Caffeine Research
Google News

Idiosyncratica...

Source:
Caffeine & Health: Clarifying The Controversies
Asia Food Information Center (AFIC)

People differ greatly in their sensitivity to caffeine. When analyzing caffeine’s effects on an individual, many factors must be weighed:

• The amount ingested
• Frequency of consumption
• Individual metabolism
• Individual sensitivity

Study — Fast and Slow Metabolizers

Source:
Coffee-Gene Interaction Raises Heart Attack Risk
Michael Smith, MedPage Today Staff Writer (7 March 2006)
Reviewed by Zalman S. Agus, MD

Original Study:
Coffee, CYP1A2 genotype, and risk of myocardial infarction.
Cornelis MC, El-Sohemy A, Kabagambe EK, Campos H.
JAMA 2006 Mar 8;295(10):1135-41

TORONTO, March 7 - People with a gene variant that causes slow metabolism of caffeine have a sharply elevated risk of a non-fatal heart attack if they drink large amounts of coffee, according to researchers here.

In a large case-control study, only people who were slow to metabolize caffeine had an increased risk of non-fatal myocardial infarction when they drank large amounts of coffee, found Ahmed El-Sohemy, Ph.D., a professor of nutritional sciences at the University of Toronto here.

The finding begins to clarify the muddy picture of the coffee-heart risk interaction, Dr. El-Sohemy and colleagues at Harvard and the University of Costa Rica reported in the March 8 issue of the Journal of the American Medical Association.

"It reveals for the first time that we need to take into account not just how much caffeine you take in but how much stays in your system," Dr. El-Sohemy said in an interview.

Caffeine is "the most widely consumed stimulant in the world" and has been implicated in the development of such cardiovascular diseases as acute MI, the authors noted.

But coffee contains a range of other chemicals and is associated with other lifestyle factors that cloud the link between consumed caffeine and unwanted cardiovascular outcomes, the researchers wrote.

They noted also that 95% of consumed caffeine is metabolized in the liver by cytochrome P450 1A2 (CYP1A2), which varies greatly in terms of activity among individuals. Specifically, a substitution - dubbed CYP1A2*1F -- in the CYP1A2 gene decreases its activity, and carriers of the allele, whether homo- or heterozygous, are called "slow" metabolizers of caffeine.

By contrast, carriers of another variant -- CYP1A2*1A -- are called "fast" metabolizers of the stimulant, Dr. El-Sohemy and colleagues noted.

In that context, between 1994 and 2004, he and colleagues enrolled 2,014 people in Costa Rica who had survived a first MI and matched them for age, sex, and area of residence. They were genotyped to see which CYP1A2 allele they carried and a food frequency questionnaire was used to assess how much caffeinated coffee they drank.

A cup of coffee was defined as 250 mL. Most of the coffee drunk in Costa Rica is filtered, rather than espresso or other varieties of the drink.

Analysis of the study population showed that 55% of cases, or 1,114, and 54% of controls, or 1,082, carried the "slow" allele. Using people who drank less than a cup of coffee a day as a reference group (with an odds ratio of 1.00), the researchers found:

• Overall, only drinking more than four cups of coffee a day increased the risk of MI -- by 40%, with a 95% confidence interval between 1.05 and 1.87. Other levels of intake were not significantly associated with increased risk.
• But for those carrying the "slow" allele, drinking two to three cups a day increased the risk by 36% (OR: 1.36) and drinking four or more increased it by 64% (OR: 1.64). (The 95% confidence intervals were 1.01 to 1.83 and 1.14 to 2.34, respectively.)
• Meanwhile, for those with the "fast" allele, there was no significant increase in risk even at or above the four-cup-a-day level, compared with those who drank less than a cup a day.

In other words, the researchers argue, "coffee consumption increases the risk of MI only among individuals with a slow metabolizer genotype."

The researchers also looked at the effects of cigarette smoking, which is associated with coffee drinking and also induces CYP1A2 activity. The effect of CYP1A2 genotype on the risk of MI was similar among smokers and nonsmokers.

