How To Know if Your Coffee Habit Is Too Much Caffeine

Here's what you should know about caffeine before heading for your next coffee refill of the day.

How many afternoons have you sluggishly moseyed over to the coffee machine and wondered, Is this really my fourth cup of the day? Or wait, is it my fifth? We've all been there, but data shows refilling your cup too often could hurt your health.

Possible Risks of Too Much Caffeine

A study published in March 2019 in the American Journal of Clinical Nutrition suggests that drinking six or more cups of coffee per day may increase your risk of heart disease by up to 22%.

Researchers from the University of South Australia analyzed the health records and self-reported dietary patterns of 347,077 participants between 37 and 73 years old. They also looked to see which study participants possessed a specific gene variant called CYP1A2. This variant enables people to metabolize caffeine faster than those without the variant.

Overall, the researchers found that people who said they drank six or more cups of coffee a day were 22% more likely to develop cardiovascular disease during the study period compared to those who drank one to two cups daily. However, they also concluded that this association was independent of genetic makeup; in other words, people with the caffeine-metabolizing gene could not safely drink more than those who don't have it.

The study authors believed that coffee (in large quantities) and heart problems might be linked because excess caffeine consumption can cause high blood pressure, a risk factor for cardiovascular disease. According to the World Health Organization, cardiovascular disease is the leading cause of death worldwide, yet it's also one of the most preventable.

"Most people would agree that if you drink a lot of coffee, you might feel jittery, irritable, or perhaps even nauseous," said co-author Elina Hyppönen, director of the Australian Centre for Precision Health, in a press release. "That's because caffeine helps your body work faster and harder, but it is also likely to suggest that you may have reached your limit for the time being."

Symptoms of Having Too Much Caffeine

Consuming the amount of caffeine in your regular coffee habit is likely safe. However, according to a Stat Pearls publication on caffeine, updated in May 2022, side effects of too much caffeine may begin to develop after a moderate amount. The amount of caffeine needed to cause unwanted side effects can vary between individuals, as people can have different levels of sensitivity to caffeine.

Moderate side effects of too much caffeine can include feelings of anxiety or restlessness, having to urinate more frequently, an increased heart rate, stomach upset, and facial flushing. More severe side effects after significant amounts of caffeine can be dangerous and include symptoms such as feeling disorientated and experiencing hallucinations.

If you are wondering how much is too much, a review published in November 2017 in the journal Food and Chemical Toxicology found that intake levels of up to 400 mg a day, or about four 8-ounce cups of coffee, are not associated with health risks for adults.

Benefits of Drinking Coffee

Previous research has found numerous health benefits of coffee. A study published in BMJ in 2017, described how coffee may actually reduce the risk of many diseases, including cardiovascular disease. This study also mentioned coffee's association with reduced risk of various cancers, such as prostate cancer, endometrial cancer, and melanoma (a type of skin cancer). They highlighted many of the other health benefits of coffee too, such as its high number of antioxidants.

Additionally, an article published in the journal Beverages in June 2019 discussed several other possible health benefits of coffee. These include caffeine's role in possibly reducing the risk of Parkinson's Disease and Alzheimer's Disease. Caffeine may also help protect the liver and reduce the risk of chronic liver disease.

So no, there's no reason to completely cut out coffee, but it is wise to pay attention to how much you're really drinking. "Knowing the limits of what's good for you and what's not is imperative," Hyppönen said in the press release. "As with many things, it's all about moderation; overindulge, and your health will pay for it."

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