Smoking cessation and weight gain: the gut microbiota, my slimming partner!

Unfortunately impedes some attempts to stop smoking: former smokers tend to put on weight. On average an extra 4.5 kg on the scales 6–12 months after the last cigarette. Something that discourages the best intentions. Unless our gut microbiota offers us welcome assistance? In any event, this is what is suggested by a recent study in mice.

^{Sources : OMS (sidenote: https://www.euro.who.int/en/health-topics/disease-prevention/tobacco )}

Smoking cessation: a microbiota that carries weight

As in humans, mice exposed regularly to cigarette smoke tend to gain weight after stopping smoking. After a long series of experiments, the researchers seem to have identified the mechanism potentially in play. Some compounds in tobacco (nicotine?) are thought to be able to reach the digestive system of “smoker” mice after traveling in the blood. They are then thought to modify the composition of the gut microbiota. And in fact, it is enough to transplant the microbiota of smoker mice into non-smoker mice to make them gain weight. Something that designates this microbiota as being partially responsible for the kilos gained.

The mechanisms involved elucidated?

But in practice, how is this possible? It would appear that smoking disrupts the delicate balance between the molecules that promote weight gain and others that restrict it. In smokers, the molecule that promotes weight gain is thought to be produced in greater quantities, whilst the molecule that blocks it becomes increasingly scarce. So why don't they get fat? Because the mechanism is gradual, allowing the body time to adjust by associating every cigarette lit to the necessity to eat less. Except that on stopping smoking, this appetite-suppressant effect of the tobacco disappears immediately, while the imbalance in the microbiota that encourages weight gain lasts much longer. Direct consequence: the scales go into panic mode!

Supporting ex-smokers

said Prof. Evan Elinav who led the research team. While waiting to find out how to repair the microbiota of ex-smokers (diet? microbial therapy, postbiotics (sidenote: Postbiotics A preparation of inanimate microorganisms and/or their components that confers a health benefit on the host  Salminen S, Collado MC, Endo A, et al. The International Scientific Association of Probiotics and Prebiotics (ISAPP) consensus statement on the definition and scope of postbiotics. Nat Rev Gastroenterol Hepatol. 2021 Sep;18(9):649-667.    ) ?) in order to limit weight gain after quitting smoking, this study makes a “weighty” argument for never smoking your first cigarette, or exposing those around you to passive smoking: protecting the equilibrium of the microbiota.