As we enter the festive season it’s a good time to think about what all those celebratory alcoholic drinks can do to your gut.

Alcohol can interfere with the time it takes for food to go through your gut (also known as the “transit time”). In particular, it can affect the muscles of the stomach and the small bowel (also known as the small intestine).

So, how and why does alcohol make your poos goes weird? Here’s what you need to know.

Diarrhoea and the ‘transit time’

Alcohol’s effect on stomach transit time depends on the alcohol concentration.

In general, alcoholic beverages such as whisky and vodka with high alcohol concentrations (above 15%) slow down the movement of food in the stomach.

Beverages with comparatively low alcohol concentrations (such as wine and beer) speed up the movement of food in the stomach.

These changes in gut transit explain why some people can get a sensation of fullness and abdominal discomfort when they drink vodka or whisky.

How long someone has been drinking a lot of alcohol can affect small bowel transit.

We know from experiments with rats that chronic use of alcohol accelerates the transit of food through the stomach and small bowel.

This shortened transit time through the small bowel also happens when humans drink a lot of alcohol, and is linked to diarrhoea.

Alcohol can also reduce the absorption of carbohydrates, proteins and fats in the duodenum (the first part of the small bowel).

Alcohol can lead to reduced absorption of xylose (a type of sugar). This means diarrhoea is more likely to occur in drinkers who also consume a lot of sugary foods such as sweets and sweetened juices.

Chronic alcohol use is also linked to:

• lactose intolerance
• overgrowth of small bowel bacteria and
• reduced absorption of fats from the pancreas not producing enough digestive enzymes.

This means chronic alcohol use may lead to diarrhoea and loose stools.

How might a night of heavy drinking affect your poos?

When rats are exposed to high doses of alcohol over a short period of time, it results in small bowel transit delay.

This suggests acute alcohol intake (such as an episode of binge drinking) is more likely to lead to constipation than diarrhoea.

This is backed up by recent research studying the effects of alcohol in 507 university students.

These students had their stools collected and analysed, and were asked to fill out a stool form questionnaire known as the Bristol Stool Chart.

The research found a heavy drinking episode was associated with harder, firm bowel motions.

In particular, those who consumed more alcohol had more Type 1 stools, which are separate hard lumps that look or feel a bit like nuts.

The researchers believed this acute alcohol intake results in small bowel transit delay; the food stayed for longer in the intestines, meaning more water was absorbed from the stool back into the body. This led to drier, harder stools.

Interestingly, the researchers also found there was more of a type of bacteria known as “Actinobacteria” in heavy drinkers than in non-drinkers.

This suggests bacteria may have a role to play in stool consistency.

But binge drinking doesn’t always lead to constipation. Binge drinking in patients with irritable bowel syndrom (IBS), for example, clearly leads to diarrhoea, nausea and abdominal pain.

What can I do about all this?

If you’re suffering from unwanted bowel motion changes after drinking, the most effective way to address this is to limit your alcohol intake.

Some alcoholic beverages may affect your bowel motions more than others. If you notice a pattern of troubling poos after drinking certain drinks, it may be sensible to cut back on those beverages.

If you tend to get diarrhoea after drinking, avoid mixing alcohol with caffeinated drinks. Caffeine is known to stimulate contractions of the colon and so could worsen diarrhoea.

If constipation after drinking is the problem, then staying hydrated is important. Drinking plenty of water before drinking alcohol (and having water in between drinks and after the party is over) can help reduce dehydration and constipation.

You should also eat before drinking alcohol, particularly protein and fibre-rich foods.

Food in the stomach can slow the absorption of alcohol and may help protect against the negative effects of alcohol on the gut lining.

Is it anything to worry about?

Changes in bowel motions after drinking are usually short term and, for the most part, resolve themselves pretty efficiently.

But if symptoms such as diarrhoea persist beyond a couple of days after stopping alcohol, it may signify other concerning issues such as an underlying gut disorder like inflammatory bowel disease.

Researchers have also linked alcohol consumption to the development of irritable bowel syndrome.

If problems persist or if there are alarming symptoms such as blood in your stool, seek medical advice from a general practitioner.

Vincent Ho, Associate Professor and clinical academic gastroenterologist, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The anterior cruciate ligament (ACL) is an important ligament in the knee. It runs from the thigh bone (femur) to the shin bone (tibia) and helps stabilise the knee joint.

