What the scientists are saying…

Caffeine: no boost for one in ten Downing an espresso is supposed to boost energy levels, but for around one in ten people, it may have the opposite effect. Some years ago, scientists discovered that variations in a specific gene control the way the body metabolises coffee. People with two copies of this variant (about 50% of the population) are “fast” metabolisers: coffee gives them a jolt, and then it’s gone. Some 40% have one copy and are “moderate” metabolisers. The rest are “slow” metabolisers. This means the drug lingers longer in the body – and that appears to have consequences. In 2006, a team from the University of Toronto found that slow metabolisers who drink a lot of coffee are more likely to suffer heart attacks than faster metabolisers; now they have found evidence that caffeine also saps their energy levels. For their study, the team recruited 100 male athletes and tested their DNA to determine how fast they metabolise coffee. They then gave them either a dose of caffeine or a placebo, and asked them to cycle 10km as fast as possible. The fast metabolisers completed the course 7% faster, on average, after ingesting caffeine than after the placebo; the moderate metabolisers performed about the same both times; while the slow metabolisers were 14% slower. The researchers speculate that when caffeine stays in the body, it narrows the blood vessels, restricting the flow of blood and oxygen to tiring muscles.

New drugs to fight MRSA The discovery of a class of drugs that attacks the superbug MRSA has raised hopes of progress in the fight against antibiotic resistance. A team of scientists at Rhode Island Hospital in the US tested 82,000 lab-made molecules on roundworms infected with methicillinresistant Staphylococcus aureus, and found that two showed particular promise. Created in the 1960s to treat cancer and acne, they are forms of retinoid, chemically similar to vitamin A. In tests, these killed not only normal MRSA cells by weakening their cell membranes, but also the ones that lie dormant, evading detection and then emerging later – with added resistance – to reignite the infection. When used in tandem with an existing antibiotic on mice infected with a resistant form of MRSA, the drugs wiped out 95% of the “persister” cells. The team described their findings as very promising, but warned that it will be years before they’re ready for human trials – and in the meantime, resistance will keep growing.

A glimpse of the distant universe A “blue supergiant” nine billion light years away has become the most distant star ever spotted. With the exception of supernovae – the dazzling explosions of dying stars – individual stars (as opposed to clusters) are normally only detectable by telescopes up to a distance of about 100 million light years. In this case, however, an unusual magnifying effect known as gravitational lensing caused the star, dubbed Icarus, to become visible at nearly 100 times this distance. The phenomenon occurs when gravity from objects within the normal range of telescopes bends the light emitted by objects behind them, creating “cosmic telescopes”. Astronomers from institutions including the University of California, Berkeley, first noticed Icarus in 2016 as a small point of light that became progressively brighter. They eventually calculated that it was a star bigger than our Sun whose light was being boosted by a factor of about 2,000 by a massive galaxy cluster five billion light years away. Icarus’s light has travelled so far that astronomers were seeing it at a point when the universe was some five billion years old, long before our solar system formed.

No weight gain from pasta Eating pasta regularly needn’t cause you to pile on the pounds, provided it’s part of a healthy diet. People often assume that because pasta is a refined carbohydrate it’s best avoided. But unlike potatoes, white bread and short-grain white rice, pasta is a low-glycaemic food: it releases energy slowly and doesn’t cause blood sugar to spike. Scientists from Canada analysed 30 trials involving people who had eaten pasta as part of a low-gi diet, and found no evidence that it led to increased weight or higher fat levels; in fact, the pasta eaters often lost weight. However, they were only consuming it in modest quantities (three half-cup servings a week, typically).