Overview

Coffee is a drink made from coffee beans, which are the roasted fruit of the Coffea arabica bush.

People most commonly drink coffee to relieve mental and physical fatigue and to increase mental alertness. Coffee is also used to prevent Parkinson disease, dementia, and many other conditions, but there is no good scientific evidence to support many of these uses.

How does it work ?

Coffee contains caffeine. Caffeine works by stimulating the central nervous system (CNS), heart, and muscles. Coffee also contains other chemicals that might have other benefits.

Uses & Effectiveness ?

Likely Effective for

  • Mental alertness. Drinking coffee and other beverages that contain caffeine throughout the day seems to increase alertness and clear thinking. Caffeine can also improve alertness after sleep deprivation. Even one drink of coffee can reduce fatigue and increase alertness.

Possibly Effective for

  • Impaired movement of food through the intestines after surgery. Drinking coffee might speed up the first stool and a person's ability to eat solid food after certain gut surgeries.
  • Diabetes. People who drink more coffee seem to have a lower risk of developing type 2 diabetes. The greater the intake of coffee, the lower the risk. People with type 2 diabetes who drink more coffee might also have a slightly lower risk of dying.
  • Death from any cause. Drinking coffee every day is linked to a slightly lower risk of dying from any cause or from heart disease. It's unclear if drinking coffee is linked with a lower risk of death from cancer.
  • Parkinson disease. There is evidence that people who drink caffeinated beverages such as coffee, tea, and cola have a decreased risk of Parkinson disease. Interestingly, coffee does not seem to help prevent Parkinson disease in people who smoke cigarettes.

Possibly Ineffective for

  • Cancer of the esophagus. Most people who drink more coffee don't seem to have a lower chance of developing cancer of the esophagus.

