element content in adult men and women in relation to body mass index. Skalnaya MG, Tinkov AA, Demidov VA, Serebryansky EP, Nikonorov AA, Skalny AV. Biol Trace Elem Res. 2014 Oct;161(1):13-9.

Higher values of scalp hair mercury and lead content were observed in men and women with increased body mass index independently of their age.

Lee, SH, et al. Low hair copper concentration is related to a high risk of nonalcoholic fatty liver disease in adults. J. Trace Elem Med Biol. 50, 2018.

Lower hair copper was correlated with higher body mass index, waist circumference, blood pressure, and low HDL. Individuals with NAFLD had significantly lower hair copper levels.

Wang, CT, et al., Concentrations of Calcium, Copper, Iron, Magnesium, Potassium, Sodium and Zinc in Adult Females hair with Different Body Mass Indexes in Taiwan., Clin. Chem. Lab. Med. 43, 4, 2005

Hair mineral analysis was performed on over three-hundred adult females with BMI’s ranging between low, normal and high. Significant differences were noted in zinc levels between women with a low BMI compared to those with a high BMI. The obese group had the lowest zinc levels as well as the lowest ratios of sodium/potassium, iron/copper and zinc/copper. “..we suggest that hair concentrations of Ca, Cu, Fe, Mg, K, Na and Zn may be correlated with adult female BMI, but further studies are needed.”

Concentrations of chromium, selenium, and copper in the hair of viscerally obese adults are associated with insulin resistance. Kim HN, Song SW. Biol Trace Elem Res. 2014 May;158(2):152-7. doi: 10.1007/s12011-014-9934-6. Epub 2014 Mar 19

Thus, chromium and selenium levels in the hair of viscerally obese adults were inversely associated with insulin resistance, whereas copper levels in the hair were positively associated with insulin resistance. This suggests that the mineral status of viscerally obese adults might play a role in the development of insulin resistance.

Miekeley, N., et al. Elemental Anomalies in Hair as Indicators of Endocrinologic Pathologies and Deficiencies in Calcium and Bone Metabolism., J. Trace Elem. Med. Biol. 15, 1, 2005

Statistical evaluation of these data by multivariant analysis (MANOVA) using a contrast matrix and by discriminant analysis showed that elemental hair anomalies can be used to diagnose correctly the above-mentioned pathologies, demonstrating the usefulness of hair analysis as a complementary tool for the detection of disturbances in calcium/bone metabolism.

Changes of Selenium, Copper and Zinc Content in Hair and Serum of Patients with Idiopathic Scoliosis. Dastych, M, et al. 2008 Orthopedic Research Society. Wiley Periodicals, Inc. J. Orthop. Res.

Various changes in the content of trace elements in biological samples taken from patients with idiopathic scoliosis are not accidental. What might bring a shift in our knowledge is speciation of various forms of trace elements in the organism in relation to idiopathic scoliosis.

Associations of Calcium and Magnesium in Serum and Hair with Bone Mineral Density in Premenopausal Women. Song, CH, et al. Biol. Trace Elem. Res. 118, 1, 2007.

Higher serum magnesium was associated with lower bone mineral density at the spine, whereas high hair magnesium was associated with higher bone mineral density. The study concluded that magnesium in serum and hair was associated with bone mineral density in premenopausal women and the ratio of serum calcium to magnesium appears to be a significant indicator of bone density.

Trace elemental distribution in the scalp hair of bipolars using PIXE technique. Pradeep AS, Naga Raju GJ, Sattar SA, Sarita P, Prasada Rao AD, Ray DK, Reddy BS, Reddy SB. Med Hypotheses. 2014 Apr;82(4):470-7. doi: 10.1016/j.mehy.2014.01.028. Epub 2014 Feb 2.

While the imbalance of certain trace elements leads to generation of more free radicals, the imbalance of some other trace elements causes changes in dopamine (neurotransmitter) activity. It is essential to monitor before and periodically during treatment the levels of essential trace elements for effective treatment of bipolar disorder.

Trinchi V, Nobis M, Cecchele D., Emission spectrophotometric analysis of titanium, aluminum, and vanadium levels in the blood, urine, and hair of patients with total hip arthroplasties., Ital J Orthop Traumatol. 1992;18(3):331-9.

The patients were divided into three groups of ten; one group was studied two years after total hip replacement, one at four years, and one at six years. High levels of titanium and aluminum were found in the hair, especially in the group studied six years after implantation, while the levels of the three ions in the blood and urine were not significant.

Comparative study of trace elements in blood, scalp hair and nails of prostate cancer patients in relation to healthy donors. Qayyum MA, Shah MH. Biol Trace Elem Res. 2014 Dec;162(1-3):46-57.

Multivariate apportionment of trace elements in the blood, scalp hair and nails of the patients was also significantly different than that in the healthy donors.

Janabai, G, et al. Investigation of Trace Elements in the Hair and Nail of Patients with Stomach Cancer. Indian j Clin Biochem. 33,4 2018.

Magnesium and strontium levels were markedly lower in the cancer group and iron levels were found to be significantly higher. The mean levels of iron, selenium and phosphorus increased with advanced cancer stages in nail samples. Their results show that the increase in trace elements could a potential diagnostic marker to help predict cancer progression and its etiology.

Ozgen, IT, et al. Hair Selenium status in children with leukemia and lymphoma. J. Pediatr Hematol Oncol. 29,8, 2007.

The hair selenium levels were found to be significantly lower in the cancer group. In conclusion, it was found that the hair selenium levels of children with leukemia and lymphoma, particularly in those that were malnourished were low compared to the healthy group.

Leung PL, Huang HM., Following the recovery of naso-pharyngeal cancer patients by trace elements in hair using statistical pattern recognition methods., Biol Trace Elem Res. 1998 Jun;62(3):235-53.

By implementation of statistic pattern recognition methods, it has been found that the concentrations of TEs in hair can remarkably reflect different recovery phases of NPC patients.

Determination of Cadmium in Whole Blood and Scalp Hair Samples of Pakistani Male Lung Cancer Patients by Electrothermal Atomic Absorption Spectrometer. Kazi, TG, et al. Sci. Total Environ. 389,2, 2008.