Earlier studies have hinted that the risk of MI associated with caffeine is greater in younger people, Dr. El-Sohemy and colleagues noted. To look at that issue, they examined risk among participants above and below the median age of 59 and found a significant gene/coffee interaction only among those younger than 59.

A similar pattern was found when they looked at participants younger than 50. There were 448 cases and 478 controls. For carriers of the "slow" allele, the odds ratios of MI associated with consuming less than one, one, two to three, or four or more cups of coffee per day were 1.00, 2.12, 2.43, and 4.07. The latter two were significant, with 95% confidence intervals ranging from 1.89 to 8.74 and 1.22 to 4.82, respectively.

By contrast, fast metabolizers had corresponding odds ratios of 1.00, 0.39, 0.35 and 0.81, with 95% confidence intervals of 0.15 to 0.97, 0.17 to 0.76, and 0.32 to 2.05, respectively.

Dr. El-Sohemy said he and his colleagues can't explain yet why drinking coffee might have an apparent protective effect in young fast metabolizers. "We do know that coffee contains a number of different compounds, including anti-oxidants," he said, adding it might be that because the caffeine is removed relatively quickly beneficial compounds are "unmasked."

He said the finding has no immediate clinical application, since there is no commercially available test for the different CYP1A2 genes. But he added one conclusion that could be drawn from the study is that a single cup of coffee a day has no adverse effect -- no matter what the genotype.

Harvard Health — Excerpt

Source:
Coffee: For most, it's safe
Harvard Health Publications, September 2004
MSN Health & Fitness

...STAYING ALERT WITH COFFEE
Many of us like to drink a cup or two of coffee in the morning to get going, and perhaps take another cup in the afternoon. But research suggests that you’ll stay more alert, particularly if you’re fighting sleep deprivation, if you spread your coffee consumption over the course of the day. For instance, if you usually drink 16 ounces in the morning, try taking a 2–3 ounce serving every hour or so...

CARDIOVASCULAR EFFECTS ARE MODEST
Coffee has several cardiovascular effects.

Constricted arteries. The caffeine in a cup of coffee can constrict arteries that lie in areas away from the heart and lungs, such as the brain. This is one reason drinking a cup of coffee sometimes relieves a throbbing headache caused by dilated blood vessels in the brain. It’s also why caffeine is added to several over-the-counter analgesics. Increased heart rate. In some people, coffee can slightly speed the heart rate. Increased blood pressure. A cup of coffee temporarily boosts blood pressure, in much the same way as an activity such as climbing stairs does. But a coffee habit doesn’t cause chronic high blood pressure. And several studies have found that blood pressure changes tend to occur only in people who don’t usually drink coffee.

Irregular heartbeat. The American Heart Association says that caffeine (which is also found in tea, some soft drinks, and chocolate) may cause an occasional irregular heartbeat. If you think coffee affects you this way, slowly cut back on the amount you drink each day, and talk to your clinician.

Increased cholesterol levels. The coffee oils kahweol and cafestol can increase levels of total and LDL (bad) cholesterol. Paper filters trap these compounds, so they’re not found in most cups of coffee in America, and are a problem only for those who drink espresso, pressed, boiled, or other unfiltered coffee.

Homocysteine. Several studies have linked coffee consumption to increased levels of homocysteine, a substance in the blood that may increase the risk for heart disease. A Dutch study found that while caffeine alone (the amount in 4 cups of strong coffee) raised homocysteine levels by 5%, getting that amount in coffee more than doubled the effect. This suggests that compounds other than caffeine are involved. But high homocysteine levels are also associated with some nutritional deficiencies (such as low folate). In one study, coffee had no effect on homocysteine levels in people who ate a healthy diet. Heart disease. The American Heart Association has concluded that moderate coffee use (which it defines as 1–2 cups per day) is not harmful. And large, long-term studies (including Harvard’s Nurses’ Health Study) have found that drinking even as many as 5–6 cups of coffee a day doesn’t increase the risk for heart disease.

