Probiotics have been in the wellness spotlight for some time—all thanks to their gut health benefits. But now, companies are selling the popular supplement with other health benefits beyond keeping you regular. During peak cold and flu season, you may see more claims about probiotics for immune system support. But can probiotics truly help boost your immune system and help your body fight off illnesses like the common cold?
According to the International Scientific Association for Probiotics and Prebiotics, probiotics are live microorganisms that, when taken in specific amounts, provide certain health benefits. They are considered ‘good’ bacteria that can help stop the overgrowth of ‘bad’ bacteria in the gut and produce beneficial compounds like short-chain fatty acids that can help regulate metabolism, inflammation, and disease. Some studies have even found that probiotics may be linked to helping absorb vitamins, reinforce the gut barrier, and neutralize toxins. Essentially, it’s well-documented that probiotics are good for your gut.
But can these good bacteria help with immune system function, too? We spoke with Miguel Freitas, PhD, a nutrition scientist, vice president of health and scientific affairs at Danone North America, and one of the world’s leading experts on the complex interactions between probiotics, the gut, and the microbiota, to find out.
So, can probiotics strengthen your immune system?
Dr. Freitas says when considering probiotics for immune system support, it’s important to understand that the benefits of probiotics will largely depend on the strain you take. Not all probiotics have the same health benefits. While one may work against bloating, another may be more effective at relieving constipation, for instance.
Some research suggests certain probiotic strains could help your immune system, but the exact way these strains work to support immunity is an area of ongoing study, Dr. Freitas says. Currently, it has been proposed that probiotics can interact directly with intestinal immune cells or produce certain substances that serve as mediators of this cross-talk (i.e., the communication between probiotics and immune cells in the gut,).
In addition to working directly with immune cells in your gut, studies have found probiotics may potentially enhance your immunity in other ways, including:
- Producing substances that kill harmful microorganisms.
- Competing with harmful microorganisms and toxins for adherence to the gut wall, preventing them from taking hold in the gut.
- Promoting survival of intestinal cells.
- Enhancing gut barrier function (i.e., how strong and healthy the gut lining is).
- Stimulating protective responses from intestinal cells toward foreign substances.
- Enhancing innate immunity (the body’s first response to harmful, foreign substances).
- Influencing harmful microorganism-induced inflammation via immune cell signaling pathways.
The gut and immune system are highly connected
“Many are surprised to learn that 70 percent of our immune system is located in our gut,” shares Dr. Freitas. It’s true: along with the trillions of microbes that live in our digestive tract, immune cells help us fight off foreign bacteria and viruses. Thus, prioritizing gut health (and balancing the good and bad bacteria within it) could also support your immune system and other microbiomes in your body, including your skin, oral, and vaginal microbiome.
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Bottom line? Taking probiotics will not completely safeguard you from catching colds or the flu, but it may help support your immune system as it works to fight off illness. “The more we can learn about the gut microbiome, the more we can leverage it to benefit health,” Dr. Freitas adds.
What is the best type of probiotic strain to take for immune health?
“Because probiotic benefits are strain-specific, you’ll want to look for a product that contains a strain of bacteria clinically shown to support the immune system,” says Dr. Freitas. One example is Lactobacillus casei DN-114 001—a strain found in products such as DanActive Probiotic Dailies yogurt drinks. You can also find probiotic supplements with this specific strain, but consult your healthcare provider to determine if they’re appropriate for you. They can recommend specific brands with quality ingredients that are third-party tested.
Concerning dosage, Dr. Freitas explains that the amount of colony-forming units (CFUs)—the unit of measurement for probiotics—required for benefits will depend on the strain, including amounts studied in clinical trials. While the recommended dosage can range from 100 million to over a trillion CFUs daily, most strains have been studied for use between one and ten billion CFUs per day.
Other ways to support your immune system
While certain probiotics may help support your immune system, there are other strategies to keep your immune health in peak condition:
1. Eat colorful fruits and veggies
“There isn’t one single food or nutrient that will magically ‘boost’ your immune system, but eating an array of colorful fruits and vegetables can help give your body what it needs to keep your immune system working at its best—like vitamins C, D, and A, and minerals like zinc,” says Dr. Freitas.
2. Get daily physical activity
According to Dr. Freitas, emerging evidence suggests that physical activity could benefit your immune system. Adults should aim for at least 150 minutes of moderate-intensity exercise and two days of muscle-strengthening work. Remember, you don’t have to get all 150 minutes in one go. Splitting up workout time throughout the week is perfectly acceptable.
3. Reduce alcohol intake
While moderate drinking isn’t likely to harm your immune system, excessive alcohol use can lead to a weakened immune response, increasing your chances of illness. Consider mocktails a few nights per week or adopting mindful drinking habits to reduce intake.
4. Prioritize sleep
Good sleep is crucial for a healthy immune system, says Dr. Freitas. Research suggests that poor sleep habits make individuals more susceptible to illnesses like the common cold. To achieve the physical and mental health benefits of quality sleep, aim for 7 to 9 hours of sleep each night, and try to maintain consistent sleep schedules.
5. Visit your healthcare provider
If you frequently fall ill or know you are immunocompromised, consult your healthcare provider. They can request bloodwork and other tests to identify underlying issues and offer treatments to enhance your immune system.
The final takeaway
While evidence suggests certain probiotics may support your immune system, researchers still have much to learn about their exact role in immune health. Furthermore, there’s no guarantee that taking probiotic supplements will prevent illnesses like colds or flu.
However, if you are interested in probiotics for gut health and immunity, consider those containing the Lactobacillus casei DN-114 001 strain. Ensure these supplements are third-party tested for quality by organizations like the USP or NSF, or those recommended by your healthcare provider.
Ultimately, maintaining other lifestyle habits that support immunity—such as reducing alcohol intake, prioritizing sleep, and getting exercise—will enhance your ability to fight off germs this cold and flu season.
