Study: green tea and L-theanin with a slight cognitive impairment

Reference

Park SK, Jung IC, Lee WK, et al. A combination of green tea extract and L-theanine improves memory and attention in people with a slight cognitive impairment: a double-blind, placebo-controlled study. j med food. 2011; 14 (4): 334-343.

Design

randomized, placebo -controlled prospective study. Neuropsychological tests were carried out at the beginning of the course and 8 and 16 weeks after the treatment.

These tests included the Rey-Kim Memorial test and the stroop-op color word reading test. Twenty-four subjects were randomly selected for EEG measurements.

participant

91 participants (25 men) took part in this study. The age was between 40 and 75 years. 46 received treatment and 45 a placebo. Everyone complained about a bad memory, scored values ​​between 21 and 26 on the mini mental scale exam K (MMSE-K) and lays between the second and third stage of the global determination scale (GDS). ^{1.2 The MMSE-K is a Korean version of the MMSE and serves to quickly measure various cognitive functions with values 0 and 30, whereby a value of 30 is normal. The GDS is a test to assess the clinical symptoms and the severity of Alzheimer's disease. The GDS values ​​range from "no cognitive decline" (GDS 1) to "very difficult" (GDS 4–7). The study participants ranged from GDS 2 (normally with subjective memory disorder) to GDS 3 (slight dementia). Caffeinated foods and drinks were restricted during the study period.}

study medication and dosage

The test subjects were randomized either a treatment group or a placebo group. All took two 430 mg capsules twice a day 30 minutes before eating for 16 weeks. The treatment capsules consisted of 360 mg green tea extract and 60 mg L-theanin, which corresponds to a daily dose of 1,440 mg green tea extract and 240 mg L-the-leanin. The strength of the green tea extract is not specified in the study.

target parameter

The EEG was used to evaluate the short -term reaction to a daily dose of the medication taken at once. The Rey-Kim Memorial test was used to assess changes in the verbal and visual-spatial memory, and the stroop test for reading color words was used to report attention.

most important knowledge

In the area of ​​verbal and visual spatial memory, the test subjects with an initial MMSE-K score from 21 to 23 showed a significant increase in memory quotient (MQ) after 16 weeks ( p = 0.0478). The treatment also improved the immediate memory ( p ≤0.01) after 16 weeks compared to the starting value. No improvement could be observed in the patients who received a placebo. The total differences between the treatment and placebo group did not achieve significant values. When measuring attention using the Stroop color word reading test, the sub-group of the participants with a MMSE K score of 21–23 after 8 weeks again showed a significant increase compared to placebo ( p = 0.0306) and 16 weeks ( p = 0.133). There was no significant effect in the placebo group. The activity of the Theta brain waves started an hour after taking the medication and stopped up to three hours when the eyes are open. EEGS measured during reading showed increased theta waves after 2 and 3 hours. The combination of green tea and L-theanine tested in this study significantly improved the cognitive functions by increasing memory and attention to subjects with a slight cognitive impairment, the MMSE-K value between 21 and 23

effects on practice

There is no reason to question the need for additional non-toxic and inexpensive therapies that slow down the development of Alzheimer's disease. We leave it to other reviews to summarize the high financial and emotional costs of this disease.

green tea and in particular L-theanine should be added to a growing list of possible therapies to treat the early Alzheimer's disease. Although the improvements measured in this study were modest, this data in connection with other studies provide a convincing argument that L-The -icin offers clinical benefits together with green tea polyphenols and caffeine.

Kakuda reported in 2002 that green tea had several neuroprotective effects. It protected neurons from the toxic effects caused by exposure to glutamic acid. Preliminary explanation of L-theanin-protected hippocampus-Ca1 pyramid neurons against temporary ischemia of the front brain in racing mice. L-theanin also protected the neurons in the Ca3 region of the hippocampus from injuries caused by Kainat exposure. L-theanin also protected lipoproteins of low density (LDL) from oxidative changes that lead to arteriosclerosis. ^{3 EGashira confirmed protection against ischemic damage in 2008}

a work by Nathan et al. From 2006 this protective effect partially explains: "L-theanin increases the serotonin, dopamine and gaba levels in the brain and has micromolar affinities to ampa, kainat- and nmda receptors." In addition, it may have been shown in animal models that it has neuroprotective effects. … Overall, L-theanin shows a neuropharmacology that indicates a possible neuroprotective and cognitive means and requires further examinations in animals and humans. ”

The combination of caffeine with green tea ePicatechin, epigallocatechin and epigallocatechingallate induces enzyme activity.

Another possible explanation for the benefits of green tea in Alzheimer's disease is its effect on the activity of enzymes, which are called neutral endopeptidases. These enzymes break down amyloid beta-peptide plaques in the brain. The combination of caffeine with green tea epicatechin, epigallocatechin and epigallocatechingallate induces enzyme activity. ⁶

Of particular interest, a study from 2009 is in mice. She protected the five-week pretreatment of the mice with L-theanin in her drinking water from brain damage when beta-amyloid protein was then injected. ⁷

of the same interest is a paper published in April 2011. In it, Kakuda describes "an examination of older people with normal or easier cognitive dysfunction, volunteers, the powdered green tea with a high theanin center (corresponds to 47.5 mg/day (-1)) from Theanin)." They "showed a significantly lower decline in cognitive function compared to the placebo group."

There is another aspect of this research. Patients who suffer from Alzheimer's disease, as well as their family members who act as supervisors can suffer from anxiety. Reduction of anxiety.

Green tea and L-theanin should be included in the list of foods and nutrients that we consider when treating Alzheimer's disease in the early stages.