Lactobacillus delbrueckii is a species of probiotic, a type of beneficial bacteria known for its role in fermentation. One of the most well-known members of this species is Lactobacillus delbrueckii subsp. bulgaricus, a bacterium with a rich history. In 1905, a Bulgarian medical student named Stamen Grigorov first identified this rod-shaped bacterium in traditional Bulgarian yogurt. This discovery captured the interest of Nobel laureate Élie Metchnikoff, who linked the longevity of Bulgarian peasants to their daily yogurt consumption. His work at the Pasteur Institute helped popularize yogurt and its bacterial cultures throughout Europe and the United States.
Impact on Digestive Wellness
Lactobacillus delbrueckii contributes to digestive health by fermenting lactose, the sugar in milk. This process converts lactose into lactic acid, making dairy products more digestible for individuals with lactose intolerance, a condition caused by a deficiency of the lactase enzyme. By consuming products with L. delbrueckii, these individuals ingest a bacterium that pre-digests the lactose, often alleviating symptoms like bloating and discomfort.
Beyond aiding lactose digestion, this probiotic helps maintain the health of the gut lining. A strong intestinal barrier is important for preventing harmful substances from passing from the gut into the bloodstream. Research suggests that components of L. delbrueckii can enhance this barrier’s integrity by promoting proteins that keep intestinal cells tightly bound together.
The presence of Lactobacillus delbrueckii also fosters a balanced intestinal environment. The gut contains a wide variety of microorganisms, some beneficial and others potentially harmful. By producing lactic acid, L. delbrueckii creates a more acidic gut environment that is less hospitable to many pathogenic bacteria. It also competes with these organisms for nutrients and attachment sites on the intestinal wall, limiting the growth of undesirable microbes.
Immune System Modulation
The influence of Lactobacillus delbrueckii extends beyond the digestive tract to the body’s immune system. A large portion of the immune system resides in the gut, where the microbial balance can shape immune responses. This bacterium and its byproducts, such as exopolysaccharides (EPS), can modulate immune activity. These interactions may help temper excessive inflammatory responses linked to many chronic conditions.
Specific strains of L. delbrueckii can influence the behavior of immune cells. For example, extracts from this bacterium can promote the proliferation of lymphocytes, a type of white blood cell central to the adaptive immune response. It can also enhance the activity of macrophages, which are cells that engulf pathogens and cellular debris. This stimulation helps fortify the body’s innate defenses.
This probiotic also helps regulate the production of cytokines, proteins that act as messengers for the immune system. L. delbrueckii and its EPS can inhibit pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF-α). By managing these signaling molecules, the bacterium contributes to a more balanced immune state, preventing overreactions that could damage the body’s tissues.
Sources and Practical Application
Incorporating Lactobacillus delbrueckii into a diet is most commonly achieved through fermented dairy products. Bulgarian yogurt is the most famous source, as L. delbrueckii subsp. bulgaricus is one of the two primary starter cultures required for its production. This bacterium is also found in kefir, a fermented milk drink with similar probiotic properties, and some types of cheese.
For those who do not consume dairy or prefer a concentrated dose, probiotic supplements are another option. When choosing a supplement, check the label for specific strains like Lactobacillus delbrueckii subsp. bulgaricus. The potency is measured in Colony Forming Units (CFUs), indicating the number of viable bacteria per dose. While no standard dose exists, many supplements offer dosages ranging from a few billion to tens of billions of CFUs.
The viability of the bacteria is a factor in both foods and supplements. Live and active cultures in yogurt and kefir are necessary to provide a probiotic effect. For supplements, proper storage according to the manufacturer’s instructions, often refrigeration, helps maintain the number of live organisms.
Safety and Potential Side Effects
Lactobacillus delbrueckii is considered safe for most people, with a long history of use in fermented foods. Many probiotic species, including this one, are classified as Generally Recognized as Safe (GRAS), a designation for substances not known to cause harm when used as intended.
When first introducing a new probiotic, some individuals may experience temporary and mild digestive side effects, such as gas, bloating, or a slight change in bowel habits. These effects usually subside within a few days as the digestive system adjusts.
While L. delbrueckii is safe for the general population, certain individuals should exercise caution. People who are severely immunocompromised, critically ill, or have serious underlying health conditions are advised to be cautious with probiotic supplements. In these cases, it is recommended to consult with a healthcare professional before adding a new supplement to their regimen.