HK L-137 is a Heat-Killed Probiotic with Powerful Immune Effects
Introduction
One of my all-time favorite natural products is HK L-137. It is an extremely interesting immune-enhancing product from a probiotic organism, yet the bacteria are heat-killed to stabilize its active components. Now, you have probably heard that bacteria and probiotics have to be alive to produce their benefits, but HK L-137 is much different. Its active compounds are able to interact with immune cells in a powerful way whether the organism is alive or not. That makes it super interesting, right?
The name HK L-137 stands for Heat-Killed Lactobacillus plantarum strain L-137. The commercial name listed on the label of dietary supplements and functional food products for this natural ingredient is Immuno-LP20TM.
Introduction
One of my all-time favorite natural products is HK L-137. It is an extremely interesting immune-enhancing product from a probiotic organism, yet the bacteria are heat-killed to stabilize its active components. Now, you have probably heard that bacteria and probiotics have to be alive to produce their benefits, but HK L-137 is much different. Its active compounds are able to interact with immune cells in a powerful way whether the organism is alive or not. That makes it super interesting, right?
The name HK L-137 stands for Heat-Killed Lactobacillus plantarum strain L-137. The commercial name listed on the label of dietary supplements and functional food products for this natural ingredient is Immuno-LP20TM.
The History of HK L-137
Researchers working with one of Japan’s most prestigious immunology laboratories, the Medical Institute of Bioregulation at Kyushu University, spent 5 years looking at probiotic organisms looking for something unique to improve immune health. Ultimately, they discovered a special lactic acid bacteria, Lactobacilllus plantarum 137, that possessed very potent immune enhancing actions.
plantarum 137 was initially isolated from Narezushi – Japan’s original form of sushi that is made by fermenting raw fish and rice with the aid of lactic acid bacteria. Narezushi is basically pickled fish. In Japan it is renowned for its health benefits. And it appears that some of these benefits are due to Lactobacilllus plantarum strain 137.
Dead or Alive?
One of the interesting things the researchers discovered about the immune enhancement was that the active compounds in L. plantarum strain 137 were located on the surface of the cell walls of the bacteria. These special compounds, lipotechoic acids, exert remarkable effects on human immune cells.1 These compound are active whether the bacteria is dead or alive. In fact, HK L-137 actually outperforms equal amounts of live bacteria as it is more resistant to the damaging effects of gastric acid.2 The heat-stabilized lipotechoic acids show greater immune enhancement.
Further research discovered that the concentration of lipotechoic acids was highest at a specific time in the bacteria’s life cycle and if the researchers applied just the right amount of heat they could kill the bacteria and liberate the lipotechoic acids. The stabilized, liberated lipotechoic acids are better able to interact with immune cells. The end result of this process is HK L-137 (Immuno-LP20TM). Each 10 mg dose of Immuno-LP20TM contains over 12 billion L. plantarum strain 137 bacteria that have liberated their lipotechoic acid.
Figure 1. Heat treatment locks in the highest levels of both bacteria growth and immune-stimulating
activity before these levels naturally decline throughout the production process.
HK L-137 is an Immunobiotic
An “immunobiotic” is a biological compound that promotes proper immune function. It is not about stimulating the immune system, it is all about enhancing the ability of the immune system to function properly. Human studies have confirmed HK L-137 exerts such an enhancing effect on immune function. Specifically, HK L-137 improves immune function in people with low immune status who are prone to infections while at the same time also improving function in those people who may have an overly active immune state due to allergies or autoimmune conditions.
Many of the effects of HK L-137 on the immune system are due to its components inducing the production of potent chemical mediators of white blood cells – interleukin-12 and type 1 interferon.1,3 The increased production is the result of lipotechoic acids being transferred across the gastrointestinal lining by specialized cells known as M cells. Once transferred across gut lining by M cells, the lipotechoic acids then interact with specialized white blood cells to increase the release of interleukin-12 and beta-interferon that activate other white blood cells that enter the bloodstream to enhance systemic immunity throughout the body.
By increasing the effects of interleukin-12, HK L-137 also leads to improvements in the ratio of different types of white blood cells known as T cells. Technically speaking, HK L-137 improves the helper to suppressor T-cell ratio. This action has a balancing effect on immune function making it useful in fighting both low immune that makes a person prone to infections while at the same time protecting against allergies and autoimmune reactions.4
Figure 2. M cells that line the gastrointestinal tract process HK L-137 components and present them
to white blood cells to produce powerful chemical messengers to the immune system.
Clinical Effects of HK L-137
HK L-137 has been well-studied in both pre-clinical and human studies. Not only do studies show it to produce tremendous clinical effects on the immune system, the studies also show HK L-137 improves quality of life scores. Basically, it makes people healthier and feel better. The immune system is known to influence our mood and the way that we feel. By improving the balance in immune function, HK L-137 appears to help improve the balance in the way that we feel.
What one study showed was the degree of improvement in quality of life scores was directly related to the improvement in the ratio of helper to suppressor T cells. The greater the improvement, the bigger the boost in feeling better. The improvement was accomplished primarily by increasing the number of helper T cells. These specialized white blood cells are the real workhorses of immune function. And as a result, by increasing helper T cells, supplementation with HK L-137 not only makes us feel better, it also improves natural immunity and antibody formation.4
Other human clinical studies with HK L-137 show it exerts beneficial effects on other aspects of immune function. One of the big effects noted was an increased production of type 1 interferon, which is an important immune system regulator especially important against viral infections.3
This effect undoubtedly played a big role in HK L-137’s positive effects on immune function in helping subjects with psychological stress reduce the development of an upper respiratory infection in another double-blind, placebo-controlled trial.5 The subjects received HK L-137 or a placebo daily for 12 weeks. The number of people experiencing an upper respiratory tract infection in the HK L-137 group was significantly lower than the control group. And in addition to reducing the number of people who had an upper respiratory tract infection, HK L-137 also reduced the duration and severity of any infection.