FOR WOMEN ONLY
Many women, particularly those of childbearing age, wonder whether coffee and other caffeine-containing foods and drinks are safe for them. Fortunately, there’s plenty of scientific evidence about the effects of coffee and caffeinated beverages on women’s health.

Fertility. There’s no credible evidence that caffeine lowers a woman’s fertility. Pregnancy. Although the evidence is somewhat mixed, low caffeine consumption (1–2 cups per day) appears to be safe during pregnancy. Most of the studies that have linked caffeine to miscarriage, birth defects, or low birth weight have either not taken into account other factors, or involved higher levels of caffeine or coffee consumption (more than 300 mg of caffeine, or more than 3 cups of coffee, per day). A 2003 Danish study published in the British Medical Journal found that pregnant women who drank 4 or more cups of coffee per day were at increased risk of stillbirth. Most authorities, including the FDA, the March of Dimes, and the American College of Obstetricians and Gynecologists, agree that pregnant women should limit their consumption of caffeine to the equivalent of no more than 1–2 cups of coffee (about 100–200 mg of caffeine) per day.

Breast health. Some women believe that abstaining from coffee and caffeinated beverages alleviates the symptoms of fibrocystic breast disease (a condition of benign lumps in the breast). The available research does not support this association.

Cancer. Over the years, some flawed studies have linked caffeine and coffee to several cancers, including cancers of the breast and ovaries as well as the pancreas and bladder. More thorough investigations carried out during the 1990s have found no connection between coffee and cancer. The American Cancer Society has concluded that caffeine is not a risk factor for cancer.

Osteoporosis. Although caffeine can increase urinary excretion of calcium, the jury is still out on whether it’s a factor in osteoporosis. Some studies, including Harvard’s Nurses’ Health Study, suggest that drinking 4 cups or more per day can contribute to bone loss and hip fracture. On the other hand, one study of lifetime coffee drinking (amounting to 2 cups per day) found no evidence of bone loss in women who also drank at least 1 cup of milk per day. Until we know more, it’s best to avoid heavy coffee consumption. Women who regularly drink coffee and caffeinated beverages should also be sure they get adequate calcium (1,000–1,200 mg per day) from food and supplements...

POSSIBLE BENEFITS
Most studies investigating the health effects of coffee or caffeine consumption have focused on possible harms. But some large investigations have identified several potential benefits from coffee drinking. Diabetes. The risk for type 2 diabetes is lower among regular coffee drinkers than among those who don’t drink coffee. In two studies, Harvard researchers found that women who drank 6 cups or more per day reduced their risk for type 2 diabetes by 30% (Annals of Internal Medicine, Jan. 6, 2004). This result is particularly significant because the studies tracked a total of 125,000 men and women for a dozen years or more. Similarly, Finnish scientists following nearly 15,000 men and women, ages 35–64, found that women who drank 3–4 cups per day had a 29% lower risk for diabetes, and drinking 10 or more cups per day lowered the risk even further (Journal of the American Medical Association, March 10, 2004). But no one is recommending that women drink 10 cups a day, or even more than 3 or 4 cups. Not enough is known about its other effects at high doses. We know that it may be harmful in some circumstances, including pregnancy.

Gallstones. A Harvard study found that women who drink 4 cups of coffee per day have a reduced risk of developing gallstones. Coffee may alter the metabolism of bile acids, which trigger the formation of the cholesterol crystals that become gallstones. Coffee also stimulates gallbladder contractions, which may curb stone formation.

Colon cancer. Several studies have found a reduced risk of colon cancer in people who drink 4 or more cups of coffee per day, compared with those who rarely or never drink coffee. In 2003, German researchers reported that they identified an antioxidant in coffee called methylpyridinium, which boosts the activity of enzymes that may discourage the development of colon cancer. The compound is found in both regular (caffeine-containing) and decaffeinated coffee.

Cognitive function. Research involving older men and women participating in the Rancho Bernardo Study found that lifetime coffee intake is associated with better performance by women (but not men) on several cognitive tests. No relationship was found between cognitive function and decaffeinated coffee consumption.

