Alcohol is part of all our lives; we encounter it at events and meals, and sometimes enjoy a glass of wine in the evening to unwind. However, it is still a substance that can be dangerous, with many struggling with alcohol addiction, finding it difficult to stop or reduce their consumption. It's not uncommon for this to lead to problems in relationships, work, and of course, health, as past research has already shown that chronic alcohol consumption causes long-term damage and nerve pain, known as “alcoholic neuropathy.”
A 2019 study also showed that more than half of those addicted to alcohol suffer from chronic pain during withdrawal known as allodynia – pain from non-painful sources, like a breeze touching the skin or fabric touching the skin, with this phenomenon being more common in women than in men. If you consume alcohol regularly or even just moderately and suffer from persistent pain, it's recommended to consider whether it might be the cause.
How does alcohol cause pain?
The relationship between alcohol and pain is quite complex, as not only is pain a symptom of excessive alcohol use, but sometimes people suffering from chronic pain turn to alcohol to relieve it. The pain-relieving ability of alcohol has been known for many years, as it can indeed relieve pain to a moderate level. Researchers suggest it has an effect that dulls the pain and can even reduce hyperalgesia – increased sensitivity to pain – even in non-intoxicating amounts.
Despite all these findings, the exact mechanism linking excessive alcohol consumption to the onset of chronic pain is still unknown to researchers. To shed light on the issue, particularly on alcoholic neuropathy pain and alcohol withdrawal, Dr. Vittoria Borgonti and colleagues from the Scripps Research Institute in California conducted a study, comparing pain among rats that developed alcohol dependence, rats that consumed alcohol moderately, and rats not exposed to alcohol at all.
How was the study conducted, and what did researchers examine?
The study used both male and female rats. The research team divided them into 3 groups:
- The alcohol-naive group – these rats were not exposed to alcohol at all.
- The non-dependent group – these rats had access to two bottles, one containing water and the other alcohol, and could choose freely between them. These rats drank alcohol moderately.
- The dependent group – these rats also had a water bottle and an alcohol bottle, but were also exposed to ethanol vapor and periods of withdrawal. These rats were meant to mimic humans suffering from alcoholism.
Throughout the study period, the researchers tracked the allodynia pain in the rats using Von Frey filaments – nylon fibers of different thicknesses and lengths, pressing them on the rats' paw pads to determine the minimum force required to elicit a pain response.
Since a previous study showed that the immune system is activated in response to peripheral alcoholic neuropathy, the researchers also examined the immune system's response in rats from the non-dependent group who suffered from neuropathic pain. They used a technique called “Western Blot,” which allows for the assessment of protein molecule levels in the spinal cord, appearing as a response to immune system activity.
Alcohol activates immune cells in the spinal cord
Researchers found that the dependent group had significantly higher alcohol consumption than those in the non-dependent group. During the 72-hour withdrawal period, the rats in the dependent group developed allodynia, but it disappeared immediately when they were allowed to drink alcohol. However, almost half of the rats in the non-dependent group also showed signs of allodynia, compared to the alcohol-naive group.
What the researchers discovered was an increase in the levels of IBA-1 and CSF-1 proteins in the spinal cord tissues, among both rats suffering from withdrawal-induced allodynia and rats with neuropathic pain who consumed alcohol. This suggests immune system cell activity in spinal cord tissues in both cases, though rats with allodynia also had higher levels of IL-6 and ERK44/42, two other proteins associated with the immune system.
What do these findings actually mean?
The topic of neuropathic pain stemming from alcohol consumption has not been sufficiently studied in models that allow conclusions to be drawn regarding humans, making it very challenging to investigate the pathological processes causing pain in people addicted to alcohol. This study is essentially the first to present such a preclinical model, and the way it was conducted opens up possibilities for further studies on this topic.
Dr. Mitchell Notham from the Barker Labs at Drexel University in Philadelphia, who was not involved in the study, commented in an interview with Medical News Today: “This study uniquely demonstrated how alcohol dependence is not required to exacerbate pain, and that even moderate drinking can cause pathological pain. Therefore, alcohol consumption is not at all a recommended way to deal with pain.”
So whether you use alcohol to relieve pain or habitually drink a glass of wine each evening to relax but suffer from unexplained pain, it's recommended that you reconsider your habit, and if needed, seek professional help. If you are parents, it's important to know that alcohol addiction can start at a very young age – even from age 12 and you can click here to find some tips to help you talk about this topic with your children and prevent it if necessary.
