Prone To Heart Attacks? Be Careful How Many Daily Cups of Coffee You Drink

Proactive Health

By Pauline Jose, M.D. and the pH health care professionals

March is Caffeine Awareness Month! Since caffeine is probably one of the most frequently consumed drugs in the world, it is important we educate ourselves about it. Education allows us to make informed decisions about whether and how we consume caffeinated products.  

Sodas are probably the most common source of caffeine in younger people. But caffeine is also found in tea, chocolate, energy drinks and, of course, coffee. Coffee is the most commonly consumed drink today next to water. Americans consume the most coffee in the world.  

The amount of caffeine in coffee varies. A standard 8 oz cup has about 95-200 mg of coffee, and the large sizes have about 180-300 mg. Decaffeinated coffee has between 5-15 mg per 8 oz. Tea generally has less caffeine than coffee, and different teas have varying amounts of caffeine. Black tea has 14-70 mg in an 8 oz cup, green tea has 24-45 mg, decaffeinated black tea has 0-12 mg and bottled tea has 5-40 mg. For more information about caffeine content in various sodas, chocolates or energy drinks, read here

So how much caffeine can we safely have each day?

It depends. The answers you will get are as varied as the different sources of caffeine. Some studies show no harmful effects especially when consumed at moderate doses of about 300 mg a day. It has been suggested by some medical institutions that up to 400 mg of caffeine may be safe for most healthy adults. That is usually the amount of caffeine in four cups of coffee, 10 cans of cola or two “energy shot” drinks, according to The Mayo Clinic. And many people drink 2-5 cups of coffee or tea every day without consequence.

According to data from NHANES III (National Health and Nutrition Examination Survey), most coffee drinkers over 17 years old did not show an increased risk of stroke after drinking more than 3 cups a day even when a large percentage of them were also smokers. On the other hand, a study in Greece concluded drinking more than 2 cups a day was not safe for patients who already had a heart attack after a 10 year follow up after adjusting for confounders.   

Doses more than 750 mg a day may increase calcium and magnesium loss in the urine, which may affect bone health. It can also cause palpitations and tremulousness and even death when consumed in higher amounts as in energy drinks. For additional information on caffeine, there is a comprehensive summary here.

There are some people for whom the recommended daily allowance (RDA) described above are inapplicable because they are sensitive to caffeine even in small doses. There is an enzyme in the liver that metabolizes caffeine, p450 1A2 (CYP1A2). This enzyme does not function the same in everyone. Some individuals are called slow metabolizers while others are rapid metabolizers. Slow metabolizers keep caffeine longer in their system, and this may cause the untoward effects specifically in the heart, including myocardial infarction.   

The reason some people may be more sensitive to caffeine even in small doses is because of this genetic variant. Others can drink all the coffee and tea they want and not feel any adverse effects. We can now test for this gene, and though those who have the variant probably already know based on their response to caffeine all their lives it is best to check as this can affect their children and other family members too.

Proactive Health Labs offers Whole Genome Sequencingwhich will not only tell you if you have this gene variant but others as well.

Enjoy your healthy life!

The pH professional health care team includes recognized experts from a variety of health care and related disciplines, including physicians, health care attorneys, nutritionists, nurses and certified fitness instructors. To learn more about the pH Health Care Team, click here.


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