Performance. Caffeine has been shown to improve endurance performance in long-duration physical activities such as running, cross-country skiing, and cycling. Studies suggest this effect occurs at doses of 2–9 mg of caffeine per 2.2 pounds of body weight. This is about the amount of caffeine found in 2–5 cups of coffee.

Liver disease. Researchers at the National Institute of Diabetes and Digestive and Kidney Diseases have found a strong association between coffee drinking and a reduced risk for liver damage in people at high risk for liver disease. This includes heavy drinkers of alcohol, people with hepatitis B or C, and those with iron overload disorders, such as hemochromatosis. The highest consumption, more than 2 cups of coffee per day, was correlated with the greatest benefit.

Parkinson’s disease. Several large studies have shown a reduced risk for Parkinson’s disease in coffee drinkers. Although most of the data come from research in men, a 2001 Harvard School of Public Health study found that women who consumed 1–3 cups of coffee per day had a 50% reduction in risk for Parkinson’s disease, with no increased benefit at higher levels of intake...

Those who view their morning coffee as a guilty pleasure can banish their misgivings. The latest research discounts the notion that moderate coffee consumption — which we interpret to be about 2–4 cups per day — causes significant or lasting harm. Indeed, some studies suggest that coffee and caffeine may offer some real health benefits.

Health Canada Review

Source:
It's Your Health — Caffeine
Health Canada

The Issue
Caffeine in its natural and added forms is found in a growing list of products including coffee, tea, cola beverages, new "energy" drinks, chocolate and even some medicines. The increasing presence of caffeine in our lives raises the question of how much is too much for the average consumer.

Health Canada's recommendations on caffeine intake for women of child-bearing age and children were lowered in 2003 based on new research. For the rest of the general population of healthy adults, the long-standing advice still applies of no more than 400 - 450 mg of caffeine per day, the equivalent of about three 8-oz (237 ml) cups of brewed coffee.

Background
Caffeine is a natural ingredient found in the leaves, seeds or fruit of a number of plants, including coffee, tea, cocoa, kola, guarana and yerba maté. It is also manufactured and used as a food additive in some carbonated drinks, and as an ingredient in certain drug products, such as cold and headache remedies.

Canadian adults get an estimated 60% of their caffeine from coffee and about 30% from tea. The remaining 10% comes from cola beverages, chocolate products and medicines.

For children aged one to five, about 55% comes from cola drinks, about 30% from tea, and about 14% from chocolate. The rest comes from other sources, including medicines.

The Health Effects of Caffeine
It is difficult to link precise intake levels of caffeine to specific health effects because tolerance to caffeine differs widely from person to person. For healthy adults, a small amount of caffeine may have positive effects, such as increased alertness or ability to concentrate. However, some people are more sensitive to caffeine. For them, a small amount could cause insomnia, headaches, irritability and nervousness.

There have been many studies over the years dealing with caffeine and human health. These studies have looked at the potential adverse effects of caffeine in such areas as:

• general toxicity (e.g., muscle tremors, nausea, irritability);
• cardiovascular effects (e.g., heart rate, cholesterol, blood pressure);
• effects on calcium balance and bone health (e.g., bone density, risk of fractures);
• behavioural effects in both adults and children (e.g., anxiety, mood changes, attentiveness);
• potential links to cancer; and
• effects on reproduction (e.g., male and female fertility, birth weight)

Health Canada scientists recently reviewed these studies and found that:

• The general population of healthy adults is not at risk for potential adverse effects from caffeine if they limit their caffeine intake to 400-450 mg per day;
• People who get an adequate daily amount of calcium have greater protection against the possible adverse effects of caffeine on bone health. For most people, choosing foods according to Canada's Food Guide to Healthy Eating can provide the calcium needed for good health;
• Compared to the general adult population, children are at increased risk for possible behavioural effects from caffeine; and
• Women of childbearing age are at increased risk of possible reproductive effects.

