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Is Coffee Good For You?

2020-03-19 · Long video (solo, talking head or whiteboard) · Ali · recording, 18:17 · watch on YouTube

Topic: Health, sleep and habits · mode: Explanation and tutorial · tags: Evidence-based framing, Sponsor segment present

In the first Journal Club episode Ali, who drinks about four cups of coffee a day, reviews studies on caffeine's effects on alertness, memory, mood, exercise and long-term disease risk, and concludes that coffee helps provided you do not drink too much, with no coffee after 2 p.m. for the sake of sleep.

What is said

The parts of the video and what is said in each (★ — how much it matters to the video).

00:00:00 — Four cups of coffee a day and the first episode of Journal Club

  • ★★ Ali says he drinks around four cups of coffee every day and has often wondered whether that is good or bad for him. — 00:00:00
  • ★★ Ali explains that caffeine blocks adenosine, an inhibitory neurotransmitter in the brain, which raises overall neuronal firing and the activity of dopamine, changing energy, mood and attention. — 00:00:00

00:00:21 — What caffeine does in the brain; alertness, vigilance and attention

  • ★★ Ali cites a 1987 study of 20 healthy male volunteers in which just 32 mg of caffeine, less than half a cup of coffee, increased auditory vigilance and sped up visual reaction times. — 00:00:58
  • ★★ The European Food Safety Authority reviewed 22 randomised, double-blind, placebo-controlled trials and found a cause-and-effect link between 75 mg of caffeine, about one cup of coffee, and increased attention and alertness. — 00:00:58
  • ★★ According to the European Food Safety Authority review, caffeine increases both selective attention, focusing on one thing, and sustained attention, focusing for long periods, which Ali says helps when studying. — 00:01:27
  • ★★ Ali cites a 2013 review of 66 double-blind placebo-controlled trials that found simple and complex attention tasks consistently affected by caffeine and concluded that caffeine clearly benefits attention. — 00:01:57
  • ★ Ali says that whenever he has his cup of coffee he feels more alert and can focus more on what he is doing. — 00:02:26
  • ★★ Ali cites a 2009 study in which college students given caffeine recalled more words from six 15-word lists than those on placebo but also recalled more related wrong words; he calls it not fully conclusive. — 00:02:26

00:02:39 — Coffee, memory, recall and mood

  • ★★★ A 2014 Johns Hopkins University study Ali cites concluded that caffeine enhanced the consolidation of long-term memories 24 hours later, and that at least 200 mg, about two regular cups of coffee, is needed for the effect. — 00:03:24
  • ★★ A 2011 Harvard study of 50,000 women followed over 10 years found that the risk of depression fell as caffeinated coffee consumption rose; Ali calls the causal link probably a little dubious. — 00:04:23
  • ★★ A 2016 meta-analysis of 12 studies covering 346,913 people found that 300 mg of caffeine, about three or four cups of coffee, could help protect against depression. — 00:04:52
  • ★★ Ali says caffeine gives him a mental boost and helps him get out of a slump. — 00:05:21

00:05:31 — Coffee to get out of a slump and the Brilliant sponsor read

00:07:11 — Physical performance, perceived fatigue and recovery from exercise

  • ★★ Ali explains that caffeine's extra neuronal firing makes the body produce more adrenaline, which increases blood flow to the muscles and the heart rate. — 00:07:18
  • ★★ Ali cites a 1978 study of nine competitive cyclists who rode for 90.2 minutes to exhaustion after caffeinated coffee and 75.5 minutes after decaffeinated coffee, about 20% longer. — 00:07:47
  • ★★ Ali says coffee can reduce the perception of tiredness during exercise: the European Food Safety Authority's 2015 meta-analysis of 23 randomised controlled trials established a cause-and-effect link between caffeine and endurance capacity. — 00:08:16
  • ★★ A University of Illinois study Ali cites found that men who took caffeine before bicep curls had significantly less delayed onset muscle soreness on days two and three than a placebo group. — 00:08:46
  • ★★ Ali says the University of Illinois study, backed by many other studies, suggests that caffeine might help recovery from physical exercise. (hedged) — 00:09:44
  • ★ Ali says the World Anti-Doping Authority banned high quantities of caffeine from Olympic events between 1984 and 2004, then in 2004 said caffeine did not meet its criteria for an unfair performance enhancer. — 00:09:44

00:10:26 — Long-term effects: micronutrients, antioxidants and lower risk of disease

