Irish Examiner - Feelgood - - This Week -

HEAL­ING SLEEP: Just one night of poor sleep can sig­nif­i­cantly in­crease lev­els of a toxic brain sub­stance linked to Alzheimer’s dis­ease, a study has found. Re­searchers used a ra­dioac­tive tracer to mea­sure the buildup of amy­loid-beta pep­tide in the brains of 20 vol­un­teers aged 22 to 72 over the course of two nights. For one of the nights, par­tic­i­pants were al­lowed a rest­ful pe­riod of sleep. For the other, they were sleep de­prived. Positron Emis­sion To­mog­ra­phy (Pet) scans were used to track the tracer. They showed that re­strict­ing sleep to as lit­tle as five hours led to a “sig­nif­i­cant in­crease” in amy­loid-beta bur­den in two brain re­gions vul­ner­a­ble to dam­age in Alzheimer’s pa­tients.

The hip­pocam­pus plays a key role in mem­ory while the thal­a­mus acts as a re­lay cen­tre for mo­tor and sen­sory nerve sig­nals. Amy­loid-beta is a pro­tein build­ing block that ac­cu­mu­lates in sticky plaques in the brains of peo­ple with Alzheimer’s, lead­ing to de­struc­tion of neu­rons. Sleep may play an im­por­tant role in a nat­u­ral “waste dis­posal” sys­tem that clears po­ten­tially harm­ful ma­te­rial in­clud­ing amy­loid-beta out of the brain, sci­en­tists be­lieve. The new find­ings are pub­lished in the jour­nal Pro­ceed­ings of the Na­tional Academy of Sciences.

SKINNY GENES: A gene that makes hu­mans eat more sugar can also lower body fat, new re­search sug­gests. Sci­en­tists have known since 2013 that a ver­sion of the gene FGF21 makes peo­ple con­sume more car­bo­hy­drates. Now a group of re­searchers is show­ing that de­spite the ef­fect it has on diet this gene vari­ant de­creases fat in the body. Sci­en­tists at the Univer­sity of Ex­eter said the find­ings went against the per­cep­tion that eat­ing sugar was bad for health. The FGF21 hor­mone, which is made mostly in the liver, has mul­ti­ple func­tions. It acts on the hy­po­thal­a­mus in the brain to sup­press sugar and al­co­hol in­take, stim­u­lates glu­cose up­take by fat cells, and acts as an in­sulin sen­si­tiser. Anal­y­sis showed that, although the ‘A’ ver­sion of the FGF21 gene leads to greater sugar and al­co­hol con­sump­tion, it is as­so­ci­ated with a lower per­cent­age of to­tal body fat. It was also as­so­ci­ated with higher blood pres­sure and a higher waist-to-hip ra­tio. The find­ings are pub­lished in the jour­nal

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