The effects of HK L-137 also produces benefits on inflammation and cholesterol metabolism. In a double-blind, placebo-controlled study in 100 healthy, but overweight subjects, those given HK L-137 showed improved immune functions similar to previous studies and also showed benefits in reducing markers of inflammation as well as decreases in both total cholesterol and LDL cholesterol.6 These effects were stronger in the subjects with higher C-reactive protein levels (a marker of systemic inflammation. These findings indicate daily intake of HK L-137 can improve inflammation and lipid metabolism in subjects at risk of inflammation. Again, HK L-137 produces a balancing effect in its action on the immune system.
HK L-137 Improves Gum Health
Periodontal disease and poor gum health are major contributors to systemic inflammation because the chronic infection overstimulates the immune system. In addition, periodontal disease also leads to the leakage of bacterial toxins such as gingiopains that can further cause inflammation. Fortunately, HK L-137 has also shown positive results in improving the health of the gums and periodontal tissue.
In a double-blind, placebo-controlled clinical study, 39 subjects with poor periodontal health were randomly assigned to receive a capsule containing HK L-137 or a placebo capsule daily for 12 weeks. The primary outcome measure that showed the most improvement was the measured depth of “bleeding upon probing” and the number of teeth or sites with a pocked depth greater than 4 mm. Results showed that HK L-137 significantly reduced the number of teeth with pockets depths greater than 4 mm compared to the placebo group at week 12. These clinical findings show that daily HK L-137 intake can improve the health of the gums and connective tissue even in individuals with poor periodontal health.7
Summary of HK L-137 (Immuno-LP20™)
- It is a well-defined, clinically tested natural product using a heat-stabilized probiotic organism common to fermented foods.
- It is not technically a probiotic as the organism is not viable.
- It is referred to as an “immunobiotic” or “paraprobiotic.”
- Lipotechoic acids on the cell surface are responsible for its effects.
- Human clinical studies show systemic effects:
- Promotes improvements in quality of life scores.
- Induces production of an important immune system regulator: interleukin-12.
- Increases the ratio of T helper cells to T suppressor cells (Th1 to Th2 ratio), thereby producing a balancing effect on immune function (useful in both infections and conditions associated with an overactive immune system)
- Reduces the incidence, duration and severity of upper respiratory tract infections.
- Promotes oral health by reducing pocket depth in periodontal disease.
- Two mechanisms of action:
- Immune enhancement via increasing interleukin-12 levels
- Promotion of connective tissue matrix in the gums
- Two mechanisms of action:
Final Comments:
HK L-137 can be used anytime the immune system is challenged, but it is best used and suitable for daily, long-term, continued use to keep the immune system primed for optimal function. To identify products that contain HK L-137, look for the trademarked name of Immuno-LP20TM on the label. The standard dosage for Immuno-LP20TM is 50 mg per day providing 10 mg of HK L-137 and over 12 billion heat-killed cells of Lactobacilllus plantarum strain 137.
Click here for the products on iHerb that contain Immuno-LP20™
References:
- Hirose Y, Murosaki S, Fujiki T, Yamamoto Y, Yoshikai Y, Yamashita M, et al. Lipoteichoic acids on Lactobacillus plantarum cell surfaces correlate with induction of interleukin-12p40 production. Microbiol Immunol. 2010 Mar;54(3):143-51.
- Fujiki T, Hirose Y, Yamamoto Y, Murosaki S. Enhanced immunomodulatory activity and stability in simulated digestive juices of Lactobacillus plantarum L-137 by heat treatment. Biosci Biotechnol Biochem. 2012;76(5):918-22.
- Arimori Y, Nakamura R, Hirose Y, Murosaki S, et al. Daily intake of heat-killed Lactobacillus plantarum L-137 enhances type I interferon production in healthy humans and pigs. Immunopharmacol Immunotoxicol. 2012 Dec;34(6):937-43
- Hirose Y, Murosaki S, Yamamoto Y, Yoshikai Y, Tsuru T. Daily intake of heat-killed Lactobacillus plantarum L-137 augments acquired immunity in healthy adults. J Nutr. 2006 Dec;136(12):3069-73. doi: 10.1093/jn/136.12.3069. PMID: 17116721.
- Hirose Y, Yamamoto Y, Yoshikai Y, Murosaki S. Oral intake of heat-killed Lactobacillus plantarum L-137 decreases the incidence of upper respiratory tract infection in healthy subjects with high levels of psychological stress. J Nutr Sci. 2013 Dec 6;2:e39.
- Tanaka Y, Hirose Y, Yamamoto Y, Yoshikai Y, Murosaki S. Daily intake of heat-killed Lactobacillus plantarum L-137 improves inflammation and lipid metabolism in overweight healthy adults: a randomized-controlled trial. Eur J Nutr. 2020 Sep;59(6):2641-2649.
- Iwasaki K, Maeda K, Hidaka K, et al. Daily Intake of Heat-killed Lactobacillus plantarum L-137 Decreases the Probing Depth in Patients Undergoing Supportive Periodontal Therapy. Oral Health Prev Dent. 2016;14(3):207-14.