Insufficient Evidence for

  • Hardening of the arteries (atherosclerosis). The buildup of calcium-containing plaque in the arteries is an early sign of possible atherosclerosis. Drinking coffee doesn't seem to be linked with a lower buildup of calcium-containing plaque in the arteries.
  • Irregular heartbeat (atrial fibrillation). Drinking more coffee doesn't seem to be linked to a lower risk of atrial fibrillation.
  • Bladder cancer. Drinking coffee doesn't seem to change the risk of bladder cancer.
  • Brain cancer. Some early evidence suggests that Asian people who drink more coffee have a lower risk of developing brain cancer. This does not seem to be true for non-Asian people.
  • Breast cancer. People who drink more coffee don't seem to have a lower chance of developing breast cancer.
  • Heart disease. It is unclear if drinking coffee lowers the chance of developing heart disease. But it might lower the risk for heart failure and the likelihood of death from heart disease.
  • Long-term kidney disease (chronic kidney disease or CKD). People who drink coffee seem to have a slightly lower chance of developing CKD. People with CKD who drink coffee might have a slightly lower risk for kidney failure or death due to kidney failure.
  • Memory and thinking skills (cognitive function). There is developing evidence that drinking more coffee over a lifetime might improve thinking skills among women older than 80 years of age. Coffee also might improve the thinking speed and certain types of memory in healthy adults.
  • Colon cancer, rectal cancer. There is some evidence that Japanese people who drink more coffee have a lower chance of developing colon or rectal cancer. But research conducted in North America and Europe has not found a link between drinking coffee and the risk of colon and rectal cancer. Drinking more coffee seems to slightly reduce the risk of death in people who have colon or rectal cancer.
  • Diseases, such as Alzheimer disease, that interfere with thinking (dementia). People who drink more coffee don't seem to have a lower chance of dementia.
  • Depression. People who drink more coffee might have a lower chance of depression.
  • Cancer of the lining of the uterus (endometrial cancer). The effect of coffee on the risk of endometrial cancer is unclear. Some research suggests that women who drink more coffee have a lower risk of developing endometrial cancer. But other research has not found a link between drinking coffee and the risk of endometrial cancer.
  • Gallbladder disease. People who drink beverages such as coffee that provide at least 400 mg of caffeine per day seem to have a lower risk of developing gallstones. The greater the intake of caffeine, the lower the risk.
  • Stomach cancer. People who drink more coffee don't seem to have a lower risk of stomach cancer.
  • Gout. There is some evidence that both caffeinated and decaffeinated coffee seem to help to prevent gout. But caffeinated coffee seems to work better.
  • Hearing loss. Males who drink at least one cup of coffee daily seem to have a slightly lower chance of hearing loss. But drinking coffee doesn't seem to have this effect in females.
  • High levels of cholesterol or other fats (lipids) in the blood (hyperlipidemia). Some research suggests that drinking caffeinated coffee seems to reduce levels of total cholesterol, LDL or "bad cholesterol", and blood fats called triglycerides by a small amount. But other research suggests that drinking coffee increases triglyceride and cholesterol levels.
  • High blood pressure. People who drink coffee long-term might have a lower risk for high blood pressure. But smoking might eliminate this benefit. Drinking 1-3 cups daily seems to be most beneficial.
  • Low blood pressure. Drinking caffeinated beverages like coffee seems to increase blood pressure in elderly people who experience dizziness after meals due to low blood pressure.
  • Kidney failure. People with long-term kidney disease who drink coffee seem to have a slightly lower chance of kidney failure or death due to kidney failure.
  • Liver cancer. People who drink more coffee might have a lower risk of liver cancer.
  • Liver disease. People who drink more coffee might have a lower risk of liver disease.
  • Lung cancer. Some research suggests that drinking caffeinated coffee may help to prevent lung cancer, but other research disagrees. It's too early to draw firm conclusions. Meanwhile, some research suggests that drinking decaffeinated coffee may help to prevent lung cancer.
  • The most serious type of skin cancer (melanoma). When factors such as age and sun exposure are taken into account, drinking coffee doesn't seem to be linked with a lower chance of developing skin cancer.
  • Build up of fat in the liver in people who drink little or no alcohol (nonalcoholic fatty liver disease or NAFLD). It's unclear if drinking coffee reduces the risk of NAFLD.
  • Nonmelanoma skin cancer. Some research shows that drinking many cups of coffee per day might reduce the risk of a specific form of skin cancer called basal cell carcinoma. But drinking decaffeinated coffee does not seem to have any effect on skin cancer risk.
  • Obesity. The effect of coffee on weight loss in people who are overweight or obese is unclear. Results from research are conflicting. Some research suggests that taking coffee chemicals, called mannooligosaccharides, for 12 weeks might help with weight loss in men, but not women. Drinking a dark roast coffee seems to help reduce food intake and help with weight loss, whereas a light roast coffee does not. Other research suggests that drinking coffee with or without caffeine does not help with weight loss.
  • Mouth cancer. People who drink more coffee don't seem to have a lower risk of mouth cancer.
  • Ovarian cancer. Drinking coffee doesn't seem to change a person's risk for ovarian cancer.
  • Swelling (inflammation) of the pancreas (pancreatitis). Some early research suggests that drinking 3 or more cups of coffee reduces the pancreatitis risk.
  • A type of throat cancer (pharyngeal cancer). People who drink more coffee might have a lower chance of developing pharyngeal cancer.
  • Prostate cancer. In general, people who drink more coffee seem to have a slightly lower risk of developing prostate cancer that has not spread outside the prostate.
  • Thyroid cancer. Drinking more coffee seems to be linked with a lower risk of thyroid cancer.
  • Attention deficit-hyperactivity disorder (ADHD).
  • Constipation.
  • Other conditions.
More evidence is needed to rate the effectiveness of coffee for these uses.

Side Effects

When taken by mouth: Coffee is LIKELY SAFE for most healthy adults when consumed in moderate amounts (about 4 cups per day). Coffee containing caffeine can cause insomnia, nervousness and restlessness, stomach upset, nausea and vomiting, increased heart and breathing rate, and other side effects.

Caffeinated coffee is POSSIBLY UNSAFE when taken by mouth for a long time or in high doses (more than 4 cups per day). Drinking large amounts of caffeinated coffee might cause headache, anxiety, agitation, ringing in the ears, and irregular heartbeats. Larger doses might cause headache, anxiety, agitation, and chest pain.

When given as an enema (rectally): Coffee is POSSIBLY UNSAFE when given rectally as an enema. Coffee enemas have been linked to cases of severe side effects, including death.

Special Precautions and Warnings

Pregnancy and breast-feeding: Caffeinated coffee is POSSIBLY SAFE for pregnant women in amounts of 3 cups per day or less. This amount of coffee provides about 300 mg of caffeine. Consuming larger amounts during pregnancy or when breast-feeding is POSSIBLY UNSAFE. Drinking more than 3 cups per day during pregnancy has been linked to an increased risk of miscarriage, premature birth, and low birth weight. These risks increase as the amount of coffee the mother drinks during pregnancy increases. Also, caffeine can pass into breast milk, so nursing mothers should closely monitor caffeine intake to make sure it is on the low side (1-2 cups per day). High intake of caffeine by nursing mothers can cause sleep problems, irritability, and increased bowel activity in breast-fed infants.