Mineral levels of one hundred and twenty male lung cancer patients were compared to one hundred-fifty controls. The study showed that the average cadmium concentration was high in the blood and scalp hair of lung cancer patients at different stages compared to controls.

Screening of trace elements in hair of the female population with different types of cancers in wielkopolska region of poland. Czerny B, Krupka K, Ożarowski M, Seremak-Mrozikiewicz A. ScientificWorldJournal. 2014;2014:953181. doi: 10.1155/2014/953181. Epub 2014 Dec 15

Conclusions. It seems safe to conclude that our results confirmed usefulness of hair element analysis in screening tests for the assessment of the biomarker of various cancer diseases in a female population.

Interaction between carcinogenic and anti-carcinogenic trace elements in the scalp hair samples of different types of Pakistani female cancer patients. Wadhwa SK, Kazi TG, Afridi HI, Talpur FN, Naeemullah. Clin Chim Acta. 2015 Jan 15;439:178-84. doi: 10.1016/j.cca.2014.10.007. Epub 2014 Oct 15

The study revealed that low level of trace elements (Se, Zn) and high level of heavy elements (As, Cd, and Ni) were associated with increased risk of cancer.

Metallomics Study Using Hair Mineral Analysis and Multiple Logistic Regression Analysis: Relationship Between Cancer and Minerals. Yasuda, H, et al. Environ. Health Prev.Med. 24,5, 2009.

Their research findings suggested that some minerals such as arsenic, selenium and probably iodine, zinc, sodium and vanadium contribute to the regulation of cancer and that a metallomics study using multiple logistic regression analysis is a useful tool for estimating cancer risks.

Lee, SH, et al. Coronary Calcification is Reversely Related with Bone and Hair Calcium: The Relationship Among Different Calcium Pools in Body. J. Bone Metabol. 23, 4, 2016

Hair samples were analyzed in fifty women along with their coronary calcium scores, bone mineral density. They found that coronary calcium scores were negatively correlated with bone mineral density and hair calcium levels.

Mercury as a Risk Factor for Cardiovascular Disease. J. Nutr. Biochem. 18, 2007.

A study of men over a period of thirteen years found that for each microgram of mercury found in the hair, the risk of acute coronary events increased by an average of eleven percent and cardiovascular disease death rate by ten percent.

The Role of Mercury and Cadmium Heavy Metals In Vascular Disease, Hypertension, Coronary Heart Disease and Myocardial Infarction. Houston, MC. Altern. Ther. Health Med. 13,2,2007.

Mercury, cadmium and other heavy metals have a high affinity for sulfhydryl groups, inactivating enzymatic reactions, amino acids, and sulfur-containing antioxidants. Cadmium concentrations in the kidney induce renal dysfunction and contribute to hypertension due to sodium retention, glucose intolerance, dyslipidemia and zinc deficiency. Heavy metal toxicity should be evaluated in any patient with hypertension, cardiovascular heart disease, or other vascular disease. Specific testing for acute and chronic toxicity and total body burden using hair, nail, urine and serum with baseline and provoked evaluation should be done.

MacPherson A, Bacso J., Relationship of hair calcium concentration to incidence of coronary heart disease., Sci Total Environ. 2000 Jun 8;255(1-3):11-9.

Hair calcium concentration did reflect the risk of CHD on a population basis and was strongly influenced by both the hardness of the water supply and the annual sunshine hours which also independently affected the SMR for CHD.

Detection of Potentially Myocardial Infarction Susceptible Individuals in Indian Population: A Mathematical Model Based on Copper and Zinc Status. Taneja, SK, et al. Biol. Trace Elem. Res. 75, 2000.

Zinc and copper concentrations were measured in the hair and urine of patients who were hospitalized for myocardial infarction (MI). Mineral concentrations were also measured in descendants of the patients and compared to a control group. The study suggests that in MI patients, a genetic disorder of mineral imbalance at a younger age can be used in predicting susceptibility to heart disease in individuals prior to onset and diagnosis in asymptomatic patients.

Virtanen JK, Voutilainen S, Rissanen TH, Mursu J, Tuomainen TP, Korhonen MJ, Valkonen VP, Seppanen K, Laukkanen JA, Salonen JT., Mercury, fish oils, and risk of acute coronary events and cardiovascular disease, coronary heart disease, and all-cause mortality in men in eastern Finland., Arterioscler Thromb Vasc Biol. 2005 Jan;25(1):228-33. Epub 2004 Nov 11.

High content of mercury in hair may be a risk factor for acute coronary events and CVD, CHD, and all-cause mortality in middle-aged eastern Finnish men.

Afridi, HI., et al. Evaluation of Toxic Elements in Scalp Hair Samples of Myocardial Infarction Patients at Different Stages as Related to Controls. Biol. Trace Elem. Res.134, 1, 2010.

Heavy metals are being increasingly recognized as mediators or factors in the development and progression of cardiovascular disease and that a deficiency, lack of homeostatic control or excess intake of some metals may lead to cardiovascular mortality.

Park, B, et.al. High Calcium­Magnesium Ratio in Hair is Associated with Coronary Artery Calcification in Middle Aged and Elderly Individuals. Biol.Trace Elem.Res. 179,1, 2017

Coronary calcification scores were strongly associated with a higher calcium­to­magnesium ratio in the hair than lower calcium to magnesium ratios found.

Metals and Neurotoxicology. Wright, RO, et al. J. Of Nutr. 138,12, 2007.

It is well known that nutritional mineral deficiency can impair neurological development. Some transitional nutrients can cause later-life health disturbances when deficient in the diet, but in excess can be just as harmful and include iron, copper, manganese, zinc and others. Heavy metals such as lead, cadmium, mercury and arsenic are also neurotoxins and when present early in life can contribute to impaired neuro-development and detrimental health effects later in life and have been called the “fetal origins of disease.” Hair concentrations of cadmium compared to reference groups were found to be higher in children with mental retardation, learning disabilities, dyslexia and lower I.Q.

