Acute effect of smoking and smoking abstinence on energy intake and appetite-related hormones blood concentrations

Metabolic Changes Following Smoking Cessation in Patients with Type 2 Diabetes Mellitus

BACKGROUND

Smoking cessation is crucial for reducing complications of type 2 diabetes mellitus (T2DM), but associated weight gain can worsen glycemic control, discouraging quitting attempts. Varenicline, a partial agonist of α4β2 nicotinic receptors, aids smoking cessation. This study examines the effects of varenicline on body weight and metabolic parameters in patients with T2DM and prediabetes.

METHODS

Fifty-three patients were enrolled, of which 32 successfully quit smoking after a three-month course of varenicline and were examined after an additional month with no medication. Measurements taken at baseline, 2.5 months, and 4 months included body weight, blood pressure, resting metabolic rate (RMR), glycated hemoglobin (HbA1c), fasting glucose, blood lipids, C-reactive protein (CRP), appetite-related hormones, and physical activity.

RESULTS

Post-treatment, there were no significant changes in body weight, blood pressure, RMR, or glycemic control. Total (CHOL) and low-density lipoprotein (LDL-C) cholesterol decreased significantly at 4 months of the study (from 168 to 156 mg/dL, p = 0.013, and from 96 to 83 mg/dL, p = 0.013, respectively). Leptin levels increased (from 11 to 13.8 ng/dL, p = 0.004), as did glucagon-like peptide-1 (GLP-1) levels (from 39.6 to 45.8 pM, p = 0.016) at 4 months of follow-up. The percentage of participants who reported moderate-intensity activity increased from 28% to 56%, while those reporting high-intensity activity increased from 19% to 22%, respectively (p = 0.039).

CONCLUSIONS

Our study showed that smoking cessation with varenicline in smokers with T2DM and prediabetes led to significant improvements in lipid profile, significant increase in plasma leptin and GLP-1 levels, and increased physical activity, without significant weight gain. Thus, smoking cessation without weight gain or deteriorated glycemic control is feasible for these smokers, with added benefits to lipid profiles, GLP-1 regulation, and physical activity.

Body weight change during a smoking cessation intervention for individuals with overweight or obesity

INTRODUCTION

A more comprehensive understanding of the factors regarding weight control in individuals with overweight or obesity after quitting smoking is needed. The study aimed to analyze the changes of in-treatment variables during a smoking cessation intervention and examine their impact on weight.

METHODS

A total of 120 individuals who smoke with overweight or obesity (MBMI = 31.75 ± 4.31; 54.16 % female) participated in a cognitive-behavioral therapy for smoking cessation and weight control or the same treatment plus contingency management. Weight, smoking variables (cotinine and continuous abstinence), eating behaviors (appetite, grazing), exercise, and sleep were assessed weekly throughout the treatment.

RESULTS

More participants gained weight over time with reduced nicotine use or abstinence. There was a tendency during treatment to increase appetite and exercise time, while grazing episodes and sleeping hours remained stable. Higher baseline weight (p < .001), greater cotinine reduction (p = .021) and time (p = .009) were associated with greater weight gain, while more hours of exercise (p = .003), no appetite changes (p = .003) and diminished appetite (p < .001) were associated with less gain over the treatment. Both treatment conditions showed similar results in all in-treatment variables.

DISCUSSION

Individuals with overweight and obesity with higher baseline weight and higher baseline cotinine levels during smoking cessation interventions may require special attention to improve weight outcomes. Exercise and appetite regulation may be useful for mitigating weight gain in smoking cessation interventions for individuals with overweight or obesity.

Effects of Smoking on the Gut Microbiota in Individuals with Type 2 Diabetes Mellitus

Smoking affects eating habits; however, few studies on smoking and the gut microbiota have reported the effects of diet in detail. This cross-sectional study aimed to determine the association between smoking and the gut microbiota, considering the impact of smoking on dietary intake. Dietary habits and the composition of the gut microbiota were assessed in 195 men with type 2 diabetes (164 non-current smokers and 31 current smokers) using a brief self-administered diet history questionnaire and 16S ribosomal RNA gene sequencing of fecal samples. The data were compared according to the current smoking status of the participants. Current smokers had high alcohol and sugar/sweetener intake and low fruit intake. The proportion of the Coprococcus genus was higher among current smokers. Multiple regression analysis adjusted for current smoking, age, exercise habits, alcohol intake, sugar and sweetener intake, and fruit intake showed that smoking was associated with the proportion of the Coprococcus genus. Current smoking was associated with both dietary intake and composition of the gut microbiota. Although dietary intake should be considered when investigating the association between smoking and the gut microbiota, the results suggest that the direct effect of smoking is more significant.