Injuries to the ACL, often called a “tear” or a “rupture”, are common in sport. While a ruptured ACL has just sidelined another Matildas star, people who play sport recreationally are also at risk of this injury.

For decades, surgical repair of an ACL injury, called a reconstruction, has been the primary treatment in Australia. In fact, Australia has among the highest rates of ACL surgery in the world. Reports indicate 90% of people who rupture their ACL go under the knife.

Although surgery is common – around one million are performed worldwide each year – and seems to be the default treatment for ACL injuries in Australia, it may not be required for everyone.

What does the research say?

We know ACL ruptures can be treated using reconstructive surgery, but research continues to suggest they can also be treated with rehabilitation alone for many people.

Almost 15 years ago a randomised clinical trial published in the New England Journal of Medicine compared early surgery to rehabilitation with the option of delayed surgery in young active adults with an ACL injury. Over half of people in the rehabilitation group did not end up having surgery. After five years, knee function did not differ between treatment groups.

The findings of this initial trial have been supported by more research since. A review of three trials published in 2022 found delaying surgery and trialling rehabilitation leads to similar outcomes to early surgery.

A 2023 study followed up patients who received rehabilitation without surgery. It showed one in three had evidence of ACL healing on an MRI after two years. There was also evidence of improved knee-related quality of life in those with signs of ACL healing compared to those whose ACL did not show signs of healing.

Regardless of treatment choice the rehabilitation process following ACL rupture is lengthy. It usually involves a minimum of nine months of progressive rehabilitation performed a few days per week. The length of time for rehabilitation may be slightly shorter in those not undergoing surgery, but more research is needed in this area.

Rehabilitation starts with a physiotherapist overseeing simple exercises right through to resistance exercises and dynamic movements such as jumping, hopping and agility drills.

A person can start rehabilitation with the option of having surgery later if the knee remains unstable. A common sign of instability is the knee giving way when changing direction while running or playing sports.

To rehab and wait, or to go straight under the knife?

There are a number of reasons patients and clinicians may opt for early surgical reconstruction.

For elite athletes, a key consideration is returning to sport as soon as possible. As surgery is a well established method, athletes (such as Matilda Sam Kerr) often opt for early surgical reconstruction as this gives them a more predictable timeline for recovery.

At the same time, there are risks to consider when rushing back to sport after ACL reconstruction. Re-injury of the ACL is very common. For every month return to sport is delayed until nine months after ACL reconstruction, the rate of knee re-injury is reduced by 51%.

Historically, another reason for having early surgical reconstruction was to reduce the risk of future knee osteoarthritis, which increases following an ACL injury. But a review showed ACL reconstruction doesn’t reduce the risk of knee osteoarthritis in the long term compared with non-surgical treatment.

That said, there’s a need for more high-quality, long-term studies to give us a better understanding of how knee osteoarthritis risk is influenced by different treatments.

Rehab may not be the only non-surgical option

Last year, a study looking at 80 people fitted with a specialised knee brace for 12 weeks found 90% had evidence of ACL healing on their follow-up MRI.

People with more ACL healing on the three-month MRI reported better outcomes at 12 months, including higher rates of returning to their pre-injury level of sport and better knee function. Although promising, we now need comparative research to evaluate whether this method can achieve similar results to surgery.

What to do if you rupture your ACL

First, it’s important to seek a comprehensive medical assessment from either a sports physiotherapist, sports physician or orthopaedic surgeon. ACL injuries can also have associated injuries to surrounding ligaments and cartilage which may influence treatment decisions.

In terms of treatment, discuss with your clinician the pros and cons of management options and whether surgery is necessary. Often, patients don’t know not having surgery is an option.

Surgery appears to be necessary for some people to achieve a stable knee. But it may not be necessary in every case, so many patients may wish to try rehabilitation in the first instance where appropriate.

As always, prevention is key. Research has shown more than half of ACL injuries can be prevented by incorporating prevention strategies. This involves performing specific exercises to strengthen muscles in the legs, and improve movement control and landing technique.

Anthony Nasser, Senior Lecturer in Physiotherapy, University of Technology Sydney; Joshua Pate, Senior Lecturer in Physiotherapy, University of Technology Sydney, and Peter Stubbs, Senior Lecturer in Physiotherapy, University of Technology Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.