What the sci­en­tists are say­ing…

The Week - - News | Health & Science -

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

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