Talpur, S., et al. Interaction of Lead, with Calcium, Iron and Zinc in Biological Samples of Malnourished Children. Biol. Trace Elem. Res. Aug. 2017

Results showed twice the level of lead in the malnourished group compared to the control group and half the levels of calcium, iron and zinc.

Ozden, TA, et al. Copper, Zinc and Iron Levels in Infants and Their Mothers During the First Year of Life: A prospective Study. BMC Pediatr. 15,157, 2015

Hair zinc levels and serum iron levels decreased significantly toward the end of the first year. The maternal hair copper and serum iron also decreased. The study concluded that infants appear to require an increase in zinc intake after six months of age.

Grabeklis, AR, et al. Hair Mineral and Trace Element Content in Children with Down’s Syndrome. Biol. Trace Elem. Res. Sept. 12, 2018.

Findings concluded that 1 to 2 year old children with Down’s syndrome are characterized by significant alterations of mineral and trace elements status.

Tippairote, T, et al. Hair Zinc and Severity of Symptoms Are increased in Children with Attention Deficit and Hyperactivity Disorder: a Hair Multi-element Profile Study. Biol. Trace Elem Res. 179,2, 2017.

Copper to zinc and phosphorus to zinc ratios were found to be significantly lower in affected children than controls. Apparently elevated higher hair zinc levels were correlated with more symptoms of inattention, hyperactivity and total ADHD symptoms.

Afridi, HI, et al. Assessment of selenium and mercury in biological samples of normal and night blindness children of age groups (3-7) and (8-12). Environ. Monit. Assess. 187,3, 2015.

The concentrations of selenium were lower in scalp hair and blood samples of male and female children with night blindness. Mercury was higher in hair, blood and urine compared to controls. The authors concluded that the data obtained from this study can provide guidance to clinicians and other professionals investigating deficiency of essential trace elements and excess toxic elements in children with night blindness.

Skalny, AV, et al. Whole blood and hair trace elements and minerals in children living in metal-polluted are near copper smelter in Karabash Chelyabinsk region, Russia. Environ Sci Pollut Res Int. 25,3, 2018.

Hair copper and phosphorus was highest in children living in the polluted area along with reduced levels of magnesium and calcium. The authors propose that adverse health effects in individuals living near the copper smelters may be associated not only with toxic metal exposure but also with altered mineral homeostasis.

Kim, Hy, et al. Nutrient Intakes and Hair Mineral Contents of Young Children. Pediatr Gastrol Hepatol Nutr. 19,2, 2016.

Insufficient dietary intake of calcium and iron seems to be related with decreased hair mineral contents in young children.

Cho, JM, et al. Hair Mineral and Trace Element Contents as Reliable Markers of Nutritional Status Compared to Serum Levels of These Elements in Children Newly Diagnosed with Inflammatory Bowel Disease. Biol. Trace Elem. Res. 185,1 2018.

Serum micronutrient levels need cautious interpretation in conjunction with inflammatory markers. Whereas, hair trace element measurement may support understanding micronutrient status in children with inflammatory bowel disease.

Concentrations of Selected Bioelements and Toxic Metals and Their Influence on Health Status of Children and Youth Residing in Szczecin. Kedzierska, E. Ann. Acad. Med. Stetin. 49, 2003.

This study was performed to establish a relationship between elements in the serum, red cells and hair and included one hundred and seventy-four children. Tests measured the concentrations of the heavy metals, cadmium and lead, as well as calcium, magnesium, copper, zinc and iron. Serum and red blood cell concentrations of cadmium and lead were within normal allowable levels, but hair levels exceeded maximum levels. Supplementation of magnesium and vitamin B6 was begun in children with elevated hair heavy metals. Follow-up tests showed a marked reduction in the lead and cadmium concentration in the hair and erythrocytes.

Hair Mercury Negatively Correlates with Calcium Pump Activity in Maternal and Cord Blood Erythrocytes. Huel, G, et al. Environ. Hlth. Perspect. 116,2, 2008.

Lead and mercury levels were analyzed in eighty one hair and blood samples obtained at delivery of newborns. The results found that hair mercury and lead negatively correlated with calcium pump activity in maternal and cord blood erythrocytes.

Serum and Hair Levels of Zinc, Selenium, Iron, and Copper in Children with Iron Deficiency Anemia. Gugoze, MK, et al. Biol. Trace Elem. Res. 111, 2006.

Hair levels of iron, zinc and selenium were found lower in the study group of fifty-two children diagnosed with anemia, compared to controls.

TH Ha, J Lee, YJ Kim. Hair Zinc Level Analysis and Correlative Micronutrients in Children Presenting with Malnutrition and Poor Growth. Pediatr. Gastroenterol. Hepatol, Nutr. 19, 4, 2016.

Hair mineral analyses were performed in 56 children presenting with malnutrition, poor growth, poor appetite, anorexia, with/without other GI symptoms. Zinc deficiency was found in the hair of eighty­ eight percent of the study group. Serum zinc was found low in fifty ­five percent of the affected group. Zinc therapy resulted in improvement in clinical signs and symptoms in most of the children including increase in body weight, appetite and growth.

Hair zinc and selenium levels in children with recurrent wheezing. Razi CH, Akelma AZ, Akin O, Kocak M, Ozdemir O, Celik A, Kislal FM. Pediatr Pulmonol. 2012 Dec;47(12):1185-91. doi: 10.1002/ppul.22628. Epub 2012 Sep 4

In this study, we found that TAC, hair Zn, and hair Se levels were lower in children with recurrent wheezing than healthy children and negatively correlated with wheezing episodes in the last 6 months. Also body Zn and Se levels can be reliably measured in hair samples.

Hair Minerals and Growth Ozmen, H, et al. The Levels of Calcium and Magnesium, and Of Selected Trace Elements,in Whole Blood and Scalp Hair of Children with Growth Retardation. Iran, J.Ped. 23,2, 2013.

The levels of iron and zinc were significantly lower in the whole blood of children with growth retardation compared to the control group.

Copper, Chromium, Manganese, Iron, Nickel and Zinc Levels in Biological Samples of Diabetes Mellitus Patients. Kazi, TS, et al. Biol. Trace Elem. Res. 122,1, 2008.

