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The joy of mastication: Can chewing gum be addictive?

“Every time I go to the store I have to buy a [chewing gum called] ‘Big Red’. I chew three packs every day. I love the taste, and it’s sweet. I started chewing gum excessively when she couldn’t find a job after graduation. I became depressed because I thought that with my qualifications I would find a job immediately but I did not. Since I’ve been chewing gum I have had to make visits to the dentist more than once due to tooth pain” (Tamika Wilbourn, 22-year old US college graduate).

“I used to have an addiction problem. No, I was not addicted to drugs, alcohol, gambling, video games or any other typical vice that you can think of. I was addicted to chewing gum. A lot of you are probably thinking, ‘I have the same problem!’ or ‘I chew a lot of gum too!’  but I’ve yet to meet someone who chews as much gum as I once did. Some might argue that using the word ‘addiction’ in this context is going a little too far; I beg to differ. I used to NEED gum. I would chew so much gum that even when my jaw started to hurt, I kept chewing. I chewed in the morning, I chewed at night, I chewed when I was bored, stressed and nervous. I needed gum more than coffee; I was a chain chewer for about 7 whole years…I always carried at least 2 packs of gum with me at all times, and made it a point to stop and buy some if I was running low. I often went through 1-2 packs per day, maybe more. I would chew a piece for 5 minutes, spit it out and chew another. No matter what I did, I could convince myself that chewing just one piece of gum was enough…After a while I didn’t even like the taste anymore. Sure I liked the initial burst of minty sweetness, but what I really craved was the chewing motion. After a while the chain chewing did not feel good anymore, it felt necessary” (Stellina Saia, US business graduate).

A few months ago, I was contacted by a researcher from an American television production company. I was told that the company was planning to make a documentary film on people that were allegedly addicted to chewing gum. They had come across my blog and wanted to know if I thought chewing gum could be addictive. I had never come across a study that had examined the chewing of gum as an addiction but added that I thought it was theoretically possible. As an occasional gum chewer myself, I answered all the questions from a personal and anecdotal perspective but was unable to respond to any of the questions from an empirical standpoint (i.e., I had no data to support a single thing that I said. Everything I said was pure speculation).

I remember being asked about why people chew gum and I said there were multiple reasons. I know that I only ever chew gum after I have eaten – using it as a way to clean my teeth and remove food that may have stuck to my teeth. Occasionally I will chew mint gum to help freshen my breath or because I like the taste of a particular gum. I also made reference to English soccer managers (most notably Alex Ferguson and Sam Allardyce) that appear to chew gum as a stress relieving activity. In fact, there appear to appear to be many cognitive benefits to mastication (i.e., chewing). A recent (2013) review by Dr. Kin-ya Kubo and colleagues in the book Senescence and Senescence-Related Disorders noted that chewing helps improve learning and memory, may help people suffering from dementia, and provide stress relief:

“Although mastication is primarily involved in food intake and digestion, it also promotes and preserves general health, including cognitive function. Functional magnetic resonance imaging (fMRI) and positron emission topography studies recently revealed that mastication leads to increases in cortical blood flow and activates the somatosensory, supplementary motor, and insular cortices, as well as the striatum, thalamus, and cerebellum. Masticating immediately before performing a cognitive task increases blood oxygen levels in the prefrontal cortex and hippocampus, important structures involved in learning and memory, thereby improving task performance. Thus, mastication may be a drug-free and simple method of attenuating the development of senile dementia and stress-related disorders that are often associated with cognitive dysfunction. Previous epidemiologic studies demonstrated that a decreased number of residual teeth, decreased denture use, and a small maximal biting force are directly related to the development of dementia, further supporting the notion that mastication contributes to maintain cognitive function”.

