Probiotics have become increasingly popular in recent years. You might already eat a lot of probiotic foods, such as yogurt or kimchi, or take a daily probiotic supplement to reap their potential benefits.

Your body, especially your digestive system, naturally contains probiotics, which are beneficial bacteria. There’s a balance in your body between helpful bacteria, or probiotics, and potentially harmful bacteria. Disruptions to this balance may contribute to a range of health conditions.

In recent years, some experts have turned their attention to a special group of probiotics, sometimes called psychobiotics. These bacteria could potentially help to treat a range of mental health conditions, including depression, and boost your overall mood.

You might wonder how bacteria known for promoting digestive health can have an impact on mental health symptoms. Many experts believe there’s a strong connection between your gut, which refers to your gastrointestinal tract, and your brain.

This connection is called the gut-brain axis (GBA). It links your central nervous system, which includes your brain and spinal cord, to your gastrointestinal tract.

Experts believe microorganisms living in your gut, including probiotics, play a crucial role in the GBA by:

  • producing and expressing neurotransmitters that can affect appetite, mood, or sleep habits
  • reducing inflammation in your body, which can contribute to depression
  • affecting cognitive function and your response to stress

It’s unclear how probiotics carry out these functions, but a 2015 research review suggests the GBA may be the “missing link” in our understanding of depression and its causes. More research is underway on this topic.

Existing research on probiotics for depression and other mental health issues is largely promising, but many of the existing studies are very small. This makes it hard to know just how effective probiotics are for depression.

Existing research

Results of a small 2017 study suggest the probiotic Bifidobacterium longum NCC3001 may improve quality of life and reduce symptoms of depression in people with irritable bowel syndrome.

In a small 2016 study, people with major depression took a probiotic supplement containing three bacteria strains for eight weeks. At the end of the study, most had lower scores on the Beck Depression Inventory, a common method of evaluating depression symptoms.

A 2017 research review looking at how probiotics affect symptoms of depression found that taking a daily probiotic supplement seemed to help with symptoms of both depression and anxiety.

Probiotics also seemed to work best when used in conjunction with other treatments, including medication and psychotherapy.

The authors of each of these studies generally agree that larger trials are needed to further explain how probiotics can affect symptoms of depression and other mental health conditions.

Future research

Experts are currently working to identify particular probiotics that might have mental health benefits. Probiotics aren’t identical, so it’s important to find out which strains work best for certain things.

In addition, dosing guidelines are based on the use of probiotics for digestive issues. Another important area of research will involve finding the appropriate dosages for depression, anxiety, and other mental health conditions.

This area of research can be particularly difficult because people generally don’t experience mental health symptoms in identical ways. Similarly, probiotics may not have the same effects for each person.

A number of factors, including genetics, bacterial exposure, and life experiences, can affect the unique composition of your gut bacteria. This, in turn, may impact both the depression symptoms you experience as well as which probiotics will work best for you.

If you’re considering trying probiotic supplements for depression, you may want to talk to your healthcare provider first. Probiotics are considered safe to use, but it’s generally a good idea to get their advice before trying any new supplement or medication.

In clinical trials, Lactobacillus and Bifidobacterium bacteria appeared to be most helpful for mental health. You can purchase probiotic blends on Amazon, like this one, that combine strains of both of these.

You can also try adding more probiotic foods to your diet, such as:

  • yogurt
  • tempeh
  • miso
  • tofu
  • sauerkraut

If you decide to take a supplement, follow the manufacturer’s recommendation for dosage. There’s no evidence that taking more than the recommended amount offers any extra benefits.

Probiotics may be helpful, but they don’t replace therapy, medication, or other depression treatments. You might notice an improvement in your symptoms after you start taking probiotics, but it’s important to still keep up with any other treatments.

This is especially true if you take antidepressants. Abruptly stopping these medications can have potentially serious psychological and physical effects.

Instead, work with your healthcare provider to come up with a plan that will allow you to slowly taper off your medication, if that’s something you’re interested in doing.

Probiotics generally don’t cause any side effects. When they do, they’re usually mild.

Some people might experience bloating, gas, or diarrhea for a few days while initially taking a probiotic supplement.

Stop taking the supplement if you experience:

  • stomach pain
  • gas or bloating that doesn’t go away
  • general gastrointestinal distress

If you experience stomach pain, persistent gas or bloating, or other gastrointestinal distress, it’s a good idea to stop using the probiotic and talk to your doctor before trying it again.

You may be taking too much or need to switch to a different blend of probiotic strains. Taking more than the recommended dose may also cause pain, gas, and bloating.

Probiotics are pretty safe, largely because they already exist naturally in your body. They’re also found in many foods you likely already eat.

However, if you have a weakened immune system or cancer, it’s best to avoid probiotics so you don’t overload your system. They can also interact with some medications, including antibiotics and some antifungal treatments.

It’s always best to check with your healthcare provider before starting any new supplement, especially if you’re:

  • pregnant
  • breastfeeding
  • living with a chronic health condition

When talking to your provider, make sure to tell them about any medications you take, including over-the-counter drugs, vitamins, or other supplements.

Probiotics are a promising potential treatment for depression and other mental health conditions. But more research is needed to fully understand how effective they are.

In the meantime, it might be worth trying a probiotic supplement if you’re looking to add a new element to your depression treatment plan. Just make sure to keep up with other ongoing treatments.

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