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LONDON: Nicotine suppresses the appetite by switching off the receptors associated with appetite and food intake, American researchers have found.
Their findings, published in the current issue of Science show how smoking creates an anorexic effect in particular parts of the brain in mice. This could eventually help scientists develop nicotine-based therapies to aid both the ongoing battle against obesity and smoking addiction in humans.
"We have to be very cautious," said Yann Mineur from Yale School of Medicine, one of the authors of the study, "but the basic biology, as far as we can tell, is fairly similar to what's happening in humans."
A way to lose weight
Smoking is one of the leading preventable causes of death in Western countries and has been increasingly cited as a way to lose weight, a theory confirmed by the fact that smokers are on average thinner than non-smokers.
Conversely, a high proportion of people cite weight gain as a negative result of quitting smoking.
Although previous studies have attributed the effects of smoking on the appetite to nicotine, exactly how nicotine influences the brain in terms of food intake and consequential body weight has not been shown until now.
Smokers less hungry
Mineur and collages reported that they have determined the pathways affected by nicotine receptors on the central nervous system that result in loss of appetite and subsequent weight loss.
The researchers performed a combination of molecular, pharmacological, electrophysiological, behavioral and genetic knockdown experiments on mice to discover that nicotine influences a collection of central nervous system circuits, known as the body’s hypothalamic melanocortin system, by activating certain receptors.
These receptors, in turn, increase the activity of POMC neurons, known for their effects on obesity in humans and animals, along with a specific set of melanocortin 4 receptors.
It was found that the mice subjected to nicotine and nicotine-effect stimulants lost approximately 15-20% of their body mass over time and consumed almost half the portion of food, with water intake remaining unaffected.
Lose weight AND quit smoking?
The results shed light on the molecular and synaptic mechanisms that underlie the weight loss and decreased appetite that comes with nicotine and could contribute to the development of both smoking cessation therapies and helping with obesity and metabolic disease, the researchers said.
But does this mean that the appetite suppressant properties of nicotine could one day be exploited to combat obesity and help with smoking cessation, ultimately addressing two of the biggest health problems in one cure?
John McNel, Head of Preventative Medicine at the Monash University School of Public Health and Preventive Medicine, who was not involved in the study, is hopeful, "Fear of weight gain after ceasing smoking is a common reason why people continue to use cigarettes," he said.
"The understanding of a mechanism for this may lead to ways to stop weight gain after smoking cessation and may also lead to new insights into weight control per se."
Why smoking keeps you skinny
There is no reliable evidence that suggests that after quitting smoking, people eat more. There is no one clinical study that suggests that smokers eat more after quitting smoking.
Even if some eat more after quitting smoking, the weight gain is not due to an increase of food intake. In reality, the majority of people after they quit smoking, they eat less, but still after quitting smoking they experience weight gain or accelerated weight gain.
Weight gain after quitting smoking is due to changes in the biomechanics of walking.
1. Smoking affects the neuromuscular control centre.
2. Walking is a physical activity and at the same time, is a neuromuscular control centre activity.
Much more about biomechanics and weight gain can be found on my website.
Luke Tunyich
Biomechanics and Health
http://www.biomechanicsandhealth.com/
Open Hand, Remove Cig AND Food
The reason they are thinner is because the thing they are puttin in their mouth doesn't give the body extra calories, just cancer. When they quit smoking they keep the hand to mouth action except its not a cig they are holding, it might be a snickers bar. Becoming aware of the action is the first step to changing or avoiding it all together. http://blog.mydiscoverhealth.com/