A study by Dr. Yoshiyuki Hirano and colleagues in a 2013 issue of Brain and Cognition showed that chewing boosts thinking and alertness and that reaction times among chewers were 10% faster than non-chewers. The research team also reported that up to eight areas of the brain are affected by chewing (most notably the areas concerning attention and movement). It has been claimed that chewing increases arousal levels and that this increased arousal causes increased temporary blood flow to the brain. Commenting on these findings to the Daily Mail, Professor Andy Smith of Cardiff University, said that: “The effects of chewing on reaction time are profound. Perhaps football managers arrived at the idea of chewing gum by accident, but they seem to be on the right track”.

There are dozens and dozens of academic papers all showing the many benefits of mastication but I didn’t come across a single one that looked at whether chewing gum can be addictive. (If you type in ‘chewing gum’ and ‘addiction’ into any academic database you simply get loads of papers about the effectiveness of chewing nicotine gum in helping smoking cessation). However, as the opening quote highlights, there are online self-confessions of ‘chewing gum addiction’. Although the benefits of chewing gum appear to greatly outweigh the disadvantages, there are a number of online articles that take great pride in pointing out the negatives.

In a 2011 article on the Organic Authority website, Jill Ettinger provided a list of reasons of why people should give up chewing gum including jaw aches (accompanied by headaches), intestinal pressure for irritable bowel syndrome sufferers, over-production of saliva, and her assertion that most of the sugar-free chewing gum on the market is sweetened with aspartame, which has been linked to cancer, diabetes, neurological disorders, tinnitus and birth defects”. For those people that don’t chew sugar-free gum, she added that “the rest of the gum out there is typically sweetened with high fructose corn syrup, which in addition to a number of health issues (obesity, diabetes, cancer), is also one of the main causes of tooth decay”. An article in The Delphian by Valgina Cooper also claims chewing gum can be hazardous to your health (and partly based on her own chewing gum experiences). She reported:

“Did you know you could get addicted to gum? Jaws hurt. Teeth hurt because you have been popping gum all day. Millions of people chew gun but could it be an addiction? A person can be addicted to just about anything. People may buy 20 packs of gum a day because chewing gum can calm your nerves…But the taste can get you. Once you pop you can’t stop. Gum addiction can happen to you if you don’t know how to control yourself. First, you start chewing gum because you like the taste. Then you realize that you’re chewing gum when nervous or bored. It can be used to pacify you so it seems like you have something to concentrate on. Therefore the amount of gum chewed within a day increases. After this stage your body comes to a point where it needs gum all the time to feel comfortable…While many people chew gum, few realize that it can become an addiction that can leave you with serious health risks. How do you know you’ve become addicted to gum chewing? When you feel like you have to chew gum to function through the day – as I learned through my own experience”.

From what I have read on the topic, there is little in the empirical literature to suggest chewing gum can be an addiction. There is loads of anecdotal evidence that a minority of individuals chew gum excessively but little evidence among these individuals that it could be classed as an addiction. While I don’t rule out the theoretical possibility of becoming addicted to chewing gum, I have yet to see or read about a case that would fulfil my own criteria for addiction.

Dr. Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Brook, C. (2013). Chewing over a problem? Chomping on gum can boost alertness by 10%. Daily Mail, February 4. Located at: http://www.dailymail.co.uk/news/article-2272800/Chewing-gum-GOOD-brain-boost-alertness-10.html

Cooper, V. (2003). Warning! Chewing gum can be hazardous to your health. The Delphian, December 10. Located at: http://students.adelphi.edu/delphian/2003.12.10/articles/q.shtml

Ettinger, J. (2011). Hate to burst your bubble but…9 reasons to stop chewing gum. Organic Authority, September 16. Located at: http://www.organicauthority.com/health/bubble-gums-reasons-to-stop-chewing-gum-health.html

Griffiths, M.D. (2005). A ‘components’ model of addiction within a biopsychosocial framework. Journal of Substance Use, 10, 191-197.

Hirano, Y., Obata, T., Takahashi, H., Tachibana, A., Kuroiwa, D., Takahashi, T., … & Onozuka, M. (2013). Effects of chewing on cognitive processing speed. Brain and Cognition, 81(3), 376-381.

