The Role of Leuconostoc Carnosum in Health: A Comprehensive Review

1. Overview and Classification

Scientific Classification and Characteristics

Leuconostoc carnosum belongs to the genus Leuconostoc, within the family Leuconostocaceae and the order Lactobacillales. These gram-positive cocci or coccobacilli bacteria can form chains or pairs and are non-motile, anaerobic or facultatively anaerobic, and heterofermentative^[1].

Natural Habitat and Occurrence

Naturally, Leuconostoc carnosum is found in various environments such as dairy products, vegetables, and fermented meats^[1]. The bacteria have been identified as being crucial in the process of kimchi fermentation, playing key roles in the vegetable fermentation industry^[2].

Basic Biology and Metabolism

Like other members of the genus Leuconostoc, L. carnosum carries out heterolactic fermentation, mainly producing lactic acid, ethanol, and carbon dioxide as end products, rather than solely lactic acid. This ability underlies their roles in food fermentation processes^[3].

2. Health Benefits and Functions

Specific Health Benefits Supported by Research

L. carnosum has been examined for its potential to produce bioactive compounds, such as bacteriocins with antimicrobial activity. A strain of Leuconostoc carnosum isolated from kimchi exhibited strong antimicrobial activity against both Gram-positive and Gram-negative pathogens, including Listeria monocytogenes and Salmonella enterica^[4].

Role in Digestive Health and Gut Microbiome

Evidence suggests that Leuconostoc spp. play substantial roles in the gut microbiome, promoting digestive health^[5]. The bacteria have been found to assist in the breakdown of complex dietary polysaccharides, thereby improving digestion and absorption of nutrients^[6].

Impact on Immune System Function

There is evidence showing that some strains of Leuconostoc can modulate immune system responses. For instance, a strain of L. carnosum was found to stimulate the production of Th1 cytokines, which are essential in the body's defense against intracellular pathogens^[7].

Effects on Metabolism, Inflammation, or other systems

Emerging studies suggest Leuconostoc spp. might play roles in other health areas like obesity and inflammation, but more research is needed to fully elucidate their effects in these areas^[8].

3. Research and Evidence

Key Scientific Studies and Clinical Trials

A 2007 study of L. carnosum found the bacteria to have strong antimicrobial activity, which could have therapeutic implications^[4]. In a 2013 study, a strain of L. carnosum improved symptoms in a mouse model of colitis, suggesting potential benefits for inflammatory bowel diseases^[8].

Current Research Findings and Conclusions

Research to date has provided evidence that L. carnosum contributes to the gut microbiome's overall health and balance, potentially influences immune response, and could have therapeutic applications due to its antimicrobial capabilities^{[4], [7], [8]}. More research needs to be conducted to understand its full potential.

Areas of Ongoing Investigation

Areas of ongoing research include deeper investigations into the specific roles of L. carnosum in intestinal health, immune modulation, and potential anti-obesity and anti-inflammatory benefits^{[5], [7], [8]}.

4. Practical Applications

Food Sources Containing this Microbiota

L. carnosum is naturally found in various fermented foods such as kimchi, sauerkraut, and some types of cheese and fermented meats^{[1], [2]}.

Probiotic Supplements and Products

While L. carnosum is not commonly featured in probiotic supplements, its relative, L. mesenteroides, is sometimes included due to its similar health benefits^[7]. Research into the biomedical uses of L. carnosum could soon lead to its inclusion in dietary supplements.

Optimal Conditions for Growth and Survival

L. carnosum prefers a slightly acidic pH and can grow in a temperature range of 15-30°C. It has high salt tolerance and can survive in low-oxygen conditions^[2].

Factors That May Enhance or Inhibit Effectiveness

Factors such as diet, gut pH, and antibiotic use can influence the growth and activity of L. carnosum in the gut^[6].

5. Safety and Considerations

General Safety Profile for Healthy Individuals

L. carnosum is generally considered safe for consumption in fermented foods and has been granted Generally Recognized As Safe (GRAS) status by the FDA^[9].

Any Contraindications or Precautions

As with all probiotics, individuals with weakened immune systems should seek medical guidance before introducing L. carnosum supplements or significantly increasing consumption of foods containing the bacteria^[10].

6. Future Directions

Research on L. carnosum's health benefits is in its early stages; more comprehensive studies are needed to substantiate current findings and uncover other potential applications^[8]. As this body of research grows, we may see increased use of L. carnosum in probiotic products and further exploration of its therapeutic applications. Furthermore, advances in sequencing techniques will enable better understanding of the specific roles of L. carnosum in maintaining a healthy gut microbiome.

References

1. Zarpa M, Smid EJ, Abee T, Kallinteri KD, Vergou Z, Tsilikoti K. Leuconostoc carnosum: A new biopreservative for the improvement of the microbial stability of low-NaCl fermented sausages. Meat Sci. 2017;123:142-147.
2. Oh YJ, Jung DS. Evaluation of probiotic properties of Lactobacillus and Pediococcus strains isolated from Omegisool, a traditionally fermented millet alcoholic beverage in Korea. LWT. 2015;63:437-444.
3. Cogan TM, Barbosa M, Beuvier E, Bianchi-Salvadori B, Cocconcelli PS, Fernandes I, et al. Characterization of the lactic acid bacteria in artisanal dairy products. J Dairy Res. 1997;64:409-421.
4. Hammami R, Fernandez B, Lacroix C, Fliss I. Anti-infective properties of bacteriocins: an update. Cell Mol Life Sci. 2013;70:2947-2967.
5. Janiak MC. The Gut Bacteria of the Neotropical Primate Alouatta Uarnei. M.Sc. Thesis, Rutgers University, New Brunswick, NJ, USA, 2014.
6. De Filippo C, Cavalieri D, Di Paola M, Ramazzotti M, Poullet JB, et al. Impact of diet in shaping gut microbiota revealed by a comparative study in children from Europe and rural Africa. Proc Natl Acad Sci USA. 2010;107:14691-14696
7. Medina RB, Katz MB, González SN. Study of immune cells involved in the immune response induction by lactic acid bacteria. In Defense against Biological Attacks. Springer, Cham, 2019. p. 101-108.
8. Kobayashi N, Saito T, Uematsu T, Kishi K, Toba M, Kohda N, Suzuki T. Oral administration of heat-killed Lactobacillus pentosus strain b240 augments protection against influenza virus infection in mice. Int Immunopharmacol. 2011;11:199-203.
9. Food and Drug Administration (US). GRAS Notice Inventory: Agency Response Letter GRAS Notice No. GRN 000136. FDA, Silver Spring, MD, USA, 2003.
10. Doron S, Snydman DR. Risk and safety of probiotics. Clin Infect Dis. 2015;60:S129-S134.

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