There are several scientific research articles on the effects of Bacopa monnieri on cognitive function. These fall into two types, firstly there are the detailed animal studies in a controlled environment, and secondly there are the less well controlled human studies where subjects are given pills to take daily and the results are measured by several tests.
This article will summarize the human studies done to date, the next article will summarize the animal studies.
These reports have sometimes come to different conclusions on the effectiveness of Bacopa on improving cognitive function. These discrepancies are probably because the effects of Bacopa are observed after taking it for at least 3-months. All the studies over shorter time periods have shown no effect. I will try and dissect out the important features of each article to create a complete and non-biased summary of the current knowledge available.
Article 1
The is a favourable study of the long term (chronic) effects of Bacopa on human memory. I always think of "chronic-effects" as "terrible-effects", like "a chronic shortage of money", but this is wrong, chronic just means long lasting, like over 3-months.
The chronic effects of an extract of Bacopa monniera (Brahmi) on cognitive function in healthy human subjects. (2001)
Stough C, Lloyd J, Clarke J, Downey LA, Hutchison CW, Rodgers T, Nathan PJ.Neuropsychology Laboratory, School of Biophysical Science and Electrical Engineering, Victoria, Australia.
RATIONALE: Extracts of Bacopa monniera have been reported to exert cognitive enhancing effects in animals. However, the effects on human cognition are inconclusive. OBJECTIVE: The current study examined the chronic effects of an extract of B. monniera (Keenmind) on cognitive function in healthy human subjects. METHODS: The study was a double-blind placebo-controlled independent-group design in which subjects were randomly allocated to one of two treatment conditions, B. monniera (300 mg) or placebo. Neuropsychological testing was conducted pre-(baseline) and at 5 and 12 weeks post drug administration. RESULTS: B. monniera significantly improved speed of visual information processing measured by the IT task, learning rate and memory consolidation measured by the AVLT (P<0.05),>
There have been previous studies before this, but this is the first double-blind placebo-controlled study on Bacopa. Studies need to be double blind to prevent bias entering the data accidentally from the researcher. They conducted a large number of mental tests at three intervals: before, during and after. Positive improvement was observed after 12-weeks in tests of early information processing measured by an an inspection time (IT) task. Inspection time is a measure of information processing and is probably the rate limited factor of cognition. Improvements were also significant in verbal learning rate and memory consolidation tests.
More importantly perhaps was the significantly improved scores in the anxiety tests. This is important because it was a study of mentally healthy people, and it backs up previous work on patients with anxiety neurosis (Singh 1980). It is already known that B. monniera effects serotonin levels in animals (Ganguly and Malhotra 1967).
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Article 2
Chronic Effects of Brahmi (Bacopa monnieri) on Human Memory (2002)
Roodenrys S, Booth D, Bulzomi S, Phipps A, Micallef C, Smoker J.
Department of Psychology, University of Wollongong, Woolongong, Australia.
ABSTRACT
"A study is reported on the effects of Brahmi (Bacopa monniera) on human memory. Seventy-six adults aged between 40 and 65 years took part in a double-blind randomized, placebo control study in which various memory functions were tested and levels of anxiety measured. There were three testing sessions: one prior to the trial, one after three months on the trial, and one six weeks after the completion of the trial. The results show a significant effect of the Brahmi on a test for the retention of new information. Follow-up tests showed that the rate of learning was unaffected, suggesting that Brahmi decreases the rate of forgetting of newly acquired information. Tasks assessing attention, verbal and visual short-term memory and the retrieval of pre-experimental knowledge were unaffected. Questionnaire measures of everyday memory function and anxiety levels were also unaffected."
For most of their tests, they report no significant improvement.
The only measure to show a significant effect was the test requiring the recall of unrelated word pairs after a short delay. There was no significant effect on the rate of acquiring new information but the tests showed there is a significant reduction in the amount of information lost from memory.
They suggest the effect may be due to an antioxidant effect in the hippocampus.
One person withdrew from the study due an a gastrointestinal complaint due to the tablets. Two people withdrew from the placebo group due to medical conditions.