Kubo, K. Y., Chen, H., & Onozuka, M. (2013). The relationship between mastication and cognition. In Wang, Z. & Inuzuka (Eds.), Senescence and Senescence-Related Disorders. InTech. Located at: http://www.intechopen.com/books/senescence-and-senescence-related-disorders

Saia S. (2013). How I stopped chewing gum. My Yoghurt Addiction, February 25. Located at: http://myyogurtaddiction.com/2013/02/25/how-i-stopped-chewing-gum/

Fat chance: The British ‘obesity epidemic’

Obesity has become a major problem across the Western world including Great Britain. Some academic scholars claim that obesity is a natural consequence of ‘food addiction’. While I can share this viewpoint, there are many examples of obese people whose eating behaviour would not be classed as addicted using the addiction components model. However, that does not mean obesity is not a problem. Academically, I only became interested in obesity when I was appointed a member of the Department of Health’s Expert Working Group on Sedentary Behaviour, Screen Time and Obesity chaired by Professor Stuart Biddle and led to a major report that we published on obesity and sedentary behaviour in 2010 (see ‘Further reading).

Obesity is measured using a calculation based on a person’s Body Mass Index (BMI). BMI is calculated by dividing a person’s weight measurement [in kilograms] by the square of their height [in metres]. In adults, a BMI of 25kg/m2 to 29.9kg/m2 means that person is considered to be overweight, and a BMI of 30kg/m2 or above means that person is considered to be obese. A recent 2013 report by the Health and Social Care Information Centre presented a range of information on obesity in England drawn together from a variety of sources. The report noted that:

“NICE [National Institute for Health and Care Excellence] guidelines on prevention, identification, assessment and management of overweight and obesity highlight their impact on risk factors for developing long-term health problems. It states that the risk of these health problems should be identified using both BMI and waist circumference for those with a BMI less than 35kg/m2. For adults with a BMI of 35kg/m2 or more, risks are assumed to be very high with any waist circumference”.

The main source of the report’s data on the prevalence of overweight and obesity is taken from the annual Health Survey for England (HSE) that is written by NatCen Social Research, and published by the Health and Social Care Information Centre (HSCIC). Most of the information presented in the 2013 report is taken from the HSE 2011.The main findings were that:

  • The proportion of adults with a normal Body Mass Index (BMI) decreased from 41% to 34% among men and from 50% to 39% among women between 1993 and 2011.
  • The proportion that were overweight including obese increased from 58% to 65% in men and from 49% to 58% in women between 1993 and 2011.
  • There was a marked increase in the proportion of adults that were obese from 13% in 1993 to 24% in 2011 for men and from 16% to 26% for women.
  • The proportion of adults with a raised waist circumference increased from 20% to 34% among men and from 26% to 47% among women between 1993 and 2011.
  • In 2011, around three in ten boys and girls (aged 2 to 15) were classed as either overweight or obese (31% and 28% respectively), which is very similar to the 2010 findings (31% for boys and 29% for girls).
  • In 2011/12, around one in ten pupils in Reception class (aged 4-5 years) were classified as obese (9.5%) which compares to around a fifth of pupils in Year 6 (aged 10-11 years) (19.2%).
  • In 2011, obese adults (aged 16 and over) were more likely to have high blood pressure than those in the normal weight group. High blood pressure was recorded in 53% of men and 44% of women in the obese group and in 16% of men and 14% of women in the normal weight group.
  • Over the period 2001/02 to 2011/12 in almost every year more than twice as many females than males were admitted to hospital with a primary diagnosis of obesity.
  • In 2011, there were 0.9 million prescription items dispensed for the treatment of obesity, a 19% decrease on the previous year.

Using regression analysis, the HSE also examined the risk factors associated with being overweight and obese. For both men and women, being ‘most at risk’ was positively associated with: age; being an ex-cigarette smoker; self-perceptions of not eating healthily; not being physically active; and hypertension. Income was also associated with being ‘most at risk’, with a positive association for men and a negative association for women. It was also reported that among women only, moderate alcohol consumption was negatively associated with being ‘most at risk’.

