Good news for coffee drinkers

Lately, it seems like any jitters from coffee beans have been coming from its rising prices, not from the caffeine in it!

Yet, there is more good news for coffee drinkers amid some long-abiding concerns about coffee, especially irregular heartbeats, also known as arrhythmias.?Some recent studies are indicating that coffee drinking doesn’t lead to arrhythmias.?Actually, there might be an association between higher coffee intake and lower risk of arrhythmias).?

Researchers looked at about 400,000 people, mostly white subjects, derived from UK Biobank from 2006 to 2018.?Daily coffee intake and genetic predisposition to breaking down caffeine-slow or fast metabolizers-were accounted for.?This study confirmed that higher intake of coffee was associated with lower risks of arrhythmias.?Even those with a propensity to slower caffeine metabolism were not seen to be predisposed to arrhythmias.?However, this association doesn’t mean that coffee prevents arrhythmias ((https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2782015).

The weakness of this latest study lies in the fact that it examined self-reported intake at one point in time-what if some of these people had a change in the number of coffee drinks later??

This study must be reassuring to people that get benign palpitations-the feel that your heart is racing or skipping beat- after consuming caffeine-containing drinks.

On the other hand, there have been some reports that coffee consumption can cause abnormal heartbeats or arrhythmias in the atria (atria are two of the upper chambers in the heart). ?Coffee, the caffeine in it, does stimulate the releases of the hormones epinephrine and its cousin norepinephrine that can raise the heart rate (https://www.webmd.com/heart-disease/atrial-fibrillation/coffee-atrial-fibrillation-link).?Consuming caffeine and alcohol can sometimes cause an extra heartbeat or a skipped heartbeat ?

So far, the preponderance of studies suggests that except in documented cases in which there was a time-dependent effect of coffee on arrhythmias, 3-4 cups of coffee per day would be safe. ??A comprehensive search of multiple studies published in the Journal of Ammerican Cardiac Council found that coffee intake doesn’t increase the risks of arrhythmias (https://www.jacc.org/doi/10.1016/S0735-1097%2822%2902446-9). A meta-analysis- a study that analyzes the findings of multiple single studies-of 10 single studies involving more than 700000 individuals and 30.000 atrial fibrillation events found that coffee consumption could lower the risks of atrial fibrillation (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9299433/).?Atrial fibrillation is a type of arrhythmia when the upper chambers of the heart or the atria beat abnormally and blood flow to the venricles is impacted(https://www.cdc.gov/heartdisease/atrial_fibrillation.htm#:~:text=An%20arrhythmia%20is%20when%20the,heart%20(the%20two%20ventricles). ?Should people with documented atrial arrhythmias drink coffee or caffeinated beverages??No, the recommendation is to avoid caffeine products. More studies are needed to ascertain if any of the ingredients in coffee plays a role in causing atrial fibrillation.

The thought of drinking coffee can sometimes scare us if we think of reports about the effects of pure caffeine on the heart, especially heart rate, but coffee is loaded with many beneficial chemicals besides caffeine. As you might know, coffee and caffeine are two different things: coffee has a bunch of ingredients such as caffestol, chlorogenic acid, and theobromine……… that have anti-oxidant and anti-inflammatory properties.

Having known about many beneficial effects of coffee- such as an association between coffee consumption and lower rates of liver cancer in Latin America, I researched more.?A long-term study in the United Kingdom involved half a million people and followed them for about 11 years, the endpoint being liver disease/cancer. 78 % of the participants drank either caffeinated or decaffeinated coffee (https://bmcpublichealth.biomedcentral.com/articles/10.1186/s12889-021-10991-7).?Only 3600 of the enrollees developed chronic liver disease (CLD), 5439 had chronic liver disease or steatosis (fatty liver disease) and there were less than 200 cases of hepatocellular carcinoma. ?There were about 300 deaths from CLD at follow-up. The risks of incident CLD, incident CLD or steatosis, and death from chronic liver disease were 21 %, 20%, and 49% lower, respectively, among consumers of both caffeinated and non-caffeinated coffee, after adjustments were made for alcohol consumption, obesity, age, diabetes, and other risk factors. The study didn’t adjust for chronic infection with hepatitis B or C> ?Moreover, when it comes to very high levels of coffee consumption, the law of diminishing returns did apply-drinking more than 5 cups of coffee wasn’t much than 3-4 cups.??

Weaknesses of this cohort study include a demographic bias toward mostly white, affluent subjects that may not represent different ethnic and socioeconomic groups inhabiting Britain. This is a selection bias and may not have been intentional. ?Cohort studies in general have another disadvantage in that they can’t be used if the end-point is a disease that has a latency period. Suppose, some participants went on to develop liver disease or die shortly after the study ended, the data will become skewed.?There is also a loos to follow-up rate issue-

How about the mechanisms of coffee’s protective effects on liver disease? Both caffeinated and decaffeinated coffee had the same effects, so caffeine is ruled out. Other ingredients such as kahweol and caffestol-present in ground, unfiltered coffee, which was the most protective against liver disease- might be playing a role since very little of the ingested kahweol/caffestol is excreted in urine with most??of it recirculating in the liver. Another ingredient is chlorgenic acid-a phenolic compound- and its benefits are still being evaluated.

Yet another useful property of coffee is that it can help with constipation.?It has been found that in about 29 % of healthy young population, coffee induces bowel movements. This is akin to what happens in Irritable Bowel Syndrome patients in whom coffee aggravates symptoms.?A significantly higher proportion of women was affected in both the general population and in IBS population.

So how does this bowel response occur??This response takes place after about 4 minutes of drinking coffee whereas it would take longer than that for coffee to reach the colon. It is likely that this response is mediated via receptors on epithelial cells in the stomach or small intestine.?It could also be due to the release of gut hormones or neural effects.?One hormone that is likely to be involved is cholecystokinin. Gastrin is another hormone that increases motor activity in the colon.

Which constituents in coffee might be responsible for coffee’s effects on the colon??Endorphins in coffee can bind opioid receptors. Theobromine is another ingredient in coffee and cell culture studies have shown that it can protect against inflammatory damage to the gut from animal-based cholesterol and its oxidized product called oxysterol (https://www.sciencedirect.com/science/article/abs/pii/S0003986120306007)?It is definitely not caffeine since decaffeinated coffee produces the same effects. ?

Some studies have also examined the drawbacks of coffee drinking.

A small short-term study looked at?100 healthy adults in San Francisco-participants were asked to drink coffee ad libitum on 2 days and abstain form coffee for two days over a 15-day period. It was found that on days when they drank coffee, activity went up in participants, but sleep went down.

How about coffee and the heart? While coffee drinking does not cause any premature atrial contractions, drinking more than one cup of coffee predisposed to a 50% greater likelihood of premature ventricular contractions in …………..(https://pace-cme.org/2021/11/14/coffee-consumption-linked-to-more-pvcs-more-physical-activity-and-less-sleep/). So if people get jittery or anxious after a cup of coffee, or if they are genetically slow metabolizers, it would be advisable for those to avoid coffee.

This was a short-term study and did not look at the long-term benefits or harms of coffee. Neither did this study observe the effects of coffee on people with health problems.

Okay. Is the jury out on coffee yet? Well, studies are still ongoing to make sure it is safe for the heart. We think it sharpens the mind and lifts our moods. On the downside, it can keep you awake longer than you might like. So far, the best advice is to talk to your licensed healthcare provider if you have any concerns about your coffee drinking. I, in the meantime, will continue to drink as much coffee as I do, even stealing some from my wife’s cup!

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