Children: Caffeinated coffee is POSSIBLY SAFE when taken by children and adolescents in amounts commonly found in foods and beverages.

Anxiety disorders: The caffeine in coffee might make anxiety worse.

Bipolar disorder: The caffeine in coffee might make symptoms of mania worse.

Bleeding disorders: There is some concern that coffee might make bleeding disorders worse.

Heart disease: Drinking unfiltered (boiled) coffee increases the amount of cholesterol and other fats in the blood, and also raises the level of homocysteine, all of which are associated with an increased risk of developing heart disease. Some research suggests an association between heart attacks and drinking coffee.

Diabetes: Some research suggests that caffeine contained in coffee might change the way people with diabetes process sugar. Caffeine has been reported to cause increases as well as decreases in blood sugar. Use caffeine with caution if you have diabetes and monitor your blood sugar carefully.

Diarrhea: Coffee contains caffeine. The caffeine in coffee, especially when taken in large amounts, can worsen diarrhea.

Epilepsy: Coffee contains caffeine. People with epilepsy should avoid using caffeine in high doses. Low doses of caffeine should be used cautiously.

Glaucoma: Drinking caffeinated coffee increases pressure inside the eye. The increase starts within 30 minutes and lasts for at least 90 minutes.

High blood pressure: Drinking caffeinated coffee might increase blood pressure in people with high blood pressure. However, this effect might be less in people who drink coffee regularly.

Irritable bowel syndrome (IBS): Coffee contains caffeine. The caffeine in coffee, especially when taken in large amounts, may worsen diarrhea and other symptoms of IBS.

Loss of bladder control: Coffee contains caffeine. Caffeine can make bladder control worse by increasing frequency of urination and the urge to urinate.

Osteoarthritis: Drinking 7 cups or more of coffee per day has been linked to a greater chance of knee osteoarthritis in Korean men, but not women.

Thinning bones (osteoporosis): Drinking caffeinated coffee can increase the amount of calcium that is flushed out in the urine. This might weaken bones. If you have osteoporosis, limit caffeine consumption to less than 300 mg per day (less than 3 cups of caffeinated coffee). Taking calcium supplements may help to make up for calcium that is lost. If you are generally healthy and getting enough calcium from your food and supplements, taking up to 400 mg of caffeine daily (about 4 cups of coffee) doesn't seem to increase the risk of getting osteoporosis. Postmenopausal women who have an inherited condition that keeps them from processing vitamin D normally, should be especially cautious when using caffeine.

Interactions ?

    Major Interaction

    Do not take this combination

  • Ephedrine interacts with COFFEE

    Stimulant drugs speed up the nervous system. The caffeine in coffee and ephedrine are both stimulant drugs. Drinking coffee and taking ephedrine might cause too much stimulation and sometimes serious side effects and heart problems. Do not take caffeine-containing products and ephedrine at the same time.

    Moderate Interaction

    Be cautious with this combination

  • Adenosine (Adenocard) interacts with COFFEE

    The caffeine in coffee might block the affects of adenosine (Adenocard). Adenosine (Adenocard) is often used by doctors to do a test on the heart. This test is called a cardiac stress test. Stop consuming coffee or other caffeine-containing products at least 24 hours before a cardiac stress test.

  • Alcohol interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Alcohol can decrease how quickly the body breaks down caffeine. Taking coffee along with alcohol might cause too much caffeine in the bloodstream and caffeine side effects including jitteriness, headache, and fast heartbeat.

  • Alendronate (Fosamax) interacts with COFFEE

    Coffee can decrease how much alendronate (Fosamax) the body absorbs. Taking coffee and alendronate (Fosamax) at the same time can decrease the effectiveness of alendronate (Fosamax). Don't drink coffee within two hours of taking alendronate (Fosamax).

  • Antibiotics (Quinolone antibiotics) interacts with COFFEE

    The body breaks down caffeine to get rid of it. Some antibiotics might decrease how quickly the body breaks down caffeine. Taking these antibiotics along with coffee can increase the risk of side effects including jitteriness, headache, increased heart rate, and other side effects.

    Some antibiotics that decrease how quickly the body breaks down caffeine include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).

  • Clozapine (Clozaril) interacts with COFFEE

    The body breaks down clozapine (Clozaril) to get rid of it. The caffeine in coffee might decrease how fast the body breaks down clozapine (Clozaril). Taking coffee along with clozapine (Clozaril) can increase the effects and side effects of clozapine (Clozaril).

