Liver expert on the benefits of drinking coffee regularly
Published on: Sunday, February 28, 2021
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Chopra: Coffee drinkers have longer telomeres.
Prof Dr Chopra Sanjiv (Liver Disease Expert, Professor of Medicine, Harvard Medical School, Boston): That’s a great question. So as you mentioned, I am a liver expert and I got very intrigued about 25 years ago when I read that coffee drinkers have low level of liver enzymes in the blood.
So when we go see our primary care physicians once a year, they do a battery of blood tests and amongst them, they test two liver enzymes – ALT and AST, and this was an observation that people who drank coffee had lower levels of ALT and AST.
When somebody has elevated levels of AST and AST, it’s almost always indicative of liver disease. So this is intriguing. But what does it mean? Maybe there is something in coffee that interferes with AST/ALT and so you get lower levels. But then studies came out that coffee drinkers have less hepatic fibrosis (scar tissues), they have less scar tissues in the liver.
If there’s lots of scar tissues in the liver, they totally distort the liver architecture, with islands of liver cells totally surrounded by scar tissues, fibrosis we call cirrhosis. So coffee drinkers had low levels of liver enzymes, they had less fibrosis.
What two cups of coffee a day means
Then a study in (journal) Gastroenterology that people who drank two cups of regular coffee a day had a 50pc reduction in hospitalisation and mortality from chronic liver disease. It turns out that primary liver cancer – cancer rising from in the liver, is now the third leading cause of cancer mortality in the world. And multiple studies and a meta analysis have shown that people who drink two cups of regular coffee have 40pc reduction in primary liver cancer mortality.
So, low liver enzymes, less scarring, less fibrosis, less hospitalisation, less mortality, less liver cancer. It turns out that coffee drinkers also have a lower risk of four other common cancers – metastatic prostrate cancer, colon cancer, skin cancer, including malignant melanoma – a very deadly skin cancer and endometrial cancer. So five cancers – people who drink coffee have a lower incidence. Low risk of Parkinson disease, low risk of cognitive decline and early dementia, lower risk of Type 2 diabetes.
And for Type 2 diabetes, one has to drink six cups of coffee regular or decaf and then there is a 40pc to 54pc reduction in risk of developing Type 2 diabetes. If someone already has Type 2 diabetes, and they drink two cup of coffee a day, regular and decaf, there is a 30pc reduction in cardiovascular mortality. So pretty impressive. These are mechanistic explanations: Coffee drinkers have low levels of CRP (C- reactive protein), low levels of TNF (Tumour necrosis factor) alpha.
Coffee drinkers have longer telomeres
Dr. Titov: ...which improves and reduces the inflammation.
Prof Chopra: Yes, that maybe the mechanism how coffee decreases many conditions, the risk of developing them or even cancer, which we now know is linked to inflammation.
Dr Titov: C-reactive protein is…
Prof Chopra: C-reactive protein is a marker for inflammation. So a study in the New England Journal of Medicine about four years ago and that day I got about a hundred emails from colleagues around the country: “Sanjiv, you have been talking about coffee all these years and its potential health benefits – you are vindicated!”
And the study in the New England Journal of Medicine said: “Men and women who drink coffee have lower total and cause-specific mortality.” And then about six to eight months ago (before interview with Dr. Titov in April 2020), an article in the nutrition journal showed that people who drink coffee have longer telomeres (essential part of human cells that affect ageing).
So telomeres were described by Elizabeth Blackburn, an Australia scientist who got the Nobel Prize in medicine of physiology in 2009 with two other colleagues. And shortened telomeres are linked with accelerated cellular ageing. So who has shortened telomeres? Mothers of chronically disabled children; Caregivers of people who have Alzheimer.
Who has longer telomeres and by inference they live longer, we think they live longer? People on the Mediterranean diet, people who meditate, and then the recent study showed that people who drink coffee have longer telomeres.
Which coffee?
Dr Titov: Does it matter which coffee to drink? How much coffee one should drinks and what’s the frequency of coffee consumption for health benefits?
Prof Chopra: It’s a great question. The studies have simply asked: Do you drink coffee, yea or no? If you drink coffee how many cups? And do you drink regular or decaf? And what is the size of the cup? My take on it is, drink regular coffee if you can. It has more benefits than decaf. And don’t add cream or sugar substitutes. So I like to drink it black, make it simple. And I don’t have to worry about sugar and Splenda, and do I put milk?
And is milk cold and it’s going to make my coffee cold? So I drink black coffee. If somebody wants to sweeten it, add sugar, don’t use artificial substitutes.
Artificial sugars are turning out to produce worse glucose intolerance because it actually changes the microbiome in the GI tract. This is one of the hottest topics in medicine. Microbiome has been called the second human genome, the inner bacterial rainforest.
There are trillions of bacteria in our GI tract. In aggregate they weigh three pounds. It’s a newly discovered organ. So if you want to have a Coca Cola, have a Coca Cola maybe one third, savour it, rather than have a Diet Coke which has only one calorie actually have many injurious health effects.
Dr Titov: Interviewer
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