Report on Coffee Side Effects and Usage


Natural health supplements sometimes have unexpected side effects or interactions with medication that can lead to adverse reactions that are sometimes life threatening. The following is a list of warnings that you should be aware of if you drink coffee. These are referred to as drug/herb interactions.

Warning 1 – Counterindications: Coffee can damage the lining of the digestive organs, causing gastritis and ulcers. It is not recommended for people with gastritis, colitis, and ulcers.

Warning 2 – Pregnancy: In a Danish study of 18,478 women heavy coffee consumption during pregnancy was linked to a significant increase in the risk of stillbirths. “The results seem to indicate a threshold effect around four to seven cups per day,” the study reported. Those who drank 8 or more cups a day increased risk of stillbirth by 220% compared with nondrinkers.

The caffeine molecules in coffee are small enough to penetrate the placenta and enter a baby’s bloodstream. Unlike adults, the fetus is not capable of fully metabolizing caffeine and excreting it. Caffeine tends to remain in the fetus’s blood 10 times longer than in adults. Frequent consumption of coffee will accumulate in the baby’s body and just as it does to adults; caffeine could send the baby’s pulse and breathing rate racing and affect its sleep pattern.

Coffee consumption can lead to iron deficiency anemia in mothers and infants. Coffee also interferes with the absorption of supplemental iron.

Warning 3 – Benzodiazepines: Coffee decreases the effect of benzodiazepines.

Warning 4 – Beta-blockers: The caffeine in coffee increases blood pressure in those taking beta-blockers.

Warning 5 – Lithium: Coffee decreases levels of lithium.

Warning 6 – MAOIs: Experts recommend avoiding the use of large amounts of coffee; may cause hypertensive reaction.

Warning 7 – Xanthines: Large amounts of coffee increase the action of xanthines such as theophylline.

Warning 8 – Bronchodilators: Large amounts of coffee may increase the action of some bronchodilators.

Warning 9 – Osteoporosis: The caffeine in coffee can flush calcium out of the body leading to bone loss. This calcium loss might help to weaken bones. To minimize this problem, don’t use more than 300 mg of caffeine per day. Taking calcium supplements may also help to offset these calcium losses.

Warning 10 – Digestive disorders (GERD): Coffee relaxes the muscle that separates the esophagus from the stomach. This may lead to GERD or heartburn and other disorders. Discontinuing coffee may allow that muscle to start doing its job again.

Used as a natural health remedy: coffee is used internally for the following benefits:

  • The latest study, published in April 2012 in the American Journal of Clinical Nutrition1, confirms earlier studies that coffee may actually reduce your risk for developing type 2 diabetes.
  • Evidence shows that the caffeine in coffee intensifies muscle contractions, masks the discomfort of physical exertion and speeds up the use of the muscles’ short-term fuel stores.
  • Researchers have looked at thousands of healthy men and women and discovered that in the women, drinking 2 to 3 cups of coffee daily was associated with an 18% reduction in death from all causes, while 4 to 5 cups daily showed a risk reduction of 26%. The results in men were smaller and could have been due to chance, but followed similar trends.
  • Coronary artery disease: The Iowa Women’s Health Study showed that women who consumed coffee actually had fewer cardiovascular disease incidents and lower cancer rates than the general population. For women who drank 6 or more cups a day, the benefit was even greater. However, this study excluded 35% of its original participants who already had cardiovascular disease and other chronic diseases when the study began. Since the participants in this study were all over the age of 55, a good conclusion can not be drawn about the long-term effect of drinking coffee on heart disease.
  • Gout: Coffee consumption decreases risk of gout in men over age 40. In a large study of over 45,000 men over a 12-year period, the risk for developing gout in men over 40 was inversely proportional with the amount of coffee consumed.
  • Laxative: Coffee is a powerful stimulant for peristalsis and is sometimes considered to prevent constipation. However, coffee can also cause excessively loose bowel movements. This stimulating effect on the colon is found in both caffeinated and decaffeinated coffee.
  • Cancer: The consumption of coffee has been correlated to a reduced risk of oral, esophageal, pharyngeal, and aggressive prostate cancer.
  • Antidiabetic: Coffee intake may reduce the risk of diabetes mellitus type 2 by up to half. While this was originally noticed in patients who consumed high amounts (7 cups a day), the relationship was later shown to be linear.
  • Liver protection: Coffee can also reduce the incidence of cirrhosis of the liver and has been linked to a reduced risk of hepatocellular carcinoma, a primary liver cancer that usually arises in patients with preexisting cirrhosis.
  • Analgesic enhancement: Caffeine has been found to increase the effectiveness of pain killers, especially migraine and headache medications. Many over-the-counter headache products not include caffeine in their ingredients.
  • Reduced risk of Alzheimer’s disease and Dementia: Several studies have found that those who drank more coffee were significantly less likely to develop Alzheimer’s disease later in life. A longitudinal study in 2009 found that moderate coffee drinkers had reduced risk of developing dementia in addition to Alzheimer’s disease.
  • Reduced risk of gallstones: Caffeinated coffee consumption has been correlated with a lower incidence of gallstones and gallbladder disease in both men and women in two studies performed by the Harvard School of Public Health. This reduced risk was not seen in those who drank decaffeinated coffee.
  • Increase short-term memory: In tests of simple reaction time, choice reaction time, incidental verbal memory, and visuospatial reasoning, participants who regularly drank coffee were found to perform better on all tests, with a positive relationship between test scores and the amount of coffee drank on a regular basis. Elderly participants were found to have the largest effect associated with regular coffee drinking. Another study found that women over the age of 80 performed significantly better on cognitive tests if they were regular coffee drinkers during their lifetimes.
  • Reduced risk of Parkinson’s disease: A study comparing heavy coffee drinkers (3 plus cups a day) with non-drinkers found that the coffee drinkers were significantly less likely to develop Parkinson’s disease later in life. Likewise, a second study found an inverse relationship between the amount of coffee regularly consumed and the likelihood of developing Parkinson’s disease.
  • Reduced herpes symptoms: A Japanese study showed that topical application of caffeine decreases the pain and itching of herpes outbreaks.

Side Effects of Coffee

The known side effects of using coffee include:

  1. “Coffee jitters” is a nervous condition that occurs when one has had too much caffeine.
  2. Withdrawal from coffee may cause caffeine headache.
  3. May cause insomnia
  4. Excessive coffee consumption can cause anxiety and irritability.
  5. Excessive coffee consumption may increase herpes outbreaks for some people.

Other side effects may also occur when using coffee. (See form below)

As with any herb, a serious allergic reaction is possible. Seek immediate medical attention if you notice any symptoms of a serious allergic reaction. These may include a rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, or trouble breathing.

Return to the Herb List.

For questions and answers about the side effects of herbs see the Herb Forum

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