These conclusions prompted Health Canada to establish new recommendations on maximum daily caffeine intakes for the groups that may be at higher risk.

Health Canada's New Recommendations For children age 12 and under, Health Canada recommends a maximum daily caffeine intake of no more than 2.5 milligrams per kilogram of body weight. Based on average body weights of children, this means a daily caffeine intake of no more than:

• 45 mg for children aged 4 - 6;
• 62.5 mg for children aged 7 - 9; and
• 85 mg for children aged 10 - 12.

Those recommended maximums are equivalent to about one to two 12-oz (355 ml) cans of cola a day.

For women of childbearing age, the new recommendation is a maximum daily caffeine intake of no more than 300 mg, or a little over two 8-oz (237 ml) cups of coffee.

For the rest of the general population of healthy adults, Health Canada advises a daily intake of no more than 400-450 mg... [Read more]

Pharmacologic Overview...

Source:
STIMULANTS: Methylxanthines/Xanthines (pp.1-7)
Margaret H. White PhD
California State University Fullerton

STIMULANTS: Methylxanthines/Xanthines...
("minor" stimulants)

1. PLANT SOURCES OF XANTHINES (ALKALOIDS)
   
   
   • Coffee
     
     • Coffea Arabica (Ethiopia originally)
     • Coffea robusta (African Congo originally)
   • Tea
     
     • Camellia sinensis (China, India, Burma, Thailand, Laos & Vietnam)
   • Chocolate
     
     • Theobroma cacao (Amazon & Orinoco rivers)
   • So.Amer. Holly
     
     • Ilex guayusa (Amazon, Peru, Ecuador)
       Achuar Jivaro tribesmen (xanthines act to repel insects)



2. SPECIFIC ACTIVE INGREDIENTS & PLANT SOURCES
   
   • Caffeine
     – found in coffee, tea, colas, & So.Amer. holly
   • Theophylline
     – found in tea
   • Theobromine
     – found in chocolate (along with phenylethylamine & caffeine)
   (caffeine > theophylline > theobromine)



3. USERS OF XANTHINES
   
   • Mean age of initial use:
     of coffee = 19 years;
     of tea = 22 years;
     of colas = 14 years;
     of choc?
   • In USA > 85% of population consumes caffeine weekly > 98% of children/adolescents (5-18 yrs) consume weekly 210-238 mg caffeine/person/day (all sources)(mostly coffee) (Julien says 80-400 mg, = 3 to 5 5oz. "cups" of coffee/day)(vs. 444 mg caffeine/person/day in United Kingdom!)(mostly tea)[.] [C]offee consumption was dropping & colas increasing – in early 1990’s (PS)
   • In U.K. per capita consumption of chocolate is 16 lbs./year (vs. 12 lbs./year in USA). [I]n U.K. around 20% of yearly chocolate is consumed at Xmas/NewYrs
   • Worldwide 70mg caffeine/person/day (tea > coffee)[;] 80% of adult population consumes caffeine daily[.]
     Summary: Xanthine use is worldwide & daily!



4. GENERAL POSITIVE EFFECTS
   
   • increased mental alertness
   • wakefulness
   • increased energy
   • sense of well-being
   [D]oes it have potential for toxicities? YES...
   [D]oes it have potential for physical dependence? YES...



5. PHARMACOKINETICS
   
   • taken PO, rapidly absorbed from GI tract
   • are alkaloids[,] so “should” ionize & get trapped in stomach[,] but do not ionize easily in acidic environment; therefore remain in nonionized form & readily pass out of stomach into bloodstream
   • absorbed w/i 15-45 minutes, completely by 1½-2 hours
   • peak plasma levels 2 hours after drinking, decrease thereafter freely distributed to all body tissues
   • crosses BBB easily & quickly crosses placental barrier easily & quickly[;] 90% metabolized by liver enzymes (CYP1A2), 10% excreted unchanged[,] mostly in urine[,] small amounts excreted in feces, sweat, breast milk, etc.
   • ½ life varies: 3½ to 5 hours (2½ - 7) in most adults
     ½ life increases in infants, pregnant women (3-10 hours), & elderly
     ½ life decreases in smokers (via liver enzyme induction)
   • note: some TCAs & SSRIs, & grapefruit can inhibit CYP1A2 production which then --- increases caffeine effects
     e.g. Luvox/fluvoxamine (vs. Effexor/venlafaxine) caffeine metabolized into 3 active (stimulant) metabolites: theophylline & paraxanthine – active, acts like caffeine theobromine – active, but does not act like caffeine



