Herbs & spices
A couple of studies reported at the recent Annual Conference of the British Psychological Society are intriguing.
In the first study, 180 healthy adults completed questionnaires relating to their mood before being given either a drink of peppermint tea, chamomile tea or hot water. Twenty minutes later, their memory and cognition were tested, followed by another mood questionnaire.
Peppermint tea significantly improved long term memory, working memory and alertness compared to both chamomile and hot water, while chamomile tea (consistent with its reputed calming/sedative effect) significantly slowed memory and attention speed compared to both peppermint and hot water.
In the second study, 150 older adults (65+) were tested on their prospective memory while in one of three rooms: a room that was scented either with rosemary or lavender, or an unscented room.
The scented rooms had four drops of either lavender or peppermint essential oils placed on an aroma stream fan diffuser, switched on five minutes before the participants entered the room. Prospective memory was tested by needing to remember to pass on a message at a given time during the procedure, and having to switch tasks when a specific event occurred.
The room scented with rosemary significantly enhanced prospective memory compared to the room with no aroma. It also significantly increased alertness, while lavender significantly increased calmness and contentedness.
As I said, these are conference papers, and I know no more than revealed in the press release. However, these strategies are easy and harmless enough that you might want to try them for yourself.
Bussey, L. 2016. I really must post that letter! Aromas of essential oils impact on prospective memory in an older cohort. Presented at the British Psychological Society's 2016 Annual Conference in Nottingham.
Moss, M. 2016. Contrasting Effects of Peppermint and Chamomile Tea on Cognition and Mood. Presented at the British Psychological Society's 2016 Annual Conference in Nottingham.
I’ve been happily generous with cinnamon on my breakfast ever since the first hints came out that cinnamon might help protect against Alzheimer’s (it’s not like it’s an ordeal to add cinnamon!). Now a new study has revealed why.
Rosemary is a herb long associated with memory. A small study now provides some support for the association, and for the possible benefits of aromatherapy. And a rat study indicates that your attitude to work might change how stimulants affect you.
A small study involving 20 people has found that those who were exposed to 1,8-cineole, one of the main chemical components of rosemary essential oil, performed better on mental arithmetic tasks. Moreover, there was a dose-dependent relationship — higher blood concentrations of the chemical were associated with greater speed and accuracy.
Participants were given two types of test: serial subtraction and rapid visual information processing. These tests took place in a cubicle smelling of rosemary. Participants sat in the cubicle for either 4, 6, 8, or 10 minutes before taking the tests (this was in order to get a range of blood concentrations). Mood was assessed both before and after, and blood was tested at the end of the session.
While blood levels of the chemical correlated with accuracy and speed on both tasks, the effects were significant only for the mental arithmetic task.
Participants didn’t know that the scent was part of the study, and those who asked about it were told it was left over from a previous study.
There was no clear evidence that the chemical improved attention, but there was a significant association with one aspect of mood, with higher levels of the scent correlating with greater contentment. Contentment was the only aspect of mood that showed such a link.
It’s suggested that this chemical compound may affect learning through its inhibiting effect on acetylcholinesterase (an important enzyme in the development of Alzheimer's disease). Most Alzheimer’s drugs are cholinesterase inhibitors.
While this is very interesting (although obviously a larger study needs to confirm the findings), what I would like to see is the effects on more prolonged mental efforts. It’s also a little baffling to find the effect being limited to only one of these tasks, given that both involve attention and working memory. I would also like to see the rosemary-infused cubicle compared to some other pleasant smell.
Interestingly, a very recent study also suggests the importance of individual differences. A rat study compared the effects of amphetamines and caffeine on cognitive effort. First of all, giving the rats the choice of easy or hard visuospatial discriminations revealed that, as with humans, individuals could be divided into those who tended to choose difficult trials (“workers”) and those who preferred easy ones (“slackers”). (Easy trials took less effort, but earned commensurately smaller reward.)
Amphetamine, it was found, made the slackers worked harder, but made the workers take it easier. Caffeine, too, made the workers slack off, but had no effect on slackers.
