In folk medicine, rosemary has been
associated for centuries with having a good memory. But is it worth
investigating whether it really has any powers, asks Dr Chris Van
Tulleken.
In scientific terms there are different kinds of memory.
There's
past memory - your experiences and what you learned at school. There's
present memory, which is your working minute-to-minute memory. And
there's future memory or "remembering to remember".
This is for
many of us the trickiest one. When it fails bad things happen - we
forget to take our vital heart medicine or worse still to buy our
spouse's birthday presents. It's the reason letters decompose in my back
pocket over months even though I cycle past a postbox every day.
There
are plenty of examples of people who have enormously improved their
past memories, committing decks of cards to memory or whole new
languages. But remembering to remember is more complicated. Like most
people I would do almost anything for an improved future memory.
Medicine has little to offer. There are some drugs for
treating the memory loss that happens with dementia but they are not
hugely effective. They give some measurable benefits but whether they
are "clinically significant" is controversial. Certainly they are no
miracle cure for people with dementia, nor do they improve the memory of
anyone else.
So I was not that hopeful travelling up to
Newcastle to see Prof Mark Moss at Northumbria University. His team is
running an experiment to test whether rosemary essential oil could
benefit future memory. I'll be honest - this seemed hokey.
Rosemary
has been linked to memory for hundreds of years. Ophelia in Hamlet says
to her brother Laertes: "There's rosemary, that's for remembrance." But
that's no kind of basis for a study. She had after all gone insane
after the death of her father and was to kill herself shortly after this
scene.
Ophelia's speech
Sir John Everett Millais's 1852 painting "Ophelia" depicts her death after going insane
"There's rosemary, that's for
remembrance; pray/ Love, remember: and there is pansies. that's for
thoughts... There's fennel for you, and columbines: there's rue/ For
you; and here's some for me: we may call it/ Herb-grace o' Sundays: O
you must wear your rue with/ A difference." (Hamlet, Act IV, Scene 5) Rosemary
is used in aromatherapy for similar reasons but this hardly seems like
stronger evidence. Briefly, here's my position on alternative therapies -
I think they're great. They have few side effects and they empower
people. From my own work in remote communities around the world I think
that ancient traditions of healing have much to teach us and
historically they have provided many useful drugs. For me aromatherapy
falls at that end of the therapeutic spectrum where I would expect to
find little effect. It uses nice smells to make people feel… well, nice.
Or so I thought.
Here's how the experiment worked. The team at
Northumbria recruited 60 older volunteers to test the effects of not
only rosemary oil but also lavender oil. They then tested these
volunteers in a room infused with either rosemary essential oil,
lavender essential oil or no aroma. Participants were told they were
there to test a vitamin water drink. Any comments about the aromas were
passed off as irrelevant and "left over from the previous group to use
the room".
Lavender oil had a sedative effect on volunteers
The volunteers (and I) then
took a test which was designed to test their prospective memory. It's a
clever test with many layers so you never quite know what's being
tested.
At the start, objects are hidden around the room in
places which you have to remember at the end of the test. Then you
perform a series of distracting but fun word puzzles while increasingly
complex demands are made of your memory by the testers (in my case two
extraordinarily nice and competent graduate students, Kamila and
Lauren). "In seven minutes' time from now can you hand me this book?" or
"when you come across a question about the Queen in the word puzzles
can you remind me to call the garage".
My marks were squarely
average. I didn't remember to remind Kamila to get her car from the
garage in much the same way that I would have forgotten myself.
What
Mark's team found was remarkable. The volunteers in the room with the
rosemary infusion did statistically significantly better than those in
the control room but lavender caused a significant decrease in
performance. Lavender is traditionally associated with sleep and
sedation.
Was the lavender sending our volunteers to sleep and
decreasing their performance? How could vaporised essential oils
possibly have this effect?
Rosemary (Rosmarinus officinalis)
Perennial herb with evergreen, needle-like leaves and white, pink, purple or blue flowers
Name derives from Latin "dew of the sea"
Mediterranean in origin, the plant is nevertheless hardy in colder climates and is used as flavouring for many foods
BBC Food: Rosemary recipes It
turns out that there are compounds in rosemary oil that may be
responsible for changes in memory performance. One of them is called
1,8-cineole - as well as smelling wonderful (if you like that sort of
thing) it may act in the same way as the drugs licensed to treat
dementia, causing an increase in a neurotransmitter called
acetylcholine.
These compounds do this by preventing the
breakdown of the neurotransmitter by an enzyme. And this is highly
plausible - inhalation is one of the best ways of getting drugs into the
brain. When you eat a drug it may be broken down in the liver which
processes everything absorbed by the gut, but with inhalation small
molecules can pass into the bloodstream and from there to the brain
without being broken down by the liver.
As further confirmation
Mark and his team analysed blood samples and found traces of the
chemicals in rosemary oil in the blood.
The implications of this
kind of research are huge, but they don't mean you need to spend your
days smelling of rosemary and your night sleeping on a pillow of
lavender. The effects were measurable but modest and they give us a clue
that further research into some of the chemicals in essential oils may
yield therapeutics and contribute to our understanding of memory and
brain function.
It's also important to remember that any drug
that has a measurable effect, even if inhaled from a traditionally
prepared essential oil, may also have a measurable side-effect. You
can't tinker with brain biochemistry and expect things to be simple.
But
if these studies may help eventually contribute to new drugs to treat
dementia there is another very nice benefit - they also restore some
credibility to the much maligned alternative health field.
Traditional
healing practices weren't all quackery. Modern medicine of the kind I
practise in London may have many sophisticated treatments but it comes
with side effects and can leave people feeling disempowered.
We
have spent many years rubbishing alternative treatments but there is, I
believe, a real benefit in allowing people to take control of their own
health with treatments that make them feel better - even if we haven't
been able to prove how.
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