6. PHARMACOLOGICAL EFFECTS OF CAFFEINE
   (at low to medium doses)
   
   • increased alertness, increased wakefulness
   • increase in faster, clearer thinking
   • increased mood, sense of well being, sociability
   • decreased fatigue
   • decreased sleep, increased restlessness, sensitivity to stimuli
   • increased skeletal muscle activity (increased shaking, tremors --- decreased fine motor control)
   • increased respiratory drive & rate
   • increased urine output (is a diuretic)
   • increased HR, cardiac force, BP, dilation of coronary arteries (vs. cocaine)
   • decreased smooth muscle activity (is a vasodilator in peripheral blood blood vessels, but a vasoconstrictor of CNS blood vessels; opens bronchi)
   • increased basal metabolic rate
   
   
7. TOXIC PHARMACOLOGICAL EFFECTS OF CAFFEINE
   (at medium to high levels)
   • usually seen at about 1 to 1.5 grams/day levels (= 12 cups coffee)
   • increased agitation, anxiety (esp. in sensitive [Subjects])
   • increased tremors, restlessness
   • increased rapid, shallow breathing
   • increased insomnia
   • increased peripheral vasoconstriction (cold, sweaty hands)
   
   
   
   • lethal dose = 10 grams caffeine/day (= 100 cups coffee)
     (therefore, TI = 40)
   
   
   
   • "caffeinism" – a clinical pattern seen with caffeine OD anxiety, agitation, severe insomnia, labile mood swings (esp. irritability to rage), tachycardia, HBP, cardiac arrhythmias, severe GI disturbances, incl. diarrhea, gas, & cramping, and acid reflux, SOB, tinnitus, delerium usually seen at > 500-1000 mg/day (= 5-10 cups coffee/day)



8. MECHANISMS OF ACTION OF CAFFEINE (p.4)
9. TOLERANCE & DEPENDENCE OF CAFFEINE (p.5)
10. USE OF CAFFEINE IN PREGNANCY (p.6)
11. THERAPEUTIC USES OF CAFFEINE (p.6)
12. OTHER MISCELLANEOUS ON CAFFEINE No content
13. THEOPHYLLINE (p.7)
14. THEOBROMINE (p.7)

Coffee and Caffeine Consumption

Source:
Neurologic Effects of Caffeine
Anthony P. Winston, Elizabeth Hardwick and Neema Jaberi Advances in Psychiatric Treatment (2005) 11: 432-439
emedicine.com
Last Updated: 7 June 2006

Coffee and Caffeine Consumption
The 2 major coffee types are Arabica and Robusta. In a standard 150 mL cup, the content of caffeine ranges from 71-120 mg per cup for Arabica coffee and from 131-220 mg per cup for Robusta. Caffeine is present in a number of dietary sources including tea, coffee, cocoa beverages, candy bars, and soft drinks. The caffeine content of these food items varies, ranging from 71-220 mg/150 mL for coffee, 32-42 mg/150 mL for tea, 32-70 mg/330 mL for cola, and 4 mg/150 mL for cocoa. Average caffeine consumption from all sources is approximately 76 mg/person/day but reaches 210-238 mg per person per day in the United States and Canada and more than 400 mg per person per day in Sweden and Finland, where 80-100% of the caffeine intake is from coffee alone. In the United Kingdom, the consumption of caffeine is similar to that in Sweden and Finland, but 72% is from tea.

Credit: B. Iverson

Credit: Wikipedia. Adapted.

Credit: Biological Magnetic Resonance Data Bank. Adapted.

