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Disclaimer: This article is for informational purposes only and is not intended to diagnose any conditions. LifeDNA does not provide diagnostic services for any conditions mentioned in this or any other article.
Have you ever wondered how certain bacteria in food can actually be good for your health? The idea of probiotics isn’t new. It goes back more than a hundred years. In the late 1800s, Louis Pasteur showed that fermentation in wine and beer happens because of living microbes, not just chemical reactions. Building on this, scientist Élie Metchnikoff suggested that some bacteria in fermented foods could improve health and even help people live longer. This was the start of the idea behind probiotics.
A big breakthrough came in 1930 when Dr. Minoru Shirota isolated a type of Lactobacillus that could survive in the human gut. He used it to create Yakult, one of the first probiotic drinks sold commercially. This changed probiotics from just a natural curiosity into products made specifically to help people’s health. Since then, science has advanced a lot. With new DNA discoveries and genomic tools, researchers can study exactly how probiotics work in the body. Interestingly, probiotics don’t affect everyone in the same way. Individual biology may influence how well they work. This has led scientists to ask a new question, can our genes determine how our bodies respond to probiotics?
The World Health Organization defines probiotics as “live microorganisms which, when given in the right amount, give a health benefit.” Probiotics are friendly bacteria that can support your health when consumed in the right amounts. They are most commonly found in fermented foods such as yogurt, kefir, sauerkraut, and kimchi, or in dietary supplements. These beneficial microbes can help maintain a balanced gut environment, support digestion, and even influence the immune system.
Probiotic bacteria are classified into different genera and species, each with specific functions in the body. The most widely used and studied probiotics belong to two main genera:
Bifidobacteria: Bifidobacteria are commonly included in foods and dietary supplements. These bacteria help support the immune system, prevent the overgrowth of harmful bacteria in the gut, and also aid in breaking down lactose into simple sugars that the body can absorb more easily.
Lactobacillus: Lactobacillus bacteria, such as Lactobacillus acidophilus, produce lactase, the enzyme responsible for digesting lactose, and also generate lactic acid. Lactic acid helps control harmful bacterial populations, provides energy for muscles, and improves mineral absorption. Lactobacilli naturally reside in the mouth, small intestine, and vagina.
You might want to read: Can Lactobacillus Rhamnosus Improve Gut Health?
Probiotics can provide a variety of health benefits, which can be grouped by their main effects:
Research on probiotics highlights how advances in microbial genomics have reshaped our understanding of probiotics. In the past, probiotic research focused mostly on broad health benefits that were assumed to apply to everyone in the same way. Now, it has revealed that individual genetic differences in both the microbes and humans, as well as variations in gut microbiome composition, may affect how people respond to probiotics.
This shift means researchers are beginning to see them as part of a personalized approach to health, where genes may help predict which probiotic species are most effective for a given person. For example, genomics now may uncover how specific genetic pathways interact with microbial functions, influencing outcomes like immune support, digestion, or nutrient absorption. This directly supports the idea that your genes could influence how well probiotics work for you, pointing to a future where probiotic use may be personalized much like nutrition or medicine.
It also shares important insights into why probiotics may work differently for different people. It shows that the ability of probiotic bacteria to survive the harsh conditions of the gastrointestinal tract and stick to the intestinal lining depends on specific genes and molecular systems. For example, certain Lactobacillus species adjust their cell membranes, activate stress-response genes, and produce specialized surface proteins or pili to withstand acid, bile, and digestive enzymes. These mechanisms are essential for the bacteria to survive, colonize, and exert their beneficial effects in the gut.
These findings support the idea that individual responses to probiotics may vary, because just as the bacteria rely on their own genetic systems to function, the host’s own biology such as gut environment, immune factors, and human genetic variations, may influence how well these microbes survive, adhere, and benefit the body.
Research shows that how well probiotics work can depend on both the bacteria’s and the person’s genetics. A study on 42 strains of Lactobacillus plantarum found that certain bacterial genes control how probiotics affect the immune system. These genes are involved in nutrient transport, communication between bacteria, and production of antimicrobial compounds. When these genes were removed, the bacteria could no longer stimulate immune cells to produce important cytokines like IL-10 and IL-12. This shows that specific bacterial genes are key to probiotic activity.
Human genetics also plays a role. In a study where healthy volunteers received Lactobacillus acidophilus, L. rhamnosus GG, or L. casei, researchers examined gene activity in the intestinal lining. They found that responses were more influenced by each person’s genes than by the type of probiotic. For instance, L. acidophilus affected immune and growth-related genes, L. rhamnosus influenced cell growth and wound-healing genes, and L. casei shifted the balance of immune responses. Probiotics can also directly regulate immune cells. A protein from L. rhamnosus GG called p40 reduced intestinal inflammation and protected the gut barrier in mice, while certain Bifidobacterium strains increased regulatory T cells, helping control immune reactions.
Overall, these studies show that both bacterial and human genes determine how probiotics work and what kind of probiotics are needed. This explains why probiotics may help one person more than another and points toward the future of personalized probiotics tailored to an individual’s genetic profile.
Probiotics can be obtained from both natural foods and dietary supplements. Including them in your diet may help maintain a healthy balance of gut bacteria.
Probiotics are generally considered safe for most healthy people, but they may cause side effects in some individuals, especially when first introduced. The most common mild effects include:
People with weakened immune systems, severe illnesses, or those who have undergone recent surgery should consult a healthcare provider before using probiotics, as there is a small risk of infections or other complications in these cases. It’s also important to note that not all probiotics are the same. Different species and strains have different effects.
Precautions When Using Probiotics
While probiotics are generally safe for healthy individuals, some precautions can help ensure their safe and effective use:
