If you have a goal to improve your health, you may join a gym, buy protein powder, drink more water, remove added sugars from your diet, or sign up for a 5k. All of these actions may get you closer to wellness, but you can also work toward longevity without leaving your house. Did you know that the catalyst for some of the healthiest everyday changes you can make lives in your gut?
The contents of your belly—called your gut microbiota—help determine how you look and feel. Trillions of tiny bacteria live inside your intestines and these little microorganisms play a major role in controlling digestion, communicating what hormones to signal, and even triggering emotional shifts.
This “little brain,” called the enteric nervous system (ENS), is made up of two layers of more than 100 million nerve cells that line your gastrointestinal tract. The ENS “talks” to the grey matter in your skull just like you might communicate with and react to a friend.
So, how can you keep those conversations friendly, productive, and beneficial for your health? You can experiment with probiotics, live microorganisms from bacteria or yeast, to improve your gut health.
You have both good and bad bacteria inside your body and, ideally these live in a balanced state called homeostasis. When you get an infection, more harmful bacteria invades your body through the mucosal lining of your gut. Probiotics can help restore the body’s balance of good and bad bacteria.
Probiotics are found in fermented food sources, such as yogurt and kefir, sauerkraut, and soy sauce, and in pill and powdered supplements.
Probiotic dosage is expressed in CFU, or colony-forming units, which means the number of live strains in each dose. Supplemental probiotics come in a wide range of CFUs—from the high millions to as many as 200 billion. The type of strain, product formula, quality, dose, and duration of time you take it can depend on what condition you want to improve by using the supplement. Consult with your doctor before you start taking any new supplements.
For example, if you want to treat antibiotic-induced diarrhea, 10 billion CFUs of multi-strain probiotics<sup>1</sup>, such as Bacillus clausii and coagulans, are effective. The same strain and amount of CFUs probably won’t be effective in stopping sneezing attacks any time you come into contact with dandelions.
If your goal is to improve your gut health and/or treat a specific health condition, foods that contain probiotics and higher doses of probiotic supplements may help. Read our guide to become a pro on probiotics and keep straight on probiotics’ many strains, uses, and benefits.
How to Implement Probiotics Into Your Health Regimen
How do you know which probiotic strains to try if you can’t stop sneezing every time your partner gives you fresh flowers? Can probiotics help calm your irritable bowel syndrome? What foods contain probiotics if you prefer not to take supplements? Our guide to probiotics below is organized by health goal or ailment, and suggests research-backed probiotic strains to test for that condition.
1. Boost immunity and build an iron-clad gut barrier
Your intestinal mucosal barrier stands in first-line defense against the bad bugs that breach the gut wall and spread infections. Even in COVID-19, thought to be an acute respiratory illness, scientists are researching the efficacy of probiotics in restoring the damage the virus imposes on the gut barrier<sup>2</sup> and decreasing inflammation.
A review of scientific studies explains how gut microbiota is becoming one of the main mechanisms tied to the growing number of immunity-related disorders such as type 2 diabetes, cardiovascular disease, metabolic disorder, neurodegenerative diseases, asthma, and even certain types of cancer.
Increasing evidence shows that the microbiome can directly initiate the body’s immune response<sup>3</sup> when germs try to invade. While your genes may influence the composition of your intestinal flora, your environment—including what you choose to eat and drink—may impact your gut composition in a way that could help ward off chronic disease<sup>4</sup>.
Probiotics to try for improving immunity:
Lactic acid bacteria<sup>5</sup>, found in:
<ul role="list"><li>fermented veggies like kimchi and sauerkraut</li><li>pickles</li><li>sourdough, wheat, or rye bread</li><li>tempeh</li><li>fermented milk, yogurts, cheeses</li><li>miso</li><li>fermented meat like salami</li><li>fermented sauces like soy sauce or balao-balao</li><li>Kefir, particularly for gut inflammatory disorders<sup>6</sup></li><li>Prebiotics, food for your gut bugs, can enhance the effect of probiotics<sup>7</sup>, such as:</li><ul><li>alginate, a polysaccharide found in brown algae</li><li>fenugreek, seeds that taste like burnt sugar often used in Indian cooking</li><li>psyllium, fiber made from Plantago ovata plant</li></ul></ul>
<p class="pro-tip"><strong>Learn more about </strong> <a href="/blog/probiotics-metabolic-health">probiotics and metabolic health</a>.</p>
2. Treat and possibly prevent gastrointestinal issues
They don’t call it irritable bowel syndrome for nothing. IBS symptoms, such as cramps, diarrhea, constipation, excessive gas, stop-everything-at-once to sprint for the toilet—are irritating and disruptive.
