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Coffee: Good or Bad?

By: Dr Allie Butler, PharmD

Is coffee good or bad? We get this question a lot during consultations. Like most things, it depends. There have been a number of studies that have shown the beneficial effects of coffee. But there are also studies indicating potential harm. The truth is, coffee is perfectly fine for some and not recommended for others. 

Learning how to interpret evidence based medicine takes a lot of training and education. In medicine, when we evaluate data in order to make recommendations, there are certain types of phrases that are used. Correlation, association and causation. Causation means the observed data shows that a direct relationship exists between the variables. Association means it is thought to show a relationship, but not proven. 

In this situation, coffee consumption would cause something good or bad to happen as proven in a study designed in alignment with proper evidence based medicine. An association means there is evidence that coffee may or may not cause something, but no actual proof. Some studies are designed while other studies simply review components of other studies or get data through surveys. Often, the study wasn’t designed ahead of time and is simply a survey or observation of a specific population. Causation is not determined in these types of reviews. Associations are made in these scenarios. 

If you are into evidence based medicine, check out this large review of multiple studies of coffee exposure. It’s an interesting read if you are a geek like we are! If you aren’t, we will summarize. 

Overall, caffeine is thought to have more positive effects than negative effects. A positive association of coffee consumption was made for lowering risk of all-cause mortality, cardiovascular mortality and total cancer. In more simplistic terms, coffee is thought to help with heart health, cancer prevention and overall death-rates, but there is no actual proof. The specific types of cancer mentioned in this review are prostate, endometrial, melanoma, non-melanoma skin cancer and liver cancer. For example, some of the liver cancer studies revealed a 43% decrease in liver cancer for those who had 2 cups of coffee per day, as reported by people included in the study. The study did not specifically test the theory and therefore, only an association can be made. Positive associations were also made in relation to Parkinson’s disease, depression and Alzheimers. 

But what YOU want to know, is what about coffee and diabetes? Beneficial associations were seen with metabolic conditions, including type 2 diabetes. High consumption (between 1 to 6 cups) was associated with a 9% lower risk for developing the disease. 

So, does coffee CAUSE a decrease in these issues? No, but there is still an association. A properly designed study would need to be executed in order to determine if causation is present. 

So who should avoid caffeine? 

It is generally accepted that coffee consumption during pregnancy should be limited. Caffeine lasts longer in the body of a pregnant women and also crosses the placenta. Have you ever seen a child have a dose of caffeine for the first time? It looks like something out of the Exorcist. This might help you understand why caffeine exposure to a developing baby in utero is not the best. Their growing bodies are sensitive. Complications occur more frequently in high consumption coffee drinkers than low consumption. The type of study that would need to be done in order to determine if coffee CAUSES these issues will never be done. The association alone would make this a highly unethical practice.

Another condition where coffee might be avoided is with acid reflux. Caffeine and acid are generally detrimental to a person’s diet when they manage this particular condition. Coffee contains both. 

So how much coffee are we talking about? Most evidence points towards an average of 2 cups (probably 1 coffee for most of you big mug drinkers). Similar benefits were seen in decaffeinated coffee as well. But remember the theme we often discuss, “everything in moderation”. Too much of a good thing can be bad. Have you ever had so much caffeine that your heart fluttered or your hands started shaking? This is your body’s way of saying ENOUGH. As someone with a chronic disease, you need to listen to your body and know when to cut yourself off. Coffee is no exception. If you can’t fall asleep at night, you are probably drinking too much or drinking it too late in the day. 

If you have diabetes, you can probably still enjoy your coffee. Just don’t load it up with the carbs. If you are adding cream and sugar, the health benefits are likely canceled out. Remember, cow’s milk has sugar in it. Most flavoring syrups have sugar. Whipped cream has sugar. The associated benefits of coffee are seen with black coffee. So keep that in mind as you pour your java and get ready for the day. And remember, if you are here, you have already started your journey to a healthier you. You can win the battle within!

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This page is for informational and educational purposes only and may not be construed as medical advice. While this information is retrieved from reputable sources, it is not intended to replace physician offered medical diagnosis, treatment or advice. Never ignore professional medical advice in seeking treatment. For all medical emergencies, please contact your doctor immediately or call 911. Please refer to full medical disclaimer here