• Green Tea – a “smart” drug? by Dr Jack

    SYBO 1 year oldRoom For One More?

    In the Smart Drugs chapter of the book I wrote with Adrian Webster “Sort Your Brain Out” we argued that of the various nootropics available in this day and age it makes sense to give preference to substances that have been around for eons rather than the new kids on the block. This really is the only way you can enjoy the benefits without having to worry about the potential unknown long term problems and side effects.

    The brain benefits of regular coffee drinking were described, but due to space limitations we were only able to discuss a few other substances. This month’s blog highlights some of the many published studies that have indicated a wide variety of health benefits associated with regularly imbibing green tea – something that people have indeed been doing for hundreds of years.

    Green & Black

    Tea_grade_of_fermentationCamellia sinensis is the name of the plant that gives us white, yellow, green, black and oolong teas. Black tea has more than twice the amount of caffeine as green tea, whilst green tea has more polyphenols (the very antioxidant substances that mop up all those dangerous free radicals). The difference in concentrations of these substances can be accounted for by the fact that black tea requires fermentation before preparation – which increases the caffeine content and decreases the polyphenol content – whilst green tea is prepared from unfermented leaves.

    All The Tea In China

    GreenTeaPotGreen Tea has been used in traditional Chinese and Indian medicine for thousands of years where it has been exploited for it’s stimulant, diuretic and astringent properties; not to mention improving heart health, flatulence and body temperature regulation. The stimulant effects are thanks to the alkaloids contained within the tea leaf including caffeine, theobromine and theophylline. As green tea contains about half the caffeine of black tea and MUCH less than a cup of coffee, dosing yourself with green tea throughout the day is much less likely to disrupt your sleep come bedtime than the other options.

    Typing “green tea” into an internet search engine yields a huge number of websites dedicated to promoting the ubiquitous benefits of regular green tea ingestion to improve the effectiveness of exercise, improving weight loss and even helping to manage diabetes. Of course its always difficult to know which sources you can and can’t trust. Hard data is required to establish whether green tea really does help to ameliorate symptoms of the various complaints for which it has been traditionally recommended.

    Is Green Tea Really Good For You?

    Yes! When individual research studies are published in a peer-reviewed scientific journal they can provide evidence to support or reject any particular scientific hypothesis, but a single study cannot “prove” or “disprove” any given theory. Meta-analyses are much more powerful in this regard because they look at many different studies all investigating similar hypotheses. If, despite being conducted on a completely different group of subjects, often in a completely different location and undertaken by a different group of researchers, they all point towards the same conclusion this provides for a much more powerful argument to support, or refute, any given claim when the consensus points to a benefit. Just looking at the meta-analysis data it has been confirmed that green tea is effective at lowering blood pressure, reducing risk of several different cancers and improving cardiovascular/metabolic health, to name but a few.

    Any Brain Benefits of Green Tea?

    keep-calm-and-drink-green-teaDrinking green tea has long been associated with relaxation and, indeed, scientific investigation has now backed this up. Epigallocatechine-3-gallate, the most active of the tea polyphenols (known collectively as “catechins”) is found in much higher quantities in green tea than other teas and is known to inhibit an enzyme that converts cortisone to cortisol. Cortisol is a so-called stress hormone and cortisone the inactive form. By preventing the enzyme in question – 11 beta-hydroxysteroid Dehydrogenase Type 1 – from doing its job, the active ingredient of green tea is able to reduce levels of the stress hormone. (In case you were wondering, the other 5 catechins are: catechin, gallaogatechin, epicatechin, epigallocatechin and epicatechin gallate).

    Can Green Tea Can Improve Cognition?

    Yes! Anecdotal accounts of the brain benefits of regular tea drinking in the elderly inspired research to establish whether green tea really could improve cognition. Over the last ten years huge amounts of data have been generated on this topic. The more green tea a person consumes, the lower prevalence of cognitive impairment (Full article available for free). Early research trying to ascertain the mechanism by which such benefits are realised demonstrated that spatial cognition was improved in rats that drank water infused with polyphenols from green tea (full article available for free).

    In the last few years experiments dosing healthy, younger humans with green tea versus placebo have demonstrated an increase in functional connectivity between frontal and parietal brain areas during a working memory task (Full article available for free). Bearing in mind that improvements in working memory can translate into better fluid intelligence and therefore a higher score in the IQ test – swapping green tea into your daily hot drink regime might make sense for your brain’s sake as well as your body’s.

    As well as these monthly blogs you can follow me on twitter by clicking here. It’s always great to hear your suggestions on topics for my brain blogs, so please do get in touch by clicking here.

    I also do a weekly science podcast called Geek Chic’s Weird Science which you can download for free from iTunes or alternatively, if you’re not an iPhone or iPad user, you can download/stream it from a variety of online sources such as Podbay, Libsyn, and PodcastChart, amongst others!

    Read more »
  • Caffeine Nation – good or bad for you?

    Coffee-BeansWhat Does Caffeine Do To Your Brain?

     As a neuroscientist who spends much of his working life giving brain talks at events all around the country (at schools, conferences and science festivals) I’ve noticed that one theme catches public imagination over and over again: How does caffeine work? What does it do to my brain? How long does it stay in my system? Is it really that bad for me? This is one reason why it became one of the key topics in the “Smart” Drugs chapter of my book: Sort Your Brain Out. In this blog I’ll cover some of the most regularly asked questions.

