A cup of coffee is surrounded by coffee beans.
Caffeine is generally safe when consumed in moderation, but there are limits. Your health and genetics will often dictate what’s best for you. (For Spectrum Health Beat)

Every day, more than 90% of adults in America consume caffeine in some form.

Most of them turn to coffee. Others reach for soda, tea or energy drinks.

So what effect is America’s habit having on our health?

Spectrum Health dietitian Kristi Veltkamp unpacks our questions.

Is caffeine bad for you?

The short answer: It depends, Veltkamp said.

Caffeine, a natural stimulant, can actually have some health benefits.

Among them: improved mood and brain function, reduced risk of depression, reduced risk of Parkinson’s disease and improved liver health. It can even help a little with insulin sensitivity, she said.

And coffee or tea—regardless of whether it’s caffeinated—provide beneficial phytochemicals that have been shown to reduce oxidative stress (the free chemicals that damage cells and increase inflammation) and improve your gut biome.

Green tea, in particular, has polyphenols which can be good for lowering cholesterol and promoting weight loss.

But the big question to consider is how does caffeine affect you, which could be very different from how it impacts someone else.

“There’s a genetic difference in people,” she said. “Some people can tolerate it very well and have no effects, while others can get jittery and have headaches and not be able to sleep.”

Acidity in coffee may also irritate a sensitive stomach, cause heartburn and exacerbate symptoms of irritable bowel syndrome and reflux.

“You always have to listen to your body,” Veltkamp said. “I am one of those people who cannot tolerate it.”

What does caffeine deliver?

It’s very important to consider what you’re ingesting with your caffeine, Veltkamp said.

Are you adding cream and sugar to your coffee? That’s added calories, especially in coffee drinks like lattes, mochas and cappuccinos.

Are you drinking soda? That’s added sugar. Diet soda? That’s artificial sweeteners.

And energy drinks? Those are a red flag, Veltkamp said.

First, many have more than the recommended amount of daily caffeine. Second, they can include artificial sweeteners as well as megadoses of B vitamins, which nobody needs.

“I would never recommend them,” Veltkamp said. “If you’re really looking for energy, what any dietitian is going to tell you, is to eat healthy, get sleep and get exercise.”

How much is too much?

The risks of negative side effects from caffeine consumption increase with amount, Veltkamp said.

For most adults, the recommended maximum is 400 milligrams of caffeine per day—and no more than 200 milligrams at one time.

For reference, some energy drinks have 400 milligrams in one serving. You’ll get about 100 milligrams of caffeine from an 8-ounce cup of coffee, 50 milligrams in black tea, 30 milligrams in green tea and 50 milligrams in a can of soda.

“Most people are drinking more than a cup in one serving,” she said.

In fact, given the large sizes served in coffee shops, “it’s hard to remember what 8 ounces even looks like anymore,” she said.

A Starbucks short cup is 8 fluid ounces and a grande is 16 ounces.

If you’re getting too much caffeine, you could experience negative side effects such as increased insomnia, anxiety and higher blood pressure.

Keep in mind pregnant and breastfeeding women should talk with their doctor about caffeine consumption. The American College of Obstetricians and Gynecologists recommends limiting daily caffeine intake to 200 milligrams a day, or about two cups of coffee.

Certain medications also impact the recommended daily intake of caffeine, so check with your doctor.

What about kids and caffeine?

Veltkamp urged caution around kids consuming caffeine.

The recommended daily maximum of caffeine intake for children is based on body weight—2.5 milligrams per 2.2 pounds, or about 50 milligrams for a 50-pound child.

“If you are a smaller person, the caffeine is going to affect you more strongly,” she said.

She also urged parents to talk with their teens about the risks of consuming energy drinks. They could very easily be getting too much caffeine if they’re regularly drinking them.

How can I quit or cut down?

Veltkamp encourages people to think about their relationship with caffeine and ask questions.

Has this become a dependency? Am I only drinking caffeinated beverages or am I also drinking plenty of water throughout the day? Am I getting enough sleep—and is it good quality sleep?

If you decide to quit or reduce caffeine, Veltkamp suggests gradually weaning down over a period of time, to avoid withdrawal symptoms such as headaches, fatigue, depression and feeling generally sick.

So if you’re among the 90% for whom caffeine is a critical part of your day, it usually doesn’t create health risks.

But keep an eye on the amount you’re getting and how it makes you feel. Speak with your doctor if you have concerns.