Another summary report on adult weight published earlier this year by the National Obesity Observatory briefly reviewed the scientific data and concluded that in the UK: (i) an estimated 62% of adults (aged 16 and over) are overweight or obese, and that 2.5% have severe obesity; (ii) men and women have a similar prevalence of obesity, but men (41%) are more likely to be overweight than women (33%); (iii) the prevalence of obesity and overweight changes with age, and prevalence of overweight and obesity is lowest in the 16-24 years age group, and generally higher in the older age groups among both men and women; and (iv) women living in more deprived areas have the highest prevalence of obesity and those living in less deprived areas have the lowest, but there is no clear pattern for men.

The 2013 Health and Social Care Information Centre report also contextualized the obesity problem in the UK by comparing obesity rates with other European countries and worldwide using data published by the Organisation for Economic Co-operation and Development (OECD). In 2012, the OECD has published a number of ‘Health at a Glance’ reports including one on European health comparisons, and one on worldwide health comparisons (published in 2011). The data from these reports was summarised as follows:

“More than half (52%) of the adult population in the European Union reported that they were overweight or obese. The obesity rate has doubled over the last twenty years in many European countries and stands at between 7.9% in Romania and 10.3% in Italy to 26.1% in the UK and 28.5% in Hungary. The prevalence of overweight and obesity among adults exceeds 50% in 18 of 27 EU member states…[Worldwide] more than half (50.3%) of the adult population in the OECD reported that they were overweight or obese. The least obese countries were India (2.1%), Indonesia (2.4%) and China (2.9%) and the most obese countries were the US (33.8%), Mexico (30.0%) and New Zealand (26.5%). Obesity prevalence has more than doubled over the past 20 years in Australia and New Zealand. Some 20-24% of adults in Australia, Canada, the United Kingdom (UK) and Ireland are obese, about the same rate as in the United States in the early 1990s. Obesity rates in many western European countries have also increased substantially over the past decade. The rapid rise occurred regardless of where levels stood two decades ago. Obesity almost doubled in both the Netherlands and the UK, even though the current rate in the Netherlands is around half that of the UK”.

From an addiction perspective, there’s also some interesting data examining the co-relationship between obesity and drinking alcohol. For instance, a 2012 report by Gatineau and Mathrani examining the relationship between obesity and alcohol consumption reviewed the literature and made a number of conclusions. These were that (i) there is no clear causal relationship between alcohol consumption and obesity, although there are associations between alcohol and obesity and these are heavily influenced by lifestyle, genetic and social factors; (ii) many people are not aware of the calories contained in alcoholic drinks; (iii) the effects of alcohol on body weight may be more pronounced in overweight and obese people; (iv) alcohol consumption can lead to an increase in food intake; (v) heavy, but less frequent drinkers seem to be at higher risk of obesity than moderate, frequent drinkers; (vi) the relationships between obesity and alcohol consumption differ between men and women; (vii) excess body weight and alcohol consumption appear to act together to increase the risk of liver cirrhosis; and (viii) there is emerging evidence of a link between familial risk of alcohol dependency and obesity in women.

Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Biddle, S., Cavill, N., Ekelund, U., Gorely, T., Griffiths, M.D., Jago, R., et al. (2010). Sedentary Behaviour and Obesity: Review of the Current Scientific Evidence. London: Department of Health/Department For Children, Schools and Families.

Gatineau, M & Mathrani, S. (2012). Obesity and alcohol: An overview. Oxford: National Obesity Observatory.

Health and Social Care Information Centre (2013). Statistics on Obesity, Physical Activity and Diet: England, 2013. London: Health and Social Care Information Centre.

Organisation for Economic Co-operation and Development (2011). Health at a Glance 2011. Available at: http://www.oecd.org/dataoecd/6/28/491 05858.pdf

Organisation for Economic Co-operation and Development (2012). Health at a Glance: Europe 2012. Available at: http://www.oecd.org/health/healthatagla nceeurope.htm

National Obesity Observatory (2013). Adult weight. Oxford: National Obesity Observatory.

