http___metro-portal.hr_kako-pretilost-utjece-na-mozak_57605_1.xml
1.1 3.1 3.2 4.1 6.1 9.1 9.2 10.1 10.2 10.3 10.4 11.1 13.1 16.1 16.2 17.1 17.2 17.3 19.1 22.1 22.2 22.3 22.4 23.1 25.1 28.1 28.2 29.1 29.2 29.3 30.1 30.2 32.1 35.1 35.2 35.3 36.1 36.2
Intro Putting on the pounds not only transforms your belly, but it also alters your brain, a number of studies suggest. These brain changes may, in turn, fuel overeating, leading to a vicious cycle that makes losing weight and keeping it off challenging. Here are five ways obesity changes the brain: Obesity causes food 'addiction' Gaining weight may  desensitize the brain to the pleasure we get from sugary and fatty foods  , prompting us to eat more cookies and cake than we did when we were leaner, research shows. A similar effect is seen in drug users, who eventually require more cocaine or heroin in order to achieve their original high. In a study published Sept. 29 in the Journal of Neuroscience, researchers scanned the brains of women as they drank a milkshake. They saw the sugary drink activated an area known as the striatum. Half a year later, the researchers repeated the experiment on the same women some of whom had gained some weight. The more weight the women had put on in the interim, the less their brains responded to the milkshake in the second experiment. Research on animals has also shown rats fed a diet rich in sugar and fats are less sensitive to the pleasure-inducing neurotransmitter dopamine. Obesity may make us more impulsive In obese children, a region of the brain in charge of controlling impulsively, called the orbitofrontal cortex, appears to be shrunken compared with that of lean children, according to a study presented this year at the American Academy of Child and Adolescent Psychiatry meeting in New York. Moreover, the smaller this brain region was, the more likely the adolescents were to eat impulsively, the researchers said. While the study did not prove a cause-effect link, it's possible that the children's  obesity reduced the size of their orbitofrontal cortex  , the researchers said. Obesity is known to cause changes to the immune system, boosting inflammation in the body. This increased inflammation may impact the brain and "lead to a vicious cycle, where the obesity leads to inflammation, which damages certain parts of the brain, which in turn leads to more disinhibited eating and more obesity," said study researcher Dr. Antonio Convit, of the New York University School of Medicine. Obesity raises the risk of dementia Having more belly fat is associated with a  decrease in total brain volume  in middle-aged adults, according to a study published in May in the journal Annals of Neurology. It's possible that the extra fat triggers inflammation, which puts stress on the body and perhaps impacts the brain, the researchers said. The finding suggests something particular about belly fat, also known as visceral fat the fat located between organs in the abdominal cavity may play a role in reducing brain size. Visceral fat releases a unique profile of hormones, which may impact the body in a manner different from the hormones released by subcutaneous fat, or fat under the skin, the researchers said. Previous studies have found that people with smaller brain volumes are at higher risk for dementia, and tend to do poorer on cognitive tests. Yo-yo dieting may prompt binge eating under stress It's not just putting on weight that alters the brain taking it off does too, studies suggest. Dieting may change how the brain responses to stress  , so that the next time we find ourselves in a bind, or just plain frazzled, we eat more, according to a study published Dec. 1 in the Journal of Neuroscience. In the study, researchers put a group of mice on a diet so that they lost 10 to 15 percent of their body weight. Then, the mice were allowed to put the weight back on, similar to the way human dieters often see the pounds creep back. When the mice were exposed to stressful situations, such as hearing sounds at nighttime, they ate more food than those who had never been placed on a diet. The mice also had what are known as epigenetic changes changes in the way genes are expressed that don't involve changes in the gene sequences themselves particularly in genes involved in regulating responses to stress. The researchers said these modifications may have altered the animals' eating behavior during stress. Obesity harms memory Obesity may impair memory, at least for women after menopause. A study published July 14 in the Journal of the American Geriatric Society looked at memory test scores for 8,745 women ages 65 to 79. The researchers found a 1-point increase in an woman's body mass index (BMI) was associated with a 1-point decrease on a 100 point memory test. Hormones released by fat could impair memory, the researchers said. These hormones can cause inflammation, which may affect cognition.
1.1 2.1 3.1 4.1 5.1 5.2 6.1 6.2 6.3 6.4 7.1 8.1 9.1 9.2 10.1 10.2 10.3 11.1 12.1 12.2 12.3 12.4 13.1 14.1 15.1 15.2 15.3 15.4 15.5
Kako pretilost utječe na mozak Višak kilograma ne samo da transformira vaš fizički izgled, nego može također utjecati i na mozak, sugeriraju brojne studije Te promjene u mozgu mogu poticati prejedanje, što u konačnici dovodi do zatvorenog kruga skidanja kilograma i borbe s prekomjernom težinom. Pretilost uzrokuje ovisnost o hrani Višak kilograma može oslabiti senzibilnost mozga na užitak koji dobivamo od slatke i masne hrane, poradi čega jedemo više takve hrane nego inače. Sličan efekt može se vidjeti kod konzumenata droge, koji s vremenom zahtijevaju sve veće doze kako bi postigli željeni učinak. U recentnoj studiji, istraživači su promatrali mozgove žena koje su konzumirale slatki mliječni napitak. Uočili su kako slatko piće aktivira područje u mozgu koje se zove strijatum. Pola godine kasnije, eksperiment je ponovljen, a neke žene u međuvremenu su dobile višak kilograma. Što je taj višak bio veći, manje je mozak odgovarao na piće u drugom eksperimentu. Istraživanja na životinjama također su pokazala da su štakori koje se hranilo slatkom i masnom hranom pokazivali manju osjetljivost na neurotransmiter dopamin koji inducira užitak. Pretilost povećava impulzivnost Kod pretile djece, regija mozga zadužena za kontrolu impulzivnosti po imenu orbifrontalni korteks, bila je manja nego kod djece s normalnom težinom, navodi se u studiji koja je prošle godine predstavljena na skupu Američke akademije za psihijatriju djece i adolescenata. Što je manja ta regija bila, veće su bile šanse da će adolescenti hranu jesi impulzivno i nekontrolirano. I dok studija nije dokazala uzročno-posljedičnu vezu, moguće je da upravo pretilost reducira veličinu ove regije mozga. Poznato je da pretilost mijenja imunološki sustav, pojačavajući upale u tijelu. Ove upale mogu utjecati na mozak, te dovesti do zatvorenog kruga gdje pretilost stvara upale, što oštećuje određene dijelove mozga, a ukonačnici dovodi do nekontrolirane konzumacije hrane i još veće pretilosti. Pretilost povećava rizik od demencije Višak sala povezan je sa smanjenjem ukupnog volumena mozga u srednjim godinama. Moguće je da višak sala potiče razne upale, što dovodi tijelo u stanje stresa, te utječe na mozak, navode istraživači. Studije sugeriraju da specifična stvar vezana za salo, tzv. organsko salo koje se nalazi između organa u trbušnoj šupljini, može igrati ulogu u redukciji veličine mozga. Organska mast oslobađa unikatan tip hormona, koji mogu utjecati na tijelo na drugačiji način nego hormoni koje oslobađa potkožno salo. Prijašnje studije su pokazale da ljudi s manjim volumenom mozga imaju veći rizik od demencije, te postižu slabije rezultate na testovima kognitivnih sposobnosti. Pretilost narušava mogućnost pamćenja Pretilost može utjecati na memoriju, barem kod žena nakon menopauze. Studija objavljena prošle godine analizirala je rezultate testova memorije za 8745 žena u dobi 65 do 79. Istraživači su otkrili da je povećanje indeksa tjelesne mase od jednog boda, bilo povezano s gubitkom jednog boda na testu u kojem se moglo ostvariti ukupno 100 bodova. Hormoni koje oslobađaju masne naslage mogu utjecati na pamćenje. Ti hormoni mogu uzrokovati upale, koje ometaju kognitivne sposobnosti.