Is Caffeine Safe?

Stephen W. Parcell, N.D.

As long ago as 2737 B.C., Chinese Emperor Shen Nung was boiling drinking water when the leaves of a nearby bush fell into the pot, creating a wonderful smelling drink and the first pot of tea. Coffee originated in Africa around 575 A.D., where beans were used as money and consumed as food. Eleventh century Arabs were known to have coffee beverages.  While exploring the New World, Spanish conquistadors were treated to a chocolate drink by Aztec Emperor Montezuma in 1519. The world’s first caffeinated soft drinks were created in the 1880’s.

Patients often ask “Doc, should I give up coffee?”. As a result we have compiled a large file on this subject and thought it would be interesting to pull it together into an article. Many of you have noticed that the pace of life and popularity of coffee seem to be rising together.  Americans turn to caffeine to be more productive as well as keep up with the pace set by others consuming caffeine.

Caffeine is a naturally occurring substance found in the leaves, seeds, or fruits of more than 60 plants. These include coffee and cocoa beans, kola nuts, Guarana, Mate, and tea leaves. Caffeine is well known for it’s stimulant effects on mental functioning, but there are a number of other effects on the body. Blood pressure, pulse rate, metabolic rate, and stomach acid production are all increased, fat stores are broken down, and fatty acids are released into the blood stream. Caffeine promotes release of adrenaline (the flight or fight hormone). It also promotes water loss through the kidneys and help open up the airways making it easier to breathe. 

These effects can last from a few hours to as long as 12, but within 4 days of regular use, the body develops tolerance to many of the effects of caffeine. For example, although caffeine increases blood pressure and pulse in a first time user, a regular user will not experience any significant change. Caffeine has also been used in the treatment of headache for the past 30 years. It can constrict the vessels both inside and outside the skull, reliving the common vascular headache. A vascular headache is caused by blood the expansion or spasm of vessels, which put excessive pressure on nerves, causing pain.

Most “energy” products contain caffeine. Guarana is often added to energy drinks either in combination with caffeine or on its own. Guarana is made from the crushed seeds of a native Brazilian plant. Most energy drinks do not exceed levels of caffeine of about 80mg/250 mL.  This caffeine level in energy drinks is comparable to the caffeine level in a strong cup of coffee.

The U.S. Food and Drug Administration (FDA) classified caffeine as Generally Recognized As Safe (GRAS) in 1958. A more recent review “found no evidence to show that the use of caffeine in carbonated beverages would render these products injurious to health.”

The American Medical Association (AMA) has a similar position on caffeine’s safety, stating that “Moderate tea or coffee drinkers probably need have no concern for their health relative to their caffeine consumption provided other lifestyle habits (diet, alcohol consumption) are moderate, as well.”

Most researchers agree that when consumed in moderation, caffeine is generally safe. Moderate consumption is defined as about 300 mg day.  Because people metabolize caffeine at different rates, sensitivity to caffeine’s effects can vary greatly. Physical conditioning, metabolic rate, medications, body weight, and genetic factors affect the rate at which a person metabolizes caffeine. Caffeine is primarily broken down in the liver. The elderly in particular, may metabolize caffeine much more slowly.

Caffeine is absorbed quickly through the stomach, and peak blood levels occur about 45 – 60 minutes after ingestion. Once in the blood stream, caffeine causes a number of responses in the body.

Positive Effects

Caffeine and Athletic Performance
Although the role of caffeine as a performance enhancer had been studies for decades, there is still no complete agreement among researchers. Most scientists agree that caffeine does not benefit short term, high intensity exercise (eg. sprinting) but can enhance performance in endurance sports like cycling and running.

Caffeine helps the body burn fat and promotes the use fat as a fuel by the muscles. This delays the depletion of sugar stored in muscle and allows for longer exercise duration.  The fuel conserved at earlier stages of exercise is then available later.
Caffeine may also alter the perception of how hard you are working, called perceived exertion. By stimulating the release of epinephrine (the flight or fight response) caffeine directs blood from the skin and organs to skeletal muscles, priming them for use.

Prevention of Neurodegenerative diseases: Studies have demonstrated that caffeine intake is associated with a significantly lower risk for Alzheimer’s disease (AD), independently of other possible factors. Coffee and caffeine intake is also associated with a significantly lower incidence of Parkinson disease. The data suggest that the mechanism is related to caffeine intake and not to other factors in coffee. The lowest risk is seen at intake of 1-3 cups of coffee/day.

