Unhealthy diet damages the brain

An unhealthy diet and obesity harm the brain

19/01/2011

Unhealthy eating makes you "fat and stupid". Obesity is often associated with damage to the brain, which in turn can affect eating habits. Thus, two recent American studies conclude that an unhealthy diet promotes obesity, which in turn leads to further brain damage that leads to further out of control eating behavior.

The overweight and unhealthy diet are directly related, has long been known. However, American scientists now come to the conclusion in two independent studies that the wrong diet in conjunction with obesity can shrink entire brain regions, which further disorders in eating behavior caused. Antonio Convit from the Nathan Kline Institute for Psychiatry Research in New York and colleagues report in the latest issue of the journal „Brain“, that in the context of their study in obese people, they have noticed a significant reduction in certain reward and appetite centers in the cerebrum as well as considerable structural damage. Terry Davidson of Purdue University in West Lafayette, Illinois, and his graduate student Scott Kanoski arrive at the journal's publication „Physiology and Behavior“ to the conclusion that the damage to the brain and the subsequent vicious circle is set in motion by the wrong diet.

Obesity affects reward and appetite areas of the brain
Antonio Convit and his colleagues from the Nathan Kline Institute studied the brains of 44 overweight and 19 normal-weight healthy people over the age of 50 using magnetic resonance imaging (MRI). The researchers took a closer look not only at the volume of different brain regions but also at their water content, because a high water content is a sign of damage in the nerve tissue. In addition, the scientists determined the blood levels of the protein fibrinogen, which serves as a marker for inflammatory processes in the nervous system. Their study found that certain reward and appetite areas of the brain are significantly reduced in obese people, the researchers report.

Inflammatory processes: Increased fibrinogen levels in overweight
In addition, significantly higher fibrinogen levels were detected in overweight persons than in normal weight persons. Although it has been known from previous studies that obesity can promote inflammatory processes in the nervous system, but their study suggests that the pro-inflammatory diet shrinks entire brain areas, the US researchers report. The higher the measured fibrinogen levels in the blood, the smaller the brain areas examined, according to the scientists. According to the experts, the most significant changes were the MRI images in the area of ​​the prefrontal cortex and in the so-called amygdala. Both regions serve to control the emotional evaluation of situations and are related to the reward system as well as the taste sensation. The prefrontal cortex (also Orbitofrontalkortex, OFC) had been significantly reduced in the overweight and the amygdala had a significantly higher water content, continue to report the US scientists.

Diet and obesity affect self-control ability
Other American scientists such as Paul Thompson of the California University in Los Angeles, who has also proven in previous studies shrinking brain regions in overweight, urge the current research results that „Diet and obesity (...) in the long term affect self-control ability ", could be OFC and almonds „famous regions in addiction research. They regulate not only appetite and cravings, but also decision-making processes that prevent someone from, for example, dangerous acts“, added Thompson. Convit and colleagues are not quite so far in their judgment, but they also warn against a vicious circle, which can develop through the damage in the reward center of the brain.

Overweight initiates vicious circle in the brain
Unhealthy eating leads to obesity, which increasingly produces inflammatory messengers that shrink in the brain just those areas that regulate cravings, explains Prof. Agnes Flöel, a neurologist at the Berlin Charité, the processes underlying the vicious circle in the brain. Then, similar to a drug addict, more and more stimuli would have to come in the form of tasty food, in order to still achieve satisfaction through the intake of food despite declining neuronal sensitivity. Although, according to the US scientists to Antonio Convit so far is not clear whether the weight gain first causes inflammatory processes and damage in the brain or vice versa, the results show „But, being overweight even in the event that the brain damage first came on, how oil can affect the flames.“ Because according to the experts run „the inflammatory processes associated with obesity, which damage the brain, (...) indeed continue acutely.“ That especially in the reward system, the mass of neurons in obesity massively decreases, is a reason that appetite and cravings - simply due to less neural interconnections - can not be regulated in an orderly manner, Convit explains in the current issue of the magazine „Brain“.

