Hair analysis and selenium shampoos

Hair zinc and selenium levels in children with recurrent wheezing

The prevalence of asthma and other allergic diseases has increased markedly in the last few decades. Oxidative stress plays a central role in asthma pathogenesis, and reduced daily consumption of antioxidants is positively correlated with increased risk of asthma. Zinc (Zn) and selenium (Se) are the main antioxidant elements. In our study, we aimed to investigate hair Zn and Se levels in children with recurrent wheezing. The study included 65 patients with recurrent wheezing (RW) and 65 healthy children (HC). The hair Zn and Se levels (µg/g) of the RW group were lower in comparison with the HC group (162.43 ± 91.52 vs. 236.38 ± 126.44, P < 0.001, and 217.37 ± 83.01 vs. 280.53 ± 122.73, P < 0.001, respectively). Total antioxidant capacity (TAC) (mmol/L) of the RW group was found to be significantly lower in comparison with the HC group (1.38 ± 0.14 vs. 1.53 ± 0.20, respectively; P < 0.001). Number of wheezing episodes in the last 6 months were negatively correlated with serum TAC, hair Zn, and Se levels in RW group (r(p)  = -0.291, P = 0.001; r(p)  = -0.209, P = 0.017; r(p)  = -0.206, P = 0.019, respectively). The number of acute respiratory tract infection (ARTI) episodes in the last 6 months was negatively correlated with serum TAC and hair Zn levels (r(p)  = -0.316, P < 0.001, and r(p)  = -0.196, P = 0.025, respectively). In this study, we found that TAC, hair Zn, and hair Se levels were lower in children with RW than HC and negatively correlated with wheezing episodes in the last 6 months. Also body Zn and Se levels can be reliably measured in hair samples.

Effects of excess selenomethionine on selenium status indicators in pregnant long-tailed macaques (Macaca fascicularis)

Forty pregnant long-tailed macaques were treated daily for 30 d with 0, 25, 150, or 300 micrograms selenium as L-selenomethionine/kg body weight. Erythrocyte and plasma selenium and glutathione peroxidase specific activities, hair and fecal selenium, and urinary selenium excretion were increased by and were linearly related to L-selenomethionine dose. Hair selenium was most sensitive to L-selenomethionine dose, with an 84-fold increase in the 300 micrograms selenium/(kg-d) group relative to controls (r = 0.917). Daily urinary selenium excretion (80-fold, r = 0.958), plasma selenium (22-fold, r = 0.885), erythrocyte selenium (24-fold, r = 0.920), and fecal selenium (18-fold, r = 0.911) also responded strongly to L-selenomethionine. Erythrocyte and plasma glutathione peroxidase specific activities increased 154% and 69% over controls, respectively. Toxicity was associated with erythrocyte selenium > 2.3 micrograms/mL, plasma selenium > 2.8 micrograms/mL, and hair selenium > 27 micrograms/g. Plasma, erythrocyte, and hair selenium concentrations may be useful for monitoring and preventing the toxicity of L-selenomethionine administered to humans in cancer chemoprevention trials.

Selenium in human urine: concentration levels and medical implications

Selenium concentration values for human urine samples are presented, and the literature on the chemical species of the element in urine is critically reviewed. Daily excretion levels in healthy persons and in pathological or experimental conditions are compiled. Medical implications and the significance of urinary selenium determination in assessing the selenium status in man are discussed.

Dietary selenium in humans toenails as an indicator

Mounting laboratory and epidemiologic evidence suggests that selenium may be important in the etiology of both cancer and heart disease. We explored the use of hair and nails as indicators of selenium intake by measuring their selenium levels using neutron activation analysis, a highly sensitive and precise nondestructive technique. Levels in duplicate samples of nails, hair, and blood were all reasonably reproducible. However, selenium-containing shampoos severely contaminated some of the hair specimens, suggesting that use of hair in epidemiologic studies could be misleading. The mean selenium level in toenails from South Dakota (a known high selenium area) was 1.17 ppm (1SE = 0.09). This was significantly higher than mean levels from Boston and Georgia (medium selenium intake area) of 0.74 ppm (0.04) and 0.81 (0.03), respectively. The mean selenium level in toenails from New Zealand (low selenium area) was 0.26 (0.02) and these levels did not overlap those of other areas. The South Dakota specimens showed marked familial aggregation, probably reflecting dietary differences. Since toenails vary in length, clippings from different toes represent different time periods of formation; clippings from all ten toes reflect selenium levels integrated over an extended period. As toenails are easily collected, transported, and stored, and reflect longterm intake, they can be useful in epidemiologic studies of selenium and chronic disease.

Misuse of hair analysis for nutritional assessment

The analysis of hair for nutritional assessment has a number of potential pitfalls, which include: (1) contamination by sweat, (2) environmental contamination, (3) influence of previous beauty treatments, (4) critical dependence upon location of the hair sample, (5) paradoxic values depending upon the rate of hair growth, and (6) lack of clear definition of a normal range. The results of measuring metal concentrations in hair even under ideal circumstances may not correlate with those obtained in blood and urine. Long-term exposure to heavy metals, including lead, cadmium, arsenic, and mercury, can be readily identified by hair analysis. Little if any value is derived from a random examination of hair as the sole procedure for nutritional assessment. Nutritional recommendations should not be based on the results of hair analysis alone.