Nicotine
Nicotine occurs naturally in the tobacco plant, which belongs to the potato plant family. Other species in this family also contain small amounts of nicotine, such as tomato and potato.
Nicotine is traditionally used as a stimulant. When snus is used, nicotine is absorbed into the bloodstream via the oral mucosa and is transferred to the brain’s reward system. Most people experience a general feeling of wellbeing, which has both a sedative and a stimulating effect.
Nicotine alone does not cause cancer. High doses can give rise to side effects such as palpitations, tremors and nausea, which are not unlike the body’s reactions to large amounts of coffee or other caffeine products.
Sensitivity to nicotine varies and genetic factors probably play a major role. Some people simply do not enjoy the effects of nicotine, while others can develop an addiction.
Children and young people are particularly sensitive to nicotine and should not use snus or any other products containing nicotine. This also applies to women who are pregnant or nursing. Nicotine may affect blood circulation in the placenta and could consequently affect growth of the fetus. Nicotine in blood is transmitted with the mother’s milk.
Nicotine affects blood circulation, increases the heart rate and constricts blood vessels.
People with various types of heart problems, such as irregular heartbeat or angina, should thus avoid nicotine. This also applies to people who have, or have recently suffered, disorders in blood circulation to the brain.
The amount of nicotine absorbed by the body depends on how long the pouch is kept in the mouth and the properties of the snus, such as the total nicotine, moisture content and pH value. The rate of absorbance also varies from person to person.
Of the total nicotine in snus, the “free-base” or available nicotine is absorbed most easily via the oral mucosa. pH value of the snus indicates the proportion of free-base available nicotine in relation to the bound unavailable nicotine. The proportion of free-base nicotine increases at higher pH values.
The tobacco in Swedish snus is ground and the product is sold either in portion packs or “loose”. The total nicotine content is about 1-2 percent with a pH value of about 8.5. These are the traditional levels for Swedish snus and they have not changed in over 200 years, which is how long snus has been used in Sweden.
Only a small amount of the nicotine in the pouch is absorbed into the bloodstream when snus is used. The higher the pH value, the easier it is to absorb the nicotine through the oral mucosa. The pH level decreases in old and dry snus, which also reduces nicotine absorption. Snus is sold refrigerated, which helps preserve the moisture and pH level.
The absorption rate of nicotine has a significant effect on how the nicotine is experienced. Rapid nicotine absorption gives a stronger effect. Normally, only 10-20 percent of the total nicotine in the pouch enters the bloodstream. Absorption studies show that nicotine absorption varies greatly between individuals, which partly explains why the effect and experience differ from one snus user to another.
Over time, the brain becomes accustomed to nicotine, which is why withdrawal symptoms may be experienced when people stop using snus temporarily or permanently. A user may experience a sense of loss due to his/her habit or the effect of the nicotine. This can take many different forms, such as becoming irritated or experiencing difficulties sleeping. The time it takes for these symptoms to disappear will vary, but the nicotine is usually completely eliminated from the body within one to two weeks after stopping.
Many people who want to quit smoking think that using snus will help them stop. This is because the nicotine in snus gives the same effect as cigarettes. An average snus user consumes about as much nicotine as a smoker. The advantage of switching to snus is that the airways will not be exposed to smoke. Exposure to carbon monoxide and other combustion products in tobacco smoke is also avoided. Many of these substances are carcinogenic, which is why smokers have a higher risk of developing lung cancer.
REFERENCES
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Ramström, L.M. and Foulds, J. 2006. Role of snus in initiation and cessation of tobacco smoking in Sweden. Tobacco Control 15:210-214.
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Läkartidningen 2007. 104 (13): 1047-9
SCENIHR Report: Health effects of smokeless tobacco products, 2008
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Lindstrom, D., H. Tonnesen, and J. Adami, Rökfrihet vid kirurgiska ingrepp - Rökstopp minskar komplikationsrisken drastiskt. Läkartidningen, 2010. 107(43): p. 2634-5.
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