Juraj Prejac

An essay on human and elements, multielement profiles, and depression

The recent development of the analytical techniques offers the unprecedented possibility to study simultaneously concentration of dozens of elements in the same biological matrix sample of 0.5–1.0 g (multielement profiles). The first part of this essay entitled “Think globally… An outline of trace elements in health and disease” aims to introduce the reader to the fascinating field of elements, there importance to our nutrition, their essentiality, deficiency, toxicity and bioavailability to the body and their overall role in health and disease, including the genetic metabolic impairments. In the second part of the essay entitled “… and act locally. The multielement profile of depression” we aimed to show the potential of such a hair multielement profile analysis for the study of human depression in a randomized, double blind, prospective, observational, cross-sectional, clinical, epidemiological, and analytical study. The preliminary results of this ongoing study lead us to put forward the hypothesis that the metabolic origin of depression may be due to some “energostat” failure, probably located in the thalamus, and activated by several essential element deficiencies.

Hair iodine for human iodine status assessment.

BACKGROUND Today, human iodine deficiency is, after iron, the most common nutritional deficiency in developed European and underdeveloped third world countries. A current biological indicator of iodine status is urinary iodine, which reflects very recent iodine exposure; a long-term indicator of iodine status remains to be identified. METHODS We analyzed hair iodine in a prospective, observational, cross-sectional, and exploratory study involving 870 apparently healthy Croatians (270 men and 600 women). Hair iodine was analyzed with inductively coupled plasma mass spectrometry. RESULTS The hair iodine median was 0.499 μg/g, and was 0.482 and 0.508 μg/g for men and women respectively, suggesting no sex-related difference. We studied hair iodine uptake by analyzing the logistic sigmoid saturation curve of the median derivatives to assess iodine deficiency, adequacy, and excess. We estimated overt iodine deficiency to occur when hair iodine concentration was below 0.1-0.15 μg/g. Then there was a saturation range interval of about 0.1-2.0 μg/g where the deposition of iodine in the hair was linearly increasing (R(2)=0.994). Eventually, the sigmoid curve became saturated at about 2.0 μg/g and upward, suggesting excessive iodine exposure. CONCLUSION Hair appears to be a valuable and robust biological indicator tissue for assessing long-term iodine status. We propose that an adequate iodine status corresponds with hair iodine uptake saturation of 0.565-0.739 μg/g (55-65%).

A novel concept to derive iodine status of human populations from frequency distribution properties of a hair iodine concentration.

Today, human iodine deficiency is next to iron the most common nutritional deficiency in developed European and underdeveloped third world countries, respectively. A current biological indicator of iodine status is urinary iodine that reflects the very recent iodine exposure, whereas some long term indicator of iodine status remains to be identified. We analyzed hair iodine in a prospective, observational, cross-sectional, and exploratory study involving 870 apparently healthy Croatians (270 men and 600 women). Hair iodine was analyzed with the inductively coupled plasma mass spectrometry (ICP MS). Population (n870) hair iodine (IH) respective median was 0.499μgg(-1) (0.482 and 0.508μgg(-1)) for men and women, respectively, suggesting no sex related difference. We studied the hair iodine uptake by the logistic sigmoid saturation curve of the median derivatives to assess iodine deficiency, adequacy and excess. We estimated the overt iodine deficiency to occur when hair iodine concentration is below 0.15μgg(-1). Then there was a saturation range interval of about 0.15-2.0μgg(-1) (r(2)=0.994). Eventually, the sigmoid curve became saturated at about 2.0μgg(-1) and upward, suggesting excessive iodine exposure. Hair appears to be a valuable and robust long term biological indicator tissue for assessing the iodine body status. We propose adequate iodine status to correspond with the hair iodine (IH) uptake saturation of 0.565-0.739μgg(-1) (55-65%).

Environmental human silver exposure

Environmental exposure to silver (Ag) was assessed in occupationally non-exposed adult human population by analyzing Ag in the hair (H · Ag) and whole blood (WB · Ag). H · Ag was analyzed in 311 (123 men, M; 188 women, W); while WB · Ag was determined in 235 of these individuals (90 M, 145 W). Women had more H · Ag than men (M 0.05 vs. W 0.076), whereas WB · Ag concentrations in men and women were not significantly different. A natural distribution of the median derivatives was utilized to generate the dataset to fit the logistic sigmoid curve to assess the current human body burden of environmental Ag population exposure for M and W separately. The H · Ag (µg g−1) below 0.0105 for M and 0.0145 for W, reflects low level of environmental Ag exposure. The adaptive physiological saturation phase followed where H · Ag rose rapidly, first for M and then for W in parallel with biological assay. Both parallel saturation curves converged and plateaued at 0.215 for M and 0.965 for W (µg g−1). The current level of human environmental Ag exposure is low, but cases of high Ag exposure occurred sporadically. In conjunction with the medical histories overt clinical neural toxicity may be expected for H · Ag at 4 µg g−1and higher. There were no significant correlation between the H · Ag and WB · Ag.

Relationship of iodine, selenium and copper in the hair and whole blood of depressed human subjects

Lack of iodine appears to the principal nutritional factor associated with human depression. Iodine deficiency should be assessed by direct measurement of the hair iodine concentration, and not indirectly by monitoring the thyroid hormone status.

Hair for a long-term biological indicator tissue for assessing the strontium nutritional status of men and women

Strontium (Sr) is a trace element that closely resembles calcium metabolism. At the present time there is no available long-term biological indicator tissue for assessing the human Sr nutritional status. Here we have presented a novel concept on how to assess the Sr nutritional status by studying the frequency distribution properties of hair Sr (SrH) concentration. In this prospective, observational, cross-sectional, and exploratory epidemiological study, we analyzed SrH in 311 apparently healthy adult Croatians (123 men, 188 women). Hair strontium was analyzed by the ICP-MS. The natural frequency distribution of SrH followed the Power law, so that the data were analyzed by fitting the logistic bioassay sigmoid curve (ogive) of median derivatives. Women tend to accumulate three and a half time more SrH than men (median men 867ngg-1 vs. median women 3120ngg-1). The normal (adequate) linear physiological response range of the sigmoid curve was 351-3489ngg-1 for men and 846-8457ngg-1 for women. Values below that linear range are considered to indicate deficient Sr nutritional status, whereas values above that linear range indicate excessive strontium exposure. Hair, as a long-term, and whole blood as a short-term biological indicator tissues were not commensurable entities. Similarly, SrH accumulation was not age dependent in either men or women. Hair strontium is a reliable long-term biological indicator tissue for assessing the strontium nutritional status.