Is Obesity Hard-Wired in The Brain?

The escalating obesity rate has become a tricky issue for many countries. This is because obesity can eventually lead to development of many diseases, including heart disease, diabetes, hypertension (high blood pressure) and stroke. The expecting cost of dealing with these diseases can be huge, which will become a burden not only on the people but also on the government.

Many health experts have frequently blamed the modern lifestyle of overeating, inappropriate diet and lack of exercise as the cause of overweight and obesity. However, a study by the researchers from the University of Southern California, Los Angeles found that obesity might be hard-wired into the brain from birth so that some people are more prone to overweight than others.

The findings of an animal study, appearing on in the February 2008 issue of Cell Metabolism, showed that obese rats had faulty brain wiring that impaired their response to the hunger-suppressing hormone leptin.

It seemed that appetite and obesity were built into the brain for obesity-prone rats, according to the researchers. The neurodevelopment differences in these animals could be seen as early as the first week. Such results showed that obesity could be wired into the brain from early life.

Leptin, produced by fat tissue, plays a central role in fat metabolism by acting as a signal to the brain about the body's energy status. Though scientists are still not clear about its role in weight regulation, they are aware that the brain calibrates the requirement for food intake partly based on leptin levels.

Learnt from previous research that the brains of obesity-prone rats were insensitive to these leptin signals, the researchers looked for brain abnormalities that could explain this.

In the study, they found defects in the brain circuits that relay leptin signals throughout the hypothalamus. Hypothalamus is the brain’s central switchboard for regulating conditions in the body.

The findings showed that exercising and eating right might improve the rat’s condition, but the propensity to gain weight could not be reversed.

The researchers also pointed out that if the findings are replicated in humans, then those individuals who are genetically predisposed to obesity as a result of their brains’ configuration should carefully pay attention to diet and energy balance.

Meanwhile, they also cautioned that the general belief that weight regulation is all a matter of nutrition or lifestyle choices might not be helpful for people whose biology predisposes them to obesity.

What Drugs Can Help Trim The Weight?

Being obese or overweight, people are at high risk of getting heart disease, diabetes, high blood pressure, and even cancer. Therefore, when one is overweight or obese, he or she will turn to weight management for help hoping to get rid of the extra weight in the body.

Although the ideal approach to reduce the weight is through managing the diet and increasing physical activities, this process could take a considerably long period. Some patients just do not have the patience to wait for the results. Many of them may seek help from their doctors for prescription of appropriate slimming pills (drugs) to trim the extra weight.

A recent study carried out on mice by researchers from the Harvard Medical School found that the hormone leptin, when combined with one of the 2 drugs approved by United States, could suppress the appetite of overweight people. The findings were published in the January 7 edition of the journal 'Cell Metabolism'.

Leptin is one that signals the brain to stop eating once the stomach is full, but such mechanism does not work effectively in most obese people.

The 2 drugs used in the study are Phenyl Butyric Acid (PBA) and Tauroursodeoxycholic acid (TUDCA). Not meant to treat obesity, these medications are normally prescribed for other maladies including neurological disease like Alzheimer and Huntington. Meanwhile, PBA is often used for liver dysfunction and cystic fibrosis, while TUDCA is employed in Chinese medicine for centuries, and is meant for treating liver ailments.

According to the researchers, the drugs seem to act as 'leptin sensitizers’ for mice to combat 'leptin resistance' in the brain's hypothalamus. The hypothalamus is the primary brain region that responds to leptin, sending a signal that suppresses appetite.

In the study, weight was reduced in normal mice treated with the drugs. The researchers claimed that the evidence they gathered is the first success in sensitizing obese mice on a high-fat diet to leptin.

Naturally, such findings have given the scientists some sort of excitement because if this could work in humans, it could provide another viable option to treat obesity.