In the western world, antibiotics and food poisoning are among the most common causes of diarrhea, with the likes of stomach infections and irritable bowel syndrome also playing their part. This upset within the gut interferes with our microflora makeup, causing the bowel to extract water from the rest of the body and ultimately, ejectfaeces as fast as possible.  

Fortunately, studies show that probiotics can help minimize the occurrence of diarrhea. A meta-analysis of 35 studies found that taking these supplements can effectively cut diarrhea duration by over 25 hours. Observational studies also show that people with specific healthy bacterial species living in their guts, like Lactobacillus Rhamnosus and Lactobacillus Casei, are less likely to suffer from diarrhea at all. 

Weight loss 

Although not guaranteed, weight loss may be another benefit to taking probiotics. Healthy bacteria could improve our metabolic function, therefore burning fat quickly and more effectively.  

One study showed that a healthier gut microbiome increases the likelihood of fat excretion. As such, some people can eat fat and then deposit it in the toilet bowl without ever absorbing it into the system, similar to how some weight loss drugs work.  

Another study found that increased microbial richness in the gut reduces the risk of high blood sugar and metabolic complications For example, those that consume a higher volume of greens and whole grains may be less likely to develop a chronic disease because they actively feed their gut with anti-inflammatory good bacteria. 

Probiotics may boost your immune system 

There is evidence to suggest that taking probiotics may boost the immune system. A healthy bacterial ecosystem in the gut can improve the body’s natural resistance to potentially harmful pathogens.  

Some studies suggest that improving gut microbiome diversity may reduce women’s risk of developing urinary tract infections (UTIs) by up to 50%. 

Of course, whether or not these results will be replicated depends on new studies. Some scientists are keen to conduct more advanced experiments to determine the microbiome effects from the protective properties of ingested food.  

Probiotics can reduce digestive discomfort symptoms from some disorders 

There is also evidence to suggest that probiotics may relieve symptoms of gut disorders like inflammatory bowel diseases (IBD) and Crohn’s disease. Ongoing research suggests that such conditions are caused by chronic microbiome-induced inflammation of the gut lining, resulting in symptoms such as bloating, cramping, and bloody stools.   

Already, researchers know that most people with IBD and Crohn’s go into remission when fed a high-fiber, plant-based diet. However, probiotics may be acting through a similar mechanism, supplying the stomach with more of the good microbes it needs to function at its best. 

Research shows that people with IBD fed Bifidobacterium and Lactobacillus supplements experienced significantly reduced symptoms compared to controls. Additional evidence also suggests that taking large quantities of probiotics may aid those with IBS. More diverse and healthier species could buffer against a diet rich in meat, sugar, and refined starch.  

Probiotics may help improve the skin 

Interestingly, there is emerging evidence that probiotics may improve skin quality. Researchers are realizing that what goes on inside the stomach can directly impact the face, neck, back, and legs.  

There is also growing evidence to suggest that improving the microbiome has knock-on effects on how our skin looks and feels. Fiber-munching bacteria generate short-chain fatty acids (SCFAs) that have an anti-inflammatory effect body-wide when absorbed into the system, including the skin. Common skin conditions such as eczema and redness are therefore often reduced after probiotic consumption.  

Probiotics may help support allergies 

There may also be some positive effects on allergies. Those that stick to a high-fiber diet and growing more beneficial bacteria in their colons appear to have lower rates of allergic rhinitis and asthma. Unfortunately, it remains unclear whether or not probiotics can directly support the skin. Nevertheless, there is a growing amount of evidence to suggest that what happens inside the gut also produces cosmetic benefits on the outside.   

Probiotic strains could improve heart health 

Another line of evidence suggests that probiotics may improve heart health by lowering low-density lipoprotein (LDL) cholesterol. Decades of scientific investigation show that this substance can create atherosclerosis (damage to the artery walls) and plaque when concentrations rise too high (usually over 70 mg/dL). However, specific bacteria may fight back against this.  

For example, lactic acid-producing bacteria can reduce cholesterol by blocking bile reabsorption. As such, they can create a one-way street where LDL gets ejected in the feces instead of making its way back into the bloodstream, where it can cause damage.  

Furthermore, good bacteria can also reduce body-wide systemic inflammation by crowding out some of the harmful strains. These then produce helpful byproducts that minimise harmful cytokine production, like TNF-alpha and the interleukins.  

Probiotics may improve mental health conditions 

Finally, probiotics could improve some mental health conditions, especially those relating to the gut. Human and animal studies reveal that improving gut microbiome composition can lead to improvements in several disorders.  

Human studies show that supplementation can positively impact conditions like anxiety and depression in just one to two months. Further evidence suggests that better bacteria makeup in the gut can also reduce obsessive-compulsive disorder symptoms.   

What is the difference between probiotics and prebiotics?  

Probiotics and prebiotics often get confused, but they aren’t the same. Prebiotics are plant-based fibres that are used to supplement your good gut bacteria, enabling it to grow stronger and healthier over time. 

The key takeaways 

When it comes to probiotics, there’s a lot to unpack. Ultimately, probiotics can benefit health through a range of mechanisms, leading to systemic improvements body-wide. Supplements may assist with everything from mental health conditions to severe bowel disorders like IBD and Crohn’s.  

Fortunately, probiotics from top brands are easy to find. These contain scientifically validated bacteria species to support gut, metabolic, immune, and psychological health.