A doctoral thesis, directed by Ana Damasus, teaching post-graduate program in Nutrition at the School of Medicine of the Federal University of São Paulo (EPM / Unifesp) – Campus São Paulo, concluded that, because of a genetic variation found in the leptin receptor gene (LEPR), some obese adolescents did not get the same reductions in body mass index (BMI) and lipid levels when compared to those not carried the variation. The leptin is an important hormone that plays a key role in regulating energy balance by inhibiting hunger and increasing energy expenditure in peripheral tissues – between which, adipose tissue.
The nutritionist Flávia Corgosinho, author of the study, selected 76 volunteers considered obese and classified them into two groups according to the incidence of that genetic variation. Among the volunteers, 39 belonged to the dominant group (classified as TT), who had no genetic variation, while the 37 remaining composed the heterozygous or recessive group (defined respectively as CT and CC), who were carriers of the change.
After a year of treatment, which included physical exercise and medical, nutritional and psychological counseling, the researcher noted that the carriers of the CT genotype and CC had not been able to reduce the lipid profile, insulin resistance and production of leptin to the same levels of the dominant group. Similarly, they were unsuccessful in decreasing body mass index (BMI) in proportion to the TT group. “We realized that adolescents with this genetic variation had significantly higher levels of orexigenic neuropeptides (hunger stimulators),” explains Corgosinho. “Genetic factors could partially explain why some obese adolescents respond best to therapy and others do not,” he adds.
Also in the production of leptin, the group free of genetic variation could make it retreat by about 30% while the other obtained practically negligible reduction. “And we know that this state of hyperleptinaemia (excess leptin production) is one of the main factors that hinder the loss and maintenance of weight. Excess leptin is a pro-inflammatory factor that will have consequences for the health of the individual, increasing cardiovascular risk, “he says.
For the researcher, the study results indicated that it is necessary to seek auxiliary strategies for those with genetic alterations related to leptin, which interfere in the weight loss process and hinder the control of cardiovascular risk, including the reduction of triglycerides and insulin and increasing adiponectin. It attaches to nutrigenomics – the science that studies the interaction between the bioactive compounds in the structure and expression of genes – the possibility of becoming one of the treatment options in the future. However, other attempts to solve the problem could be valid as the optimization of therapy, with more frequent or more intense physical activities. “It may be necessary that these individuals lose 10% or more of body weight to achieve the same results of the group without genetic modification”, he concludes.