How Much Coffee Is Safe to Drink?

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Question:

What is the recommended amount of coffee to drink daily? I have had heart surgery, (over seven years ago). My current intake of coffee is two mugs, (estimated at six cups). I have heard I should limit my intake to two cups daily. Should I cut back further?

-Garrick Little

Answer:

According to the Department of Nutritional Sciences at Pennsylvania State University, most people over the age of 35 consume at least 200 mg of caffeine daily.

Caffeine is like any other drug in that it comes with side effects.

Potential side effects include:

  • Migraine headache
  • Insomnia
  • Nervousness
  • Irritability
  • Restlessness
  • Frequent urination or inability to control urination
  • Upset stomach
  • Fast heartbeat
  • Muscle tremors

One 8-ounce cup of brewed coffee contains 91 mg of caffeine.

Check to see how many ounces your coffee cup holds. One cup may actually contain 12 or more ounces.

Around 400 mg of caffeine/day is generally considered safe for most healthy individuals. This is approximately equal to four 8-ounce cups of brewed coffee.

Safe levels vary among people living with certain medical conditions. If you have any of the following conditions, here are some recommendations for safe caffeine consumption.

Heart disease — Less than 200 mg — two 8-ounce cups of brewed coffee — per day

Research is conflicting about the impact of caffeine on heart disease. Caffeine is a stimulant leading to increased heart rate and blood pressure. If you have arrhythmia or other heart conditions, discuss caffeine intake with your doctor.

High blood pressure — Less than 200 mg — two 8-ounce cups of brewed coffee — per day

Caffeine causes the adrenal glands to release adrenaline which leads to a temporary rise in blood pressure. Check your blood pressure before drinking coffee and then again within 30 to 120 minutes after drinking coffee to learn how the caffeine impacts your blood pressure.

Diabetes — Less than 200 mg — two 8-ounce cups of brewed coffee — per day

Caffeine can interfere with glucose metabolism resulting in an increase in plasma glucose levels.

Pregnancy — Less than 200 mg — two 8-ounce cups of brewed coffee — per day

Caffeine crosses the placenta to your baby. Even though it may not affect you, it does impact your baby. The March of Dimes recommends limiting caffeine intake to less than 200 mg per day.

Nursing — Less than 275 mg of caffeine — three 8-ounce cups of brewed coffee — per day

The level of caffeine contained in breastmilk remains relatively low at 1 percent, but caffeine does accumulate in the infant’s body, according to La Leche League International.

Children — Avoid caffeine

Children under the age of 12 should avoid daily caffeine. Around 45 mg per day of caffeine (four ounces of brewed coffee) is considered safe for children after the age of 4, but it’s preferable for caffeine to not be part of a child’s daily diet. Teens should limit caffeine to 100 mg or less (eight ounces of coffee) per day.

Certain medications — Avoid caffeine

When combined with certain medications, such as theophylline and echinacea, caffeine may increase negative side effects and should be avoided. Discuss your medications with your doctor and/or pharmacist to know if caffeine is safe while taking the medication.

Caffeine sensitivity — Limit intake

Those who are sensitive to caffeine should avoid coffee consumption, but could use trial and error to see how much caffeine leads to negative side effects starting with 50 mg of caffeine (four ounces of brewed coffee).

If you love your morning coffee, but want to cut back, making the change isn’t always easy. Use my guide — How to Make Heart Healthy Changes into Lifelong Habits — to ensure success.

If you have a question for our HealthCentral experts, please submit here.

You should know: The answer above provides general health information that is not intended to replace medical advice or treatment recommendations from a qualified healthcare professional.

See more helpful articles:

Caffeine (and its effects)

What are the effects of coffee on your blood pressure?

Can Caffeine Actually Cause Insomnia?

Answered by Lisa Nelson, RD, LN