禁煙すると太るのは何故？ ― satiety

タバコをやめると太る、とよく言われます。子供のころ、私の父親がそんなことを話しているのを聞いた記憶がありますから、相当昔から使われてきた口実に違いありません！？

ところが、これには一定の科学的根拠があるらしいのです。エール大学の研究チームがマウスでの実験結果を発表したということで、ニコチンと食欲の関係が話題になっています。


It's an unfortunate fact that when smokers kick the habit, they often gain weight — a side effect that many smokers use as a reason for not quitting.

Now scientists think they've pinpointed the pathway in the brain through which nicotine helps suppress appetite, suggesting that it's possible to get the same effect without the cigarettes.

Nicotine works on many different receptors in the brain, including those in reward regions that contribute to addiction. But working with mice, a team led by Yale University School of Medicine psychiatrist Marina Picciotto found that the drug also binds to receptors on appetite-regulating neurons, which aren't involved in addiction. These neurons, located in the hypothalamus, send the "I'm full" message after a meal, helping to regulate how much you eat.

It helps explain why smokers aren't as hungry when they smoke, and why they tend to stay thinner on the habit. When they quit, however, many smokers tend to eat more, typically gaining on average about five pounds after quitting.
(Alice Park. Study: Why Quitting Smoking Makes You Fat. Time. June 10, 2011.)


タバコを吸うと（つまりニコチンを摂取すると）、食欲が抑制されるという科学的な根拠ですが、上記引用によりますと、ニコチンという物質は脳内のいろいろなレセプターに作用するそうなのですが、その中でも満腹感（satiety）をつかさどる細胞にも作用することが分かったそうです。


Understanding the link between nicotine and satiety, for example, could lead to new drugs that target the nicotine receptors on appetite-controlling cells, giving smokers a way to quit without the weight gain. Already, says Picciotto, there are plant-based quit-smoking drugs available in Eastern Europe that may work in this way, but further research needs to be done to determine whether they'd actually help quitters gain less weight.
(ibid.)


この研究成果によって、ニコチンと同様にこの満腹感をつかさどるレセプターに作用する薬の開発が期待されるそうですが、世の中に流通する禁煙補助薬なども変わってくるかもしれません。そうなると喫煙者も太ることを口実に禁煙を拒みつづけることもできなくなるのでしょうか。