The extent to which this applies to humans is of course unknown, but the idea that your attitude to cognitive effort might change how stimulants affect you is an intriguing one. And of course this is a more general reminder that factors, whatever they are, have varying effects on individuals. This is why it’s so important to have a large sample size, and why, as an individual, you can’t automatically assume that something will benefit you, whatever the research says.
But in the case of rosemary oil, I can’t see any downside! Try it out; maybe it will help.
 Moss M, Oliver L. Plasma 1,8-Cineole Correlates with Cognitive Performance Following Exposure to Rosemary Essential Oil Aroma. Therapeutic Advances in Psychopharmacology [Internet]. 2012 . Available from: http://tpp.sagepub.com/content/early/2012/02/24/2045125312436573 Abstract
 Cocker PJ, Hosking JG, Benoit J, Winstanley CA. Sensitivity to Cognitive Effort Mediates Psychostimulant Effects on a Novel Rodent Cost|[sol]|Benefit Decision-Making Task. Neuropsychopharmacology [Internet]. 2012 . Available from: http://www.nature.com/npp/journal/vaop/ncurrent/abs/npp201230a.html
First study: http://www.medscape.com/viewarticle/759506 (free reg reqd)
Second study: http://the-scientist.com/2012/03/28/stimulants-fail-to-stimulate/
An ingredient of the curry spice turmeric called curcumin is a powerful antioxidant and anti-inflammatory apparently helps learning and memory through its action on BDNF. It may also fight against amyloid plaques, and so help fight Alzheimer's.
Two small studies indicate that the herbs sage and lemon balm also help cognition. Both of these seem to increase the activity of acetylcholine, and so may be helpful to protect against Alzheimer's.
See article on Mempowered
A Finnish study involving 321 eight year old children has found that those whose mothers ate more than 500mg of glycyrrhizin per week (found in the equivalent of 100g of pure licorice) had significant decrements in verbal and visuospatial abilities and in narrative memory, compared to those whose mothers consumed less licorice. They were also more likely to have poor attention spans and show disruptive behaviour such as ADHD. The effects on cognitive performance appeared dose related (that is, higher consumption correlated with greater impairment). Glycyrrhizin may impair the placenta, allowing stress hormones to cross from the mother to the baby. These hormones (glucocorticoids) are thought to affect fetal brain development and have been linked to behavioural disorders in children. Consumption of licorice among young women is common in Finland.
 Raikkonen K, Pesonen A-K, Heinonen K, Lahti J, Komsi N, Eriksson JG, Seckl JR, Jarvenpaa A-L, Strandberg TE. Maternal Licorice Consumption and Detrimental Cognitive and Psychiatric Outcomes in Children. Am. J. Epidemiol. [Internet]. 2009 ;170(9):1137 - 1146. Available from: http://aje.oxfordjournals.org/cgi/content/abstract/170/9/1137
I’ve reported on quite a lot of studies finding beneficial effects of one food or another on the brain. Now a researcher has analyzed more than 160 studies about food's effect on the brain, and here’s the bottom line. He comes out for omega-3 fatty acids, as both improving synaptic plasticity and the expression of several molecules proteins to learning and memory, as well as protecting against attention-deficit disorder, dyslexia, dementia, depression, bipolar disorder and schizophrenia. He suggests it’s better to get it from food than supplements (which is always recommended). Salmon, walnuts and kiwi fruit are all good sources. They’re still working out which fatty acids are most important, but one is definitely docosahexaenoic acid, or DHA — which like vitamin C we’re not good at making for ourselves; we have to ingest it. He also concludes that diets high in trans fats and saturated fats are bad for cognition.Studies also support the need for folic acid (found in spinach, orange juice and yeast), which is essential for brain function, and appears to reduce age-related cognitive decline and dementia. And BDNF, important for learning and memory as well as metabolic regulation (so there’s a connection there with obesity), is helped by omega-3 fatty acids and the curry spice curcumin, and also, it seems, smaller food portions.
