Who Knew? Ge­netic Trauma And Binge Eat­ing

Forward Magazine - - Contents - By Jane Eis­ner Con­tact Jane Eis­ner at eis­ner@for­ward. com and on Twit­ter, @Jane_Eis­ner

Is it pos­si­ble for a preg­nant woman un­der great stress to pass on that trauma to her fe­tus through a bi­o­log­i­cal mech­a­nism that al­ters her genes?

And could those dele­te­ri­ous ef­fects be re­versed by diet?

An emerg­ing body of re­search has shown that sur­vivors of the Holo­caust trans­mit trauma to the next gen­er­a­tion not only psy­cho­log­i­cally but also phys­i­cally. “The chil­dren of sur­vivors — a sur­pris­ing num­ber of them, any­way — may be born less able to me­tab­o­lize stress,” Ju­dith Shule­vitz wrote in The New Re­pub­lic in 2014. “They may be born more sus­cep­ti­ble to PTSD, a vul­ner­a­bil­ity ex­pressed in their mol­e­cules, neu­rons, cells and genes.”

Now sci­en­tists at the Weiz­mann In­sti­tute of Sci­ence, in Re­hovot, who study the neu­ro­bi­ol­ogy of stress have pub­lished a new re­port sug­gest­ing that a pre­dis­po­si­tion for the de­vel­op­ment of cer­tain psy­chi­atric dis­eases may be pre­pro­grammed into us in the womb in re­sponse to a chal­leng­ing en­vi­ron­ment.

The pro­posed mech­a­nism acts through epi­ge­netic changes in gene ex­pres­sion. These changes in the ma­chin­ery that con­trols gene ex­pres­sion, rather than changes in the genes them­selves, can have pro­found ef­fects on de­vel­op­ment.

Rachel Field, who has stud­ied bio­med­i­cal medicine and first wrote about the Weiz­mann study for the Forverts, brought this fas­ci­nat­ing news to my at­ten­tion. The study, pub­lished in June in the jour­nal Cell Me­tab­o­lism, fo­cused on binge eat­ing dis­or­der, a heart­break­ing dis­ease in which a per­son loses con­trol over his or her eat­ing, fre­quently con­sum­ing large amounts of food in short pe­ri­ods of time. This of­ten leads to un­wanted weight gain and obe­sity.

BED can be se­vere, even life threat­en­ing, and is sur­pris­ingly com­mon. The Na­tional Eat­ing Dis­or­ders As­so­ci­a­tion es­ti­mates that in Western coun­tries where high-caloric food is plen­ti­ful, 3.5% of women and 2% of men may suf­fer from binge eat­ing at some point in their lives.

The Weiz­mann re­searchers, led by Alon Chen, started where sci­en­tists so of­ten be­gin: with mice. To mimic a stress­ful en­vi­ron­ment, Chen and his team gave preg­nant mice a drug that caused them to pro­duce more cor­ti­cos­terone, a hor­mone that is re­leased in the brain in re­sponse to stress.

Af­ter the mice pups were born, the sci­en­tists fol­lowed them into ado­les­cence, when they were fed a “Western” diet full of calo­ries over a short pe­riod of time, a reg­i­men known to trig­ger binge eat­ing.

“The find­ings were clear: Pups born to moth­ers ex­posed to stress dur­ing preg­nancy tended to de­velop BED symp­toms when they were given an er­ratic, high-calo­rie diet,” Weiz­mann re­ported. They did fur­ther test­ing to dis­cover that ge­netic changes in the moth­ers made the pups more sus­cep­ti­ble to eat­ing dis­or­ders.

Wait, it gets bet­ter. When the re­searchers gave the at-risk pups a diet rich in nu­tri­ents such as B12 and B6, they were able to mit­i­gate the ef­fects of the pre­na­tal stress, and the ado­les­cent mice did not eat com­pul­sively.

“We suc­ceeded in pre­vent­ing the dis­or­der from emerg­ing, sim­ply by pro­vid­ing a bal­anced diet,” Chen told Field.

Now there’s a se­ri­ous ques­tion here about whether what hap­pens in mice has any repli­ca­ble bear­ing on what hap­pens in hu­mans. Chen ar­gues that hu­mans have a sim­i­lar mech­a­nism for trans­mit­ting in­for­ma­tion about the en­vi­ron­ment to the de­vel­op­ing fe­tus. “All the bi­o­log­i­cal genes and path­ways de­scribed are shared by mice and hu­mans,” he told Field.

That said, cul­tural and so­cial norms are a much bet­ter de­ter­mi­nant of hu­man be­hav­ior than of the be­hav­ior of mice. So while this be­hav­ior in hu­mans may have ge­netic com­po­nents to it, it’s un­likely to op­er­ate as clearly as it does in those lit­tle four-legged crea­tures.

Peo­ple who suf­fer from binge eat­ing dis­or­der strug­gle with emo­tions of dis­gust and guilt, of­ten ex­pres­sions of deeper de­pres­sion and anx­i­ety. Sim­ply sug­gest­ing that they eat more vi­ta­min B12 may not ad­dress the un­der­ly­ing causes of their dis­ease.

But as re­searchers like Chen un­lock the se­crets of neu­ro­science, we may come to a bet­ter un­der­stand­ing of the way trauma is trans­mit­ted — and mit­i­gated — from one gen­er­a­tion to an­other.

“If the in­ter­gen­er­a­tional trans­mis­sion of trauma can help sci­en­tists un­der­stand the me­chan­ics of risk and re­silience,” Shule­vitz wrote, “they may be able to of­fer hope not just for in­di­vid­u­als but also for en­tire com­mu­ni­ties as they strug­gle to cast off the shadow of the past.”

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