  • Dipyridamole (Persantine) interacts with COFFEE

    The caffeine in coffee might block the affects of dipyridamole (Persantine). Dipyridamole (Persantine) is often used by doctors to do a test on the heart. This test is called a cardiac stress test. Stop drinking coffee or other caffeine-containing products at least 24 hours before a cardiac stress test.

  • Disulfiram (Antabuse) interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Disulfiram (Antabuse) can decrease how quickly the body gets rid of caffeine. Taking coffee along with disulfiram (Antabuse) might increase the effects and side effects of coffee including jitteriness, hyperactivity, irritability, and others.

  • Estrogens interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Estrogens can decrease how quickly the body breaks down caffeine. Taking estrogen pills and drinking coffee can cause jitteriness, headache, fast heartbeat, and other side effects. If you take estrogen pills limit your caffeine intake.

    Some estrogen pills include conjugated equine estrogens (Premarin), ethinyl estradiol, estradiol, and others.

  • Fluvoxamine (Luvox) interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Fluvoxamine (Luvox) can decrease how quickly the body breaks down caffeine. Taking caffeine along with fluvoxamine (Luvox) might cause too much caffeine in the body, and increase the effects and side effects of caffeine.

  • Lithium interacts with COFFEE

    You body naturally gets rid of lithium. The caffeine in coffee can increase how quickly your body gets rid of lithium. If you take products that contain caffeine and you take lithium, stop taking caffeine products slowly. Stopping caffeine too quickly can increase the side effects of lithium.

  • Medications for depression (MAOIs) interacts with COFFEE

    The caffeine in coffee can stimulate the body. Some medications used for depression can also stimulate the body. Drinking coffee and taking some medications for depression might cause too much stimulation and serious side effects including fast heartbeat, high blood pressure, nervousness, and others.

    Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.

  • Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs) interacts with COFFEE

    Coffee might slow blood clotting. Taking coffee along with medications that also slow clotting might increase the chances of bruising and bleeding.

    Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.

  • Medications for depression (Tricyclic Antidepressants) interacts with COFFEE

    Coffee contains chemicals called tannins. Tannins can bind to many medications and decrease how much medicine the body absorbs. To avoid this interaction avoid coffee one hour before and two hours after taking medications for depression called tricyclic antidepressants.

    Some medications for depression include amitriptyline (Elavil) or imipramine (Tofranil, Janimine).

  • Pentobarbital (Nembutal) interacts with COFFEE

    The stimulant effects of the caffeine in coffee can block the sleep-producing effects of pentobarbital.

  • Phenothiazines interacts with COFFEE

    Coffee contains chemicals called tannins. Tannins can bind to many medications and decrease how much medicine the body absorbs. To avoid this interaction avoid coffee one hour before and two hours after taking phenothiazine medications.

    Some phenothiazine medications include fluphenazine (Permitil, Prolixin), chlorpromazine (Thorazine), haloperidol (Haldol), prochlorperazine (Compazine), thioridazine (Mellaril), and trifluoperazine (Stelazine).

  • Phenylpropanolamine interacts with COFFEE

    The caffeine in coffee can stimulate the body. Phenylpropanolamine can also stimulate the body. Taking caffeine and phenylpropanolamine together might cause too much stimulation and increase heartbeat, blood pressure, and cause nervousness.

  • Riluzole (Rilutek) interacts with COFFEE

    The body breaks down riluzole (Rilutek) to get rid of it. Drinking coffee can decrease how fast the body breaks down riluzole (Rilutek) and increase the effects and side effects of riluzole.

  • Stimulant drugs interacts with COFFEE

    Stimulant drugs speed up the nervous system. By speeding up the nervous system, stimulant medications can make you feel jittery and speed up your heartbeat. The caffeine in coffee can also speed up the nervous system. Drinking coffee along with stimulant drugs might cause serious problems including increased heart rate and high blood pressure. Avoid taking stimulant drugs along with coffee.

    Some stimulant drugs include diethylpropion (Tenuate), epinephrine, phentermine (Ionamin), pseudoephedrine (Sudafed), and many others.

  • Theophylline interacts with COFFEE

    The caffeine in coffee works similarly to theophylline. Caffeine can also decrease how quickly the body gets rid of theophylline. Drinking coffee and taking theophylline might increase the effects and side effects of theophylline.