Hair, blood and urine minerals analyzed in diabetic patients compared to non-diabetic controls showed that the mean levels of zinc, manganese and chromium were significantly lower in the blood and scalp hair of patients diagnosed with diabetes. Higher levels of copper and iron were also found in the scalp hair of the diabetic group as well.

Krol, E, et al. The Relationship between Dietary, Serum and Hair Levels of Minerals (Fe, Zn,Cu) and Glucose Metabolism Indices in Obese Type 2 Diabetic Patients. Biol. Trace Elem. Res. Aug. 8, 2018.

Both hair and serum minerals were analyzed as well as serum insulin, HbA1c, glucose, and cholesterol. The patients with diabetes had higher hair iron and lower serum zinc than controls. Insulin levels were positively associated with the hair copper / zinc ratio.

Hotta, Y, et al. Essential and Non-essential Elements in Scalp Hair of Diabetics: Correlations with Glycated Hemoglobin (HbA1c). Biol. Pharm. Bull. 41,7, 2018.

Findings included lower tissue levels of zinc, copper and chromium in the diabetic group and these levels were significantly lower with higher HbA1c levels.

The diagnostics of diabetes mellitus based on ensemble modeling and hair/urine element level analysis. Chen H, Tan C, Lin Z, Wu T. Comput Biol Med. 2014 Jul;50:70-5.

The findings indicate that hair samples are superior to urine samples. Even so, it can provide more valuable information for prevention, diagnostics, treatment and research of diabetes by simultaneously analyzing the hair and urine samples.

Longitudinal Hair Chromium Profiles of Elderly Subjects with Normal Glucose Tolerance and Type 2 Diabetes Mellitus. Stupar, J., et al. Metabolism. 56,1, 2007.

Hair chromium levels were analyzed in a healthy elderly population and an age-matched control group with type 2 diabetes. Lower hair chromium levels were observed in the diabetic group.

Hybrid Progressive Algorithm to Recognize Type II Diabetes Based on Hair Mineral Contents. Huang, H, et al. Conf. Proc. IEEE, Eng. Med. Biol. Soc. 5, 2005.

A hybrid algorithm was applied to the hair minerals from a group of healthy individuals compared to those with diabetes and was found to be a good symptom index that could recognize individuals with type 2 diabetes.

“Reinhold, J. G.; Kfoury, G. A.; Ghalambor, M. A.; Jean, C.: Zinc and Copper Concentrations in Hair of Iranian Villagers. Am J Clin Nutr 1966; 18.

Strain, W. H.; Steadman, L. T.; Lankau, C. A.; Berliner, W. P.; Pories, W. J.: Analysis of Zinc Levels in Hair for the Diagnosis of Zinc Deficiency in Man. J Lab Clin Med 1966; 68.”

Dietary levels of some of the essential micro-elements have been reported to correspond to hair concentrations of the elements.

Ilhan A, Uz E, Kali S, Var A, Akyol O., Serum and hair trace element levels in patients with epilepsy and healthy subjects: does the antiepileptic therapy affect the element concentrations of hair?, Eur J Neurol. 1999 Nov;6(6):705-9.

We suggest that the changed element status (Zn, Mg, and Cu) in hair may play an indicator role in the diagnosis of epileptic patients.

Ng SY., Hair calcium and magnesium levels in patients with fibromyalgia: a case center study., J Manipulative Physiol Ther. 1999 Nov-Dec;22(9):586-93.

This study explored calcium and magnesium levels in patients diagnosed with fibromyalgia compared to matched controls. Findings revealed significantly higher hair levels of both calcium and magnesium in the affected group. “Wilcoxon rank sum tests showed that patients with fibromyalgia had significantly higher calcium and magnesium levels than the control subjects at alpha = .025 and .05, respectively.”

Dhaher SA, et al. Estimation of Zinc and Iron in the Serum and Hair of Women with Androgenetic Alopecia: Case-Control Study. Indian J Dermatol. 63,5, 2018.

Serum and hair zinc and iron levels were markedly lower in women experiencing hair loss compared to the control group.

BMI and levels of zinc, copper in hair, serum and urine of Turkish male patients with androgenetic alopecia. Ozturk P, Kurutas E, Ataseven A, Dokur N, Gumusalan Y, Gorur A, Tamer L, Inaloz S. J Trace Elem Med Biol. 2014 Jul;28(3):266-70.

Hence, assessing the levels of trace elements in hair of male pattern androgenetic alopecia patients may be more valuable compared to serum and urine for treatment planning.

Evaluation of chromium and manganese in biological samples (scalp hair, blood and urine) of tuberculosis and diarrhea male human immunodeficiency virus patients. Afridi HI, Kazi TG, Talpur FN, Arain S, Arain SS, Kazi N, Panhwar AH, Brahman KD. Clin Lab. 2014;60(8):1333-41.

The consequence of trace elements deficiency has been associated with an increased risk of human immunodeficiency virus type 1 (HIV-1) disease progression and mortality.

Toxic Trace Metals in Mammalian Hair and Nails. United States Environmental Protection Agency Publication 1979; EPA-600/4: 79: 049

The consensus of most workers in the field is that if hair samples are collected properly, cleaned and prepared for analysis correctly and analyzed by the best analytical methods, using standards and blanks as required, in a clean and reliable laboratory, by experienced personnel, the data are reliable.

Gilbert, R. I.: Trace Elements in Human Hair and Bone. Hair, Trace Elements and Human Illness Brown, A.C.; Crounse, R. G. ed. Praeger Publications, 1980.

The proliferation of trace element analysis as a tool for biological investigation of nutrition, growth and development, and disease processes has led to consideration of (hair) trace element analysis as a means not only of present evaluation and estimation, but also as a technique for the reconstruction of past biological events in an organism.

Batzevich VA., Hair trace element analysis in human ecology studies., Sci Total Environ. 1995 Mar 15;164(2):89-98.

The significance of hair analysis as a biological indicator of abnormal intake of trace elements in man is confirmed. Geographical variations of hair trace element concentrations, on the whole, depend on geochemical conditions or nutritional factors.

