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How much coffe and tea should I drink to protect my brain? Science has the answers: Wisdom Wednesdays · Hardiness with Dr Paul Taylor

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  Speaker 1: Everyone, Welcome to another edition of Wisdom Wednesdays. Today, I
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  Speaker 1: want to talk about something that most of us consume
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  Speaker 1: every day, which is coffee and tea, and how they
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  Speaker 1: might influence our risk of neurodegenerative diseases, including Alzheimer's, Parkinson's,
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  Speaker 1: and vascular dementia. There's been a lot of research over
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  Speaker 1: the years looking at coffee or tea individually, but a
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  Speaker 1: new study using data from the UK Biobank, which I've
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  Speaker 1: talked about before. This is the gift that keeps on
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  Speaker 1: giving for research, but this study looked at something slightly different.
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  Speaker 1: Instead of looking at coffee and tea in isolation, the
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  Speaker 1: researchers asked what happens when we look at coffee and
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  Speaker 1: tea together, because if you think about it, a lot
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  Speaker 1: of people drink both. Now, this is a pretty big study.
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  Speaker 1: There's about one hundred and thirty four thousand participants aged
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  Speaker 1: over sixty and they were followed for a median of
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  Speaker 1: thirteen half years, and during that time, more than six
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  Speaker 1: four hundred of them developed neurodegenerative diseases, including Alzheimer's, Parkinson's,
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  Speaker 1: vascular dementia, and als. And the findings were pretty interesting.
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  Speaker 1: What they find with coffee. First of all, coffee on
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  Speaker 1: its own was a jay shaped relationship between coffee consumption
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  Speaker 1: and neurodegenerative disease risk. In simple terms, what that means
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  Speaker 1: is that moderate coffee intake seemed to be a little
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  Speaker 1: bit beneficial, but higher intake appeared to increase the risk
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  Speaker 1: of neurodegenerative diseases. And in this study the risk increased
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  Speaker 1: with anything from four to six cups, and specifically, more
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  Speaker 1: than five cups of coffee per day was associated with
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  Speaker 1: the higher risk of primary neurodegenerative diseases compared with people
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  Speaker 1: who didn't drink anything. Now, that is actually pretty consistent
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  Speaker 1: with previous research. In fact, earlier uko by bag studies
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  Speaker 1: have shown that very very high coffee consumption six or
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  Speaker 1: more per day is associated with increased dementia risks, So
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  Speaker 1: this really reinforces it. Now, let's talk about TA. That
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  Speaker 1: showed a completely different story. TA consumption showed protective associations
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  Speaker 1: across multiple neurodegenerative diseases. People who drank any T at
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  Speaker 1: all had lower risk of all cause neurodegenera of diseases,
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  Speaker 1: primary neurodegeneral diseases, vascular ones, Parkinson's disease and vascular dementia.
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  Speaker 1: And for example, people who drank more than three cups
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  Speaker 1: of tea per day, and there was no real upper
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  Speaker 1: limit here, but they had about on average about a
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  Speaker 1: seventeen percent lower risk of all of those neurodegenerative diseases
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  Speaker 1: compared to people who drunk nothing. Now that is a
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  Speaker 1: pretty significant effect, but it showed that it didn't keep
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  Speaker 1: on getting better. There kind of was a cap above
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  Speaker 1: sort of three to five cups of tea. But a
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  Speaker 1: really interesting finding in this was the combination of coffee
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  Speaker 1: and tea together, and the researchers looked at both of them.
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  Speaker 1: Certain combinations appeared to give you some protection. So people
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  Speaker 1: who drank no coffee but more than three cups of
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  Speaker 1: tea per day, that's me, it's my bracket. Slightly lower
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  Speaker 1: risk of neurodegenitive diseases, as we said earlier, on about
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  Speaker 1: seventeen percent. But people who drank moderate coffee plus moderate
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  Speaker 1: or high tea intake also had to reduce risk. And
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  Speaker 1: the researchers suggested that tea may partially offset some of
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  Speaker 1: the risks associated with coffee, and that the two drinks
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  Speaker 1: may interact with each other rather than acting independently. So
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  Speaker 1: what's going on. What's the plausible mechanisms for some of
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  Speaker 1: these benefits or risks. Well, the first one is about
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  Speaker 1: caffeine and brain plasticity. We know that other caffeine intake
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  Speaker 1: can enhance neuronal resilience in plasticity, which may help protect
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  Speaker 1: against these diseases. And caffeine also influencers neurotransmitters like dopamine
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  Speaker 1: and adenazine, and they're both implicated in neurodegenerative conditions. However,
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  Speaker 1: when caffeine intake gets very high, the effects might flip
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  Speaker 1: and it may cause increased cholesterol and triglycerides, which are
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  Speaker 1: both risk factors for vascular disease and dementia. So the
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  Speaker 1: second thing that's going on here is polyphenols and antioxidants.
