Coffee: How much is too much caffeine?

If you need your morning coffee to wake up and several more cups to get through the day, you may worry that your habit isn’t healthy. Although experts say coffee is one of the best beverages you can drink, too much caffeine can have serious side effects.

Here, find out what the latest research shows and if you should cut back or cut out coffee altogether.

Coffee is nutrient-dense.
According to the National Coffee Association, 63 percent of Americans drink coffee every day and with good reason. Coffee packs a ton of nutrients including magnesium, potassium, B vitamins, niacin, and choline.

It’s also the largest source of antioxidants in our diets, said Dr. Arfa Babaknia, a family medicine physician at Orange Coast Memorial Medical Center in Fountain Valley, Calif.

What’s more, if you take your coffee with milk, it’s a great way to get vitamin D and calcium— especially because so many Americans are deficient in them, said Joan Salge Blake, a spokesperson for the Academy of Nutrition and Dietetics.

It protects from disease.
Studies show coffee may decrease the risk for liver, colon, prostate, ovarian and oral cancers, basal cell carcinoma, stroke and heart disease. It may also prevent Parkinson’s disease, Alzheimer's disease and Type 2 diabetes.

A recent study out of Cornell University found that drinking coffee may even protect the eyes from retinal degeneration as a result of glaucoma, aging and diabetes.

Although the research is promising, these studies are prospective and only look at 10 or 15 years of a person’s life so it’s not enough evidence to recommend everyone start drinking coffee, Babaknia said.

Better mood, more energy and weight loss.
Drinking coffee can also increase energy and improve memory, reaction time and mood. In fact, a study out of the Harvard School of Public Health found that people who drink two to four cups of coffee a day reduce their risk for suicide by 50 percent.

While coffee burns fat, aids weight loss and can boost your metabolism by as much as 4 percent, this effect is seen more in people who are already thin, Babaknia said.

A cup of coffee 30 to 60 minutes before exercise may improve your performance in the gym as well.

Too much of a good thing?
“Some is good, more may not be better,” Salge Blake said.

Your daily caffeine intake can add up quickly, especially when 16 ounces at many coffee shops is the norm. Plus, if you drink iced coffee, the portions tend to be large and usually aren’t watered down so a majority of the cup is coffee. Another thing to consider is that if you drink tea, soda, sports drinks, eat chocolate, or take pain relievers, you could be consuming more caffeine than you think.

Coffee can also decrease iron and calcium absorption, increase heart rate and anxiety, cause gastroesophageal reflux disease (GERD) or make irritable bowel syndrome (IBS) symptoms worse.

It can also increase blood pressure, but only in people who don’t drink it every day, Babaknia said. People who have Type 2 diabetes should avoid coffee because it elevates blood glucose levels.

Even if you drink coffee hours before going to bed, even a cup can make it hard to fall asleep or stay asleep. And the next day you end up drinking more coffee to stay alert.

“It becomes this viscous cycle where it can really have an effect on your sleep,” Salge Blake said.

Experts agree women who are struggling with infertility, or are undergoing in vitro fertilization (IVF) treatment should avoid coffee. Although it’s unclear if coffee causes miscarriage or preterm birth, pregnant women should limit their total caffeine intake to 200 milligrams a day.

If you have withdrawal symptoms like headache, fatigue, or irritability, gradually reduce your consumption or switch to decaf.

The sweet spot seems to be no more than 4 cups or 400 milligrams of coffee a day to get the health benefits and curb your cravings without any side effects.  But the right amount really depends on how it makes you feel.

“As long as coffee doesn’t make you jittery, hyper, give you a headache or cause insomnia, there is no limit,” Babaknia said.