Momcilovic, B, et al. In search of decoding the syntax of the bioelements in human hair – A critical overview. J. Trace Elem Med Biol. 50, 2018.

The complex five element interdependence is cross relate to P which proved the energy from thee phosphorus of the DNA nucleotide backbone. The hair multi element profile allows us to envisage the more complex structural metabolic features that bio-elements are playing in the body.

Barlow, P. J.; Kapel, M.: Metal and Sulfur Contents of Hair in Relation to Certain Mental States. Hair, Trace Elements, and Human Illness Brown, A.C.; Crounse, R. G., eds. Praeger Publications, 1980.

The result of research studies indicate that hair mineral analysis can be useful as a diagnostic tool in the examination of trace metal exposure, including abnormal nutritional intake, and may assist in the study of certain mental states. They (hair mineral analysis) may suggest mineral imbalances present in the body that perhaps could be rectified by a mineral supplemented diet.

Hair metal testing is a fascinating new diagnostic tool and often gives unexpected clues to mineral imbalances in the body. The authors would support this statement from the results that they have accumulated to date.

Hopps, H. C.: The Biological Bases for Using Hair and Nail for Analysis of Trace Elements. Sci Tot Environ 1977; 7.

The constituents of the hair is determined by the entry of substances from external sources and from substances which enter it from the blood stream.

Rush E, Li L, Chandu V, Whiting R., Hair zinc concentrations not subject to seasonal variation in adults in New Zealand., Biol Trace Elem Res. 2003 Dec;95(3):193-202.

The analysis of recently grown hair for zinc provides a biomarker of recent zinc status.

Contiero E, Folin M., Trace elements nutritional status. Use of hair as a diagnostic tool., Biol Trace Elem Res. 1994 Feb;40(2):151-60.

These data confirm that the analysis of Zn in hair represents an addition to conventional materials in the assessment of the nutritional status of groups of individuals.

Maugh, T. H. Hair: A Diagnostic Tool to Complement Blood Serum and Urine. Science1978; 202.

Hair may provide a continuous record of nutritional status.

Bisse E, Renner F, Sussmann S, Scholmerich J, Wieland H., Hair iron content: possible marker to complement monitoring therapy of iron deficiency in patients with chronic inflammatory bowel diseases?, Clin Chem. 1996 Aug;42(8 Pt 1):1270-4.

Changes in the hair iron concentrations were accompanied by similar changes in the concentrations of the markers most commonly used to diagnose and monitor iron deficiency. The results suggest that quantification of hair iron may be useful to complement evaluations of the body iron status.

Cadmium, Copper, Lead and Zinc Concentration in Human Scalp and Pubic Hair. Wilhelm, M, et al. Instit, Toxicol. Univ. of Dussseldorf, W. Wermany. 199-206, Vol. 92, 1990.

It is concluded that hair metal analysis in samples close to the scalp is not seriously invalidated by sources of external contamination.

Katz, S. A. Professor of Chemistry, Rutgers University.: The Use of Hair as a Biopsy Material for Trace Elements in the Body. Am Lab 1979; Feb.

The elemental analysis of hair is becoming increasingly popular for the assessment of nutritional status.

Sukumar A., Factors influencing levels of trace elements in human hair., Rev Environ Contam Toxicol. 2002;175:47-78.

Regarding certain factors (age, sex, health, occupation, etc.), the influence causing the change in element levels is obvious, whereas the influence of other factors (structure of hair, height and weight of the subject, etc.) is obscure. It is very important to consider all the factors at the time of investigation for effective interpretation, validity, and application of results of hair analysis.

Hopps, H. C.: The Biological Bases for Using Hair and Nail for Analysis of Trace Elements. Trace Substances In Environmental Health VIII. Hemphill, D.D., ed. University of Missouri, Columbia. 1974.

Research literature supports the view that trace element content of the hair and nail reflect body intake…from which one can conclude that hair and nail are suitable samples for evaluating body stores.

Gill US, Schwartz HM, Bigras L., Results of multiyear international interlaboratory comparison program for mercury in human hair., Arch Environ Contam Toxicol. 2002 Nov;43(4):466-72.

The results of the quality assurance program, which included 31 participants on four continents, are described. Of the participating laboratories, 92% consistently meet QA/QC performance limits for the determination of Hg in human hair.

Biomonitoring of arsenic, cadmium, lead, manganese and mercury in urine and hair of children living near mining and industrial areas. Molina-Villalba I, Lacasaña M, Rodríguez-Barranco M, Hernández AF, Gonzalez-Alzaga B, Aguilar-Garduño C, Gil F. Chemosphere. 2015 Apr;124:83-91. doi: 10.1016/j.chemosphere.2014.11.016. Epub 2014 Nov 27

Although human hair can be a useful tool for biomonitoring temporal changes in metal concentrations, levels are not correlated with those found in urine except for total mercury, thus providing additional information.

Ryabukhin, T.S.: International Coordinated Program on Activation Analysis of Trace Element Pollutants in Human Hair. Hair, Trace Elements, and Human Illness. Brown, A. C.; Crounse, R. G., ed. Praeger Publications, 1980.

Several research programs for studying and establishing hair trace mineral concentrations have been implemented since 1965 by the International Atomic Energy Agency. These research programs have been coordinated under “Nuclear-based Methods for the Analysis of Pollutants in Human Hair.” Hair was chosen by the I.A.E.A. due to the concentration of minerals in the hair and its reflection of both external and internal contamination. The bulk of data on trace element concentrations has been reported from hair samples obtained from the scalp.

Karpas Z, Lorber A, Sela H, Paz-Tal O, Hagag Y, Kurttio P, Salonen L., Measurement of the 234U/238U ratio by MC-ICPMS in drinking water, hair, nails, and urine as an indicator of uranium exposure source. Health Phys. 2005 Oct;89(4):315-21.

Bioassay of hair is attractive as it is an effective bio-concentrator, samples can be easily stored, the concentration reflects an integrated value, and, finally, the measurement of the (234)U/(238)U isotopic ratio in digested hair samples by MC-ICPMS is feasible and highly informative.

