What the scientists are saying…
Alcohol linked to DNA damage Numerous studies have suggested that drinking alcohol raises the risk of several common types of cancer, including breast and oesophagus – but the precise mechanism by which it might do so has always been mysterious. Now, researchers at the University of Cambridge think they may have pinpointed it. In experiments that involved giving ethanol to mice, they observed that a toxin called acetaldehyde – produced as alcohol is broken down – damages the DNA of stem cells in the blood, permanently altering the DNA sequencing. The study also looked at how the body protects itself against alcohol. The liver produces enzymes called aldehyde dehydrogenase (ALDH), which break down acetaldehyde, preventing its build-up. However, drinking too much may overwhelm this defence system – and millions of people (many of them in East Asia, where rates of oesophagal cancer are unusually high) carry a genetic mutation that renders it ineffective. The researchers found that mice bred not to produce one of these enzymes – ALDH2 – experienced four times more cell damage after being given alcohol than a control group with normal enzyme levels. “How exactly alcohol causes damage to us is controversial,” study co-author Professor Ketan Patel told The Guardian. “This paper provides very strong evidence that an alcohol metabolite causes DNA damage [including] to the all-important stem cells that go on to make tissues.”
Spinach may boost the brain People whose diets contain substantial quantities of leafy green vegetables are more likely to retain their memories in old age, scientists have opined. The study at Rush University in Chicago tracked 960 people with an average age of 81 (none of whom had dementia) for up to a decade, quizzing them about diets and giving them annual mental aptitude tests. The participants were put into five groups depending on their leafy greens consumption. Those in the group that ingested the highest amount, averaging 1.3 servings per day of vegetables such as spinach and kale were significantly less likely to have experienced cognitive decline than those in the group that consumed the least, averaging 0.1 servings. Being observational, the study does not establish a causative link between the vegetables and memory preservation, but forms part of a growing body of evidence that finds certain foods contribute to cognitive health.
The risk of a dryer world About a quarter of the world’s land surface is likely to become arid if global temperatures rise to 2˚C above pre- industrial levels, scientists have warned. Yet according to an international study of aridity – a measure of the dryness of the land – the area affected would be very much reduced if the rise were limited to 1.5˚C (temperatures are currently about 1˚C above pre-industrial levels). Researchers studied projections from 27 climate models to identify the areas where aridification would emerge as temperatures rise, and found that they covered 20% to 30% of the world’s surface, in Southeast Asia, southern Europe, southern Africa, Central America and southern Australia. A rise of 2˚C would mean that these regions, which are home to about 1.5 billion people, start to experience drought, wildfires and reduced biodiversity, the team said in the journal Nature Climate Change. However, two-thirds of the regions should avoid significant aridification if warming can be limited to 1.5˚C. The 2015 Paris Agreement states that signatories will pursue efforts to keep global increases within 1.5˚C – but some climate scientists believe that it’s already too late to prevent global warming crossing the 2˚C threshold.
Killer plant disease heading to UK A dangerous pathogen that has wiped out olive groves in Europe could be heading to Britain, horticulturalists have warned. Xylella fastidiosa, which can infect 350 species of plant, ranging from lavender to cherry trees, invades the vessels that plants use to convey water, leaving them wilted and dying. Although the EU has imposed strict measures to halt the spread, the Royal Horticultural Society believes there is a very real risk of it still reaching the UK. It is urging gardeners to buy plants propagated from seed in the UK, or that have been grown in the UK for at least a year.
Not just for the biceps