Hepatitis C virus (HCV) infection and excessive alcohol consumption are both common causes of liver disease. However, when you combine the two, they work together to speed-up the progression of liver disease. This is a good reason why it is important to limit or stop drinking alcohol if you have HCV.
HCV and alcohol abuse and dependence: a common problem
HCV occurs much more commonly in people who have a history of alcohol abuse. Studies have found that the prevalence of HCV among people who abuse alcohol ranges from 14% to 36%, many times the prevalence of HCV in the general population.1-3 In one study of US veterans with HCV, 44% of those infected had a history of alcohol abuse or dependence.2
We don’t completely understand why HCV infection is more common among people with alcohol abuse and dependence problems. It may be that this group is more likely to engage in high risk behaviors that expose them to HCV, including injection drug use and high-risk sexual activities.
The effect of alcohol on HCV progression
Studies have looked at how alcohol consumption affects the progression of HCV and found that it1:
- Speeds up the development of fibrosis and increases the risk for cirrhosis
- Increases the risk for developing liver cancer
- Increases the chances of developing a fatal complication
Fibrosis and cirrhosis. One study that included over 2,200 people with HCV found that daily alcohol consumption of 50 grams or more increased the risk of fibrosis progression by 34%. A standard drink contains 12 grams of alcohol, which is equivalent to 1.5 ounces of whiskey or other 80 proof distilled spirits, a 12 ounce beer, or 5 ounces of wine. Even modest alcohol consumption, if you have HCV infection, can speed up the development of fibrosis.
Liver cancer. The exact amount of alcohol consumption that increases risk for developing liver cancer (hepatocellular carcinoma [HCC]) is not known. Having HCV infection itself increases the chances for developing HCC by as much as 26 times. According to one study, if you have HCV and you consume 80 grams of alcohol per day, your risk for developing HCC increases by as much as 126 times compared with someone in the general population.5
What effect does alcohol have on HCV?
How alcohol worsens HCV and speeds up progression of liver disease is not completely understood. We do know that alcohol acts in several ways to worsen the impact that the virus has on the body. Specifically, excessive alcohol consumption1 :
- Increases HCV replication (the ability of the virus to reproduce)
- Decreases the ability of the immune system to fight HCV infection
- Increases the rate of HCV mutations, increasing the chances for resistant HCV quasispecies
- Has a general negative effect on the health of the body
In one laboratory study, HCV replication or reproduction was increased three-fold in HCV cells that were treated with alcohol. Other studies have looked at how alcohol affects immunity on a cellular level. Alcohol and HCV both decrease the function of specific types of immune system cells involved in protecting liver and other cells. In studies conducted in animals, alcohol consumption resulted in an impaired immune response to HCV.1
Not only does alcohol affect how the body responds to HCV, it also affect how well antiviral medications work against the virus. Alcohol inhibits the effects of antiviral medications, including interferon.1
Alcohol increases oxidative stress in people who are infected with HCV. Oxidative stress is when the body is unable to get rid of or counteract the harmful effects of free radicals, molecules that are a byproduct of oxygen use. Normally, the body can counteract the effects of free radicals by using antioxidants, which we get from our diets. However, alcohol consumption makes the body less able to do this. This allows free radicals to damage the body.1
Alcohol increases the ability of HCV to mutate into quasispecies. An increase in the number of HCV quasi species is associated with increased resistance to treatment and poor responses to interferon-based therapy.1
How does alcohol affect HCV treatment?
If you have HCV and are receiving interferon-based treatment, alcohol use can decrease the effectiveness of that treatment. If you have a history of alcohol abuse or dependence, and have quit drinking for a period of 6 to 12 months before starting treatment, evidence suggests that your alcohol history will not affect your response to treatment.1
How much alcohol can I consume?
Even modest alcohol consumption has been associated with increased oxidative stress and increased progression of fibrosis. A standard drink contains 12 grams of alcohol, which is equivalent to 1.5 ounces of whiskey or other 80 proof distilled spirits, a 12-ounce beer, or 5 ounces of wine. Since moderate alcohol consumption or about 2 standard drinks per day increases risk for progression of liver disease, you should try to avoid drinking altogether if you have HCV. This is especially true for the period before starting treatment with an interferon-based drug regimen.1