Prevention of gallstones: Consuming 3-4 cups of coffee per day is associated with preventing gallstone disease in men. Those who drank 4 or more cups per day had about half the incidence of gallstone disease compared to men in the lowest category of coffee intake  . In contrast, decaffeinated coffee was not associated with a decreased risk.

Improved digestion: The bitter substances in coffee increase the production of stomach acid. This can help those suffering from hypochlorhydria (low stomach acid). This is also the reason why anyone with excess stomach acid should consume coffee in moderation if at all.

Mental effects: In a recent review on the effects of caffeine  it was concluded that:(1) Caffeine increases alertness and reduces fatigue, especially in low arousal situations (e.g. working at night). (2) Caffeine improves performance on tasks that require sustained concentration. (3) Regular caffeine usage appears to be beneficial, with higher users having better mental functioning.

Prevention of hypoglycemia in people with diabetes: Ingestion of modest amounts of caffeine can help patients with diabetes become more aware of low blood sugar, thus preventing a glycemic crisis. Becoming more sensitive to changes in blood sugar is also how caffeine can make normal people hungry and why using it for weight loss may not be effective.

Caffeine content of common beverages and drugs
Beverage Milligrams (mg) of caffeine per serving (approx)*
Coffee (6-ounce cup) 
Drip method 105 -340
Percolator method 75
Instant (1 rounded teaspoon, dry) 80-100
Espresso (1 fluid ounce)  50-280
Drip or percolator method 2
Instant (1 rounded teaspoon, dry) 2
Espresso (1 fluid ounce) 5
Tea (6-ounce cup) 
3-minute brew 35
Instant (1 rounded teaspoon, dry) 25 to 35
Green 25
Bottled (12 fluid ounces) or instant mix (8 fluid ounces) 15
5-minute brew 1 to 5
Carbonated beverages (12 fluid ounces) 
Mountain Dew 55
Mellow Yellow 50
Colas, regular or sugar-free 35 to 50
Cherry colas 35 to 50
Cocoa, chocolate milk very low
Cocoa, unsweetened, dry powder (1 tablespoon) 10
Chocolate milk (8 fluid ounces) 10
Cocoa beverage (8 fluid ounces) 5
Nonprescription drugs
Anacin, Bromo-Selzer, Cope, Empirin 32
Excedrin, others 60
No Doz 100
Vivarin 200

*The caffeine content depends on many factors such as the caffeine content of the coffee beans, amount used, and factors such as whether the shot is a long or short pull.

Problems associated with caffeine:

Caffeine withdrawal: Caffeine withdrawal occurs within 24 hours after the last caffeine intake and the pain is relieved within 1 hour by 100mg (approx one cup of coffee) of caffeine. Caffeine-withdrawal headache begins with a feeling of fullness or pressure and develops into a diffuse, throbbing pain (sound familiar?). It happens because your body becomes used to the drug, when it is withdrawn the blood vessels in the head expand too much causing pain.
The symptoms of caffeine-withdrawal headache are worsened by physical activity. Mild nausea and feelings of depression or sadness may also occur. Withdrawal symptoms include:
• Headache
• Sleepiness/drowsiness
• Impaired concentration/lassitude/work difficulty
• Depression
• Anxiety
• Irritability
• Nausea/vomiting
• Muscle aches/stiffness

Psychological effects:
Caffeine may make some psychiatric conditions worse. In addition to causing anxiety and insomnia in sensitive individuals, caffeine can also aggravate depression, panic and mania.

Adrenal burnout: This term refers to a condition brought about by chronic over stimulation of the adrenal gland. This is the same thing that occurs when someone is under stress for a prolonged period. Caffeine causes the release the stress hormones  (mostly epinephrine/adrenaline). The gland may get “worn out” from the daily chore of pumping out these hormones. A person with burnout will need more and more and more caffeine to get going and start feeling very fatigued if they do not have it.

Pregnancy and breast-feeding: Caffeine metabolism dramatically slows during pregnancy.  Caffeine ingested by the woman in the last few months of pregnancy will remain in her system three times longer than usual and, consequently, the exposure of her unborn child to caffeine will last three times longer.  Also the livers of the fetus and newborn are unable to metabolize caffeine, so the drug stays in their systems much longer than in either children or adults. The FDA states that caffeine does not adversely affect reproduction but then also advised use in “moderation”. Studies have shown that only .5 – 1% of the caffeine ingested ends up in breast milk.