For those who suffer from this condition, the research looks promising for probiotic use to ease IBS<sup>8</sup>, but how beneficial and which strains prove the most effective needs to be studied more. A meta-analysis found that multi-strain probiotics used for eight weeks<sup>9</sup> or more may prove most beneficial in improving IBS.
To keep things moving through your intestines and exiting in a, uh, comfortable fashion, probiotics can clear up any backup you might have in your gut. Put scientifically, your gut microbiota can affect intestinal motility.
Probiotic strains for constipation
Probiotic strains that can help with constipation include:
If you have the opposite of constipation, probiotics appear to help slow the runs in both children and adults. Diarrhea can occur after taking antibiotics; one review of the scientific literature recommends Lactobacillus rhamnosus or Saccharomyces boulardii at 5 to 40 billion colony forming units/day as a safe course for children<sup>13</sup>.
For adults with antibiotic-associated diarrhea, one study found a combination of Lactobacillus and Bifidobacterium strains to be effective in delaying the onset of diarrhea<sup>14</sup> and the number of trips to the bathroom. Ten billion CFUs of Bacillus clausii and coagulans<sup>15</sup> are effective at treating diarrhea caused by antibiotic use.
3. Alleviate allergies
Research shows promise in using probiotics to control allergic rhinitis, asthma, and food-related allergies.
One study in adults with allergic rhinitis showed short-term improvement in nasal congestion<sup>16</sup> in participants who drank fermented milk containing Lactobacillus paracasei ST11.
In children suffering from asthma, Lactobacillus gasseri A5 supplementation for two months showed improvement in allergic rhinitis<sup>17</sup> and peak expiratory flow rates. A meta-analysis of studies on the impact of probiotic use in children and infants with cow’s milk allergies<sup>18</sup> showed that giving infants Lactobacillus rhamnosus GG could help them tolerate cow’s milk. Probiotics may also relieve allergic symptoms to regular milk in kids allergic to it.
4. Help reduce depression and anxiety
Research shows association between probiotic use and significant reduction in depression<sup>19</sup>.
One clinical study on patients with major depressive disorder were given 30 billion CFUs of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 every day for two months. Participants showed significant improvements in depression symptoms<sup>20</sup> when observed at week four that were sustained at week eight. Interestingly, patients also noted better sleep quality at the end of the second month.
A 2021 meta-analysis that reviewed the use of probiotics in 404 people with depression demonstrated that probiotics taken in combination with anti-depressents<sup>21</sup> reduced depressive symptoms. Researchers noted that probiotic use as a standalone treatment for depression also offered benefits.
Scientific research looks promising for probiotic use in people with anxiety, autism, and Alzheimer disease<sup>22</sup>. A systematic review of existing studies on the impact of probiotics on anxiety found some improvements in symptoms, and other studies reported no change in anxiety in those taking probiotics.
Probiotic strains that can help anxiety
The studies that reported positive results in participants with anxiety<sup>23</sup> administered the following probiotic strains:
- 24 billion CFUs/g of L. casei Shirota 9029
- 50 million CFUs/ml of L. paracasei subsp. paracasei F19, L. acidophilus La5, and B. lactis Bb12
- 3 billion CFUs/g of L. helveticus R0052, and B. longum R0175 CNCM strain I-3470
- 10 billion CFUs/g of L. plantarum P8 2g/day
Whether in real food or supplement form, probiotics play an important role in gut health and your overall wellness. Keep your gut-brain connection productive by adding fermented foods to your diet, and consider taking a probiotic supplement if you have GI issues, certain allergies, and mood disorders. Work with your doctor to devise a personalized probiotic plan. This list of studied strains can provide a good starting point to talk to your primary care physician.
<p class="pro-tip">Read next: Probiotics and managing your blood sugar levels</p>
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