Eat to the beat: What is the relationship between exercise addiction and eating disorders?

In previous blogs I briefly examined both exercise addiction and eating addiction. However, there is some research that these two disorders sometimes co-occur. In some of the papers I have co-written we have reviewed the evidence as to whether exaggerated exercise behaviour is a primary problem in the affected person’s life or whether it emerges as a secondary problem in consequence of another psychological dysfunction. In the former case, the dysfunction is usually classified as primary exercise addiction because it manifests itself as a form of behavioural addiction. In the latter case, it is usually termed as secondary exercise addiction because it co-occurs with another dysfunction, typically with eating disorders, such as anorexia nervosa or bulimia nervosa.

In primary exercise addiction, the motive for over-exercising is typically geared toward avoiding something negative, although the affected individual may be totally unaware of their motivation. It is a form of escape response to a source of disturbing, persistent, and uncontrollable stress. However, in the case of a secondary exercise addiction, the excessive exercise is used as a means of weight loss (in addition to very strict dieting). Thus, secondary exercise addiction has a different etiology than primary exercise addiction. Nevertheless, it should be highlighted that many symptoms and consequences of exercise addiction are similar whether it is a primary or a secondary exercise addiction. The distinguishing feature between the two is that in primary exercise addiction, the exercise is the main objective, whereas in secondary exercise addiction, weight loss is the main objective, while exaggerated exercise is one of the primary means in achieving the objective.

In a qualitative study published by Dr Diane Bamber (University of Cambridge), she and her team interviewed 56 regularly exercising adult women. On the basis of the analysis of the results, the authors identified three factors in the diagnostic criteria of secondary exercise addiction. Among these factors, only the presence of eating disorder symptoms differentiated secondary from primary exercise addiction. The other two factors (i.e., dysfunctional psychological, physical, or social behaviour, and the presence of withdrawal symptoms) were nonspecific to secondary exercise addiction.

However, Dr Michelle Blaydon (formerly of the University of Hong Kong) and colleagues attempted to further sub-classify secondary exercise addiction based on the primary source of the problem, which in their view was related to either a form of eating disorder or to an exaggerated preoccupation with body image. Although this appears to have face validity, to date, there is no empirical evidence for such speculation. Furthermore, a different research study by Dr Diane Bamber found no evidence for primary exercise addiction. In fact, they believe that all problematic exercise behaviours are linked to eating disorders. However, this view remains critically challenged in the literature and there are documented case studies – including one that I published myself back in 1997 where no eating disorders were present at all.

In addition to several studies that have reported disordered eating behaviour often (if not always) accompanied by exaggerated levels of physical exercise, the reverse relationship has also been established. Individuals affected by exercise addiction often (but not always) show an excessive concern about their body image, weight, and control over their diet. This co-morbidity makes it difficult to establish which is the primary disorder. This dilemma has been investigated using trait and personality-oriented investigations. In an early but widely cited controversial study led by Dr Alayne Yates (University of Hawaii) concluded that addicted male long-distance runners resembled anorexic patients on a number of personality dispositions (e.g., introversion, inhibition of anger, high expectations, depression, and excessive use of denial) and labelled the similarity as the “anorexia analogue” hypothesis.

To further test the hypothesis, Yates and colleagues examined the personality characteristics of 60 male obligatory exercisers and then compared their profiles with those of clinical patients diagnosed with anorexia nervosa. While the study did not lend support to the hypothesis, the authors claimed that running and extreme dieting were both dangerous attempts to establish an identity, as either addicted to exercise or anorexic. The study has been criticized for a number of shortcomings, including the lack of supporting data, poor methodology, lack of relevance to the average runner, over-reliance on extreme cases or individuals, and exaggerating the similarities between the groups.

