Written by Jessica Patella, ND. The results of this clinical trial suggest that Lactobacillus plantarum C29 can be safely administered to enhance cognitive function in individuals with mild cognitive impairment.
Mild cognitive impairment is the stage between normal cognitive decline with aging and a clinical diagnosis of dementia or Alzheimer’s disease 1,2. Mild cognitive impairment can show a decline in memory, language, thinking and/or judgement, but does not yet compromise daily functioning 1,2. It is estimated 3-20% of the population older than 65-years of age have mild cognitive impairment 1,3. Those that suffer from mild cognitive impairment are at an increased risk of developing dementia 1,4; therefore, the goal is to recognize mild cognitive impairment early to slow disease progression 1. Recent research has found supplementing fermented soybean probiotic of Lactobacillus plantarum C29 can help cognitive functioning 1.
Lactobacillus plantarum C29 is a probiotic found primarily in kimchi, a traditional Asian food made from fermented vegetables. In preliminary rat studies Lactobacillus plantarum C29 increased cognitive performance by decreasing brain inflammation due to an improvement in gut bacteria 1,5.
The recent research included physically healthy men and women with a diagnosis of mild cognitive impairment (diagnosed according to the Diagnostic and Statistical Manual of Mental Disorders, 5th ed). The participants either supplemented with Lactobacillus plantarum (800mg/day, n=50; DW2009) derived from defatted fermented soybean or placebo (n=50). The participants were instructed to take 2 capsules, once daily.
Computerized neurocognitive function tests were performed at baseline and repeated again at 12 weeks, at the end of the study 1. The tests included verbal learning test, auditory continuous performance test, and digit span test 1. Fecal samples were also collected to analyze any changes in the gastrointestinal bacteria 1. After 12 weeks of supplementation, participants in the Lactobacillus plantarum group showed greater cognitive improvement compared to those in the placebo group (p=0.02). The change in attention composite scores was statistically significant compared to placebo as well (z=2.34; p for interaction = 0.02) 1. There were also trends toward improvement for verbal and working memory, which warrants a longer-term trial 1.
In the Lactobacillus plantarum group, the improvement in blood serum brain-derived neurotropic factor (a marker of inflammation in the brain) was associated with an improvement in cognitive functioning (t= 2.83; p=0.007). The average change in brain-derived neurotropic factor levels in the Lactobacillus plantarum group was 412.7 pg/mL (SD= 7212.4), while for the placebo group it was -1034.3 pg/mL (SD= 5644.5) 1.
When evaluating the microbes in the gut, the lactobacilli population was significantly increased in the Lactobacillus plantarum group (p=0.045), but not in the placebo group (p=0.3334) 1. There were no changes observed in either group in bifidobacteria or clostridia populations 1.There was only one serious adverse event reported during the trial, where one participant from the Lactobacillus plantarum group withdrew due to a diagnosis of lung cancer 1.
In conclusion, supplementation with Lactobacillus plantarum in participants with mild cognitive impairment was associated with improved gut bacteria and cognitive improvement 1. This was the first double-blind, placebo-controlled randomized controlled trial to examine the effects of Lactobacillus plantarum (DW2009) on cognition in people with mild cognitive impairment 1. It is important to note this is a preliminary study and future research with a large group is needed to confirm the results and investigate the mechanism of action.
Source: Hwang, Yun-Ha, Shinwon Park, Jong-Woo Paik, Soo-Wan Chae, Dong-Hyun Kim, Doc-Gyun Jeong, Eunji Ha et al. “Efficacy and safety of Lactobacillus plantarum C29-fermented soybean (DW2009) in individuals with mild cognitive impairment: a 12-week, multi-center, randomized, double-blind, placebo-controlled clinical trial.” Nutrients 11, no. 2 (2019): 305.
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Posted October 21, 2019.
References:
- Hwang Y-H, Park S, Paik J-W, et al. Efficacy and safety of Lactobacillus plantarum C29-fermented soybean (DW2009) in individuals with mild cognitive impairment: a 12-week, multi-center, randomized, double-blind, placebo-controlled clinical trial. Nutrients. 2019;11(2):305.
- Clinic M. Mild Cognitive Impairment. 2019; https://www.mayoclinic.org/diseases-conditions/mild-cognitive-impairment/symptoms-causes/syc-20354578. Accessed October 16, 2019.
- Petersen RC. Clinical practice. Mild cognitive impairment. The New England journal of medicine. 2011;364(23):2227.
- Boyle P, Wilson R, Aggarwal N, Tang Y, Bennett D. Mild cognitive impairment: risk of Alzheimer disease and rate of cognitive decline. Neurology. 2006;67(3):441-445.
- Jeong JJ, Woo JY, Kim KA, Han M, Kim DH. Lactobacillus pentosus var. plantarum C29 ameliorates age‐dependent memory impairment in F ischer 344 rats. Letters in applied microbiology. 2015;60(4):307-314.
