08 October 2013

Obesity is "good" and "bad"

How does healthy obesity differ from unhealthy

Kirill Stasevich, Compulenta

Usually, an overweight person also suffers from a whole complex of disorders, united under the common name "metabolic syndrome", and this leads the unfortunate to type 2 diabetes. In addition, due to too high cholesterol levels with excess weight, problems with blood vessels arise, that is, the body "heaps" also receives cardiovascular diseases.

However, this whole collection of diseases does not always accompany obesity, and it happens that a person, despite being obviously overweight, remains quite healthy. To understand how this is possible and what kind of biochemical and physiological mechanisms work here, scientists from the University of Helsinki (Finland) found 16 pairs of identical twins aged 23 to 36 years; in each pair, one of the twins was necessarily thin, and the second was overweight, and the difference between them reached on average 17 kg.

Adipose tissue cells; in the case of metabolic syndrome, they are especially large and serve as a source of inflammation
(Photo by Dennis Kunkel Microscopy)The researchers compared the distribution of accumulated fat in the subjects and noticed that such twins are divided into two groups according to whether they have fat stored in the liver: some had it accumulated there, others did not.

It turned out that the obese subjects with the amount of fat in the liver equal to that of their thin brothers and sisters had neither elevated cholesterol, nor insensitivity of tissues to insulin, nor high blood pressure, nor chronic inflammation.

On the other hand, in the cells of abdominal adipose tissue in those who had a lot of fat in the liver, genes that trigger an inflammatory reaction worked, and at the same time the work of mitochondria was suppressed. In the thin and those fat men who did not have dangerous biochemical markers, inflammatory genes were silent, and mitochondria functioned normally.

There were also differences in the structure of the adipose tissue itself. In twins with signs of metabolic syndrome, there were fewer cells in the adipose tissue, they were larger, and such cells just supported sluggish inflammation. In those who were overweight without dangerous metabolic disorders, the amount of abdominal fat increased due to the number of fat cells.

In general, Jussi Naukkarinen and his colleagues managed to characterize two types of obesity quite fully – healthy and unhealthy, and one of the main differences was the presence or absence of fat in the liver.

But what in this case is the cause and what is the consequence, scientists have yet to find out. It can be assumed that the accumulation of fat in the liver is due to an inflammatory reaction provoked by large abdominal fat cells, and the formation of new cells in adipose tissue slows down due to the fact that mitochondria do not work well in it. If the authors of the work determine exactly what follows, it will be possible to predict in advance what kind of obesity threatens a person, and in accordance with this offer treatment regimens.

But we should also not forget that these results also require verification on a larger statistical sample – after all, only 16 pairs of twins participated in the study.

The results of the work are published in the journal Diabetologia: Naukkarinen et al., Characterizing metabolically healthy obesity in weight-discordant monozygotic twins.

Prepared based on the materials of NewScientist: Hefty twins shed light on obesity paradox.

Portal "Eternal youth" http://vechnayamolodost.ru08.10.2013

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