Genetics of Obesity

In the largest study of it's kind to date, researchers have looked at why a few people manage to stay thin while others gain weight easily. They have discovered that the hereditary dice are loaded in favour of thin people and against those at the obese end of the spectrum.More than six in ten adults are overweight, and one in four adults is obese. By age five, almost one in four children is either obese or overweight. Excess weight increases the risk of related health problems including heart disease and type 2 diabetes.  

While it is well known that changes in our environment, for example, easy access to high-calorie foods and sedentary lifestyles, have driven the rise in obesity in recent years, there is considerable individual variation in weight inside a populace that shares the same environment. A few people seem able to eat what they like and remain thin. This has led a few people to characterise overweight people as lazy or lacking willpower.

The researchers examine why and how some people find it easier to stay thin than others. Studies of twins have demonstrated that variation in body weight is generally affected by our genes. To date studies have overwhelmingly focused on people who are overweight. Hundreds of genes have been discovered that increase the possibility of an individual being overweight and in some people faulty genes can cause severe obesity from a young age.

Our DNA contains of a sequence of molecules known as base pairs, represented by the letters A, C, G and T. Strings of these base pairs form genetic regions. Our genes provide the code for how our body functions and changes in the spelling.

The team found a few regular genetic variants already identified as playing a role in obesity. Moreover, they found new genetic regions involved in severe obesity and some involved in healthy thinness.

To see what impact these genes had on an individual’s weight, the specialists included the contribution of the different genetic variants to calculate a genetic risk score. As anticipated, we found that obese people had a higher genetic risk score than normal weight individuals, which contributes to their risk of being overweight. The genetic dice are loaded against them.  

Importantly, the team also showed that thin individuals, had a much lower hereditary risk score they had less genetic variants that we know increased an individual's chances of being overweight.

This examination shows for the first time that healthy individuals are commonly thin because they have a lower burden of genes that increase an individual's chances of being overweight and not because they are morally superior, as certain individuals like to suggest. It's easy to rush to judgement and criticise individuals for their weight, but the science shows that things are far more complex. We have far less power over our weight than we may wish to think.    

We already know that individuals can be thin for various reasons. A few individuals are just not that interested in food whereas others can eat what they like, but never put on weight. If we can find the genes that prevent them from putting on weight, we might most likely focus on those genes to discover new weight loss strategies and help individuals who do not have this advantage.

Contact details:

Alina Grace

Program Manager | Obesity Middle East 2019

Email Id: obesityendo@mehealthevents.org

Vitamin D supplements may promote weight reduction in obese children

Vitamin D supplements may promote weight loss and reduce risk factors for future heart and metabolic disease in obese and overweight children. The findings indicate that vitamin D is the simple supplementation may be part of an effective strategy to tackle childhood obesity and reduce the risk of serious health problems, such as heart disease, in adulthood.

Obesity in childhood and adolescence represents a major health problem worldwide, which leads to the development of expensive, debilitating and serious complications, including diabetes and heart disease, in later life. Vitamin D deficiency is stereotypically associated with impaired bone health, in recent years it has been increasingly linked with increased body fat accumulation and obesity, with the precise nature of this relationship currently under intense investigation by scientists. However, the effect of vitamin D supplementation on the health and weight of obese children and adolescents had not yet been investigated.

In this study, researchers assessed 232 obese children and adolescents over 1 year, with 117 randomly assigned to receive vitamin D supplementation, in accordance with the guidelines on treatment and prevention of deficiency. Levels of vitamin D, body fat, and blood markers of liver function and heart health were assessed at the start of the study and 12 months later. The study reported that children given vitamin D supplements had significantly lower BMI, body fat and improved cholesterol levels after a year of supplementation.

These findings suggest that simple vitamin D supplementation may reduce the risk of obese and overweight children developing serious heart and metabolic complications in later life.

The team now plan to investigate the effects of vitamin D supplementation on the health of obese children and adolescents that already have unhealthy conditions, such as high blood pressure, high cholesterol and high blood glucose all of which increase the risk of heart disease, stroke and diabetes.

Although these initial findings indicate that vitamin D could be used in the treatment of obesity, there remains a lack of evidence on the safety and long-term effects of supplementation, particularly if there is no vitamin D deficiency. However, if your child is obese or overweight I recommend that you consult your primary care physician for advice, and consider having their vitamin D levels tested.

Contact details:

Alina Grace

Program Manager | Obesity Middle East 2019

Email Id: obesityendo@mehealthevents.org

Endocrine cells in the brain impact the optimization of behavior

An individual exposed to stress can usually rapidly adapt the own behavior to the specific situation. Biochemical messenger substances in the brain play a central role in this rapid transformation process. We know that hormones additionally have a stress regulating function, but that their effects are more slowly apparent. Using a combination of optical and genetic techniques, the research team has had the capacity to show that corticotrophs, the cell populations that prompts the adrenal cortex and produce the stress hormones of the hypothalamic-pituitary-adrenal axis, will quickly impact avoidance behavior immediately after the onset of a stress situation. This insight could add to the development of effective treatments which will facilitate the management of acute stress induced reactions or may even have the capacity to mitigate acute stress associated conditions.

The human body is controlled by the hormonal system and the nervous system. The hypothalamus situated in the middle of the basis of the brain has a key role here providing the link between the body and the different regions of the brain similarly as directly and indirectly controlling a progression of essential physiological vegetative functions. In addition, it is the most important control organ of the human endocrine system, because it regulates when and how much of a hormone is produced. Both the hypothalamus and its production of hormone are also subject to the impacts of emotional stress. The pituitary gland is connected to the hypothalamus and together they form a single functional unit called the hypothalamic-pituitary-adrenal axis.

Hormones secreted by the hypothalamus incorporate the supposed releasing hormones, such as the corticotropin-releasing hormone. This stimulates the production of the adrenocorticotropic hormone in the pituitary gland. The adrenocorticotropic hormone is a hormone secreted by the anterior lobe of the pituitary and it regulates the production of other hormones, such as the stress hormone cortisol.

It can be basically assumed that the neurotransmitters of the CNS quickly determine whether fight or flight behavior is to develop in a given situation. To date, medical science has conjectured that the stress-regulating effects of the hormones of the HPA axis come into play far more slowly. Stress researchers found it very problematic to establish the concrete role of the hypothalamic-pituitary-adrenal axis in the rapid adaptation of behavior in a stress situation in more detail in standard animal models. This is because the location of the pituitary gland and hypothalamus in mammals makes them difficult to access. To overcome these obstacles, the researcher decided to create an innovative optogenetic research technique. They managed to develop a hereditarily modified zebrafish larva in which they had the capacity to manipulate the activity of the HPA axis using light and subsequently observe the resultant changes to the responses of the altered cells.  

The researchers introduced a synthetic enzyme into their animal model that elevates the levels of the intracellular messenger substance cyclic adenosine monophosphate (cAMP) only in the corticotropic cells of the hypothalamic-pituitary-adrenal axis. Their rise is important for the release of hormones in the corticotropic cells of the anterior pituitary. The levels of the resulting so-called transgenetic animal stress hormones can be increased by means of exposure to light. This means the researchers can thus observe the accompanying changes to behavior.

The recently published research results that the corticotropic cells in the pituitary become directly active on the beginning of a stress situation that is seen as distressing. These then influence locomotion and avoidance behavior as well as the sensitivity to the stimulus. The specialists translate this as proof that the corticotropic cells in the pituitary play a significant role in the rapid adaptation of behavior to local environments identified as antagonistic.   

Contact details:

Alina Grace

Program Manager | Obesity Middle East 2019

Email Id: obesityendo@mehealthevents.org