Probiotics have been the subject of countless news stories and online discussions.
They have been associated with many dramatic health improvements, including weight loss, decreased depression and better digestion.
Yet, the field is also confusing and recommendations contradict one another.
The first step towards promoting your health is finding the best probiotic supplement for you.
This is going to depend on the solutions that you’re looking for, along with the health issues you face.
This post highlights the various benefits that probiotics offer and how you can choose the best ones for your needs.
What Are Probiotics?
Probiotics are simply live bacteria (and yeasts), ones that are good for health.
They’re important because our gut contains a wide range of beneficial bacteria. More than 1,000 individual species have been identified (1) and these have significant implications.
Studies suggest that these bacteria impact many processes throughout the body. In fact, the gut is sometimes called ‘the forgotten organ’ or ‘the second brain’, which shows how significant it can be.
Many factors can alter the composition of our gut bacteria.
- The diet plays a key role, as does stress.
- Some medications decrease the levels of healthy bacteria too.
- Antibiotics are the most common example but other medications can be significant as well (2).
All of these factors can lead to poor gut bacteria composition. The site Healthline lists some other factors. Health can suffer as a result. For example, poor gut bacteria composition has been linked to depression and obesity (3,4).
Probiotics typically contain multiple strains of microbes. They can potentially improve the bacteria composition in your gut, promoting health as a result. They may also influence other processes in the body.
You can get some probiotics in fermented foods, including kefir, sauerkraut, kombucha and many yogurt brands.
There are also probiotic supplements – and these are the focus of this post. Fermented foods have many advantages, especially as they contain other nutrients. But, there are also key reasons to turn to supplements instead.
- Probiotic supplements often target specific health problems.
- They contain carefully controlled strains and amounts of bacteria.
- Fermented foods are less consistent and reliable, especially if you’re making them yourself.
- Supplements are also easier to test. As a result, it’s possible to know which ones are worth using and which are not.
Indeed, many of the supplements highlighted in this post have been through independent testing. They’re also matched to the condition based on the microbe strains that are present.
Probiotics are simply microbes that can promote health. You can find them in fermented foods and probiotic supplements
Probiotics vs Prebiotics
Probiotics shouldn’t be confused with prebiotics, even though the names are similar. As the site Prebiotin explains, probiotics and prebiotics are very different to one another.
Prebiotics are non-digestible fibers from food. These help promote the growth of healthy bacteria and discourage any unhealthy microbes. Prebiotics are also more resilient and can be found in many different foods.
As a result, prebiotics and probiotics are both critical for gut health. There are many powerful sources of prebiotics, including onions, chia seeds, bananas, garlic, dark chocolate, asparagus and flax seeds. The site Mind Body Green offers some other examples.
Prebiotics act as food for microbes, while the term probiotics refers to the microbes themselves
Choosing the Best Probiotic for You
With most supplements, you can simply select a high-quality brand, perhaps one that has passed independent testing. For example, with vitamin D3 and vitamin K you just need to focus on the brand and the dose.
That’s not the case with probiotics.
This is because there are many different species of healthy bacteria – and multiple strains for each of those species. Research shows that the health benefits vary between these different strains and species (5).
As a result, you can’t just take a general probiotic and hope that it boosts your health. Instead, you need to choose a probiotic with strains that match the challenge that you’re trying to resolve.
To aid in that goal, the following sections highlight specific health needs, the associated research and which probiotic supplements may help. You can use the links below to jump to specific sections.
The benefits of probiotics are strain-specific, so you need to match the supplement with the benefits that you’re looking for
Probiotics for Decreasing Inflammation
Inflammation is a critical process in the body and plays a role in the body’s defenses. But, when inflammation becomes too prevalent or persistent, it can cause significant health problems.
Chronic inflammation may play a role in many diseases, including those that are associated with aging (6,7). Inflammation also increases with age. This may help explain why chronic diseases become more common later in life.
- One study found that supplementing with a probiotic mixture improved inflammatory cytokine profile in seniors (8). A second study also found improved inflammatory responses (9).
- Probiotic supplementation was found to delay the development of gingivitis by influencing an inflammatory cascade (10). Likewise, probiotics decrease inflammation associated with gingivitis (11), although study outcomes are mixed (12).
- A proof-of-concept study illustrated that Lactobacillus brevis had anti-inflammatory effects and reduced bone loss in experimental periodontitis (13).
