The Caffeine Effect: A Little Is All You Need

It’s a brand-new day! To power through your to-do list, you make a beeline towards your coffee machine as soon as your feet hit the floor. While counting on the burst of energy your first sip of coffee promises, you begin your first task with confidence. As noted in the IFIC Foundation’s 2020 Food and Health Survey of 1,000 U.S. households, many Americans share this routine: reaching for their preferred caffeine source soon after they wake up. Caffeine has long been a favored energizer (for centuries, actually!), and while the variety of ways to consume caffeine has evolved, it is most often taken in the form of coffee, tea and soda. But what do we really know about caffeine and how it works?

The benefits of caffeine

We often reach for caffeinated foods and drinks because they increase our attentiveness. Caffeine mildly stimulates and improves brain function. It helps us feel more energized, boosts alertness and even protects against cognitive decline. While the energetic effects may be the main reason we enjoy caffeine, its benefits extend far beyond heightening our mental performance. Moderate caffeine consumption from coffee and tea may also lower our risk for diseases like type 2 diabetes, heart disease and some cancers. These beverages contain ingredients, like polyphenols and antioxidants, that can also protect against chronic diseases and illnesses. With so many great benefits, one might think there is no harm in drinking as much caffeine as we want; however, you can have too much of a good thing.

The risks of too much caffeine

The ways our bodies break down foods and beverages can differ from person to person. This fact applies to caffeine as well—people respond to caffeine differently. Our genes may, in part, be responsible for these differences. For some people, frequently drinking caffeinated beverages leads to a higher caffeine tolerance. In other words, they must consume more caffeine than they once did to feel its usual effects. As a result, frequent caffeine drinkers may gradually increase their caffeine consumption over time. According to the U.S. Food and Drug Administration (FDA), too much caffeine can cause health concerns, including increased blood pressure, a rapid or unstable heartbeat, seizures and even death. Short-term caffeine effects can include insomnia, jitters, anxiousness, a fast heart rate, an upset stomach, nausea, headache, a feeling of unhappiness and magnified stress. Needless to say, none of these are effects we are looking for in a cup of joe. Just as caffeine tolerance varies from person to person, what counts as “too much” caffeine can vary as well. Factors including body weight, medication use and physical sensitivity can impact the amount of caffeine your body can handle.

Current dietary recommendations

To avoid the negative side effects that may come with consuming too much caffeine, the FDA and the 2020–2025 Dietary Guidelines for Americans provide recommendations for daily caffeine intake. Healthy adults can safely consume 400 milligrams (mg) (equal to what is in about four cups of brewed coffee) of caffeine each day. For pregnant women, the American College of Obstetricians and Gynecologists recommends consuming no more than half that amount, or 200 mg of caffeine. Pregnancy and oral contraceptives can slow caffeine digestion. For pregnant women in their third trimester, caffeine can stay in their bodies for up to 15 hours.

Natural vs. added caffeine: Is there a difference?

Caffeine is naturally found in tea leaves, coffee and cacao beans, while added caffeine is manufactured. If you are like most people, you may not know whether naturally occurring caffeine is any different from added caffeine (e.g., what’s found in many energy drinks and sodas). According to the 2020 Food and Health Survey, most consumers believe that natural caffeine has the same effects as added caffeine—and they are correct. Although natural caffeine and added caffeine come from different sources, they act similarly in our bodies—primarily, giving us a jolt of energy that helps us get through the day.

How much do we really need?

So, we know the recommended caffeine limits. But the question remains, “Will what’s recommended allow us enough caffeine to stay alert?” U.S. Army researchers wondered this as well and developed an algorithm to measure how much caffeine people need and when. After factoring in a person’s sleep schedule, the researchers found that the timing of caffeine consumption is what helps people remain alert and perform their bestnot just the amount of caffeine. For adults who get the recommended seven to nine hours of sleep each night, but need a slight boost in energy, morning caffeine consumption of 400 mg is more than enough. For adults who may be sleep-deprived, and whose alertness decreases later in the day, caffeine intake should be split between the morning and afternoon to maintain all-day performance.

Consume safely and enjoy

Caffeinated foods and beverages contain different amounts of caffeine. Many beverages, dietary supplements and packaged foods list the amount of caffeine they contain. This information can help you calculate the amount of caffeine you consume daily. You may find that some foods or beverages do not provide this information. If not, you can use this caffeine calculator to estimate how much caffeine you’re getting. By monitoring your caffeine intake, you can enjoy that daily energy boost safely, reaping health benefits one sip at a time.

This article was written by Casey Terrell, MPH, RD



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Caffeine Calculator

IFIC’s2020 Year-End Survey: Consumer Insights from a Year Like No Other, and a Look to the Year Ahead