How Many Cups Of Coffee Are Safe To Drink In A Day?

Studies have found that caffeine is the world’s most popular stimulant and psychoactive substance, and coffee is the most common way people consume caffeine. The latest research supports the conclusion that for most adults, consuming up to 400 mg of caffeine per day (or up to 5 cups measuring approx. 235 ml each of caffeinated coffee per day) is safe and appears to be linked to a lower risk of cardiovascular disease for some individuals.

However, higher doses of caffeine, such as levels found in energy drinks including energy shots, may cause cardiovascular harm, according to a new American Heart Association scientific statement, “Caffeine and Cardiovascular Disease,” published recently in the American Heart Association’s flagship peer-reviewed scientific journal Circulation.

“Caffeine consumed in coffee is a key part of daily life for millions of people, and in our review of the most recent research, for most adults, intake of up to 400 mg of caffeine/day, the equivalent of up to 5 cups of caffeinated coffee per day without added sugars or fillers, is safe and does not increase cardiovascular risk,” said Chair of the scientific statement volunteer writing group Gregory M. Marcus, a professor of medicine at the University of California, San Francisco School of Medicine and the associate chief of Cardiology for Research at the University of California, San Francisco Health.

“However, high doses of caffeine, such as those found in energy drinks including energy shots, may have harmful effects on the heart and should be avoided.” Energy drink shots may contain 40-69 mg of caffeine per fluid ounce, 3-4 times more caffeine than regular caffeinated coffee.

Drinking caffeinated coffee without added sugars, flavours or cream was linked to a lower risk of Type 2 diabetes, heart disease, stroke, heart failure and some irregular heart rhythms. (Getty Images)

The new scientific statement details the most recent research primarily on caffeinated coffee and the potential impact of caffeine in coffee on high blood pressure, cholesterol, Type 2 diabetes, coronary heart disease, stroke, heart failure, atrial fibrillation, other arrhythmias and other cardiovascular conditions.

Key Things To Know

1. A regular brewed, non-specialty, caffeinated coffee typically contains 9.4-20.6 mg of caffeine per fluid ounce.
2. Consuming caffeinated coffee without added sugars, flavours or cream was linked to a lower risk of Type 2 diabetes, heart disease, stroke, heart failure and some irregular heart rhythms.
3. Randomized trials, the most rigorous and reliable type of study design, have shown that caffeine consumption in coffee is associated with a lower risk of atrial fibrillation but also a higher risk of premature ventricular contractions.
4. Adding sugar, flavoured syrups, milk and/or cream to coffee likely reduces its potential health benefits, and more research is needed to understand the impact of these additives.

How Does Caffeine Affect The Body?

Caffeine consumed in coffee is metabolized by the liver and generally reaches peak concentration for most people within an hour. However, how quickly individuals process caffeine depends on their genetics, metabolism, age and past caffeine use. When more caffeinated coffee is consumed regularly, some people may develop a tolerance to higher levels of caffeine. Other people may feel stronger effects from the same amount of caffeine. Short-term effects of caffeine may include temporary increases in blood pressure, heart rate, blood sugar and alertness. Some people may experience heart palpitations and/or sleep disruption.

Specific Health Impacts Of Caffeine

Studies have found that caffeinated coffee consumption may affect blood pressure differently depending on how much is consumed. In people with optimal blood pressure, drinking 1-3 cups a day was associated with an increased risk of developing high blood pressure, while drinking more than 3 cups per day was associated with a lower risk. High doses of caffeine (such as those from energy drinks or energy shots) can significantly increase blood pressure, especially in people who already have high blood pressure.

Research suggests that caffeinated coffee may reduce insulin sensitivity in the short term. In addition, drinking black, caffeinated coffee (no additives, flavours or sweeteners) regularly was linked to a lower risk of developing Type 2 diabetes. However, this benefit may be due to compounds in coffee other than caffeine. More research is needed to clarify the impact on Type 2 diabetes of caffeinated coffee vs. various compounds in coffee.

Data from randomized clinical trials indicate cafestol, a component in both caffeinated and decaffeinated coffee, was associated with higher levels of low-density lipoprotein (also known as “bad” cholesterol). Cafestol is present in unfiltered coffee (such as espresso, French press, Turkish coffee or boiled coffee) but not present in coffee brewed with paper filters or instant coffee.

The most recent analyses of health measures with self-reported information from participants have found that drinking 1-3 cups of caffeinated coffee per day was not associated with an increased risk of atrial fibrillation or abnormal heart rhythm. However, caffeinated coffee at that same level may be associated with more early beats from the lower chamber of the heart, called premature ventricular contractions (or PVCs). Very high doses of caffeine (such as those in caffeinated energy drinks or energy shots) have been linked to abnormal heart rhythm in people usually considered to have low cardiovascular disease risk, such as healthy adults younger than age 30.

Drinking 2-4 cups of caffeinated coffee per day was linked to a lower risk of heart disease, heart failure and stroke. However, drinking more than 4 cups of caffeinated coffee a day may increase the risk of heart failure.

Not All Sources Of Caffeine Are The Same

More research is necessary to investigate the different health impacts of various types of caffeinated coffee and other products with caffeine, such as tea, soda, energy drinks and energy shots, and foods. There have been fewer studies focused on tea vs. coffee; however, tea has been associated with reduced risk of atrial fibrillation, heart failure and stroke, similar to caffeinated coffee. Energy drinks, bars, gels and caffeine-based supplements often contain other added ingredients that may increase the absorption of caffeine, may accelerate its effects on the body, may raise blood pressure and increase the risk of cardiovascular harm.

“Although research suggests that caffeine consumption may be associated with certain cardiovascular benefits for some people, it’s important to remember that there is no ‘one-size-fits-all’ strategy for safe caffeine consumption. People can respond very differently to caffeine based on various factors, such as age, medications, underlying health conditions, genetics and how quickly their bodies metabolize it. What may be a reasonable amount for one person could cause unwanted effects, such as heart palpitations, anxiety or sleep disruption, in another. That’s why it’s important to pay attention to how your body responds to caffeine and talk with your healthcare team about what is right for you,” Marcus said.

More randomized controlled trials investigating the effects of caffeine in coffee and other products that have caffeine on cardiovascular health are needed to better understand how caffeine affects different people and how different sources of caffeine impact heart health.

Source:

https://www.ahajournals.org/doi/10.1161/CIR.0000000000001454

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