Smoking reduces the effects of alcohol and may even encourage people to drink more, according to research published in the journal "Alcoholism: Clinical and Experimental Research".

Scientists who studied rats exposed to a combination of alcohol and nicotine found that nicotine reduced blood alcohol concentrations at levels which could have an impact in human smokers -- and explain why cigarettes and alcohol are often seen to go together.

"Since the desired effect of alcohol is significantly diminished by nicotine -- particularly among heavy or binge drinkers such as college students -- this may encourage drinkers to drink more to achieve the pleasurable or expected effect," said Wei-Jung Chen, from the Texas A and M University Health Science Center in College Station, who led the reeearch.

"In other words, cigarette smoking appears to promote the consumption of alcohol."

Susan Maier, health scientist administrator at the US National Institutes of Health, said: "In the human condition, persons desiring to drink 'to effect' will need to drink more alcohol while smoking in order to reach this effect, and this will lead to an increased amount and lingering presence of toxic by-products of alcohol metabolism, such as acetaldehyde.

"This would be particularly harmful for adolescents and young adult drinkers, since these populations are amenable to this type of drinking pattern, and may develop chronic alcohol-related diseases earlier in life because of it."

One effect of the nicotine/alcohol interaction might be to permanently alter metabolism, she added. This could reduce the effect of beneficial medicinal drugs in people who both smoke and drink.