Common Species: Lactobacillus brevis, Lactobacillus gasseri, Bifidobacterium bifidum, Bifidobacterium longum
Probiotics may be particularly significant at decreasing inflammation and lowering disease risk as a consequence
Probiotics for Weight Loss
Probiotics may also affect your weight, including the ability to lose weight and the likelihood of gaining it in the first place (14). For example, probiotics may help to:
- Decrease fat absorption (15).
- Suppress fatty acid release (16).
- Reduce body weight and body fat percentage (17,18).
- Support weight loss maintenance (19).
- Promote belly fat loss (20).
- Improve energy metabolism and body composition (21).
- Protect against body mass increases on a high-fat and high-energy diet (22).
As always, probiotics aren’t a miracle solution for weight loss. Most people won’t experience dramatic increases in their weight loss simply by taking a probiotic. Research is also limited.
- Many studies have been small in scope or only considered animals, not humans.
- Outcomes haven’t been consistent. One systematic review found 9 studies that showed weight loss, 3 that showed no effect and 2 that showed weight gain (23). The inconsistency reinforces the idea that outcomes are strain and/or person-specific.
Even so, the supplements may make weight loss a little bit easier. This alone makes them worth trying, especially when combined with a healthy diet and lifestyle.
Common Species: Bifidobacterium breve, Bifidobacterium lactis, Lactobacillus gasseri, Lactobacillus rhamnosus
While the effects may not be large, probiotics have some impact on weight loss
Probiotics for Improved Heart Health
Some studies also suggest that probiotics may reduce the risk of heart disease and improve overall heart health (24). This is mostly achieved by influencing cholesterol levels. Although the field is heavily debated, cholesterol is thought to be a key risk factor for heart disease.
Key research outcomes include the following.
- Decreased total cholesterol levels and LDL cholesterol (25,26,27,28,29).
- Lower triglyceride levels (30,31,32).
- Changes in fat metabolism (33).
- Decreased blood pressure (34). This was only observed in inventions of 8 weeks or more and with daily doses of more than 10 colony-forming units.
- May also slightly improve HDL cholesterol levels (35,36), although research findings are mixed (37).
Common Species: Lactobacillus acidophilus, Lactobacillus gasserim, Lactobacillus platarum, Lactobacillus reuteri
Probiotics may lower heart disease risk by improving various risk factors
Probiotics for Depression and Anxiety
Depression and anxiety are both conditions that have no immediately obvious cause. Instead, they may be influenced by multiple factors. The underlying causes may also be different from one person to the next.
They’re also challenging because treatment is often only partly effective.
But, research suggests a link between gut health and mental health – including both depression and anxiety (38). Poor gut health may even be a key component of the depression and the symptoms that it produces (39,40,41).
Some of these theories relate to inflammation (42). Many recent studies suggest that inflammation could cause or contribute to chronic depression (43,44,45). The site Kelly Brogan MD discusses this relationship in more depth.
Focusing on anti-inflammatory foods like wheatgrass, olive oil, turmeric, tart cherry juice and nuts can help in this area. But, probiotics can be just as powerful and may affect depression through multiple mechanisms. The idea isn’t just theory either.
- Research shows that probiotics can influence many brain health outcomes. Benefits were seen in areas of depression, anxiety and memory (46).
- A systematic review found that probiotics significantly improved depression scores for healthy individuals and those with major depressive disorder (47).
- One study found that 30 day supplementation with Lactobacillus helveticus and Bifidobacterium longum decreased symptoms of depression and anxiety (48).
- Another found that a multispecies probiotic helped lower negative thought patterns associated with a sad mood (49). Improving such thought patterns is important for lowering depression symptoms.
- An 8-week study found that probiotics improved depression symptoms, along with outcomes such as insulin resistance, inflammation and glutathione concentrations (50)
- Supplementation can also improve anxiety symptoms for people with chronic fatigue syndrome (51).
Common Species: Lactobacillus helveticus, Lactobacillus rhamnosus, Bifidobacterium breve, Bifidobacterium infantis, Bifidobacterium longum
Many studies link gut health to mental health. Probiotics provide a way to take advantage of the relationship
Probiotics to Treat Constipation
Many people experience constipation from time-to-time and it passes with few problems. But, chronic constipation can be a serious issue. It is particularly common in seniors, especially those who are bedridden. It can also occur as a side effect of some medications or due to a poor diet.
Laxatives and stool softeners are commonly used as treatments – but these are often unsafe in the long-term. They can sometimes be a little too effective as well.
