Alan Coss

MD FRCPI | Gastroenterology/Medicine | Music/Books/Art/Cultural Stuff | @dotMDconf | 🇵🇸

[TheLiverDoc™ @theliverdoc]

Coffee is one of the only drinks with strong evidence that benefits the liver. Here's what decades of research actually says about how to drink it right:

Coffee genuinely lowers liver disease risk.
Meta-analyses show regular drinkers have about 35% lower risk of significant liver fibrosis and nearly 50% lower risk of liver cancer compared with non-drinkers.

Aim for 2–3 cups a day, minimum.
The effect is dose-dependent. The Hepatology socities such as AASLD and EASL says 3 or more cups daily is reasonable for liver benefit, if you tolerate it.

Caffeinated works better than decaf.
But decaf still helps.
Caffeine blocks adenosine receptors that drive liver scarring. Decaf lowers chronic liver disease risk too, just by a smaller margin (UK Biobank, n=494,585).

The target dose: ~300 mg caffeine/day, or 3 cups.
Fibrosis protection kicks in around the 75th percentile of intake, roughly 308 mg caffeine, or 2.25 cup equivalents, per day - the AASLD 2023 advises 3+ cups for liver benefit.

What a "cup" actually means
One standard cup = 240 ml (8 oz), not a 60 ml tiny Indian "cup." A 240 ml filter coffee has ~95–165 mg caffeine. A single espresso shot (30 ml) has only ~60–75 mg.

Coffee-to-water ratio: 1:15 to 1:17.
For filter/drip/pour-over: 15 g of ground coffee to 250 ml water. This is the standard brewing ratio and gives clean extraction of chlorogenic acids and caffeine.

Choose medium roast, not dark.
Medium roast has significantly higher chlorogenic acid (CGAs) content than dark roast. Dark roasting thermally degrades CGAs, the main antioxidant doing liver work.

Arabica beats Robusta.
Arabica beans are richer in CGAs and polyphenols, the antioxidants doing most of the liver-protective work.

A note here:
Arabica for polyphenols, Robusta for caffeine.
Arabica (1.5% caffeine) has more CGAs and polyphenols. Robusta (2.7% caffeine) has more caffeine but a cruder phenolic profile. A 70:30 Arabica-Robusta blend is a reasonable compromise.

Water temperature: 92–96°C.
Just off a rolling boil. Too hot (>96°C) burns the grounds and extracts bitter compounds; too cool (<90°C) under-extracts CGAs and caffeine.

Grind size matters.
Medium grind (table-salt texture) for filter/drip. Coarse for French press. Fine for espresso. Brew time: 3–4 minutes for pour-over, 4 minutes for French press, 25–30 seconds for espresso.

Filtered coffee is the safest daily choice.
Paper filters trap cafestol and kahweol, naturally present plant diterpenes that raise LDL cholesterol if consumed daily in large amounts. Pour-over (V60, Kalita, Melitta) or drip machines with paper filters give you CGAs and caffeine without the cholesterol penalty.

Espresso and French press: fine, but not unlimited.
They retain more polyphenols but also more diterpenes (so more chances of increased lipids). Great occasionally; don't make them your 5-cups-a-day default if you have high cholesterol or heart disease.

South Indian filter coffee: acceptable, with caveats. The metal filter does not remove diterpenes as well as paper, so limit to 1–2 cups/day if you have dyslipidemia. The decoction itself is rich in CGAs. Use less sugar. Skip condensed milk.

BUT ULTIMATE: Drink it black. Or close to it.
Sugar, syrups, flavored creamers and whipped cream cancel the liver benefit, especially if you already have fatty liver, diabetes, or obesity. Skim milk or unsweetened plant milk is fine.

Instant coffee: still works.
UK Biobank (n=494,585) showed instant coffee drinkers had similar reductions in chronic liver disease as ground coffee drinkers. Not as potent, but far better than no coffee.

Cold brew: underrated for the liver.
Medium roast + coarse grind + 6–7 hours at room temperature extracts CGAs and caffeine efficiently with lower bitterness. pH and CGA content are comparable to hot brew.

Timing.
Spread across the day. one at breakfast, one mid-morning, one early afternoon. Stop by 2 pm if you have insomnia.

It helps across almost every major liver disease.
Evidence supports benefit in fatty liver (MASLD), alcohol-related liver disease, hepatitis B and C, cirrhosis, and liver cancer.

The mechanism isn't magic, it's chemistry.
Chlorogenic acid cuts oxidative stress and liver fat. Caffeine inhibits stellate cell activation (that promotes scarring or fibrosis). Melanoidins and polyphenols reduce inflammation.

Who should go easy.
Pregnancy, children, those with uncontrolled heart rate and rhythmn issues (arrhythmias), panic disorder, or insomnia.

