Tak­en from IFB Blog: http://www.ifb-leipzig.com/en/blog/2012–09-27-adiposity-responsible-loss-brain-cells

Is adiposity responsible for the loss of brain cells?

A new study shows that adi­pos­i­ty appar­ent­ly increas­es the risk for demen­tia. The con­nec­tion between the two dis­eases is more com­plex that pre­vi­ous­ly assumed.

In Ger­many cur­rent­ly more than one mil­lion peo­ple suf­fer from the loss of their intel­lec­tu­al capac­i­ty. Two-third of them has to deal with the Alzheimer ill­ness- the most fre­quent type of demen­tia. Every year there are 250 000 more peo­ple that suf­fer from an Alzheimer dis­ease due to the high pop­u­la­tion age. In this coun­try demen­tia has become a com­mon ill­ness that should be tak­en seri­ous­ly. How­ev­er, it could not be cleared yet how exact­ly the brain cells come to die.

Numer­ous stud­ies have point­ed that also adi­pos­i­ty and the relat­ed car­dio-meta­bol­ic dis­eases like high-blood pres­sure and dia­betes increas­es the pos­si­bil­i­ty to suf­fer from demen­tia in high­er age. There­fore, it needs to be ques­tioned how and in what way over­weight effects brain functions.

It seems to be proved: obe­si­ty increas­es the risk for demen­tia. Lat­est stud­ies have showed that over­weight is not with­out con­se­quences for the intel­lec­tu­al capac­i­ty: already peo­ple at the age of 40 till 50 with a body mass index (BMI) of 30 or more kg/m² have shown tremen­dous intel­lec­tu­al reduc­tions-appar­ent­ly due to their obe­si­ty. This is the result of a long-term study of the Insti­tute Nation­al de la San­té et de la Recherche Médi­cale (INSERM) in Paris. The researchers have accom­pa­nied over 6400 adults for about ten years and col­lect­ed and eval­u­at­ed their data in dif­fer­ent meta­bol­ic as well as in cog­ni­tive tests. All par­tic­i­pants were between 39 and 69 years old and took part in dif­fer­ent exam­i­na­tions in which their strength of lan­guage, intel­lec­tu­al capac­i­ty and their mem­o­ry were test­ed every five years.

More over, the researchers includ­ed meta­bol­ic mea­sur­ands, like data over cho­les­terol lev­el, plas­ma lipid con­cen­tra­tion, high-blood pres­sure and dia­betes type II. The researchers defined a diver­gent meta­bol­ic sta­tus if the par­tic­i­pants had fall­en ill with at least two of the men­tioned para­me­ters. 31 per cent of them there­fore suf­fered from one of the men­tioned meta­bol­ic dis­or­ders. 38 per cent of the par­tic­i­pants were over­weight, nine per cent of them even obese. In addi­tion to this, the obese test per­sons were sub­di­vid­ed ‘meta­bol­i­cal­ly strik­ing’ as well as in ‘obese healthy’. e. they suf­fered from none of the men­tioned meta­bol­ic dis­or­ders although they were strong­ly overweight.

Final­ly, an aston­ish­ing result arose after all exam­i­na­tions: both obese par­tic­i­pants with meta­bol­ic suf­fer­ings and obese healthy peo­ple had showed a sim­i­lar reduced brain func­tion dur­ing the com­plete exam­i­na­tion time. The sci­en­tists came to this con­clu­sion after they had cal­cu­lat­ed the speed of men­tal break­down for the entire study peri­od. There­fore obese peo­ple have a poor­er brain func­tion than non-obese ones even if they were not suf­fer­ing from any par­al­lel meta­bol­ic dis­or­ders. So far, sci­en­tists had assumed that an increased risk of demen­tia in obe­si­ty is due to the con­comi­tant meta­bol­ic dis­or­ders. But being over­weight can actu­al­ly shrink your brain?

Dr.  Annette Horstman from the Max-Planck Insti­tute for Human Cog­ni­tive and Brain Sci­ence explains how body size can affect cog­ni­tive per­for­mance. Togeth­er with the Inte­grat­ed Research and Treat­ment Cen­tre (IFB) Adi­pos­i­ty­Dis­eases she explores the links between obe­si­ty and changes in brain struc­ture and behav­iour of obese peo­ple: ‘We could, depend­ing on the sever­i­ty of obe­si­ty in young peo­ple, show changes in brain struc­ture. These changes went with behav­iour dif­fer­ences between obese and nor­mal weight sub­jects asso­ci­at­ed in a game task. How far our results show an out­come of the over­weight or a cause of it is com­plete­ly unclear so far. To answer this ques­tion, we must make long-term studies.’

That means, obe­si­ty doesn’t lead to demen­tia manda­to­ri­ly, how­ev­er, it is involved in the changes of brain activ­i­ties. ‘Fur­ther stud­ies need to be car­ried out, in which fac­tors such as genes, the dura­tion of over­weight phase and meta­bol­ic dis­ease as well as envi­ron­men­tal fac­tors are tak­en into account’, states the sci­en­tist.  Only then, it is pos­si­ble to make more pre­cise state­ments about the inter­ac­tion between weight and brain func­tion. To be notes until then: Those who are phys­i­cal­ly healthy are also more pro­duc­tive with their head.