Is there a relationship between tea intake and maternal whole blood heavy metal concentrations?

Lead in traditional and complementary medicine: a systematic review

Lead in the environment remains a matter of grave concern for public health. Lead has been associated with some traditional medicines and has been linked to cases of lead poisoning. A comprehensive compilation of these reports has not previously been conducted. The objective of this review is to explore how common is lead exposure after traditional medicine use, and which countries, systems and/or products are of most concern when it comes to lead contamination. A systematic search was conducted on PubMed, Ovid and EMBASE for studies published between 2005 and 2020. A grey literature search was conducted. Search terms related to lead and traditional medicine were developed for each database, and there were no limitations on language. Studies were included if they examined elevated lead in humans resulting from the use of traditional medicines reported in case reports, case-series, or observational studies. Of the papers discussing lead exposure, 85 case reports were identified and synthesized for the current review. Several themes were identified in the included studies. Traditional medicine has been used in the many parts of the world, however use is more common in South and Southeast Asian countries. The level of detectable lead in products varied widely by region and product types. Consumers of traditional medicines sought products for a wide variety of symptoms and ailments. The symptoms of lead poisoning from traditional medicine use reflected the typical symptom profile of lead poisoning, highlighting the need for awareness of traditional medicine products as a source of lead exposure. Traditional medicine usage remains an important part of health care in many regions, however there is a risk of lead exposure from several products. Health care practitioners in all regions of the world should be aware of the risk and explore the potential for traditional medicine use for patients presenting with elevated blood lead levels. Countries with a strong traditional medicine culture should explore policies for reducing lead exposure from traditional medicine products. JG, LO and MNBD are staff members of the World Health Organization. The authors alone are responsible for the views expressed in this publication and they do not necessarily represent the decisions, policy, or views of the World Health Organization.

Risk assessment of metal(loid)s in tea from seven producing provinces in China

To evaluate metal(loid) contamination in tea leaves and assess health risks of tea drinking in China, metal(loid) concentrations in tea leaves from major tea-producing provinces were determined. Nine metal(loid)s (Al, Cr, Co, Ni, Cu, Zn, As, Cd and Pb) were measured in a total of 217 tea samples representing five tea varieties (black tea, dark tea, green tea, oolong tea and white tea) from seven major tea-producing provinces of China (Fujian, Guangdong, Henan, Hunan, Jiangsu, Yunnan and Zhejiang). The results indicated that tea samples from Hunan Province had the highest metal(loid) concentrations, likely due its high prevalence of heavy industrial activities and soil pollution. The concentrations of As and Pb in dark tea were markedly higher than those in other tea varieties. A strong Spearman correlation coefficient (0.78, P < 0.001) of As and Pb in all the tea varieties has also been found, indicating their similar sources. Human health risk assessment for the nine analyzed metal(loid)s indicated that co-exposure to these metal(loids) may not cause significant health risks (hazard index [HI] > 1 suggests considerable health risks). Among the five tea varieties, metal(loids)s in dark and green tea induced relatively higher health risks, with 90th percentile HI values approached 0.8. Co (53.6 %-84.5 %) and Al (3.33 %-15.8 %) made the highest contributions to the HI of the selected tea commodities. Thus, public and regulatory agencies should reduce excessive Co and Al accumulation in these tea varieties during cultivation and production processes.

Concentrations, leachability, and health risks of mercury in green tea from major production areas in China

Green tea has many health benefits and is the most consumed type in China. However, the heavy metals and contaminants in tea can also pose a great risk to human health. In this study, mercury (Hg) concentration in green tea collected from 11 provinces in China was examined. The leaching characteristics of Hg during brewing and the associated exposure to drinkers were also evaluated. Results indicated a low potential of Hg accumulation in green tea. The Hg content of green tea from Wanshan District, Guizhou Province-which has the largest Hg mine in China and is severely contaminated by Hg-could be limited by controlling the harvest time of tea leaves. The average Hg content of green tea from 43 tea production sites in China was only 6.3 ± 6.4 µg/kg dry weight. The brewing experiments of green tea showed that the leaching ratio of Hg was 22.61 ± 7.58% for 40 min of a single brew, and increased to 32.83 ± 12.37% after four rounds (3 min/ round) of brewing. The leaching of Hg from tea leaves was significantly affected by leaching time, temperature, and solid-liquid ratio but not by water hardness. The risk of Hg exposure from green tea intake was found to be very low, with an average hazard quotient (HQ) value of only 1.82 ± 1.85% for a single brew in 40 min and 2.64 ± 2.68% after four rounds of brewing. However, in some highly contaminated areas, with HQ values as high as 43.12 ± 2.41%, green tea intake may still pose a high risk of Hg exposure, and this risk should not be ignored.