 Gómez-Pinilla F. Brain foods: the effects of nutrients on brain function. Nat Rev Neurosci [Internet]. 2008 ;9(7):568 - 578. Available from: http://dx.doi.org/10.1038/nrn2421
Full text is available online at www.nature.com/nrn/journal/v9/n7/abs/nrn2421.htmlhttp://www.eurekalert.org/pub_releases/2008-07/uoc--slh070908.php
Turmeric, an ingredient of curry, contains curcumin, which is a powerful antioxidant and anti-inflammatory that may inhibit the build-up of amyloid plaques in people with Alzheimer's. Now an investigation of 1010 older Asians (between 60 and 93 years) has found that those who ate curry "occasionally" (once or more in 6 months but less than once a month) and "often" (more than once a month) performed better on a standard test of cognitive function than those who only ate curry "never or rarely".
 Ng T-P, Chiam P-C, Lee T, Chua H-C, Lim L, Kua E-H. Curry Consumption and Cognitive Function in the Elderly. Am. J. Epidemiol. [Internet]. 2006 ;164(9):898 - 906. Available from: http://aje.oxfordjournals.org/cgi/content/abstract/164/9/898
Sage has long had a reputation for improving memory and concentration. Now, clinical trials with healthy, young adults (aged between 18 and 37) have found that those who had taken sage oil capsules performed significantly better in a word recall test. Sage is being investigated as a potential treatment for Alzheimer's Disease after earlier research found that it inhibits an enzyme called acetylcholinesterase (AChE) which breaks down the chemical messenger acetylcholine (reduced in those with Alzheimers').
Tildesley, N.T.J., Kennedy, D.O., Perry, E.K., Ballard, C.G., Savelev, S., Wesnes, K.A. & Scholey, A.B. 2003. Salvia lavandulaefolia (Spanish Sage) enhances memory in healthy young volunteers. Pharmacology Biochemistry and Behavior, 75 (3), 669-674.
Do caffeine and glucose help concentration? A recent study found that volunteers who drank a mixture containing caffeine and glucose (as well as trace levels of guarana, ginkgo and ginseng) showed clear improvements in memory and attention. Those who consumed the individual ingredients, or a placebo, did not show such improvements.Another study by the same researchers found that high doses of lemon balm improved memory and led to greater feelings of calmness in 20 volunteers. The lemon balm was found to increase the activity of acetylcholine – an important chemical messenger which is reduced in people with Alzheimer’s disease.
Scholey, A. & Kennedy, D. 2003. Report at the British Psychological Society Annual Conference in Bournemouth 13-15 March.
Research in rats has found that linoleic acid improved not only blood pressure, but also hypertension-induced memory decline, suggesting that the early incorporation of linoleic acid in the diet, may not only help in controlling hypertension, but may also improve hypertension-induced cognitive impairment. Linoleic acid is found in vegetable seed oils, such as safflower, sunflower, and hemp seed.
Holloway, V. 2002. Effects of early nutritional supplementation of linoleic acid in Hypertension. Paper presented at an American Physiological Society (APS) conference, "The Power of Comparative Physiology: Evolution, Integration and Application", August 24-28 in San Diego, CA.
More evidence for the value of the curry spice curcumin comes from animal studies indicating a curcumin-derived drug may help treat stroke.
A new molecular compound derived from curcumin (found in turmeric) holds promise for treating brain damage caused by stroke. Turmeric has a long history of use in Ayurvedic and Chinese traditional medicine. However, curcumin has several important drawbacks as far as treating stroke is concerned — mainly because it can’t cross the blood-brain barrier. The new compound can.
In rabbit experiments, the drug was effective when administered up to an hour after stroke, which correlates with about three hours in humans. This is the same time frame for which tPA — the only drug currently approved for ischemic stroke — is currently approved.
The new drug is expected to move to human clinical trials soon.
Paul A. Lapchak presented these findings at the American Heart Association International Stroke Conference in Los Angeles on February. 9.
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