Indeed, later investigations also failed to reveal similarities between the personality characteristics of people affected by exercise addiction and those suffering from eating disorders. Therefore, the anorexia analogue hypothesis has failed to secure empirical support. Numerous studies have further examined the relationship between exercise addiction and eating disorders but no consensus has emerged. One reason for the inconsistent findings may be attributed to the fact that the extent of co-morbidity could vary from case to case depending on personality predispositions, the underlying psychological problem that has led to exercise addiction, and/or the interaction of the two, as well as the form and severity of the eating disorder.

A French study led by Professor Michel Lejoyeaux (Bichat and Maison Blanche Hospital) on 125 Parisian male and female current exercise addicts reported that 70% of their sample were bulimic. In another US study by Dr Patricia Estok and Dr Ellen Rudy among 265 young American adult women runners and non-runners, 25% of those who ran more than 30 miles per week showed a high risk for anorexia nervosa. In studies of people with eating disorders, a study by Peter Lewinsohn (Oregon Research Institute, US) found excessive exercise activity among males with binge eating disorders, but not females. However, the percentage overlap was not reported. Finally, in a review by Marilyn Freimuth (Fielding Graduate University, US), she and her colleagues reported that among people with eating disorders, 39% to 48% also experienced an exercise addiction.

Basically, the major weakness of the literature is the complete lack of large-scale studies. In a recent review of the addiction co-morbidity literature that I did with Dr Steve Sussman and Nadra Lisha (University of Southern California), we didn’t locate a single study on the co-occurrence of exercise addiction with other disorders with a sample size of more than 500 participants.

Dr Mark Griffiths, Professor of Gambling Studies, International Gaming Research Unit, Nottingham Trent University, Nottingham, UK

Further reading

Bamber, D.J., Cockerill, I.M., Rodgers, S., & Carroll, D. (2003). Diagnostic criteria for exercise dependence in women. British Journal of Sports Medicine, 37(5), 393–400.

Berczik, K., Szabó, A., Griffiths, M.D., Kurimay, T., Kun, B. & Demetrovics, Z. (2012). Exercise addiction: symptoms, diagnosis, epidemiology, and etiology. Substance Use and Misuse, DOI: 10.3109/10826084.2011.639120.

Blaydon, M.J., & Lindner, K. J. (2002). Eating disorders and exercise dependence in triathletes. Eating Disorders, 10(1), 49-60.

Blaydon, M.J., Lindner, K. J., & Kerr, J. H. (2004). Metamotivational characteristics of exercise dependence and eating disorders in highly active amateur sport participants. Personality and Individual Differences, 36(6), 1419-1432.

Estok, P.J., & Rudy, E.B. (1996). The relationship between eating disorders and running in women. Research in Nursing & Health, 19, 377-387.

Freimuth, M., Waddell, M., Stannard, J., Kelley, S., Kipper, A., Richardson, A., & Szuromi, I. (2008). Expanding the scope of dual diagnosis and co-addictions: Behavioral addictions. Journal of Groups in Addiction & Recovery, 3, 137-160.

Griffiths, M. D. (1997). Exercise addiction: A case study. Addiction Research, 5, 161-168.

Lejoyeux, M., Avril, M., Richoux, C., Embouazza, H., & Nivoli, F. (2008). Prevalence of exercise dependence and other behavioral addictions among clients of a Parisian fitness room. Comprehensive Psychiatry, 49, 353-358.

Lewinsohn, P.M., Seeley, J.R., Moerk, K.C., & Striegel-Moore, R.H. (2002). Gender differences in eating disorder symptoms in young adults. International Journal of Eating Disorders, 32, 426-440.

Sussman, S., Lisha, N. & Griffiths, M.D. (2011). Prevalence of the addictions: A problem of the majority or the minority? Evaluation and the Health Professions, 34, 3-56.

Szabo, A. (2010). Addiction to exercise: A symptom or a disorder? New York, NY: Nova Science Publishers.

Yates, A., Leehey, K., & Shisslak, C. M. (1983). Running – an analogue of anorexia? New England Journal of Medicine, 308(5), 251-255.