The lactic acid bacteria are safe and useful organisms that have been widely used in fermented foods. Lactic acid bacteria Lactobacillus plantarum, to which L-137 belongs, are involved in the fermentation of certain foods such as nukazuke, kimchi, sauerkraut, pickles, and yogurt. They have been widely used in diets since ancient times. It has also been revealed that Lactobacillus plantarum not only exists in foods, but also in the mouth and digestive tract of humans.
Based on these facts, it is considered that Lactobacillus plantarum, to which L-137 belongs, are safe lactic acid bacteria with a long history of use in food.
L-137, which was isolated from Southeast Asian fermented food, is also a safe lactic acid bacterium with a long history of use in food.
So far many studies have been conducted, and the safety of HK L-137 has been scientifically verified.
Standard genotoxicity tests such as the reverse mutation test, chromosomal aberration test, and micronucleus test have been conducted to confirm the absence of genotoxicity in HK L-137.
In addition, a single-dose toxicity study (acute oral toxicity study) has been conducted to confirm the absence of acute toxicity by overdose.
Details of toxicity study items can be found here.
Reverse mutation test
This is a test to predict the presence or absence of genotoxicity by checking whether test substance causes mutation in bacteria.
Chromosomal aberration test
This is a test that predicts the presence or absence of genotoxicity by evaluating whether test substance affects proliferation or chromosome of cultured animal cells.
This is a test that predicts the presence or absence of genotoxicity by examining the induction of micronucleus (chromosome fragment caused by chromosomal abnormality and so on) in bone marrow red blood cells of mice given the test substance.
Single-dose toxicity study
This is a test that evaluates the toxicity by checking presence or absence of poisoning symptoms in mice that administered the test substance.
We have confirmed the safety of orally taken HK L-137 in healthy subjects by clinical study (double-blind randomized control study).
In this study, 30 healthy volunteers received one capsule of HK L-137 (10 mg) daily for 12 weeks, and another set of 30 healthy volunteers received one capsule of control (no HK L-137) daily for 12 weeks. The safety endpoints were examined.
As a result, no abnormalities were observed in any of the endpoints, demonstrating the safety of oral intake of HK L-137.
Details of safety evaluation items can be found here.
The results of these tests have confirmed that HK L-137 is a safe food ingredient.
Body weight, blood pressure, and pulse
Blood biochemical tests
Total protein, albumin, albumin-globulin ratio, creatine phosphokinase, glutamic-oxaloacetic transaminase, glutamic-pyruvate transaminase, lactic acid dehydrogenase, alkaline phosphatase, γ-glutamyl transpeptidase, leucine aminopeptidase, plasma glucose, total cholesterol, HDL cholesterol, LDL cholesterol, triglyceride, urea nitrogen, creatinine, uric acid, sodium, chloride, potassium, calcium, inorganic phosphorus, serum iron, and C-reactive protein
White blood cells, red blood cells, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, platelets, neutrophils, eosinophils, basophils, monocytes, lymphocytes, and red blood cell morphology
Specific gravity, pH, qualitative protein, qualitative glucose, urobilinogen, bilirubin, ketone body, and urine blood
The results of the safety studies have been published.
｢Safety studies of LP20 powder produced from heat-killed Lactobacillus plantarum L-137.｣ Hirose Y, Regul Toxicol Pharmacol. 54: 214-20 (2009)
Based on the history of use in food and the results of the safety studies, HK L-137 was approved as Self-Affirmed GRAS*1 in the United States in 2009. In the same year, HK L-137 was certified as a Non-Novel Status*2 by EU.
GRAS is an acronym for the phrase, Generally Recognized As Safe. Its status is confirmed by vigorous review process regulated by the FDA and ensuring the safety as the food.
Lactobacillus plantarum has a long history of use in food, so HK L-137 has been certified as a conventional food by EU.