Does Taking Probiotics Help to Reduce Weight?

Probiotics have a variety of benefits for your gut and overall health. They can even help promote weight loss and the treatment of diseases associated with weight gain, like diabetes and malabsorption disorders.

However, you shouldn't expect all probiotic supplements or foods to help you lose weight.

​Read more:​ 13 Surprising and Beneficial Probiotic Foods

According to a June 2017 study in the ​Biochemical Journal,​ your gastrointestinal system contains as many as 100 trillion bacteria. These bacteria are important to a variety of different aspects of your health. A March 2019 study in ​Nature Microbiology​ reported that these bacteria are likely to affect and modulate other aspects of your health, like your immune system and central nervous system.

Because these bacteria can influence so many aspects of your health, it's important to make sure that there are mainly healthy, beneficial types in your body. The ratios of these bacteria are also important, as it's possible to have too many of certain bacteria and not enough of others.

Maintaining healthy ratios of gut bacteria is easy for some people, but can be challenging for others. According to a September 2013 study in the ​Journal of Gastroenterology and Hepatology​, people with conditions like malabsorption disorders, inflammatory bowel disease and irritable bowel syndrome are all likely to have abnormalities in their gut microbiomes. In fact, this study even stated that skewed populations of gut bacteria can contribute to obesity.

​Read more:​ 7 Signs Your Gut Is Out of Whack

According to Harvard Health Publishing, commonly consumed probiotics include:

• ​Bifidobacterium animalis​ (sometimes referred to as ​Bifidus regularis​)
• ​Bifidobacterium bifidum​
• ​Bifidobacterium lactis​
• ​Bifidobacterium longum​
• ​Enterococcus faecium​
• ​Lactobacillus acidophilus​
• ​Lactobacillus casei​
• ​Lactobacillus delbrueckii​
• ​Lactobacillus johnsonii​
• ​Lactobacillus gasseri​
• ​Lactobacillus plantarum​
• ​Lactobacillus rhamnosus​
• ​Saccharomyces boulardii​

However, these are not the only probiotic bacteria you might find in foods, beverages and supplements. According to a February 2014 article in the journal ​AAPS PharmSciTech ,​ other commonly consumed bacteria with health benefits include:

• ​Bifidobacterium breve​
• ​Lactobacillus fermentum​
• ​Lactobacillus helventicus​
• ​Lactobacillus paracasei​
• ​Lactobacillus salviarus​

As you can see, members of the ​Bifidobacteria and Lactobacilli​ families are the most common types of probiotics. However, according to a July 2016 study in the ​Journal of Food: Microbiology, Safety and Hygiene,​ other bacterial families can also be probiotics. These include specific ​Streptococcus​, ​Bacillus​, ​Lactococcus​, ​Pediococcus​, ​Propionibacterium​ and ​Peptostreptococcus​ bacteria.

Consuming these bacteria should be beneficial to your health. However, the exact benefits may differ between both bacterial families and specific species.

Harvard Health Publishing says that probiotics can help:

• Improve digestion.
• Improve nutrient absorption.
• Support healthy immune system function.
  
• Provide protection from disease-causing bacteria.
  

Most healthy people can obtain sufficient probiotic bacteria from the foods they eat. A variety of different foods contain these beneficial bacteria.

Probiotics are particularly easy to find in beverages like kombucha and lassis; dairy products like kefir, yogurt and cheese; and fermented seafood products like garum or hakari. Probiotics can also be found in pickled fruits and vegetables, fermented rice products and most soy products — including tempeh, tofu, natto and miso.

​Read more:​ Which Type of Yogurt Is Best? The Pros & Cons of 13 Different Kinds

However, if you're specifically interested in using probiotics to support weight loss, you may need to consider taking supplements or creating your own fermented foods. This is because food products often use different probiotics, and according to the National Institutes of Health, not all probiotics are created equal.

Probiotic dosage is also very important. If you consume insufficient amounts of probiotics, they may have no effect at all.

A variety of both common and uncommon probiotic bacteria can help support weight loss. The study in the ​Journal of Food: Microbiology, Safety and Hygiene​ says that bacteria from the ​Acetobacter​, ​Leuconostoc​, ​Bifidobacterium​, ​Bacillus​, ​Lactobacillus​, ​Streptococcus​, ​Bifidobacterium​, ​Lactococcus​ and ​Pediococcus​ families can all help promote the loss of fat.

Many of the more common and well-studied bacteria (from the ​Lactobacillus​ and ​Bifidobacterium​ families) have also been associated with other benefits, like improving metabolism, reducing fat accumulation in the body and promoting feelings of satiety.

That being said, only specific probiotics might help you lose weight. The exact probiotic bacteria that works for you depends on factors like your individual needs and overall health. For example, ​Lactobacillus kefiranofaciens​ has been associated with a variety of benefits, including protection against: cardiovascular disease, high blood pressure, allergies, diabetes, obesity and other weight disorders.

However, if your weight gain was related to a specific condition that has altered the bacteria colonizing your gut microbiome, you may need another type of bacteria. In this case, ​Lactobacillus acidophilus​, ​Lactobacillus salivarius​, ​Bifidobacterium infantis​, ​Bifidobacterium bifidum​ and ​Bifidobacterium longum​ might all be better suited to support your weight loss needs. These bacteria can promote the colonization of healthy, beneficial bacteria in your gastrointestinal tract.

You should be aware that certain species of popular probiotic bacteria have shown mixed results when it comes to weight loss. These bacteria all come from the common ​Lactobacillus​ family.

An August 2012 study in the ​Microbial Pathogenesis Journal​ reported that certain bacteria — specifically, ​Lactobacillus acidophilus​, ​Lactobacillus ingluviei​ and ​Lactobacillus fermentum​ actually promoted weight gain, rather than weight loss. However, other ​Lactobacillus​ species, like ​Lactobacillus gasseri​ and ​Lactobacillus plantarum​, were able to support weight loss, even in people living with obesity.

Another study, published in the ​British Journal of Nutrition​ in April 2014, found that the probiotic ​Lactobacillus rhamnosus​ helped increase the amount of weight lost when dieting. However, this study is quite notable because it only worked in women. The men who took this probiotic saw no benefits in relation to weight loss.

Ultimately, probiotics are likely to benefit your health and may help you lose weight. However, an April 2013 study in ​Nutrition ​specifically states that probiotic effects on weight loss are still poorly understood. Using probiotics to support weight loss may not work for everyone.

Probiotics are generally safe, with minimal side effects. In most people, side effects are limited to mild digestive issues, like gas or bloating.

However, the National Institutes of Health warn that probiotics aren't for everyone. Consuming probiotics may not be safe if you have or have had:

• Chronic health issues
• Autoimmune conditions
• Recent surgery
• A compromised immune system (such as in older adults or people with ongoing medical problems)

If you have had such health problems and want to consume probiotics, you should consult your doctor about which ones to take. Bacteria from ​Bifidobacteria​ and ​Lactobacilli​ families are the most well-studied. Unfortunately, research is still fairly limited in regards to other probiotic species, such as those from ​Streptococcus​, ​Bacillus​, ​Lactococcus​, ​Pediococcus​, ​Propionibacterium​ and ​Peptostreptococcus​ families.

Since different bacteria can have different effects on the body, you shouldn't assume all probiotics are equivalently safe. Even if a certain Lactobacillus species is safe for older adults to consume, it doesn't that mean all Lactobacillus are.