Distribution of arsenic, cadmium, lead, and nickel levels in biological samples of Pakistani hypertensive patients and control subjects. Afridi HI, Kazi TG, Talpur FN, Arain S, Arain SS, Kazi N, Panhwar AH. Clin Lab. 2014;60(8):1309-18

The high exposure of toxic elements may be synergistic with risk factors associated with hypertension. These data present guidance to clinicians and other professionals who will be investigating the toxicity of heavy elements in biological samples (scalp hair and blood) of hypertensive patients.

Wang, B, et al. Alkaline-earth elements of scalp hair and presence of hypertension in housewives: A perspective of chronic effect. Chemosphere, 181, 2017.

Lower levels of these elements was associated an increase presence of hypertension and reflected the different dietary intake between the two groups tested.

Blood pressure and levels of Fe, Ca, Mg, Zn, Cu, Na and K in the hair of young Bantu men from Tanzania. Rębacz-Maron E, Baranowska-Bosiacka I, Gutowska I, Chlubek D. Biol Trace Elem Res. 2013 Mar;151(3):350-9. doi: 10.1007/s12011-012-9578-3. Epub 2013 Jan 3

Hair analysis used to determine mineral content in the body may be an auxiliary tool in identifying the links between factors leading to the development of hypertension.

Pihl, R. O.; Drake, H.; Vrana, F. Department of Psychology, McGill University, Montreal, Quebec, Canada.: Hair Analysis in Learning and Behavior Problems. Hair, Trace Elements, and Human Illness. Brown, A. C.; Crounse, R. G., eds. Praeger Publications, 1980.

High levels of certain minerals, especially lead and cadmium, and low levels of other minerals, especially potassium and sodium, tend to be associated with undesirable behavior.

Investigation of essential trace and toxic elements in biological samples (blood, serum and scalp hair) of liver cirrhotic/cancer female patients before and after mineral supplementation. Kolachi NF, Kazi TG, Afridi HI, Kazi NG, Khan S. Clin Nutr. 2012 Dec;31(6):967-73. doi: 10.1016/j.clnu.2012.04.015. Epub 2012 May 17.

The pathogenesis of liver cirrhosis/cancer has been associated with changes in the balance of certain essential trace and toxic elements. It was observed that the status of Se and Zn in addition to some biochemical parameters was improved in biological samples of both groups of patients after sixty days treatment with mineral supplementation.

Hair selenium levels in hepatic steatosis patients. Pan D, Huang H. Biol Trace Elem Res. 2013 Jun;152(3):305-9. doi: 10.1007/s12011-013-9624-9. Epub 2013 Feb 15

Analysis of t test showed a significant difference between NASH (P < 0.001) patients in hair selenium concentrations when compared with controls.

Hair Zinc and Copper Levels and Serum Testosterone Chang, CS, et al. Correlation between serum testosterone level and concentrations of copper and zinc in hair tissue. Biol.Trac.Elem.Res. 144, 2011.

Findings reported that individuals with normal serum testosterone levels had a significantly higher HTMA zinc level compared to a low testosterone group. Also, the study concluded that decreased testosterone was associated with a significant reduction of the zinc to copper ratio in hair samples.

Hair Mineral Concentrations and Insulin Resistance Chung, JH, Yum, KS.Correlation of Hair Mineral Concentrations with InsulinResistance in Korean Males. Biol.Trace Elem.Res. 150, 12,2012.

They found a significant correlation between the hair calcium to magnesium ratio with HOMAIR and insulin. Their findings concluded that insulin resistance was increased along with increased hair calcium to magnesium ratio and decreased concentrations of hair chromium.

A Review of Hair Analysis for Minerals, Hormones and Drugs Ahmad, G. et al. A review Hair tissue Analysis: An analytical method for determining essential elements, toxic elements, hormones and drug use and abuse. Intl.Res.J.Appl.Basic Sci. 4, 2013.

Various mineral imbalances as revealed by hair analysis can indicate metabolic dysfunctions before any symptoms occur, and that hair analysis of minerals is used not only for diagnostic purpose but also to monitor the nutritional state of the patient until treatment benefits are achieved and the effects of the program have been stabilized.

Sukumar A, Subramanian R., Elements in hair and nails of urban residents of New Delhi. CHD, hypertensive, and diabetic cases., Biol Trace Elem Res. 1992 Jul;34(1):89-97.

Thus, it is observed that there exists some positive correlation between element levels in hair and nails and CHD, hypertension, and diabetes of these subjects.

Hair Tissue Mineral Analysis and Metabolic Syndrome. Park, SB, et al. Biol.Trace Elem.Res. 130,3, 2009.

As part of the metabolic syndrome, the optimal calcium and magnesium concentrations in hair tissue may reflect decreased risk of metabolic syndrome.

Kozielec T, Salacka A, Karakiewicz B., The influence of magnesium supplementation on concentrations of chosen bioelements and toxic metals in adult human hair. Magnesium and chosen bioelements in hair., Magnes Res. 2004 Sep;17(3):183-8.

Hair tissue mineral analysis was performed on one-hundred and twenty individuals. Supplementation of magnesium and vitamin B6 was implemented in the treatment groups and placebos in the control group. Repeat hair mineral analysis revealed a positive influence as a result of supplementation. Magnesium levels were increased in the hair along with a significant reduction of the heavy metals, lead and cadmium. “The above mentioned results indicate a positive influence of magnesium supplementation on the decrease of lead and cadmium hair content in the individuals studied.”

Sauberlich, H. E.; Scala, J. H. Department of Nutrition, Letterman Army Institute of Research, San Francisco, California.

Dowdy, R. P. Department of Human Nutrition, Foods, and Food Systems Management, University of Missouri, Columbia, Missouri”

One such procedure which has shown great potential, at least for the determination of micro-element nutriture…, is the use of hair as the biological sample. Perhaps an even more important advantage would be that hair, by the very nature of the sample, should reflect a rather long-term nutritional state rather than recent (i.e. previous meal or day) dietary intake.

Casey, C. E.; Hambidge, K. M.: Trace Element Deficiencies in Man. Advances In Nutritional Research Vol.3. Draper, H. H., ed. Plenum Pub., 1980.

