Monday, August 25, 2014

True or False: You Can (Ab-)Use Nicotine Chewing Gums to Get Shredded Without Compromising Your Health

Nicotine gums are made for smokers. Smokers are leaner than non-smokers. Chewing nicotine gums helps you lean out... broscience? Logic? Or bullshit?
It's one of the better-known pieces of broscience: "Nicotine chewing gums will promote weight loss!" Aside from being "better-known", it's yet also highly controversial. In that, people usually don't question the fact that nicotine chewing gums may promote weight loss (we do all know that smokers are leaner, don't we?), but rather that they do so in the absence of significant ill-health effects.

Since this is the SuppVersity and not the bulletin board, I am not going to restrict today's analysis on the health issues. Instead, I will start by looking for scientific evidence that would confirm the common sense assumption that chewing nicotine gums does, in fact, promote weight loss -- in humans, not in rodents (Lupien. 1988).
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Let's first take a look at the connection between nicotine and body weight management in general. In 2006 Chen et al. published an intriguing paper the title of which could in fact explain why smokers tend to be lighter than non-smokers (for US citizens that's ~ 3.7% leaner; cf. Albanes. 1987): "Cigarette Smoke Exposure Reprograms the Hypothalamic Neuropeptide Y Axis to Promote Weight Loss" (Chen. 2006)

According to Chen et al., the anorexic effects they observed in a 4-week rodent study are behind the anti-obesity effects of smoking. Similar effects on appetite in general and reductions in sugar cravings (Grunberg. 1982) in human studies as well. Nevertheless, if a reduction in appetite was the only beneficial effect of nicotine would be limited to phases of ad-libitum dieting. A direct effect on fat loss, as it is implied by broscience, on the other hand, would not exist.
Beware of becoming skinny fat! While the average smoker may be lighter, he is not necessarily leaner. The results of a 1989 study by Shimokata et al. show that smokers have higher waist-to-hip ratios and "indicate that there are harmful effects of cigarette smoking on the pattern of distribution of body fat" i.e. away from the harmless body parts, i.e. the extremities and right to the epicenter of unhealthy fat: the waist! Due to the fact that cigarette smoking is also associated with unhealthy eating habits (Dallongeville. 1998), it's yet difficult to tell, whether this effect is (solely) due to the cigarettes.
If it was not for Schechter et al. and other scientists who report "nicotine-induced weight loss in rats without an effect on appetite" (Schechter. 1976), I could stop here and tell you that (a) you obviously don't want to chew nicotine gums for the rest of your life to benefit from its appetite suppressing phases and that (b) it wouldn't make sense to chew them in a phase, where you're counting calories, anyway (if you want the appetite suppressing effects, anyway, add caffeine, this will enhance them; Jessen. 2005).
Figure 1: Body weight and food intake in 13-week rodent study with 0.4mg/kg and 0.8mg/kg (right) of nicotine administered in solution or saline control thrice daily (Schechter. 1976)
Thanks to the impressive reduction in body weight Schlechter et al. observed in the previously cited rodent study in the absence of statistically significant reductions in food intake (graphs at the bottom of Figure 1), it's worth to keep digging further.
Figure 2: (a) Male body weights before, during, and after nicotine or saline administration; (b) Female body weights before, during, and after nicotine or saline administration (Grunberg. 1987)
Ladies, beware! The non-food related weight loss could be a "male only thing"! According to Grunberg et al. "the nicotine-related changes in body weight were accompanied by changes in bland food and water consumption" in female rodents - as the authors point out, a significant difference to previous studies (Grunberg. 1986). Accordingly, a follow-up study showed: "The body weight of females that had received nicotine were indistinguishable from controls up to 4 months after cessation of nicotine. The body weight of males that had received 12 mg nicotine per kg per day remained lower than controls." (Grunberg. 1897). Notably, the dreaded weight regain occurred in male & female rodents (Figure 2)!
If you take a close look at the results you will yet realize that there is a big caveat to the impressive weight loss (specifically in the 3x0.8mg/kg group | human equivalent ~ 3x4mg or three high dose nicotine chewing gums). Yes, I am talking about the nasty weight regain that occurred - likewise in the absence of increased food intakes - when the nicotine administration was seized.

Against that background, it's all the more important to find evidence from human studies. Unfortunately, the majority of studies on nicotine gums is not relevant to the topic, because they are (a) dealing with the success of smoking cessations, or (b) dealing with weight regain after smoking cessation. We will, therefore, have to resort to ostensibly unrelated results such as...
  • Figure 3: Plasma leptin levels in non-smokers, long-term nicotine gum users, and smokers after adjustment for age and body composition (Eliasson. 1999)
    the increase in leptin levels researchers from the Sahlgrenska University Hospital in Göteborg (Sweden) observed in a 1999 study in 73 subjects: 23 non-smokers, 31 smokers, and 19 long-term nicotine gum chewers (NGCs) with similar ranges of age, body mass index (BMI) and per cent body fat. As the authors of the corresponding paper point out, "[t]he increased leptin levels may be an important reason for the lower body weight in smokers." (Eliasson. 1999). Unfortunately "long-term" is nothing you would associate with the use of nicotine gums as diet adjuvant.