Fat and sugar rich foods damage the brain
As part of Terry Davidson's second American study, the expert has collaborated with a doctoral student to evaluate several studies that show that high-sugar, saturated-fat foods - often referred to as the typical western diet - cause cognitive impairment. Thus, the unhealthy diet in animal experiments in mice directly led to inflammatory phenomena in the brain. According to Davidson, the damage occurred first in the hippocampus, the brain area responsible for memory, memory, learning and spatial orientation. The impairments of the thinking through the unhealthy diet are already recognizable before the affected people get fat, the expert emphasized. In addition, the animal experiments suggested that improper diets could alter the permeability of the blood-brain barrier, favoring further impairment of brain structure, Davidson explained. According to the expert, it is easy to explain why thought disorders and brain damage first appeared in the hippocampus during the study. Because the important memory center is particularly well connected to the circulation and so located in the blood, harmful substances can be amplified here.

Unhealthy diet causes damage to the hippocampus
According to Terry Davidson, the vicious circle described above could not begin in the OCT or amygdala, as described by Antonio Convit, but directly after ingesting unhealthy food due to damage to the hippocampus. Because these may be a dysregulation of memory, in which the selective suppression of memories of enticing food, which usually helps in appetite regulation, no longer works properly. „I can better resist a creme brulee when an intact hippocampus weakens the memory of its delicious taste“, Davidson emphasized. Overall, the changes in thinking and eating habits are believed to remain subtle over many years, according to the expert, but in advanced age, significant impairments may occur. So the signs are piling up, „That dementia diseases are also favored by nutrition, obesity and the associated inflammatory and vascular problems“, stressed Thompson. On the other hand, it is gratifying to note that, at least in diabetics, there are indications that a change in diet or good medical treatment can also bring about improvements in cognitive ability, added Antonio Convit.

Degrading the nerve connections instead of destroying the nerve tissue
In view of the available study results, Prof. Flöel pointed out that magnetic resonance imaging has only a limited validity, since „you (...) in this investigation can not (say) what exactly is damaged in the brain.“ The researchers can only determine the volume and density of a particular brain region, „what happens at lower volume or density, we do not know“, explained Prof. Flöel. However, there is reason to believe that „probably (...) no nerves broken down, but the synaptic connections between the neurons (...) formed worse“ Flöel emphasized. This is, according to the expert, a far more pleasant idea than a definitive destruction of the nerve tissue, because synaptic connections can also be re-formed, as shown by the improvement in the cognitive abilities of diabetic patients after a change in diet.

Overweight and obesity on the rise worldwide
The fact that research on overweight and obesity has been significantly intensified in recent years is not least due to the fact that more and more people in the modern industrialized nations are suffering from the symptoms.
For example, at the end of last year, the Organization for Economic Co-operation and Development (OECD) warned that obesity is becoming a widespread disease and that, in particular, children in the OECD member states are far too fatigued on average. If the trend of recent years continues, two out of three people will be overweight in ten years, the OECD experts said. Around half of the population in the OECD member states already suffer from overweight today. According to the OECD, about 60 percent of men and 45 percent of women in Germany are overweight. A total of 16 percent of the population in this country would be referred to as obese (body mass index higher than 30). According to the OECD, the societal negative consequences should not be underestimated since „hard-to-obese people (...) die about eight to ten years earlier than people of normal weight, and they are (...) more likely to have diseases such as diabetes, cardiovascular disease, and cancer“ develop. Moreover, obesity has become one of the leading causes of death and disability in the developed world over the last 20 years. According to the OECD, obesity is responsible for around 2.6 million deaths annually and at least 2.3 percent of health costs worldwide. The World Health Organization (WHO) and the US health authorities are already talking about a fatty epidemic similar to that of deadly infectious diseases. (Fp)

Also read:
Overweight in children: a victim of lifestyle
Heart disease: Majority regrets unhealthy life
Eating Study: Less and less time to eat
Fat substitutes harmful to health?

Picture: sigrid rossmann