  • Verapamil (Calan, Covera, Isoptin, Verelan) interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Verapamil (Calan, Covera, Isoptin, Verelan) can decrease how quickly the body gets rid of caffeine. Drinking coffee and taking verapamil (Calan, Covera, Isoptin, Verelan) can increase the risk of side effects for coffee including jitteriness, headache, and an increased heartbeat.

  • Levothyroxine (Synthroid, Levothroid, Levoxyl, and others) interacts with COFFEE

    Drinking some types of coffee might reduce the amount of levothyroxine that is absorbed when taken by mouth. This can decrease how well levothyroxine works. Avoid drinking coffee at the same time that you take levothyroxine and for an hour afterwards.

    Minor Interaction

    Be watchful with this combination

  • Birth control pills (Contraceptive drugs) interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Birth control pills can decrease how quickly the body breaks down caffeine. Taking coffee along with birth control pills can cause jitteriness, headache, fast heartbeat, and other side effects.

    Some birth control pills include ethinyl estradiol and levonorgestrel (Triphasil), ethinyl estradiol and norethindrone (Ortho-Novum 1/35, Ortho-Novum 7/7/7), and others.

  • Cimetidine (Tagamet) interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Cimetidine (Tagamet) can decrease how quickly your body breaks down caffeine. Taking cimetidine (Tagamet) along with coffee might increase the chance of caffeine side effects including jitteriness, headache, fast heartbeat, and others.

  • Fluconazole (Diflucan) interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Fluconazole (Diflucan) might decrease how quickly the body gets rid of caffeine. Taking fluconazole (Diflucan) and drinking coffee might increase the effects and side effects of coffee including nervousness, anxiety, and insomnia.

  • Medications for diabetes (Antidiabetes drugs) interacts with COFFEE

    Coffee might increase blood sugar. Diabetes medications are used to lower blood sugar. By increasing blood sugar, coffee might decrease the effectiveness of diabetes medications. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.

    Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.

  • Mexiletine (Mexitil) interacts with COFFEE

    Coffee contains caffeine. The body breaks down caffeine to get rid of it. Mexiletine (Mexitil) can decrease how quickly the body breaks down caffeine. Taking Mexiletine (Mexitil) along with coffee might increase the caffeine effects and side effects of coffee.

  • Terbinafine (Lamisil) interacts with COFFEE

    The body breaks down the caffeine in coffee to get rid of it. Terbinafine (Lamisil) can decrease how fast the body gets rid of caffeine and increase the risk of side effects including jitteriness, headache, increased heartbeat, and other effects.

Dosing

The following doses have been studied in scientific research:

BY MOUTH:
  • For headache or improving mental alertness: The typical dose of caffeine is up to 250 mg per day, which is about 2 cups of coffee. Even a single cup of coffee with caffeine can be used.
  • For Parkinson disease: 3-4 cups of caffeinated coffee per day or 421 mg to 2716 mg total caffeine. However, a significantly lower risk of developing Parkinson disease has also been associated with as little as 124 mg to 208 mg of caffeine (approximately one to two cups of coffee).
  • For death from any cause: At least one cup of ground, instant, or decaffeinated coffee per day has been used long-term.
  • For diabetes: 900 mg caffeine per day (six or more cups of coffee per day) long-term.
  • Impaired movement of food through the intestines after surgery: 100 mL of coffee three times a day starting after surgery and continuing until the first bowel movement has been used.
The choice of coffee, grind, amount of coffee to water, and other factors determine flavor and strength of coffee.

Brewed coffee contains around 100-150 mg caffeine per cup. Instant coffee contains 85-100 mg caffeine per cup. Decaffeinated coffee contains approximately 8 mg caffeine per cup. Darker roasts contain less caffeine due to the roasting process.

View References

CONDITIONS OF USE AND IMPORTANT INFORMATION: This information is meant to supplement, not replace advice from your doctor or healthcare provider and is not meant to cover all possible uses, precautions, interactions or adverse effects. This information may not fit your specific health circumstances. Never delay or disregard seeking professional medical advice from your doctor or other qualified health care provider because of something you have read on WebMD. You should always speak with your doctor or health care professional before you start, stop, or change any prescribed part of your health care plan or treatment and to determine what course of therapy is right for you.

This copyrighted material is provided by Natural Medicines Comprehensive Database Consumer Version. Information from this source is evidence-based and objective, and without commercial influence. For professional medical information on natural medicines, see Natural Medicines Comprehensive Database Professional Version. © Therapeutic Research Faculty 2018.