Hambidge, K. M.; Walravens, P.A.: Trace Elements in Nutrition. Prac Ped 1974, 1:1″

Hair concentrations may provide useful information on longer term nutrition.

Stevens, B. J.: Determination of Aluminum, Copper, and Zinc in Human Hair. Atomic Spectroscopy 1983; 4:45

There is now a considerable body of literature on the use of hair in forensic science, in the diagnosis of disease states, and in the assessment of nutritional status.

Strain, W. H.; Pories, W. J.; Flynn, A.; Hill, O. A.: Trace Element Nutriture and Metabolism Through Head Hair Analysis. Trace Substances in Environmental Health. Hemphill, D. D., ed. University of Missouri Press, Columbia, 1972.

Human head hair is a recording filament that can reflect metabolic changes of many elements over long periods of time and thus furnish a print-out of post nutritional events.

Excess Hair Mineral Accumulation, Oxidative Stress And Parkinsonism Komatsu,F, et. al. A High Accumulation of Hair Minerals in Mongolian People: 2(nd) Report; Influence of Manganese, Iron, Lead, Cadmium and Aluminum to Oxidative Stress, Parkinsonism and Arthritis. Curr. Aging Sci. 1, 2011.

Results showed that Mongolian subjects particularly those with Parkinsonism and arthritis had high accumulation of manganese, iron, lead, cadmium and aluminum in the hair compared to the controls. It was reported that the urinary 8OHdG also correlated with the hair mineral results.

Akainy, AV, et al. Toxicological and nutritional status of trace elements in hair of women with in vitro fertilization (IVF) pregnancy and their 9-months-old children. Reprod. Toxicol. 11,81, 2018.

The children of the IVF group had low hair levels of chromium, iron, magnesium and higher mercury and molybdenum compared to the control group. Hair mineral levels were associated with infertility and pregnancy complications. The authors conclude that the results suggest the need for preconception monitoring and correction of essential elements as well as toxic metals in order to improve the course of pregnancy and child development.

Momcilvic, B, et al. High hair selenium mother to fetus transfer after the Brazil nuts consumption. J Trace Elem Med Biol. 33, 2016.

High infant hair selenium mirrored a natural high mother to fetus trans placental transfer of bio elements in the last trimester of pregnancy.

Yan, L, et al. Association of essential trace metals in maternal hair with the risk of neural tube defects in offspring. Birth defects Res. 109, 2017.

Maternal intakes of essential trace minerals played an important role in the formation of neural tube defects in our study population and is related to maternal dietary habits.

Leung PL, Huang HM, Sun DZ, Zhu MG., Hair concentrations of calcium, iron, and zinc in pregnant women and effects of supplementation., Biol Trace Elem Res. 1999 Sep;69(3):269-82.

From the analyses, it was clear that hair concentrations of Ca, Fe, and Zn could reflect the effects of supplementation.

Selenium Levels in Related Biological Samples: Human Placenta, Maternal and Umbilical Cord Blood, Hair and Nails. Lorenzo, A, et al. J. Trace Elem. Med. Biol. 19,1, 2005.

A positive correlation of selenium levels was found between samples of umbilical cord blood and the newborn’s hair. Correlation was also found between placenta and umbilical cord blood and between cord blood and maternal blood.

Huang HM, Leung PL, Sun DZ, Zhu MG., Hair and serum calcium, iron, copper, and zinc levels during normal pregnancy at three trimesters., Biol Trace Elem Res. 1999 Aug;69(2):111-20.

The hair concentrations of Ca, Fe, Cu, and Zn in the three groups of gravida were lower or significantly lower than those in controls. In sera, the differences did not show statistical significance in most cases

Hair Mineral Levels in Rheumatoid Arthritis Patients Afridi, HI, et al. Evaluation of status of zinc, copper and iron levels in biological samples of normal and arthritis patients in age groups 46-60 and 61-75 years. Clin. Lab. 58, 2012.

These data present guidance to clinicians and other professionals investigating deficiency of essential trace metals in biological samples (scalp hair and blood) of RA patients.

Rahman, A. et al. Zinc, Manganese, Calcium, Copper and Cadmium Level in Scalp Hair Samples of Schizophrenic Patients. Biol.Trace Elem. Res. 127,2, 2009.

Imbalances in the optimum levels of trace elements may adversely affect the biological process and are associated with many disease processes.

Hair Zinc Levels and Dermatitis Kim, JE, et al. Hair Zinc Levels and the Efficacy of Oral Zinc Supplementation in Children with Atopic Dermatitis. Acta Derm Venereol, 94, 2014.

HTMA studies found that those affected with atopic dermatitis had significantly reduced zinc levels compared to controls.

Kudabayeva, KI, et al. Hair Trace Elements are Associated with Increased Thyroid Volume in Schoolchildren with Goiter. Biol Trace Elem Res. 174, 2016.

We hypothesize that an increased thyroid volume in children is associated with a complex interplay of iodine with other trace elements rather than with altered iodine status itself.

Hair Trace Elements in Patients with Goiter. Farkhutdinova, LM, et al. Klin Lab Diagn. Aug. (8) 2006.

Both deficiency and excess of trace elements was shown to be of pathogenetic value in the development of thyroid disease.

Skalny, AV, et al. Whole Blood and Hair Trace Elements and Minerals in Children Living in Metal­Polluted Area Near Copper Smelter in Karabash, Chelyabinsk Region, Russia.. Environ. Sci. Pollut. Res. Int. 2016.

Their findings show that adverse health effects of individuals living near or in a polluted environment is not only associated with heavy metals exposure, but altered mineral homeostasis as well.

Shishniashvili, TE, et al. Primary Teeth and Hair as Indicators of Environmental Pollution.J. Clin. Pediatr. Dent. 40,2, 2016.

Hair and dental tests showed higher levels of lead, mercury and tin in tissues obtained from groups living in polluted areas. Therefore, hair and dental material can be used as indicators of environmental pollution.

Jamshidi, S, et al. Evaluation of scalp hair nickel and chromium level changes in patients with fixed orthodontic appliance: a one-year follow-up study. Acta Odontol Scand. 76,1 2018.