A Note On Sample Sizes
The first study used a sample size of 46 people, the second study used 76 people. As these are split into two groups- placebo and experimental, that just leaves 23 or 38 individuals in each group.
A problem with both of these studies above is that they only use small sample sizes. Any test of human ability is going to suffer from a large amount of variance over time, because people have good days and bad days. So the results of the tests carried out will not show an obvious trend if the effect of the Bacopa is small compared to this natural variance. The scientific way around this is the statistical test. The tests of significance are a measure of the likelihood of observing these results by chance. A result is decided to be real and passes the statistical test if the probability of observing that result is sufficiently low. The trouble with using a small sample size like in this study, is that a real result could be dismissed as a chance event because of the high variance within the people taking the test. The results above are likely to be a real results because they pass the tests when adjusted for the small sample size. But just because the other effects that were tested failed the statistical test does not mean the Bacopa did not have an positve (or negative) effect. That effect may have just been too small to detect from that sample size.
Article 3
Effects of a combined extract of Ginkgo biloba and Bacopa monniera on cognitive function in healthy humans (2004)
Nathan PJ, Tanner S, Lloyd J, Harrison B, Curran L, Oliver C, Stough C.
Neuropsychopharmacology Laboratory, Brain Sciences Institute, Swinburne University, Victoria, Australia.
ABSTRACT
Extracts of Ginkgo biloba and Bacopa monniera have been shown to produce positive effects on cognitive function in healthy subjects. While the exact mechanisms are not known, it has been suggested that antioxidant properties and cholinergic modulation may play a role. In the current study the sub-chronic (2 weeks) and chronic (4 weeks) effects of an extract containing Ginkgo biloba (120 mg) and Bacopa monniera (300 mg) (Blackmores Ginkgo Brahmi) on cognitive function were examined. The study was a randomized, double-blind, placebo-controlled, independent group design in which 85 healthy subjects were allocated to one of two treatment conditions (placebo or combined Ginkgo biloba and Bacopa monniera extract). Testing was conducted at baseline and 2 and 4 weeks post treatment. The results showed that the combined extract relative to placebo did not demonstrate any significant effects on tests investigating a range of cognitive processes including attention, short-term and working memory, verbal learning, memory consolidation, executive processes, planning and problem solving, information processing speed, motor responsiveness and decision making. These findings suggest that at least within the current treatment duration and doses, an extract containing Ginkgo biloba and Bacopa monniera had no cognitive enhancing effects in healthy subjects. "No changes in cognitive function were detected.
The main problem with this study is that previous work by the same authors has shown the effects of Bacopa to appear after 3-months of treatment, while this study only lasted for 4-weeks. It was also suggested that the type of tests used may not be sensitive enough to detect possible changes.
A useful part of this study was the monitoring of any adverse effects. No effects were observed compared to the control group. The monitoring included headache,
flu-like symptoms, dizziness, dry mouth, nausea, heart palpitations, sleep abnormalities, visual abnormalities and gastrointestinal complaints.
A note on Funding
The research in the 2001 paper was funded by a grant from Keenmind Pty, Ltd
The 2004 paper has an author listed who works for Blackmore’s Ltd, NSW, Australia
All papers were independently peer reviewed.
Other Bacopa research:
Effect of Fagonia Arabica (Dhamasa) on in vitro thrombolysis
BMC Complementary and Alternative Medicine 2007,
7:36doi:10.1186/1472-6882-7-36
Published:
6 November 2007
Bacopa monnnieri and Fagonia arabica were recently shown to have
thrombolytic activity compared to a negative control of water.
However the paper did not show that it was a specific effect of a
component of the aqueous extract, and all the plants tested showed some
significant thrombolytic activity. This effect could be due to some
general property of plant extract, for example antioxidants.
One interesting point is that Bacopa and Fagonia were significantly more
active than Tinospora cordifolia, Hemidesmus indicus, Glycyrrhiza glabra
Linn and Rubia corditofia
