University of Murcia

Lead exposure in children can affect their neurodevelopment. In the United States, the maximum blood concentration limit for this metal was lowered to 3.5 μg/dL (micrograms per decilitre) in 2021, down from 10 μg/dL in 2012. Now, a study has analysed data from more than 300,000 children in Iowa and found an association between higher concentrations and poorer school performance in reading and maths, even below the 3.5 μg/dL limit, prompting the researchers to reconsider this figure. The results are published in the journal JAMA Network Open.

Up to 1.4 billion people may be living in areas with soil contaminated by heavy metals such as arsenic, cadmium, cobalt, chromium, copper, nickel and lead, according to research published in Science. The paper, which used data from more than 1,000 studies, estimates that 14-17% of farmland worldwide could be contaminated by at least one toxic metal. Cadmium is the most widespread, especially in South and East Asia, parts of the Middle East and Africa.

Toddlers' screen time has a negative correlation with their language skills, according to a study published in PLoS ONE. However, the use of educational content and screen time in the company of adults show a positive association with language skills. The study included nearly 1,900 children between one and four years old from 19 Latin American countries.

Inflammation is all the rage. In fact, anti-inflammatory diets that claim to fight it. This is attested to by best-selling books and influencers, ready to give us the latest tips on how to lose weight, or rather, how to reduce inflammation. But what's the truth in all this, and what does inflammation have to do with being overweight? 

An international team of researchers has analyzed various data sources and scientific literature and identified 3,601 chemical substances in human samples such as blood, urine or breast milk that are known to be in contact with food, for example, because they are used in packaging. According to the authors of the study, “this work shows that food contact materials are not completely safe, even if they comply with regulations, because they transfer known substances to food". The research is published in the Journal of Exposure Science and Environmental Epidemiology.

A study published in Nature in which researchers from the University of Valencia have participated has identified a neuron migration route that begins in the foetus around mid-gestation and continues until between two and three years of age. The route extends from the lateral ventricle, where these cells are born, to the entorhinal cortex, an area related to the regions where memory and learning are consolidated. There, neurons await signals that induce them to mature, providing plasticity to the brain after birth.

Mercury concentrations in tuna have remained stable between 1971 and 2022, even though emissions of this metal from human activities have decreased over the same period, a study says. 'Aggressive' emission reduction targets are needed to achieve measurable declines in concentrations of this pollutant, which is toxic for human health, the authors write in the journal Environmental Science & Technology Letters. The Minimata Convention on Mercury, a global treaty that entered into force in 2017, bans new mercury mines and includes provision to reduce mercury use, but mercury has already accumulated in the ocean 'for centuries', the article says.

Heavy metals - including arsenic, cadmium and mercury - may adversely affect the ovaries of women approaching menopause, a study claims. Those with high levels of metals in their urine had lower levels of anti-Müllerian hormone, indicating diminished ovarian reserve - fewer oocytes in the ovaries compared to other women of that age. The authors, whose study is published in The Journal of Clinical Endocrinology & Metabolism, used urine data from more than 500 women in the US up to 10 years before their last menstrual period.

Drinking less than 25 grams of alcohol a day (2.5 standard drinking units, the equivalent of two and a half pints) does not reduce mortality, according to an analysis that aggregates data from 107 previous studies and 4.8 million people. Some studies claim that people who drink alcohol in low doses live longer and are less likely to die of cardiovascular disease than those who abstain completely. This meta-analysis published in JAMA Network Open, which brings together studies published between 1980 and 2022 in several countries, found no such protective effect. It did find a significant increase in the risk of mortality at 25 g per day for women and 45 g per day for men. In Spain, the Ministry of Health sets the limits for low-risk consumption at 10 g of alcohol per day for women and 20 g for men.

Using genetic data from more than 340,000 participants of European descent, research has identified five genetic variants that make people more susceptible to myopia in combination with intensive schooling, especially university studies. The results are published in PLOS Genetics.