Protective Effects of Green Tea Supplementation against Lead-Induced Neurotoxicity in Mice

The use of natural products as therapeutic agents is rapidly growing recently. In the current study, we investigated the protective effects of green tea supplementation on lead-induced toxicity in mice. Forty albino mice were divided into four groups as follows: A: control group; B: green tea receiving group; C: lead-intoxicated group; and D: lead-intoxicated group supplemented with green tea. At the end of the experiment, the animals were tested for neurobehavioral and biochemical alterations. Green tea was analyzed through Gas Chromatography–Mass Spectrometry (GC/MS) analysis. We found that supplementation with green tea ameliorated the lead-associated increase in body weight and blood glucose. Green tea supplementation also changed the blood picture that was affected due to lead toxicity and ameliorated lead-induced dyslipidemia. The group of mice that were supplemented with green tea has shown positive alterations in locomotory, anxiety, memory, and learning behaviors. The GC/MS analysis revealed many active ingredients among which the two most abundant were caffeine and 1,2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester. We concluded that green tea supplementation has several positive effects on the lead-induced neurotoxicity in mice and that these effects may be attributed to its main two active ingredients.

Occurrence, accumulation, and risk assessment of trace metals in tea (Camellia sinensis): A national reconnaissance

Accumulation of potentially toxic elements in soil and tea leaves is a particular concern for tea consumers worldwide. However, the contents of potentially toxic elements and their potential health and ecological risks in Chinese tea gardens have rarely been investigated on the national scale. In this study, we collected 225 paired soil and tea plant samples from 45 tea gardens in 15 provinces of China to survey the current risk of potentially toxic element accumulation in Chinese tea gardens. The results suggest that the average contents of most trace metals in rhizosphere soils meet the risk control standard for agricultural land in China. However, the mean contents of As, Cr, Cd, Zn, Cu, and Ni in rhizosphere soils were 1.94, 2.14, 1.23, 1.15, 1.18, and 1.19 times their corresponding background soil values in China. Cd had the highest geo-accumulation index, followed by As, Zn, Cr, Ni, Cu, Pb, and Mn in rhizosphere soils. Nearly 2.22% and 4.44% of soils were moderately to heavily contaminated with As and Cd, respectively. The risk index ranged from 18.0 to 292, with an average value of 90.0, indicating low to moderate ecological risk in Chinese tea gardens. This is the first national-scale reconnaissance of trace metals in tea across China. Our findings provide a useful reference for ensuring the quality and safety of tea production and mitigating the risk of toxic element accumulation in tea.

Herbal Teas and their Health Benefits: A Scoping Review

Herbal teas are used as therapeutic vehicles in many forms of traditional medicine and are a popular global beverage. The purpose of this scoping review was to examine the evidence relating to the clinical efficacy and safety of herbal teas, and to identify the main research themes and gaps in knowledge to inform further work. A scoping review methodology was followed that set out the research question and described the sourcing, selection and analysis of studies. Overall, a total of 145 research publications were retrieved from global bibliographic databases, and after applying exclusion criteria, 21 remained. These studies looked at herbal tea use in female health, diabetes, heart disease and weight loss, with plant species including lavender, chamomile, fenugreek, stinging nettle, spearmint, hibiscus, yerba maté, echinacea and combinations of herbs. Observational studies explored associations between herbal tea consumption and cancer risk, liver health, and the risks linked to the consumption of environmental contaminants in the plant material. Despite plant materials being the basis for drug discovery, and the popularity of herbal teas, the number of articles exploring clinical efficacy and safety is small. In this review we discuss how herbal teas may be beneficial in some areas of clinical and preventative health, and what further research is required to understand whether regular consumption can contribute to healthy living more generally.

Is maternal periconceptional smoking associated with 2D:4D digit ratio in their children?