Hair samples were analyzed in a group of individuals with orthodontic appliances after one year since placed. Elevated levels of both nickel and chromium were found in the treatment group compared to controls.

“Al-Shahristani, H.; Al-Haddad, I. K.: Mercury Content of Hair From Normal and Poisoned Persons. J Radioanalytical Chem 1973; 15.

Al-Shahristani, H.; Shihab, K. M.: Variation of Biological Half-Life of Methylmercury in Man. Arch Environ Health 1974; 28.”

An example of how mineral intake is reflected in the hair was demonstrated in a study of several thousand Iraqi peasants, whose diet contained grain heavily treated with fungicides. The fungicides contained organic mercury, which was reflected in higher concentrations in the hair when consumption was highest and decreased when consumption was lowest. Hair concentrations correlated directly with the extent of symptoms.

Spallholz JE, Boylan LM, Palace V, Chen J, Smith L, Rahman MM, Robertson JD., Arsenic and Selenium in Human Hair; A comparison of Five Countries With and Without Arsenicosis., Biol Trace Elem Res. 2005 Aug;106(2):133-44.

Hair samples collected and analyzed from five countries with known arsenic sources, both high and low included the United States, Canada, and People’s Republic of China, Bangladesh and Nepal. Hair arsenic concentration in all hair samples correlated with the amount of arsenic in drinking water and revealed the low intake of selenium in areas of high arsenic concentrations. The results demonstrate the viability of hair as a noninvasive biomonitor in assessing aspects of dietary Se and environmental As exposure.

Buononato, EV, et al. Assessment of environmental and occupational exposure to heavy metals in Taranto and other provinces of Southern Italy by mean of scalp hair analysis. Environ. Monit. Assess. 188,6, 2016.

Hair mineral analysis was used to monitor heavy metals in industrialized areas to assess exposure of environmental pollution.

Blood and hair manganese concentrations in pregnant women from the infants’ environmental health study (ISA) in Costa Rica. Mora AM, van Wendel de Joode B, Mergler D, Córdoba L, Cano C, Quesada R, Smith DR, Menezes-Filho JA, Lundh T, Lindh CH, Bradman A, Eskenazi B. Environ Sci Technol. 2014 Mar 18;48(6):3467-76.

Hair Mn concentrations were inversely associated with gestational age at sampling and positively associated with living within 50 m of a plantation and Mn concentrations in drinking water. Our findings suggest that pregnant women living near banana plantations aerially sprayed with mancozeb may be environmentally exposed to Mn.

Evaluation of Toxic Metals in Biological Samples (Scalp Hair, Blood and Urine) of Steel Mill Workers by Electrothermal Atomic Adsorption Spectrometry. Afridi, HI, et al. Toxicol. Ind. Hlth. 9, 2006.

Levels of lead, cadmium and nickel in scalp hair, blood and urine samples were significantly higher in groups of exposed workers compared to those of a control group. The determination of toxic metals in the biological samples of human beings is an important clinical screening procedure.

Nickel in Nails, Hair and Plasma from Nickel-Hypersensitive Women. Gammelgaard, et al. Acta. Derm. Venereol. 417, Vol. 70, 1990.

Nickel- sensitive women had significantly higher levels of nickel in nails, hair and plasma than control subjects.

Srivastava AK, Gupta BN, Bihari V, Gaur JS, Mathur N., Hair selenium as a monitoring tool for occupational exposures in relation to clinical profile., J Toxicol Environ Health. 1997 Aug 8;51(5):437-45.

The study holds promise that hair selenium may be used as a monitoring tool for low-level occupational exposure to selenium.

Potentially harmful elements (PHEs) in scalp hair, soil and metallurgical wastes in Mitrovica, Kosovo: the role of oral bioaccessibility and mineralogy in human PHE exposure. Boisa N, Bird G, Brewer PA, Dean JR, Entwistle JA, Kemp SJ, Macklin MG. Environ Int. 2013 Oct;60:56-70. doi: 10.1016/j.envint.2013.07.014. Epub 2013 Sep 4

Data for Pb levels in scalp hair (≤120μgg(-1)) and blood (≥650μgdL(-1); WHO, 2004) for children that have lived within IDP camps in Mitrovica indicate significant Pb uptake has indeed taken place.

Kehagia, K, et al. Hair Analysis as an Indicator of Exposure to Uranium. Radial.Prot. Dosimetry. Nov. 2010.

HTMA is a good indicator of exposure to uranium and without these tests many individuals would unknowingly be exposed to not only heavy metals such as uranium and other metals, but radon gas as well.

Black AP, Knight R, Batty J, Haswell SJ, Lindow SW., An analysis of maternal and fetal hair lead levels., BJOG. 2002 Nov;109(11):1295-7.

Hair lead levels have been found to correlate well with body lead contamination.

Metal ions released from fixed orthodontic appliance affect hair mineral content. Mikulewicz M, Wołowiec P, Loster B, Chojnacka K. Biol Trace Elem Res. 2015 Feb;163(1-2):

By implementation of statistic pattern recognition methods, it has been found that the concentrations of trace elements in hair can remarkably reflect different recovery phases of naso-pharyngeal cancer patients.

Skalny, AV et al. The impact of lifestyle factors on age-related differences in hair trace element content in pregnant women in the third trimester. Acta Sci Pol Techn Aliment. 17, 1, 2018.

Older pregnant women had lower hair zinc, vanadium and cadmium content and higher boron compared to younger women. Their data indicates that lifestyle factors has an influence on age-related changes in hair trace elements during pregnancy that may impact the outcome of pregnancy.

Cross-sectional relationship between chronic stress and mineral concentrations in hair of elementary school girls. Vanaelst B, Michels N, Huybrechts I, Clays E, Flórez MR, Balcaen L, Resano M, Aramendia M, Vanhaecke F, Rivet N, Raul JS, Lanfer A, De Henauw S. Biol Trace Elem Res. 2013 Jun;153(1-3):41-9. doi: 10.1007/s12011-013-9647-2. Epub 2013 Apr 2

This study demonstrated an independent association between chronic stress measures and hair mineral levels in young girls, indicating the importance of physiological stress-mineral pathways independently from individual or behavioural factors.