    As suggestive as they may be, the increases in leptin are thus probably not relevant for short-term decreases in body weight - or even better body fat - as you would expect them when you're dieting.
  • the association with hyperinsulinemia and insulin resistance the same Swedish researchers from the Sahlgrenska University Hospital observed in a previous investigation (Taskinen. 1996) clearly suggest that the chronic consumption of nicotine leads to insulin resistance, metabolic abnormalities associated with the insulin resistance syndrome, and increased cardiovascular morbidity.

    On the other hand, we are - I can't repeat that often enough - not talking about the chronic use of nicotine gums, but their (ab-)use for 4-6 weeks to propel your fat loss results. Eventually, the results are thus as irrelevant as the previously mentioned beneficial effects on leptin (see the previous bullet-point).
  • Figure 4: Thermogenic effect in 150min after the ingestion of nicotine and / or caffeine (Jessen. 2003)
    the "pronounced" thermogenic effect researchers from The Royal Veterinary and Agricultural University in Denmark observed in their 2003 study. Aside from scientific evidence that the administration of nicotine has thermogenic effects, the second important result of the study at hand is the observation hat the thermogenic effects  of 1 mg nicotine (measured over 150 min after the ingestion) can be (almost) doubled, if the nicotine is administered in conjunction with 100 mg of caffeine (Jessen. 2004).

    It's also important to note that "[i]ncreasing the nicotine dose to 2 mg does not increase the thermogenic effect but produces side effects in most subjects." (Jessen. 2003) More is thus, as so often, not better for nicotine (a similar non-linear dose-response effect was observed with cigarettes, as well; cf. Collins. 1996). A previous study by Collins et al. (1994) found a 7.5% increase in resting energy expenditure with 200mg of caffeine and a similarly low amount of nicotine, i.e. 0.8mg of nicotine from cigarette smoke over a 3h period.
If you take a look at the evidence I provided, it supports the previously raised concerns about the long-term use of nicotine gums. On the other hand, the study by Jessen et al., as well as the study Collins et al. who didn't just find a similar synergistic effect of caffeine and nicotine, but were also able to show that the effects occur in both smokers and non-smokers (Collins. 1994; similar results in Perkins. 1989), clearly indicate that the short-term (ab-)use of nicotine gums may in fact promote the loss of body weight and - assuming you're getting your 1.5g/kg protein and lifting heavy objects - body fat, as well.
Figure 5: The increase in thermo-genesis due to 4x20µg intranasal nicotine is impressive in men, not significant in women (Perkins. 1996)
Do men better sniff their nicotine?! While snuff is obviously not identical to an intranasal nicotine spray, the results Perkins et al. present in their 1996 study which investigated the effects of 4x20µg/kg nicotine that was administered intranasally every 30 minutes for 2h after the consumption of tonic water or alcohol are quite impressive... well, at least in men. In contrast to the male subjects in whom the nicotine only increased the energy expenditure by almost 13%, the 3.8% increase in the female study subjects was not significant! Whether that's a result of the absolutely lower dosage (remember the nicotine was dose per body weight) or a true sex-difference is uncertain.
Unfortunately, it is difficult to say whether these benefits come with significant negative effects on your health. Evidence on short-term effects of nicotine abuse in human beings is scarce. Furthermore, studies in non-smokers suggest that healthy people and people with pre-existing problems with glucose management react differently, with the former experiencing no and the latter experiencing severe reductions in insulin sensitivity in response to the acute infusion of nicotine in a 2001 study by Axelsson et al. (i.e. a problem with glucose management occurs only in those who have a problem, to begin with).
Figure 6: Negative effects of nicotine on insulin sensitivity occur only in diabetics (Axelsson. 2001)
As far as the dreaded increases in insulin resistance are concerned, you could thus argue that the contemporary evidence suggest that healthy athletic individuals have nothing to fear. Since the same appears to be true for the negative effects on platelet count (Mundal. 1995), blood pressure and other markers of cardiovascular health (Benowitz. 2002). For people who belong to one of the classic risk groups, i.e. men and women with metabolic syndrome and / or existing heart condition, the use of nicotine gum may yet easily result in a hospital stay or worse (Rigotti. 1986).
If you want to try it, try this: 200mg caffeine + 1mg nicotine from chewing gums upon rising, another 200mg of caffeine and 1mg nicotine at lunch or pre-workout, additional 2x 100mg caffeine + 1mg nicotine between breakfast and lunch and lunch and dinner.
Bottom line - True! For healthy athletic folks! Just to make that clear. I am not, by any means recommending the use of nicotine gums for weight loss. All I do is to answer the often heard question whether the bro-scientific assumption that they'd help you shed body fat is true.

And, by the way, the study that would confirm that "dieting + nicotine" = greater weight / fat loss than "dieting alone" has not yet been conducted. If you want to do your own N=1 study, do it at your own risk. Next to potential (albeit for healthy people probably controllable health issues), it appears as if there was also a minimal risk of addiction for never-smokers (Etter. 2007) | Comment on Facebook!
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