2 deaths linked to caffeinated lemonade

Earlier this month, the family of a 46-year-old man in Florida filed a lawsuit against Panera, arguing the man died after drinking three of the restaurant's charged lemonade drinks. Meanwhile, in October, the parents of a 21-year-old college student in Pennsylvania also filed a lawsuit against Panera, as she suffered a fatal cardiac arrest after consuming the lemonade.

In both cases, the people had complicating conditions. The Florida man had "a chromosomal deficiency disorder, developmental delay, and ADHD," according to his family, while the Pennsylvania woman had Long QT Type 1 Syndrome, a cardiac condition, and typically avoided energy drinks. The family of the Pennsylvania woman argue in their lawsuit that Panera didn't adequately disclose the quantity of caffeine in their drink.

A large 30-ounce Charged Lemonade with ice contains 237 milligrams of caffeine, however Panera has previously listed the drink as having 390 milligrams of caffeine.

Jennifer Temple, director of the Nutrition and Health Research Laboratory at the University of Buffalo, said the caffeine content in the Charged Lemonades is "exceptional," and noted that because it is sold in larger volumes and has the potential for free refills from a self-dispenser, the beverage is different from other energy drinks.

For example, Monster energy drinks are served in 16-ounce cans with around 164 milligrams of caffeine.

"Even if the caffeine content per milliliter of liquid is similar, the amount that you're getting when you're pouring into these large cups is much more than you would get in a commercial energy drink," Temple said, adding that she "can't think of another example where you can kind of self-dispense an energy drink."

How much caffeine is too much?

According to FDA, adults can safely consume 400 milligrams of caffeine each day, which is equivalent to around six shots of espresso, four to five cups of coffee, or eight to nine cups of tea.

The problem comes when people start "stacking" caffeine throughout the day, said Allison Childress, a registered clinical dietitian and associate professor of nutrition sciences at Texas Tech University.

"People don't realize that they've had two cups of coffee that morning, had a soda at lunch, then they get this lemonade in the afternoon, and now we're at 5-, 6-, 700 milligrams of caffeine," she said. Once a person hits around 1,200 milligrams of caffeine, they could experience heart palpitations, anxiety, agitation, high blood pressure, or seizures.

"If it's consumed in moderation, great. But people are not drinking small cups of coffee anymore," said David Ma, a professor of human health and nutritional sciences at the University of Guelph. "And energy drinks are consumed fairly rapidly."

For the average healthy adult, a lethal dose of caffeine would be around 10 grams, or 150 milligrams, per kilogram of body weight, according to Temple. That's equivalent to around 60 Monster energy drinks and is more likely to be consumed with caffeine powder or pill supplements, she said.

However, people with underlying heart problems can see dangerous effects from caffeine at "much lower doses," Temple added.

Ultimately, people need to understand their personal limits, according to Raja Mutharasan, medical director of the Northwestern Bluhm Cardiovascular Institute at Palos Hospital.

"People have to know what's in the drink when they're consuming it and know what's a safe amount," he said. "For example, this Charged Lemonade that's been in the news has actually less caffeine than a lot of large coffee cups that you might get at a local Starbucks or an Einstein Brothers."

Mutharasan recommends paying attention to the signals your body gives when you consume caffeine, and to contact your doctor if you have concerns about a fast heart rate, extra heartbeats, or an arrhythmia.

"For most people, a cup or two of coffee a day poses actually no health dangers at all," he said. "But if you're predisposed to a heart condition, or you're predisposed to having fast heartbeats, extra heartbeats, arrhythmias, then it can be dangerous." (Brown, verywellhealth, 12/13; Althimer/Martichoux, "Changing America," The Hill, 12/19; Cho, Washington Post, 12/6)

The beverage aisle in your local grocery store contains a slew of unhealthy options — but some drinks can actually help improve your health and well-being. Writing for U.S. News & World Report, Julie Upton and Ruben Castaneda outline the best drinks for gut health, brain health, relaxation, and hydration.