  • ★★ Ali says coffee contains the micronutrients vitamins B2, B3 and B5, found naturally in coffee beans, as well as natural antioxidants. — 00:10:42
  • ★★ Ali cites a study in the Journal of Nutrition showing coffee was the single biggest source of antioxidant intake, ahead of fruits, vegetables and cereal. — 00:10:42
  • ★★ A 2010 systematic review and meta-analysis of 26 studies linked 300 mg a day, three or four cups of coffee, with a 32% lower risk of developing Parkinson's disease. — 00:11:12
  • ★★ A 2010 study of 1,409 people aged 65 to 79, followed over 21 years, found midlife coffee drinking linked to a lower risk of Alzheimer's disease and dementia, lowest (65% lower) at three to five cups a day. — 00:11:41
  • ★★ A 2018 meta-analysis of over a million people found type 2 diabetes risk fell 6% for each daily cup of coffee, with five cups a day linked to a 29% lower risk. — 00:12:10
  • ★★ A 2017 review found that in healthy people three to five cups of coffee a day were linked to a 15% lower risk of cardiovascular disease, and higher intake was not linked to higher risk. — 00:12:39
  • ★★ A 2011 meta-analysis of 11 prospective studies linked two cups of coffee a day with a 14% lower risk of stroke and three cups with a 17% lower risk. — 00:13:09
  • ★★ Ali says a 2016 review by the International Agency for Research on Cancer of over a thousand studies found no link between coffee and causing cancer, and an inverse link with liver cancer. — 00:13:38
  • ★★★ Ali stresses that the links between coffee and lower risks of long-term disease are all correlational, and that causation is really quite hard to test. — 00:14:44
  • ★★★ Ali says a lot of data suggests coffee seems on the surface to be good for you, but warns against drinking gallons of it because of a few caveats. — 00:14:44

00:15:08 — Negative effects: anxiety and jitteriness, sleep and the 2 p.m. cut-off

  • ★★ Ali cites a 2010 review concluding that low doses of caffeine improve hedonic tone and reduce anxiety, while high doses raise anxiety, nervousness and jitteriness. — 00:15:13
  • ★★ The author of the 2010 review found the studies on caffeine preventing cognitive decline heterogeneous, so Ali says the claim that caffeine reduces dementia risk should not be taken at face value. — 00:15:42
  • ★★ Ali cites a 2013 study in which 400 mg of caffeine taken at bedtime, or three or six hours before it, significantly harmed sleep quality; he adds that caffeine can stay in the body for up to nine hours. — 00:16:11
  • ★★★ Ali has started following the common advice to drink no coffee after 2 p.m., because for someone who sleeps at 9, 10 or 11 p.m. it could still harm sleep quality. — 00:16:11

00:16:55 — Is coffee good for you: the conclusion and the Journal Club series

  • ★★★ Ali concludes that coffee reliably improves alertness, vigilance, memory, recall and even mood, provided you do not drink too much, since too much causes anxiety, jitteriness and restlessness. — 00:17:01

    “coffee does reliably improve alertness, vigilance, memory, recall, and even mood, provided you don't have too much of it”

  • ★★ Ali calls this the first episode of Journal Club, a new series in which he looks at the scientific evidence behind interesting questions, and asks viewers to suggest questions in the comments. — 00:17:26

  • ★★★ Ali points to three to five cups of coffee a day as a way to increase alertness and vigilance. — 00:17:26

In the description and comments

  • ★★ Ali says he goes through Brilliant's online courses mostly for general interest and takes notes only when something particularly resonates and could be useful for future projects. — creator comment · Brilliant

Threads in this video

  • first on record · Is coffee good for you, and how much should you drink? — Ali points to three to five cups of coffee a day as a way to increase alertness and vigilance. (00:17:26)
  • refine · How do you sleep better? — Ali has started following the common advice to drink no coffee after 2 p.m., because for someone who sleeps at 9, 10 or 11 p.m. it could still harm sleep quality. (00:16:11)
  • launched · Journal Club — Ali calls this the first episode of Journal Club, a new series in which he looks at the scientific evidence behind interesting questions, and asks viewers to suggest questions in the comments. (00:17:26)

Where the stories that moved here went next

  • Journal Club — last documented in 2020; last: milestone, 2020-07-26

Mentioned

Central: caffeine · Journal Club

Also: Organizations: Brilliant · European Food Safety Authority · Harvard University · International Agency for Research on Cancer · Johns Hopkins University · University of Illinois · World Anti-Doping Agency

Concepts: adenosine · Alzheimer's disease · antioxidants · cancer · cardiovascular disease · delayed onset muscle soreness · Dementia · depression · Diabetes · dopamine · Parkinson's disease · randomised controlled trial · stroke · systematic review

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