Probiotics offer an alternative method of treatment. Their effects aren’t as immediate as a laxative. But, probiotics can be better at promoting safe long-term constipation relief.
Multiple studies have found this outcome in adults and in children (52,53,54,55), with probiotics helping to increase bowel movement speed (56). Some of the benefits were observed for healthy participants. Others were for people with irritable bowel syndrome (IBS).
Common Species: Bifidobacterium bifidum, Bifidobacterium lactis, Saccharomyces cerevisiae, Lactobacillus reuteri
Probiotics provide a gentler and more persistent method of treating constipation
Probiotics to Treat Diarrhea
Surprisingly, probiotics can be effective in the other direction as well. Some studies show that they can help prevent and treat infectious diarrhea (57), antibiotic-associated diarrhea (58,59,60) and IBS-associated diarrhea (61,62,63).
Common Species: Saccharomyces boulardii, Lactobacillus acidophilus, Lactobacillus bulgaricus, Lactobacillus rhamonus GG
Some probiotics may help improve diarrhea symptoms, regardless of the cause
Probiotics for Irritable Bowel Syndrome
Probiotics are commonly researched as a treatment for IBS.
However, some studies have failed to find benefits (70). Outcomes can also vary depending on whether the IBS is diarrhea-predominant, constipation-predominant or mixed (71).
Common Species: Bifidobacterium infantis, Saccharomyces cerevisiae, VSL#3 (an 8-strain combination)
Probiotics can reduce some of the symptoms of IBS, along with improving regularity
Other Areas of Health
Probiotics have also been linked to other health improvements. This includes the ability to fight disease and infection in general (72), along with specific conditions. Some examples include the following.
- Supplementation with Lactobacillus GG significantly reduced gastrointestinal and respiratory infections in children at daycare centers (73)
- Probiotics may help to temporarily prevent the development of eczema (74)
- Supplementing with Lactobacillus brevis helped to delay gingivitis development (75). Probiotics may be relevant in treating other periodontal diseases, although much more research is needed (76)
- Lactobacillus crispatus helped prevent the development of recurrent urinary tract infections (77). However, the probiotic was administered as an intravaginal suppository.
There have been fewer studies in these areas, so it is unclear what the best probiotics are. However, choosing probiotics with a large selection of microbes may be an effective approach.
Probiotics may promote other health outcomes as well. But, research is typically more limited
Probiotics are generally considered safe. They offer many benefits and few side effects have been noted. Nevertheless, adverse events do occur on occasion.
This means you should always be careful and pay attention to how your body responds. That’s true for any type of supplement or diet, especially if you’re using it for the first time.
People most at risk of side effects include those who are critically ill and those with a compromised immune system (78). Anyone in these situations should talk to their doctor first.
Probiotics are normally considered safe but they may be unsuitable for people with compromised immune systems
Limitations of Research
Probiotics are still considered a new field. There have been many research studies but many of these are limited or are very specific.
- Studies often use small sample sizes or a design that cannot test for all effects
- Research suggests that probiotics do not help to colonize the gut, as previously thought. As a result, the impacts of probiotics may occur during supplementation, rather than being long-term (79,80). But, this may only be true for some strains or some situations.
- Observed effects often apply to specific bacteria species and strains (81) – and there is a large number of different species and strains out there.
- Likewise, effects will vary depending on the individual (82). So, any observed benefits may not apply to everyone.
- Most studies have focused on Bifidobacterium and Lactobacillus species (83). Less is known about the impact of other microbes. Some strains are also studied in more depth than others.
- Outcomes are likely to be influenced by current gut health and composition of the microbiota. As a result, some people may see benefits, others may not.
- In-depth safety research has not been conducted for every type of probiotic.
Even so, studies have consistently shown that probiotics can be beneficial.
To get the most benefits, you need to choose the supplement based on the problem that you are experiencing. This helps ensure you get the right healthy bacteria, ones that can improve your outcomes.
Much more research is needed – but it’s clear that probiotics can offer health benefits
Even with research limitations, probiotics have considerable potential.
In fact, gut health is a key component of overall well-being and has frequently been overlooked. Poor gut bacteria composition may even play a role in many different diseases, including conditions that are associated with inflammation (84).
This means that probiotics may be a powerful way to improve health. If nothing else, they’re a new direction to consider. And, if you don’t like the idea of probiotic supplements, there are plenty of fermented foods to try. You can even make them yourself.
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