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Consumption of a dark roast coffee blend reduces DNA damage in humans

ncbi.nlm.nih.gov

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Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#101

Post by nkozyra »

sp332 wrote: post #25
jimmy1 wrote: post #14

Earlier quoted context omitted.

To your parenthetical comment: May be unrelated, but totally anecdotal, smokers tend to drink a very light roast that is easily drinkable like a folgers or maxwell house, maybe a coffee shop light roast, like a Dunkin. I don't think smokers are downing cups of Starbucks dark blend and if they are god help their stomachs.

Lighter roasts have more caffeine, because the roasting process damages the caffeine molecule.

This tends to be offset due to the density changes in the bean during roasting.

In short, a cup of light roast and a cup of dark roast have negligible differences in caffeine content.

Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#103

Post by bduerst »

Florin_Andrei wrote: post #83
noobly wrote: post #7

Earlier quoted context omitted.

Beer contains tannins also. Not that I need any extra excuse..

Old school leather may be infused with tannins. Should I start licking those boots now?

Steep them in some hot water and serve with cream.

Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#104

Post by samatman »

longerthoughts wrote: post #77
rossdavidh wrote: post #47

I drink coffee nearly every day; I am reading this in a coffeeshop. But, p = 0.028? Come on. If you tested for a few dozen things, you would expect to find at least one that had a p-value like that. Was this pre-registered to look at only DNA damage, via this metric? Or did they look at 100 different things to find one with p=0.028? Of course, if they pre-registered and their theory was that it would reduce DNA damag…

It's a little annoying if they're cherry-picking but does it really impact the validity of the results? If anything, I'd think they'd have a greater incentive to skew results if they were specifically testing a theory about DNA damage.

The Relevant Xkcd is actually an excellent guide to why this is a problem: https://xkcd.com/882/

Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#105

Post by gojomo »

Florin_Andrei wrote: post #85
gojomo wrote: post #43

Earlier quoted context omitted.

Why couldn't caffeine be the main mechanism-of-action? It's a diuretic, so those treated with coffee likely drank more total liquids during the study, and perhaps flushed more older/damaged cell material.

Not a biologist or a doctor, but I'm pretty sure you don't pee out damaged cells.

I was referring to the products of cell degradation. Autophagy – destruction of cell components or full cells – is a constant, natural, necessary process. Its waste products have to go somewhere, and biomarkers related to autophagy, and all the other waste-eliminating functions of the kidneys and liver, can be detected by byproducts in urine.

It's also the case that full red and white blood cells, and epithelial cells, are found in urine, and at higher-than-trace levels in various disease states... but that may just be incidental to kidney/urinary tract functioning.

Still, more peeing from regular use of a diuretic like caffeine, and commensurate higher water intake, is going to mean more flushing of anything unwanted in your blood, like the broken DNA strands detected by this study.

Which raises my question: is there really less DNA damage, or has the detectable evidence of the damage just been swept out more rapidly?

Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#106

Post by mensetmanusman »

flyGuyOnTheSly wrote: post #42

Stopped drinking coffee months ago and I have never felt better. Anxiety is down. Sleeplessness is down. General mood is up. Best of all, I no longer get headaches due to Caffeine withdrawal.

But was it worth all the broken DNA!!

Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#107

Post by airstrike »

akinhwan wrote: post #89

Hey guys Pub Med Labs developer here. Check out this very same fascinating article in the new Labs site and please give us your feedback! Much appreciated. https://www.ncbi.nlm.nih.gov/labs/pubmed/30448878-consumptio...

It looks like the future. Thanks for the hard work on this. Great job!

Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#108

Post by stevenhuang »

tachyonbeam wrote: post #19
1_over_n wrote: post #15

"Funding This study has been supported by Tchibo GmbH, Hamburg, Germany." Tchibo is a German chain of coffee retailers and cafés known for its range of non-coffee products that change weekly. https://en.wikipedia.org/wiki/Tchibo Number of locations 700 shops (Germany) 300 (rest of world) They might want to make some in-store claims about Dark Roast...

I'm generally sceptical of all studies about coffee for this very reason. There's a lot of bullshit studies around food and supplements funded with people with strongly vested interests in selling more product. It's a real problem. For any given supplement, you can often find multiple studies supporting its use and multiple studies saying it's harmful. When it comes to coffee specifically, if you listen to the studie…

> you can often find multiple studies supporting its use and multiple studies saying it's harmful.

While true and I get your point, there isn't anything inherently wrong with that. We should expect and welcome research with the awareness of vested interests.

Afterall it's not surprising for a substance to be beneficial in certain ways yet harmful in other ways. Research from opposing groups will help identify all interesting attributes of a substance. Until we learn all there is to learn, you should approach these papers more as additional clues pointing to a certain direction and not anything conclusive about the substance in question.

Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#109

Post by angel_j »

rossdavidh wrote: post #47

I drink coffee nearly every day; I am reading this in a coffeeshop. But, p = 0.028? Come on. If you tested for a few dozen things, you would expect to find at least one that had a p-value like that. Was this pre-registered to look at only DNA damage, via this metric? Or did they look at 100 different things to find one with p=0.028? Of course, if they pre-registered and their theory was that it would reduce DNA damag…

The first author has done similar studies with lower p values: https://www.ncbi.nlm.nih.gov/pubmed/24740588 https://www.ncbi.nlm.nih.gov/pubmed/26632023

Re: Consumption of a dark roast coffee blend reduces DNA damage in humans

#110

Post by max76 »

I really hate bad science, and this is an example.

Springer Science+Business Media (the publisher) does not transfer copyright of the paper from the author to the publisher like many other journals. This begs the question, why isn't this article open access? The primary author, Dorothea Schipp, is a statistics consultant in small town Germany [0] not associated with a University and the blood work was done in Slovakia. No PHDs or MDs among them. [1].

Digging deeper into their research method [2] the study looked at DNA breakage over a four month period in blood sampling for a coffee and non-coffee/caffeine group. I have a few questions about this, mainly around how effective the time period and method for determining total DNA stability. How many individual cell gnomes were measured in the before/after? What's the random variance for genome variability among cells in the same body? I suspect the variance is high enough to explain their unbelievably low p.

My guess is that the statistician is having fun with p-hacking [3] while collecting some funding from industry.

[0] https://en.wikipedia.org/wiki/Rosenthal-Bielatal

[1]https://link.springer.com/article/10.1007/s00394-018-1863-2

[2] https://www.mdlinx.com/journal-summaries/coffee-comet-assay-...

[3] http://psychology.wikia.com/wiki/P-hacking

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