The 2nd--4th finger ratio (2D:4D) has been proposed as a potential indicator of greater androgen exposure during fetal development. Maternal periconceptional smoking may alter the homeostasis of fetal androgens, which could in turn result in differential development of 2D:4Ds in utero. The aim of the present study was to assess the effect of maternal periconceptional smoking (i.e. 1 year before through the first trimester of pregnancy) on the 2D:4D of children within The Maternal-Infant Research on Environmental Chemicals (MIREC) study. Maternal smoking history was obtained through questionnaires during the first trimester of pregnancy in 2001 women from 10 cities across Canada. The periconceptional smoking prevalence was 12%. A follow-up study was conducted to measure growth and development up to 5 years of age in a subsample of some 800 MIREC children (MIREC-CD Plus), and digital pictures of the ventral surface of both hands were obtained in mothers and children (2–5 years). The 2D:4D was calculated as the ratio of the 2nd and 4th fingers of each hand. Boys had lower mean 2D:4Ds compared with girls in both hands. Age and maternal 2D:4D were strong determinants of the children’s 2D:4D, however, the mean 2D:4D did not differ among children whose mothers had smoked during the periconceptional period compared with those who had not, irrespective of sex. In conclusion, we did not find an association between maternal periconceptional smoking and children’s 2D:4D, although the smoking prevalence was low.

Arsenic levels among pregnant women and newborns in Canada: Results from the Maternal-Infant Research on Environmental Chemicals (MIREC) cohort

Arsenic is a common environmental contaminant from both naturally-occurring and anthropomorphic sources and human exposure can be detected in various tissues. Its toxicity depends on many factors including the chemical form, valence state, bioavailability, metabolism and detoxification within the human body. Of paramount concern, particularly with respect to health effects in children, is the timing of exposure as the prenatal and early life periods are more susceptible to toxic effects. The Maternal-Infant Research on Environmental Chemicals (MIREC) cohort was established to obtain national-level biomonitoring data for approximately 2,000 pregnant women and their infants between 2008 and 2011 from 10 Canadian cities. We measured total arsenic (As) in 1st and 3rd trimester maternal blood, umbilical cord blood, and infant meconium and speciated arsenic in 1st trimester maternal urine. Most pregnant women had detectable levels of total arsenic in blood (92.5% and 87.3%, respectively, for 1st and 3rd trimester); median difference between 1st and 3rd trimester was 0.1124µg/L (p<0.0001), but paired samples were moderately correlated (Spearman r=0.41, p<0.0001). Most samples were below the LOD for umbilical cord blood (50.9%) and meconium (93.9%). In 1st trimester urine samples, a high percentage (>50%) of arsenic species (arsenous acid (As-III), arsenic acid (As-V), monomethylarsonic acid (MMA), and arsenobetaine (AsB)) were also below the limit of detection, except dimethylarsinic acid (DMA). DMA (>85% detected) ranged from <LOD to 64.42 (95th percentile: 11.99)µgAs/L. There was a weak but significant correlation between total arsenic in blood and specific gravity-adjusted DMA in urine (Spearman r=0.33, p<0.0001). Among this population of pregnant woman and newborns, levels of arsenic measured in blood and urine were lower than national population figures for Canadian women of reproductive age (20-39 years). In general, higher arsenic levels were observed in women who were older, foreign-born (predominantly from Asian countries), and had higher education. Further research is needed to elucidate sources of exposure and factors that may influence arsenic exposure in pregnant women and children.

Preconception Care: A New Standard of Care within Maternal Health Services

Emerging research suggests that much pediatric affliction has origins in the vulnerable phase of fetal development. Prenatal factors including deficiency of various nutrients and exposure to assorted toxicants are major etiological determinants of myriad obstetrical complications, pediatric chronic diseases, and perhaps some genetic mutations. With recent recognition that modifiable environmental determinants, rather than genetic predestination, are the etiological source of most chronic illness, modification of environmental factors prior to conception offers the possibility of precluding various mental and physical health conditions. Environmental and lifestyle modification through informed patient choice is possible but evidence confirms that, with little to no training in clinical nutrition, toxicology, or environmental exposures, most clinicians are ill-equipped to counsel patients about this important area. With the totality of available scientific evidence that now exists on the potential to modify disease-causing gestational determinants, failure to take necessary precautionary action may render members of the medical community collectively and individually culpable for preventable illness in children. We advocate for environmental health education of maternity health professionals and the widespread adoption and implementation of preconception care. This will necessitate the translation of emerging knowledge from recent research literature, to health professionals, to reproductive-aged women, and to society at large.