The variant of the FTO gene that increases the risk of obesity is also associated with loss of brain tissue, according to the latest American research, reported by the weekly Proceedings of the National Academy of Science.
Three years ago, several independent teams of scientists reported that one of the variants of the FTO gene significantly increases the risk of obesity – in those who have two copies of the gene, by up to 70 percent. It is estimated that this version of the FTO is owned by nearly half of the population of Western and Central Europe, and over a third of the US population, including half with European ancestry and a quarter of Hispanics.
In the meantime, it turned out that this variant may also be associated with polycystic ovary syndrome and female infertility.
Now, researchers at the University of California, Los Angeles have discovered yet another detrimental effect of having this gene – a greater risk of loss of brain tissue with age.
This is a shocking discovery, because any defect in the brain increases the risk of future problems with functioning – comments the co-author of the study, Prof. neuroscience Paul Thompson. In his opinion, this means that half of the people in Europe and more than a third in the US have an increased risk of various neurological conditions, including dementia, the most severe form of which is Alzheimer’s disease.
Prof. Thompson and his colleagues used MRI to examine the brains of 206 elderly intellectually able-bodied people. They then created three-dimensional maps of each brain to assess the differences in the volume of each brain area. The research was part of a larger study on Alzheimer’s Disease Neuroimaging Initiative.
It turned out that in the brains of those who had at least one copy of the risky FTO variant, some areas had a smaller volume than in those who did not. For example, the frontal lobes, which are the brain’s decision-making center, had an average brain tissue deficit of 8 percent, and the occipital lobes responsible for vision and perception had a deficit of 12 percent.
The authors of the study cannot yet explain exactly how the FTO variant contributes to the degeneration of the brain. Research shows that it is active in the brain, but its role in the functioning of this organ is not well understood. It is known, however, that the effects of mutations that lead to the loss of the function of this gene are disturbances in the structure of the brain and microcephaly.
According to the researchers, it is highly probable that the FTO influences the brain by contributing to the development of obesity. In earlier studies, obesity has been linked to a higher risk of dementia and a reduction in the volume of various areas of the brain.
Recent studies confirm that overweight and obesity have an effect on brain tissue, but a higher body mass index was strongly associated with brain atrophy only in risky FTO patients. In addition, brain tissue loss has not been found to be related to diabetes, high blood pressure, or high cholesterol levels – although all these factors often accompany obesity and may contribute to brain atrophy.
These results are astonishing. If someone has the wrong FTO variant, the greater body weight adversely affects their brain, increasing the loss of tissue. But if it does not have this gene, weight does not translate into the volume of the brain, and actually has nothing to do with it – comments Prof. Thompson.
The researcher also emphasizes that a healthy lifestyle – i.e. a varied, low-calorie diet and exercise – can counteract obesity and loss of brain tissue even in the case of risky FTO patients. (PAP)