The U.S. Food and Drug Administration (FDA) says it's investigating reports of five deaths and a non-fatal heart attack linked to Monster Energy drinks, one of the multitude of highly caffeinated drinks on the market. FDA spokeswoman Shelly Burgess was careful to add that these reports don't prove that the drinks caused the deaths.
The FDA likely felt compelled to report its investigation following a recent filing in California of a wrongful death suit by the parents of a 14-year-old, Hagerstown, Md., girl who died after drinking two, 24-ounce Monster Energy drinks in 24 hours. An autopsy concluded she died of cardiac arrhythmia due to caffeine toxicity. She had an inherited disorder that can weaken blood vessels. [Source: AP News]
Ingesting that much caffeine in a relatively short period would be a lot for most people, and certainly having a preexisting blood vessel disorder should be taken into account. Nevertheless, these investigations spark an interesting question about what we're doing to our bodies by slamming energy drinks like water.
The website EnergyFiend provides an exhaustive list of energy drinks/shots and their caffeine content (along with coffee, tea and soda). Here's just a sample of the most popular drinks:
16 ounce Monster Energy Drink: 160 mg of caffeine (the 24 ounce version has 240 mg)
16 ounce NOS Energy Drink: 260 mg
8.4 ounce Red Bull: 80 mg
16 ounce Rockstar: 160 mg
16 ounce Rumba Energy Juice: 180 mg
2 ounce 5 Hour Energy shot: 138 mg
8.3 ounce AriZona Extreme Energy Shot: 100 mg
Now let's see how those drinks compare to a few popular coffee brands:
10 ounce Dunkin' Donuts Coffee: 132 mg
16 ounce Starbucks Grande Caffe Americano: 225 mg
16 ounce Starbucks Grande Coffee: 330 mg
16 ounce McDonald's Coffee (large): 145 mg
16 ounce Einstein Bros Coffee: 206 mg
And to a few soda brands:
12 ounce Coca-Cola Classic: 34 mg
12 ounce Diet Coke: 45 mg
12 ounce Dr Pepper: 41 mg
12 ounce Mountain Dew: 54 mg
What's clear is that energy drinks, shots, and coffee have much more caffeine per serving than soda -- but, the more important stat to focus on is the cumulative amount of caffeine someone could ingest in a day if they swig any combination of these beverages.
Let's say you start out your day with a Starbucks Grande (330 mg), and around lunch you have a Coke (34 mg), and then before you hit the gym you drink a Monster (160 mg). Just in those three drinks you're at 524 mg of caffeine, which according to the Mayo Clinic puts you in the "heavy use" zone. The conventional recommendation is to keep daily levels of caffeine below 500 mg.
When do you approach the "caffeine poisoning" level? According to Medscape, 10 or more grams of caffeine can be fatal in adults. However, of the 3343 cases of caffeine poisoning reported to the The American Association of Poison Control Centers' National Poison Data System (AAPCC-NPDS) in 2009, no deaths were noted. 1249 of the caffeine poisoning cases were in children younger than 6 years, with the remainder of the cases distributed almost evenly between patients aged 6-19 years (942 cases) and patients older than 19 years (985 cases).
All of this data leads to a few conclusions:
- Given the amount of caffeine in energy drinks and coffee, combined with soda, it's very easy to become a clinically defined "heavy user" and experience some unpleasant side effects like insomnia, irritability, stomach upset, muscle tremors, and quickened heartbeat.
- Caffeine poisoning is certainly possible, but for most people (without a preexisting heart condition) it would require drinking a massive amount of caffeinated beverages to reach that level. Hitting the adult redline of 10 grams would take a concerted effort.
- Having said that, the stats show that most caffeine poisoning occurs in children younger than 6 years, most of which is attributable to accidental overdose.
- And the latest stats we have on caffeine poisoning indicate that it's rarely fatal; not a single death reported as of 2009.
These conclusions lead me to believe that deaths associated with consuming energy drinks (if the FDA concludes that such an association exists in the five cases it's investigating) are the result of caffeine triggering a preexisting condition.
So, the answer to the headline question is Yes, theoretically energy drinks (or coffee for that matter) can cause heart attacks, but there isn't any evidence--at least so far--to demonstrate that they can do so in healthy people not suffering from a cardiovascular condition they may or may not know about.