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HSHS: Be alert to the effects of too much caffeine on brain, body

March is Caffeine Awareness Month

Kellee Marshall, MS, RDN, LDN, CDCES, registered dietitian

As part of March’s Caffeine Awareness Month, HSHS St. Elizabeth’s Hospital and HSHS Medical Group Diabetes and Endocrinology – O’Fallon want to share how the stimulant affects our brain and body.

The U.S. Food and Drug Administration (FDA) estimates 80 percent of U.S. adults consume caffeine daily. Although it can help with alertness, health experts say overdoing it can cause dangerous side effects including increased risk of heart attack, increased blood pressure, insomnia, skin aging and wrinkling, headaches, and increased anxiety.

One known effect of caffeine is the negative stimulation of the adrenal glands. The adrenal glands sit on the kidneys and have a role in releasing hormones when we are confronted with stress. When caffeine is consumed, these glands are stimulated to release adrenaline into the body. This can affect sleep patterns and make us less alert in the morning and throughout the day.

“Caffeine is a stimulant that takes about 30 minutes to kick in, but it can stay in your system for eight to 10 hours,” said Kellee Marshall, MS, RDN, LDN, CDCES, registered dietitian with HSHS Medical Group Diabetes & Endocrinology – O’Fallon.

The FDA recommends no more than 400 milligrams (mg) of caffeine daily for adults, less is recommended for those who are more sensitive to the effects of caffeine and how quickly it breaks down in the body. Keep in mind, the amount of caffeine contained in foods and beverages varies widely:

One eight-ounce cup of black coffee: 95mg

One eight-ounce cup of green tea: 35-70 mg

One eight-ounce energy drink: 50-250mg

One 12-ounce can of cola: 40-50mg

One eight-ounce can energy coffee: 145mg

Caffeine is not recommended for children, and women who are pregnant, trying to become pregnant, or breast feeding. It also should not be mixed with certain medications, so talking with your health care provider about medication management is important.

If you decide to lower your caffeine intake, Marshall says drink more water to avoid dehydration and cut back gradually to avoid withdrawal symptoms such as headache and anxiety.

If you’d like to schedule an appointment with an HSHS Medical Group primary care physician or provider, call Patient Advocate Kim Schneider at 844-520-8897. To learn more about HSHS Medical Group, visit

For more information about HSHS St. Elizabeth’s Hospital, visit

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