The daily intake of caffeine from all sources in the United States is estimated at 3 mg/kg/person, with two thirds of it coming from coffee consumed by subjects older than 10 years. If only caffeine consumers are evaluated, the daily caffeine consumption is 2.4-4.0 mg/kg (170-300 mg) in individuals weighing 60-70 kg. In children, soft drinks represent 55%, chocolate foods and beverages represent 35-40%, and tea represents 6-10% of the total caffeine intake.

Caffeine, or 1,3,7-trimethylxanthine, is related structurally to uric acid. It is metabolized by demethylation and oxidation. The major human pathway results in paraxanthine (1,7-dimethylxanthine), leading to the principal urinary metabolites, l-methylxanthine, 1-methyluric acid, and an acetylated uracil derivative. Minor degradation pathways involve the formation and metabolism of theophylline and theobromine. No evidence exists to suggest that methylxanthines are converted to uric acid or that their ingestion can exacerbate gout.

The rate of elimination of methylxanthines varies by individual due to both genetic and environmental factors, and 4-fold differences are not uncommon. In most cases, metabolism obeys first-order elimination kinetics within the therapeutic range. At higher concentrations, however, zero-order kinetics occur with the saturation of metabolic enzymes. This prolongs the decline of caffeine concentrations.

The metabolism of methylxanthines also is influenced by the presence of other agents or specific diseases. For example, cigarette smoking and oral contraceptives produce a small but appreciable increase in methylxanthine clearance. The half-life of theophylline can be prolonged significantly in patients with hepatic cirrhosis, congestive heart failure, or acute pulmonary congestion; values of more than 60 hours have been reported.

Caffeine has a half-life in plasma of 3-7 hours; this increases by about 2-fold in women during the later stages of pregnancy or with long-term use of oral contraceptive steroids... [Read more]

Caffeine Withdrawal

Source:
Is Caffeine Withdrawal a Mental Disorder?
1 in 8 People Can't Function Without Daily Fix
Sid Kirchheimer, WebMD Medical News; Reviewed By Michael Smith MD.
WebMD Health

Sept. 30, 2004 -- Researchers are saying that caffeine withdrawal should now be classified as a psychiatric disorder.

A new study that analyzes some 170 years' worth of research concludes that caffeine withdrawal is very real -- producing enough physical symptoms and a disruption in daily life to classify it as a psychiatric disorder. Researchers are suggesting that caffeine withdrawal should be included in the next edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM), considered the bible of mental disorders.

"I don't think this means anyone should be worried," says study researcher Roland Griffiths, PhD, professor of psychiatry and neuroscience at Johns Hopkins School of Medicine. "What it means is that the phenomenon of caffeine withdrawal is real and that when people don't get their usual dose, they can suffer a range of withdrawal symptoms."

His research, published in the October issue of Psychopharmacology, analyzes 66 previous studies on the effects of caffeine withdrawal... Griffiths' analysis shows as little as one cup of coffee can cause an addiction and withdrawal from caffeine produces any of five clusters of symptoms in some people:

• Headache, the most common symptom, which affects at least of 50% of people in caffeine withdrawal
• Fatigue or drowsiness
• "Unhappy" mood, depression, or irritability
• Difficulty concentrating
• Flu-like symptoms such as nausea, vomiting, muscle pain, and stiffness.

"Onset of these symptoms typically occurs within 12 to 24 hours of stopping caffeine and peaks one to two days after stopping," Griffiths tells WebMD. "The duration is between two and nine days."

A new revelation in Griffith's analysis may be what upgrades caffeine withdrawal from its current "more study is needed" status to "disorder" status: These withdrawal symptoms are severe enough in about one in eight people to interfere with their ability to function on a day-to-day basis.

"The withdrawal symptoms can be mild or severe, but it's estimated that 13% of people develop symptoms so significant that they can't do what they normally would do -- they can't work, they can't leave the house, they can't function," he says.

Search for the latest research articles
on the National Center for Biotechnology Information (NCBI) Web site: