Anonym (ack ja) skrev 2015-01-07 14:28:03 följande:
Har du källa på det?
Alltså, finns det siffror och statistik?
Ja för i helvete, det finns det! Och jag har postat om det också men fakta kan vara lite svårlästa.
Här är en sammanfattande (review) artikel angående vilka evidens som finns för genetisk och epigenetisk påverkan på obesitas. Artikeln baseras på många olika studier, är peer reviewed och publicerad i en ansedd vetenskaplig tidskrift.
www.ncbi.nlm.nih.gov/pmc/articles/PMC3213306/
Kanske orkar man inte läsa hela denna, men läget (2011) var i alla fall följande:
[GWA= Genome Wide Association, alltså att man söker väldigt brett efter gener som (i detta fall) kan tros påverka metabolism och därmed kroppsvikt.]
"Despite successes in susceptibility loci identification for obesity through the first wave of GWAs, the combined effect of the loci explains only 2?3% of the inherited contribution to obesity risk."
"
The current obesity epidemic is clearly not of genetic origin per se, but due to unfavourable changes in lifestyle and environment (the ?obesogenic? environment). The obesogenic environment has different effects on different individuals in the same environment, highlighting an underlying, inherited susceptibility to obesity and fat-distribution."
"Despite the success of GWAs in obesity loci identification,
we still only explain a low fraction of the inter-individual variation of obesity. Extensive work including identification of more obesity susceptibility loci, a better understanding of the gene(s) through which the effect is executed, as well as further molecular and physiological characterization of the associated genes, is now necessary before any of these findings will lead to any useful therapeutic interventions."
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Här en lite mer lättsmält tidningsartikel
healthland.time.com/2013/07/19/news-genes-idd-in-obesity-how-much-of-weight-is-genetic/som
a) förklarar den dramatiska effekten på möss som har vissa mutationer- de äter faktiskt samma antal kalorier som andra möss utan gendefekten, och lyckas gå upp i vikt!
"In the mouse study, the research team determined that mutations in the Mrap2 gene led the animals to eat less initially but still gain about twice as much weight as they normally would. While their appetites returned, these mice continued to gain weight despite being fed the same number of calories as a group of control animals. That led the scientists to figure out that the mice with the mutated gene were simply sequestering fat rather than breaking it down for energy. The mice, like people, possessed two copies of the gene, and mice with even one defective copy experienced significant weight gain, although not as much as those who had two mutated versions of Mrap2.
The scientists found a similar pattern among a group of 500 obese people; they detected four mutations in the human version of Mrap2, and each of the obese individuals possessed only one bad version of the gene."
b) ändå slutar med att nämna att det bara är ca 5% av de obesa som har en genetisk förklaring till sin övervikt, med vårt nuvarande kunskapsläge.
?Thus far
mutations in about eight genes are known to cause obesity in humans. But these mutations account for under five percent of the obesity in our society, and certainly are not, by themselves, responsible for the current obesity epidemic, since the mutation rate in these genes could not have changed dramatically during the past twenty years,? says Dr. Joseph Majzoub, the chief of the division of endocrinology at Boston Children?s Hospital and an author on the
Science paper."