The Effect of Smoking Cessation on Body Weight and Other Metabolic Parameters with Focus on People with Type 2 Diabetes Mellitus

Smokers with diabetes mellitus substantially lower their risks of microvascular and macrovascular diabetic complications, in particular cardiovascular disease, by quitting smoking. However, subsequent post-smoking-cessation weight gain may attenuate some of the beneficial effects of smoking cessation and discourage attempts to quit. Weight gain can temporarily exacerbate diabetes and deteriorate glycemic control and metabolic profile. The molecular mechanisms by which quitting smoking leads to weight gain are largely associated with the removal of nicotine's effects on the central nervous system. This review addresses mechanisms of post-smoking-cessation weight gain, by reviewing the effects of nicotine on appetite, food intake, eating behaviour, energy expenditure, fat oxidation and appetite-regulating peptides. We also highlight correlations between post-cessation weight gain and risk of type 2 diabetes, consequences of weight gain in people with type 2 diabetes and the role of pharmacotherapies, which combine treatment of nicotine addiction and promotion of weight control.

Tobacco withdrawal increases junk food intake: The role of the endogenous opioid system

BACKGROUND

The aims of this study were to 1) determine whether acute nicotine withdrawal increases the intake of junk food (high in salt, fat, and sugar) and 2) assess whether the endogenous opioid system is involved in junk food intake during nicotine withdrawal using naltrexone as a pharmacological probe.

METHODS

Smokers were randomly assigned to 24-hr withdrawal from tobacco products (n = 42) or smoking ad libitum (n = 34). A non-smoking group (n = 29) was included. Participants completed two laboratory sessions where a placebo or 50 mg of naltrexone was administered. At the end of each session, participants were given a tray of snack items that differed in high to low energy density and dimensions of salty, sweet, and fat. Self-reported mood and withdrawal measures were collected immediately before the snacks were offered. Generalized linear and logistic models were used to assess the effects of acute smoking withdrawal, drug, and sex on the intake of snack items and self-reported measures.

RESULTS

Choice and consumption of food items were impacted by smoking condition (withdrawal > ad lib smoking and non-smokers; p < .05), the opioid blockade (naltrexone < placebo; p < .05), and sex (male > female; p < .05). The effects were evidenced in high sweet and high fat foods. No differences were found in low sweet and fat foods.

CONCLUSIONS

These findings extend earlier studies indicating impact of tobacco use on appetite, and identify the regulatory influence of the endogenous opioid system on appetite during nicotine withdrawal.

Nicotine and energy balance: A review examining the effect of nicotine on hormonal appetite regulation and energy expenditure

Nicotine has been shown to decrease appetite, food intake (FI) and body weight, but the mechanisms are unclear. The purpose of this review was to examine research on the effects of nicotine on energy balance by exploring physiological mechanisms and hormone regulation related to FI, subjective appetite and energy expenditure (EE). We searched PubMed and MEDLINE, and included articles investigating the effects of nicotine on central appetite regulation, FI, leptin, peptide-YY (PYY), ghrelin, glucagon-like peptide-1 (GLP-1), adiponectin, cholecystokinin (CCK), orexin, and EE. A total of 65 studies were included in the qualitative synthesis and review. Our findings suggest that the decrease in appetite and FI may be attributed to nicotinic alterations of neuropeptide Y (NPY) and pro-opiomelanocortin (POMC) but the effect of nicotine on FI remains unclear. Furthermore, nicotine increases resting EE (REE) and physical activity EE (PAEE) in both smokers and non-smokers; and these increases may be a result of the catecholaminergic effect of nicotine. Decreases in body weight and appetite experienced by nicotine users results from increased EE and changes in the central hypothalamic regulation of appetite. There is not enough evidence to implicate a relationship between peripheral hormones and changes in appetite or FI after nicotine use. Although nicotine increases REE and PAEE, the effect of nicotine on other components of EE warrants further research. We conclude that further research evaluating the effect of nicotine on appetite hormones, FI and EE in humans is warranted.

Tobacco Smoking, Eating Behaviors, and Body Weight: A Review

Purpose of review

This narrative review provides an overview of the relationships among tobacco smoking, eating behaviors, and body weight. The aims are to (1) examine the concurrent and longitudinal associations between tobacco smoking and body weight, (2) describe potential mechanisms underlying the relationships between smoking and body weight, with a focus on mechanisms related to eating behaviors and appetite, and (3) discuss management of concomitant tobacco smoking and obesity.

Recent findings

Adolescents who smoke tobacco tend to have body mass indexes (BMI) the same as or higher than nonsmokers. However, adult tobacco smokers tend to have lower BMIs and unhealthier diets relative to nonsmokers. Smoking cessation is associated with a mean body weight gain of 4.67 kg after 12 months of abstinence, though there is substantial variability. An emerging literature suggests that metabolic factors known to regulate food intake (e.g., ghrelin, leptin) may also play an important role in smoking-related behaviors. While the neural mechanisms underlying tobacco smoking-induced weight gain remain unclear, brain imaging studies indicate that smoking and eating cues overlap in several brain regions associated with learning, memory, motivation and reward. Behavioral and pharmacological treatments have shown short-term effects in limiting post-cessation weight gain; however, their longer-term efficacy is limited.

Summary

Further studies are needed to identify the exact mechanisms underlying smoking, eating behaviors, and body weight. Moreover, effective treatment options are needed to prevent long-term weight gain during smoking abstinence.