Does obesity have more to do with the brain than we first thought?

Does obesity have more to do with the brain than we first thought?

Share on Pinterest
Obesity is a complex disease that may have environmental and genetic factors involved. ALFRED PASIEKA/SCIENTIFIC PHOTO LIBRARY/Getty Images
  • Obesity is a risk factor for a number of leading causes of preventable premature death.
  • One-fifth of children in the United States are considered obese.
  • New research in mice has shown that environmental and nutritional changes during pregnancy and early development can cause epigenetic changes in the region of the brain related to food intake, activity and metabolism in mice.
  • The work also highlights similar links between the human and mouse genome, suggesting that similar epigenetic changes may also occur during human fetal development.

Obesity can seriously compromise a person’s physical and mental health. He is defined as “abnormal or excessive accumulation of fat which may impair health” and is a known risk factor for heart disease, type 2 diabetes and certain cancers, all of which are leading causes of preventable premature death.

Obesity rates have tripled since 1975, more than 41% adults and almost 20% of children in the United States are classified as obese. People are considered obese if they have excess body fat and a body mass index (BMI) above 30.

BMI is a simple but rather controversial measurement, defined as a person’s weight in kilograms divided by the square of their height in meters (kg/m2).

Recently, researchers at Baylor College of Medicine suggested that the risk of obesity in humans may be determined by environmental and genetic factors during early development and argued that obesity should be considered a neurodevelopmental disease.

Study leader Dr. Robert A. Waterland, a professor at Baylor College of Medicine, said Medical News Today:

“[…] genetic variation certainly contributes to individual differences in body weight, early environmental influences on the development of body weight regulatory mechanisms (developmental programming) may, in general, play a more important role in determining individual propensity to ‘obesity.

Works published in the journal Scientists progress uses epigenetics show that obesity is linked to nutrition during certain phases of development.

A number of things such as poor diet, lack of exercise and lack of “good” sleep are known to increase the risk of obesity.

The type and amount of food eaten is also directly linked to the risk of obesity, consuming excess calories and burning very little will create a calorie surplus leading to weight gain. That said, the public health message to eat less and exercise more has not stemmed the tide of obesity.

Once thought to be the result of a lack of willpower and self-control, the biological nature of obesity has turned out to be much more complex. Indeed, prenatal and early life studies have linked undernutrition and obesity in rats.

The effect of nutrition during early development in human studies showed that starvation in the first trimester of pregnancy led to higher obesity rates, but starvation in the last trimester and first months of life was linked to lower levels of obesity.

It is widely accepted that body weight is also influenced by genetics. The CDC reports over 50 different genes that have been linked to obesity. Genes determine the signals transmitted by hormones to the brain, where they tell the body to eat or move.

Large-scale human genome studies found changes in BMI-related genes are expressed in the developing brain.

Epigenetics studies how genes work, allowing scientists to study how behavior and the environment can alter how genes work. Epigenetic changes don’t change the DNA sequence, they change how the body reads the DNA sequence.

For this study, 2- to 4-month-old mice were followed during pregnancy and their offspring were studied during post-natal development.

Whole genome analysis and RNA sequencing were performed on neurons and glial cells and studied for epigenetic markers and gene expression. Specifically, the researchers used tissue from the arcuate core of the brain’s hypothalamus, the area that controls hunger and satiety.

The researchers noted that the postnatal period in mice is critical for obesity-related epigenetic changes and the regulation of energy balance, suggesting that obesity may be a “consequence of dysregulated epigenetic maturation “, according to Dr. Harry MacKay, first author of the study.

Interestingly, by comparing epigenetic data with data from human genome studies, researchers found a strong correlation between regions of the human genome linked to BMI and areas of epigenetic changes in mice, which leaves hear that adult obesity may be determined in part by epigenetic development in the arcuate nucleus.

The authors propose that this new understanding can create “effective interventions to prevent obesity.” This work provides the argument that early prenatal and postnatal development may at least partly determine the risk of human obesity.

“[E]Evidence from the past decades indicates that once an individual is obese, it is extremely difficult to achieve “normal” body weight. And, when obese adults are successful in losing substantial weight, it is extremely difficult to maintain the weight loss over the long term. We hope that a better understanding of the developmental neuroepigenetic mechanisms underlying the establishment of body weight regulation will enable effective approaches to prevent obesity.
— Dr. McCarthy. Robert A.Waterland

When asked if the work could lead to new nutritional recommendations for pregnancy, Dr Waterland said the current research, which was conducted in mice, “does not provide a basis for making nutritional recommendations for humans. Although we don’t have the data yet, it is reasonable to assume that the postnatal epigenetic maturation we cataloged in this mouse study occurs during late fetal development in humans.”

“[…] such data would reinforce existing recommendations that women try to achieve a healthy body weight before becoming pregnant, as maternal obesity during pregnancy not only increases the risk of pregnancy complications such as preterm birth and diabetes gestational, but also appears to promote positive energy balance throughout life. developing child,” he added.

The study is not without limits.

The ever-changing nature of the cell population during early development makes data interpretation complicated, it is possible that changes in the cell population between time points could affect the results.

The authors plan to overcome this in future studies by using more time points and using computer modelling.

The next step for the research is to extend it to human studies.

“[…] an obvious next step is to determine when this BMI-associated epigenetic maturation occurs in humans. Since many neurodevelopmental processes occur earlier in humans than in mice, it is likely that this hypothalamic epigenetic maturation occurs during late fetal development in humans,” Dr. Waterland said.

“[A]An obvious next step would be to try to determine whether maternal obesity during pregnancy somehow impairs these developmental changes, resulting in persistent regulation of energy balance in her child.
— Dr. McCarthy. Robert A.Waterland

#obesity #brain #thought

Leave a Comment

Your email address will not be published. Required fields are marked *