And no, coffee does not undo a bad diet or bad choice - such as alcohol, herbal supplement or that Ayurvedic "liver tonic."

Sources: Modi et al., Hepatology 2010; Kennedy et al., BMC Public Health 2021 (UK Biobank); Fuller & Rao, Sci Rep 2017; AASLD MASLD Clinical Care Pathway 2023; EASL 2016 CPG, Frontiers in Nutrition 2026 (Italian coffee cohort).

[Galway International Arts Festival @GalwayIntArts]

We are very sorry to hear of John Byrnes death. John was a loyal and valued volunteer with Galway International Arts Festival for many years. Our sincere condolences to John’s family, friends and fellow volunteers. May his kind and gentle soul rest in peace. We will miss you John

[National Screening Service @NSShse]

Patient advocates Mary and Peter tell us about their experience taking part in #BowelScreen, encouraging others to #choosescreening.

BowelScreen is for everyone aged 57 to 71. It's a simple test you do at home, and it's free.
🔗https://t.co/Xb1bSdAx5w

#BowelCancerAwarenessMonth

[Alan Coss @AlanCoss]

@CovidHse Not true for most of us.

[WiMIN @WomenMedIreland]

So many fabulous women in healthcare who encourage and support each other, and will continue to inspire generations to come!
#SundayWiMIN

[Alan Coss @AlanCoss]

@MooseAllain So sorry to hear this, Moose. My thoughts are with you and your family.

[WiMIN @WomenMedIreland]

The Countdown is ON to Conference 2026 in @GalwayBayHotel 20-22 March. Registration is open! For programme highlights and to meet some of our speakers: https://t.co/2FiaWl3COF #womeninmedicine

[Sarah Fitzgibbon @SarahFitzWiMIN]

I wrote this at the start of the year when I was feeling more uncertain than usual about my future.
I am delighted that I will continue to be an irritating backseat passenger in @WomenMedIreland &amp; I look forward to seeing everyone in Galway on March 21st!
https://t.co/oLvBTPOuB0

[Keith Siau @drkeithsiau]

State of the art review in IBD (December 2025; BMJ) 🫡🔢

1️⃣ Pathophysiology (+ therapeutic targets)
2️⃣ Extraintestinal manifestations
3️⃣ Mx of acute severe UC
4️⃣ Postoperative Crohn’s disease

📸: https://t.co/MNoKwDgnEd

[Alan Coss @AlanCoss]

“Looking back, haemochromatosis was the hidden thread connecting every one of my random symptoms... But I had never even heard of the condition until I was diagnosed.” @ArleneHarris11 @IrishTimes
https://t.co/h7OKlhsk7E

[Ebony Jade Hilton, MD @EbonyJHilton_MD]

Tell me you don’t practice medicine without telling me you don’t practice medicine.

Hepatitis B/C wasn’t a problem for some, until it caused liver cancer later.

HPV was “handled well by the young” until it’s linked to cervical/esophageal cancer.

EBV was no big deal until MS.

[Prof Peter Hotez MD PhD DSc(hon) @PeterHotez]

In the 1970s-80s measles was the single leading killer of children, 2-3 million died annually. Through EPI @WHO we brought it down to 450,000 kids who died annually by 2000. Through @gavi it came down to &lt;100,000. Now the ignorant careless chuckleheads want to erase all our gains

[HSEWestNorthWest @HSE_West_NWest]

HSE West &amp; North West is hosting a free walk-in children’s nasal flu vaccine clinic in Galway this Christmas 🎄
📍 Galway East Primary Care Centre
🗓 Mon 29 Dec | ⏰ 10am–1pm
For children aged 2–17. Quick, painless &amp; free.
Check https://t.co/NogjhiAecJ for updates.

[HSEWestNorthWest @HSE_West_NWest]

Winter brings unique challenges to our health.
As we reach our busiest time of the year, Dr Áine McNamara, Regional Director, of Public Health shares advice on what to do if you or your family feel unwell.
Info on how to manage common illnesses click: https://t.co/319aARJbcO

[Niall Conroy @NICU_doc_salone]

Jaysis, Anthony Fauci is 85 today! I’d be delighted if I looked like that when I’m 55 😁

[Samuel Hume @DrSamuelBHume]

10 breakthroughs in medicine in 2025

Read it here: https://t.co/YyaYTKd3Cs

[Daniel Park @Daniel_E_Park]

Quick personal note. A close friend recently died from a heart attack a week after COVID.
COVID increases risk of cardiac events.
It may have faded from the news cycle, but COVID continues to take people from their families. Please take it seriously.

[Alan Coss @AlanCoss]

In with the new: an Irish citizenship ceremony in pictures

https://t.co/M5fdYNkpKc

[Francesca Albanese, UN Special Rapporteur oPt @FranceskAlbs]

Two remarkable women.
Real power is made of empathy and generosity, not Alpha culture.