When anyone mentions the benefits of probiotics, it’s usually something to do with improving digestion. In other cases, it’s about restoring the gut flora after a course of antibiotics.
But the benefits of probiotics go far beyond breaking down food and rebalancing the gut.
In fact, you might be surprised to know just how powerful these little bacteria can be – not just for your gut, but for your immune system, your mind, and even your skin!
Few people realize how intimately the gut is linked to the brain. This has been termed ‘the gut-brain connection’.
The microorganisms in your gut have been shown to interact with the nervous system, influencing all the messages and actions sent from your brain around the body.
Gut microbiota can affect the messages and chemicals associated with your body’s response to stress, anxiety and even memory function.
Improving this microbiota with probiotics has been shown to improve this interaction and reduce effects of anxiety, stress and depression.
Around 70 percent of your immune cells live in the lymphatic tissue of the gut, and boosting the health of these cells is one benefit of probiotics.
One study in particular found that lactic acid bacteria and Bifidobacteria are effective in boosting the immune system, and that they can help prevent a wide range of immunity-related diseases. (1)
This is partly due to their ability to prevent pathogenic bacteria from thriving, as well as their powerful anti-inflammatory effect.
Just as the gut is connected to the brain, it’s connected to the skin, too.
Because Western diet is largely comprised of sugary, processed foods, and our lives are highly stressed, our bodies are highly prone to chronic inflammation. This inflammation often shows up on our skin.
Probiotics can help with your skin too. It’s been found that certain strains of probiotics can reduce antigen-specific skin inflammation, which in turn brings down the inflammatory process that causes acne.
One study found that participants who were given a daily fermented milk drink that contained L. casei had significantly better skin. Researchers suggested that this was due to the probiotics inhibiting the priming and expansion of cells that trigger a certain immune response. (2)
Gastroenteritis – aka a tummy bug – generally means nausea, aches, pains and diarrhea. While certain medications can alleviate the symptoms, the only real treatment is to attack the bacteria causing the upset – which is what probiotics do.
The healthy bacteria in probiotic supplements work to counter the ‘bad’ bacteria causing your symptoms. Probiotics also help to restore the healthy colonies of bacteria in the colon that may have been lost to diarrhea.
One of the best strains to treat gastroenteritis is Lactobacillus rhamnosus, which has been shown to reduce symptoms in children with acute gastroenteritis. (3)
And remember – if the stomach bug is a virus, antibiotics can’t treat it!
As mentioned above, the gut is intrinsically linked to the brain. It’s also known that the neurons lining your gut can play a major role in your mood.
These neurons produce serotonin, a neurotransmitter linked to mood.
A study assessing the effect of a combination of Lactobacillus helveticus and Bifidobacterium longum on both human subjects and rats showed that these probiotics reduced anxiety and had beneficial psychological effects, including a decrease in serum cortisol. (4)
While scientists aren’t quite sure how this works, they do know that some probiotics can lower inflammatory cytokines, decrease oxidative stress and improve nutritional status. By modulating systemic inflammation and oxidative stress, probiotics can potentially increase brain-derived neurotrophic factor, which is known to be involved in depression and anxiety. (5)
The respiratory tract is home to many different species of microorganisms, so it makes sense to optimize their functions with probiotics.
Upper respiratory tract infections include the common cold and inflammation of the trachea and larynx. Symptoms of these infections involve fever, cough, pain and headaches.
Most acute URTIs are caused by viral infections, so antibiotics cannot treat them.
Probiotics have been found to reduce the incidence of these infections, especially for children and old people. (6)
Probiotics were even found to be better than placebo in reducing acute URTI by about 47% and the duration of an infection by about 1.89 days. Probiotics were also found to reduce the use of antibiotics, as well as the number of days that children had to take off school.
Bacteria also reside in the mouth – and bad breath is often a sign that all is not well in your microbial population.
Halitosis is not a disease but it is certainly an unpleasant condition. Studies have shown that in around 90% of cases, the origin of halitosis is found in the oral cavity, and probiotics are believed to be successful in treating both mouth- and gut-associated halitosis. (7)
A few clinical studies have found different probiotic strains or products to be effective in treating bad breath. These include S. salivarius, three Weissella confusa isolates, and a lactic acid–forming bacterial mixture.
As with mood regulation, probiotics also help to improve sleeping patterns by producing and regulating a number of neurotransmitters and hormones involved with restfulness.
Probiotics can increase blood levels of tryptophan, an amino acid that converts into serotonin and then into melatonin. This is the hormone involved with your feelings of wellbeing.
Gut microbes are also in involved serotonin production, which not only regulates mood but plays a major role in sleep quality. Research has shown that serotonin deficiency in rats leads to disrupted circadian rhythms and sleep-wake cycles, which typically means restless sleep. Most serotonin in the body (over 90%) is manufactured in the gut.
Certain strains of probiotics can not only kick-start weight loss but help you to keep it off.
In a study involving a group of 125 overweight men and women, half of the subjects were given a daily probiotic supplement containing Lactobacillus rhamnosus, while the other half took a placebo.
All of the subjects underwent a weight loss program for 12 weeks, followed by a 12-week maintenance program. The women taking the probiotic supplement showed an average weight loss of 4.4kg, while the women receiving the placebo lost only 2.6kg. (8)
The effects continued after the 12-week maintenance period, with the women in the probiotic group going on to lose even more weight. The women in the placebo group did not.
By the end of the study, the women taking the probiotic supplement had lost an average of 5.2kg each, twice as much weight as the women taking the placebo.
B vitamins are a group of vitamins largely responsible for helping your body to break down food into energy.
It’s now been shown that certain strains of probiotics are able to synthesize water‐soluble vitamins such as those included in the B‐group. The most notable of these are folate, riboflavin and vitamin B12, among others. (9)
Vitamin B12 is mostly found in animal products, particularly shellfish, crustaceans and beef, which is why many vegetarians are deficient in B12. However, it now appears that B12 and other B-vitamins can be produced by eating foods containing typical probiotics such as Bifidobacterium and Lactobacillus.
The most well-known producer of B12 is Lactobacillus plantarum, which is used in many probiotic products, and is naturally found in human intestines.