     

    How long caffeine takes to leave your system?

    It depends what other drugs you’re on. If you’re on the contraceptive pill it can take up to twice as long for your liver to remove caffeine from your system. So people “on the pill” can find themselves particularly sensitive to its effects because consecutive doses stack up and are not cleared out as swiftly as in everyone else. But if you’re a smoker it is the other way around. Caffeine is removed from your system at double the speed of a non-smoker.
    If you’re neither a smoker nor on the contraceptive pill the concentration of caffeine in your bloodstream is halved every 5-6 hours, but it really does depend on the individual as this “half-life” varies greatly from person-to-person.

     

    Is it beneficial to have caffeine before a meeting / presentation / to improve concentration?

    coffee-loverCaffeine blocks the receptors of an inhibitory neurotransmitter called adenosine, which under normal circumstances reduces overall activity across the brain. By blocking these receptors and removing the dampening influence on brain activity, caffeine increases activity across brain pathways involved in alertness, focusing attention and initiating body movements. This why people dosed up on caffeine can get quite jittery.
    Whether or not caffeine is beneficial for you in a meeting / presentation or to improve concentration whilst working depends on how much you’ve already had. There’s a sweet spot where you will feel more alert and switched on at moderate levels, but beyond that you can become so wound up that it has effects that are deleterious to performance (see description of caffeinism below).
    However the increase in feelings of alertness and ability to focus attention only gets regular coffee drinkers up to levels enjoyed by non-caffeine drinkers everyday. This is because once you’re a caffeine addict the brain tends to increase the numbers of adenosine receptors to compensate for the fact that there’s loads of caffeine swimming around in your brain on a daily basis. This means that your average coffee drinker has more inhibitory receptors in their brain dampening activity levels to a greater degree – so they will feel more sluggish whenever they don’t have caffeine in their system.

     

    Is caffeine good or bad for you in the long run?

    There seem to be some long-term benefits to drinking caffeine even if the short-term benefits don’t amount to a whole hill of (coffee) beans. It has been observed that regular drinkers of moderate amounts of caffeine (3 cups / day) have a lower incidence of Parkinson’s, Alzheimer’s, liver and heart diseases. This may be due to the increased numbers of inhibitory receptors triggered by ever-present levels of caffeine dampening activity levels in body and brain. The decreased activity levels across the brain caused by the larger numbers of inhibitory receptors in the caffeine drinkers’ brains may relieve the pressure on dopamine neurons that are compromised in Parkinson’s disease and the acetyl choline neurons that get clogged up with various proteins in Alzheimer’s disease. In other words caffeine seems to slow down the process of cell death so that symptoms of these diseases kick in several years later than in your average non-caffeine drinker. At the moment this mechanism is purely speculative. The jury’s still out on the precise mechanism that might account for these observations, but the evidence supporting the concept of moderate amounts of caffeine having a neuroprotective influence on the brain is steadily increasing.

     

     

    Is it important to control and monitor your caffeine intake?

    CoffeeOnDripA dose of 10g is deadly – 100 cups and a human may well find themselves popping their clogs as a typical cup of brewed coffee contains 100mg of caffeine. (NB you may notice that in the above video from the lovely people at ASAPscience they say 1 cup of coffee has 150mg – presumably they brew it stronger over in Canada 🙂 For the non-coffee drinkers out there here are some average caffeine contents of some other popular drinks. There are 80mg in a can of Red Bull, 75mg in a cup of instant coffee, 50mg in a cup of tea, 30mg in a can of Coca Cola.

    Very high but not deadly doses can lead to a quite severe psychiatric condition known as caffeinism: “which is characterised by restlessness, agitation, excitement, rambling thought and speech, and insomnia.” (Winston et al, 2005). It is important to control and monitor caffeine intake because too much can interfere with appetite, make people anxious or depressed, not to mention the fact that anything that interferes with sleep will have a deleterious effect on the brain. Everyone’s sensitivity to caffeine is slightly different, but if you have trouble sleeping then you’d be well advised to avoid caffeine at least 5-6 hours before bedtime – for your brain’s sake.

    3 cups of coffee per day is considered a “moderate dose” for most people. Get these in early enough to avoid any potential for them to interfere with sleep and you should get the apparent long-term brain benefits without the negative consequences associated with excessive consumption (DISCLAIMER: this should not be interpreted as medical advice – it is just the science-based opinion of the author who has a Ph.D. in neurobiology i.e. not a medical degree!).

     

    I don’t like tea or coffee, are there any other sources of caffeine?

    head in coffee beansCaffeine is also found in kola nut (one of the original ingredients of coca cola) and guarana – a wonder berry from the Brazilian rainforest; it’s also found in low quantities in chocolate. Caffeine is also included as a stimulant in many cold and flu remedies – so beware what you reach for when you wake up in the middle of the night with a bunged up nose!

    By the way: if you study the picture on the left very carefully you’ll find a face amongst the coffee beans – can you find it?

    Keep looking… he’s definitely there and you’ll kick yourself for doubting me when you find him!!

    If you liked this you’ll love my daily brain tweets so please follow me on Twitter by clicking here.

    Read more »