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  Speaker 1: Both coffee and tea contain large amounts of polyphenols which
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  Speaker 1: have anti inflammatory and antioxidant effects and ourselves, but the
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  Speaker 1: types of polyphenols differ. Coffee is rich in something called
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  Speaker 1: hydrosnamic acids, and t contains catechins including EGCG. Now, these
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  Speaker 1: compounds can reduce o of stress, reduce inflammation, protect your neurons,
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  Speaker 1: and improve your mitrochondrial function, and importantly, they may work
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  Speaker 1: through different molecular pathways, and this might explain why moderate
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  Speaker 1: coffee with moderate to high TA might produce additive effects.
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  Speaker 1: And then the third plausible mechanism here is amyloid beta
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  Speaker 1: and Alzheimer's disease. You have heard that accumulation of amyloid
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  Speaker 1: beta is associated with Alzheimer's disease. We don't know if
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  Speaker 1: it's a cause yet, but we know that T polyphenols,
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  Speaker 1: particularly EGCG, they appear to inhibit amyloid beta aggregation, potentially
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  Speaker 1: slowing neurodegenerative processes. And animal studies also suggest that T
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  Speaker 1: polyphenols can protect dopamine neurons, which may explain this association
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  Speaker 1: with reduced Parkinson's risk. And then the last thing that
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  Speaker 1: could be at play here is brain structure changes. Some
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  Speaker 1: research suggests that high coffee consumption, very high coffee consumption
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  Speaker 1: may reduce gray matter volume in the brain. Our animized
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  Speaker 1: control trials showed a daily caffeine intake for one week
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  Speaker 1: significantly reduced gray matter volume and impowered working memory performance
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  Speaker 1: compared with placebo. Now, the effect may be temporary, but
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  Speaker 1: it does highlight that caffeine is a powerful neuroactive compound,
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  Speaker 1: and more isn't always better. Now, there's one other potential
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  Speaker 1: mechanism that comes from another research paper that showed the
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  Speaker 1: people who drank coffee primarily in the morning had a
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  Speaker 1: lower mortality risk. I actually talked about this quite recently,
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  Speaker 1: whereas people who drank coffee throughout the entire day did
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  Speaker 1: not see the same benefit. And it appears that caffeine
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  Speaker 1: later in the day and coffee tens have much more
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  Speaker 1: than tea. But that can disrupt your sleep, affect your
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  Speaker 1: circadian rhythms, increased night time cordisol, reduced slow way of
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  Speaker 1: sleep or deep sleep, and poor sleep is one of
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  Speaker 1: the strongest risk factors for generaldegenerate diseases, particularly Alzheimer's disease,
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  Speaker 1: and it's the deep sleep where the brain's glymphatic system,
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  Speaker 1: which clears the waste is activated and lay a day.
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  Speaker 1: Caffeine particularly disrupts deep sleep, So that may be what's
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  Speaker 1: going on here. So what's all the takeaways here? I
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  Speaker 1: think you can get a few reasonable conclusions here. Moderate
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  Speaker 1: coffee intake seems fine somewhere for around one to three
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  Speaker 1: cups a day. It seems to be the sweet spot,
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  Speaker 1: but when you get to five or more that's where
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  Speaker 1: you get into the risk range here. But T appears
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  Speaker 1: to be consistently protective across multiple neurodegenital diseases, and combining
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  Speaker 1: both of them may be beneficial as long as you
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  Speaker 1: keep your coffee moderate. But the key really is to
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  Speaker 1: do it earlier in the day, particularly the coffee UH
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  Speaker 1: and tee, particularly if it's low caffeine or if it's weak,
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  Speaker 1: and that's probably fine to have liater in the day,
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  Speaker 1: So hopefully that gives you a little bit of insight
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  Speaker 1: in a complex area. But that is it for this week, folks,
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  Speaker 1: catch you next time.