Lactococcus Lactis Lactis
Also known as: L. lactis, Lactococcus lactis, Lactococcus lactis subsp. lactis
Overview
Lactococcus lactis subsp. lactis is a Gram-positive, facultative anaerobic bacterium widely recognized for its pivotal role in the fermentation of dairy products such as cheese and buttermilk. As a member of the lactic acid bacteria group, it contributes significantly to the flavor, texture, and preservation of fermented foods. Beyond its industrial applications, L. lactis lactis is increasingly investigated for its potential probiotic properties. Research indicates its ability to produce lactic acid and various extracellular metabolites with bioactive properties, which may modulate inflammatory responses and support overall host health. While its use in food science is well-established, clinical evidence for its specific health benefits as a probiotic is emerging, with studies exploring its immunomodulatory, anti-inflammatory, and gut health-supporting effects. The current body of evidence includes in vitro studies, animal models, and some human clinical trials, though more comprehensive human data are needed to fully elucidate its therapeutic potential.
Benefits
Lactococcus lactis subsp. lactis exhibits several potential health benefits, primarily demonstrated in preclinical models. Its most significant effect is its anti-inflammatory and immunomodulatory capacity. In a cellular sepsis model and an in vivo mouse model, extracellular products of L. lactis lactis significantly reduced inflammatory cytokines and decreased mortality in mice subjected to LPS-induced sepsis, indicating strong anti-inflammatory potential. This suggests a role in mitigating severe inflammatory conditions. While direct human evidence for L. lactis lactis alone is limited, systematic reviews on probiotics, including strains of L. lactis, suggest potential benefits on muscle mass, though these findings often involve multi-strain formulations. Additionally, L. lactis lactis contributes to gut health and infection prevention, although specific direct evidence for this strain is still emerging. Its long-standing use in dairy fermentation also implies a role in delivering health-promoting metabolites through food. In the sepsis mouse model, mortality was reduced from 82% to significantly lower rates after L. lactis treatment, highlighting a clinically significant effect in that context. However, human effect sizes are not yet well quantified for L. lactis lactis alone.
How it works
Lactococcus lactis subsp. lactis primarily exerts its effects through the modulation of inflammatory cytokine production. Its extracellular products appear to interact with immune cells and signaling pathways involved in inflammation, leading to a reduction in pro-inflammatory cytokines. This mechanism is thought to be responsible for its observed anti-inflammatory properties and improved survival rates in inflammatory conditions, such as sepsis models. As a probiotic bacterium, L. lactis lactis acts locally within the gastrointestinal tract, where it can interact with the gut microbiota and the host's immune system. While the bacterium itself is not absorbed systemically, its metabolites may exert indirect systemic effects. The exact molecular targets are not fully elucidated, but the inhibition of LPS-induced cytokine release by its extracellular metabolites is a key aspect of its mechanism.
Side effects
Lactococcus lactis subsp. lactis is generally regarded as safe (GRAS) due to its extensive history of use in food fermentation, particularly in dairy products. No significant safety concerns or adverse effects have been reported in the reviewed animal studies. While typical probiotic side effects such as mild gastrointestinal discomfort (e.g., bloating, gas) can occur with probiotic supplementation in general, these have not been specifically documented for L. lactis lactis in the available research. Uncommon or rare side effects have also not been reported. There are no known drug interactions specifically identified for L. lactis lactis. As with other probiotics, caution may be warranted in severely immunocompromised individuals, although no specific contraindications have been identified for this strain. Data on special populations are limited, but animal studies suggest potential benefits in severe inflammatory states without adverse effects.
Dosage
The minimum effective dose for Lactococcus lactis subsp. lactis in humans has not been clearly established. Animal studies investigating its anti-inflammatory effects used extracellular product doses ranging from 0.2–0.4 g/kg. Optimal dosage ranges for human consumption are currently undefined, as human clinical trials focusing solely on L. lactis lactis are limited. Similarly, a maximum safe dose has not been established. In animal studies, pretreatment with L. lactis lactis or its products prior to an inflammatory insult was shown to be beneficial, suggesting that consistent intake over time might be important for prophylactic or therapeutic effects. L. lactis lactis is typically administered as live bacteria in fermented foods or as part of probiotic supplements. Its extracellular metabolites have also been studied in purified forms in animal models. As a probiotic, its efficacy depends on its survival through gastric passage to reach the gut, where it exerts its local effects. No specific cofactors are identified as required for its action.
FAQs
Is Lactococcus lactis lactis safe to consume?
Yes, it is generally considered safe due to its long history of use in fermented dairy products and has not shown significant adverse effects in studies.
Does it help with inflammation?
Animal studies indicate that L. lactis lactis can reduce inflammatory cytokines and improve outcomes in models of severe inflammation like sepsis, suggesting anti-inflammatory potential.
Can it improve muscle mass?
Some systematic reviews on probiotics, including L. lactis strains, suggest potential benefits for muscle mass, but this evidence is often indirect and from multi-strain formulations.
How should it be taken?
It is typically consumed through fermented foods or probiotic supplements. Specific dosing for health benefits in humans is not yet well-defined.
Are there any side effects?
No significant side effects have been reported in studies. As with other probiotics, mild gastrointestinal symptoms like bloating are theoretically possible but not specifically documented for this strain.
Research Sources
- https://pmc.ncbi.nlm.nih.gov/articles/PMC11288810/ – This animal study investigated the effects of Lactococcus lactis extracellular products on sepsis in mice. It found that pretreatment significantly reduced mortality rates from 82% to much lower levels and inhibited inflammatory cytokines, demonstrating strong anti-inflammatory potential in a severe inflammatory model.
- https://www.mdpi.com/2072-6643/16/12/1921 – This systematic review analyzed 24 studies on probiotic supplementation and muscle mass, including some L. lactis strains. It concluded that probiotics improved muscle mass relative to placebo, although the effects were not isolated to L. lactis lactis alone, indicating a potential but indirect benefit.
- https://www.mdpi.com/2311-5637/10/1/16 – This narrative review discusses the applications of Lactococcus lactis in dairy fermentation and its potential health benefits. It highlights the bacterium's role in food safety and its emerging probiotic effects, noting that specific clinical evidence for L. lactis lactis alone is still limited.