According to the American Academy of Pediatrics “Caffeine tends to build up in babies’ systems because their bodies cannot get rid of it very easily. A morning cup of coffee is not likely to harm your baby, but too much caffeine can cause problems such as poor sleeping, nervousness, irritability, and poor feeding.”

The British government’s Food Standards Agency (FSA) warned that their scientists had found some evidence that a caffeine intake as low as 150 mg, or two cups of coffee, could increase the risk of miscarriage or underweight babies.
To date there is no real evidence that caffeine causes birth defects. We have found it best for our patients to quit drinking coffee during pregnancy and keep it down to one cup during breast-feeding.

Cancer: Studies have also been conducted to evaluate the possible risk of cancer from decaffeinated coffee. Trichloroethylene, a solvent once used to decaffeinate coffee, was tested by the National Cancer Institute (NCI) in 1976 and shown to cause liver tumors in mice. Since the 1970s, coffee companies have switched to other solvents such as methylene chloride (dichloromethane), ethyl acetate, or other types of processing to decaffeinate coffee. However, because methylene chloride is now strongly suspected to cause cancer in humans, most coffee producers no longer use it. Companies that produce coffee can be contacted to learn about their decaffeination method.

Weight loss: No studies indicate that weight loss from large amounts of caffeine is either significant or permanent.  It may decrease appetite because it is a stimulant. It also can promote water loss, not fat loss. Caffeine may also increase appetite due to its ability to increase sensitivity to low blood sugar.

Fibrocystic breast disease: Caffeine may aggravate this condition.  It is not believed to cause the condition, however.

Osteoporosis: Though not a probable cause of osteoporosis, caffeine ingestion has been shown to increase calcium excretion, negatively effecting calcium stores. Certainly anyone with osteoporosis should not consume excessive amounts of caffeine. There is no evidence that caffeine has any harmful effect on bone status or on the calcium balance in individuals who ingest the currently recommended daily allowances of calcium. 1,200 –1,500 mg/day.

Cardiovascular disease: Caffeine does not cause any significant persistent increase in blood pressure. Some people may experience a temporary rise in blood pressure, usually not lasting more than several hours. Caffeine may cause irregular heart rate and high cholesterol, however. Filtered coffee has been reported not to cause elevations in cholesterol because, it seems, the filter removes the offending constituents from coffee. It seems that both unfiltered (espresso) and filtered (drip) coffee can raise homocyteine (tHcy ) and cholesterol (both substances in the blood that increase your chance of a heart attack). A number of studies have confirmed this but the researchers do not know exactly why coffee does this. Chemicals called diterpenes in coffee beans that are extracted by hot water but are retained by a paper filter are the probable culprit. This explains why filtered coffee does not affect cholesterol, whereas Scandinavian “boiled,” espresso, French press, and Turkish coffees do.

Abstaining from even commonly consumed amounts of filtered coffee may lower the concentrations of both tHcy and total cholesterol  . If you have concerns about your levels of homocysteine and cholesterol have them checked regularly by your doctor and switch to filtered coffee (among other things).

Although not definitive, consumption of coffee appears to be positively associated with an increased risk of stroke caused by clot formation in middle-aged men with high blood pressure. Research suggests it may be a good idea for older middle-aged men with high blood pressure who consume large amounts of coffee to consider reducing their coffee intake  .

Skin conditions: Coffee consumption is associated with outbreaks of eczema and other itchy skin rashes. In addition to causing sweating (which worsens itching), caffeine increases anxiety and makes the adrenals pump out stress hormones. In patients with skin conditions made worse with stress reducing or eliminating caffeine seems to help.

Ulcers and heartburn: Both decaf and caffeinated coffee increase stomach acid production making these conditions worse.

Summary: Caffeine is a natural substance that has been consumed by humans for millennia. Used in moderation (less than 300 mg/day), it should pose no heath problem unless you are pregnant, breastfeeding, have high blood pressure, are elderly, have osteoporosis, have heartburn or ulcers, or have skin rashes made worse with stress. Coffee and caffeine may help with sustained mental work, athletic performance, digestion, and the prevention of Alzheimer’s, Parkinson’s and gallstones.

For more information contact: Steve Parcell, ND 303.884.7557