Caffeine: How Much is Too Much?

If your morning doesn't start without a hot cup of coffee or tea, that's OK. In fact, along with that energy boost you feel, a regular dose of caffeine could stave off several chronic diseases and even improve your immunity, says Karolin Saweres RD, LD, a clinical dietitian atBethesda North Hospital. But, she strongly cautions more research is needed to prove it.

Like many foods, when consumed in moderation, caffeine does not cause adverse effects in healthy adults, Karolin says. A moderate amount per day is 300 mg or less, which is equivalent to about three 8 oz. cups of coffee.

For those with hypertension, insomnia or digestive issues, such as gastroesophageal reflux disease (GERD), caffeine could elevate their blood pressure or exacerbate symptoms, Karolin says.

Pregnant women also should watch their caffeine consumption, but studies do not point to caffeine as a cause for birth defects, miscarriage, premature birth or low birth weight. "Moderate intake of 300 mg per day should be OK (for pregnant women)," Karolin says.

"A lot more research is needed on adverse effects of caffeine," Karolin says; however, some studies have shown that consuming more than 700 mg per day can lead to increased urinary excretion of calcium and magnesium. "For patients who need calcium - for example, patients who have osteoporosis - there is a drawback to excreting more calcium."

In addition, studies show that as caffeinated coffee consumption increases, milk intake decreases, she says.

On the plus side, caffeine could help reduce the risk of several chronic diseases, including:

It's also been shown that four to six cups per day has anti-inflammatory effects, and regular caffeine consumption could help slow the rate of cognitive decline in older adults, Karolin says.

Along with the obvious caffeinated drinks - coffee, tea, soft drinks and energy drinks - caffeine is found in other foods, dietary supplements and medications. A one oz. piece of dark chocolate contains about 20 to 25 mg of caffeine, and cold medications and dietary supplements may contain 60 to 200 mg.

"I just want people to look at their foods more carefully, because some foods do contain caffeine in them that we're not aware of," Karolin says. A lack of caffeine information on nutrition labels sometimes leaves individuals in the dark about how much caffeine they're consuming.

In addition, caffeine is a mild diuretic and could contribute to dehydration. Karolin recommends drinking water to supplement caffeinated beverages. "Water is the best way to stay hydrated."