Caffeine side effects,
negative reactions
Excessive caffeine intake can lead to unpleasant, negative caffeine effects
including fast heart rate, palpitations, diuresis (excessive urination), nausea and
vomiting, restlessness, anxiety, depression, tremors, and
insomnia or shallow
sleep. Consumption may also cause ringing in the ears or tinnitus. Anxiety from
caffeine is a common occurrence.
Interactions with supplements
Q. With regard to minimising any interaction with caffeine (coffee and tea), how
long before and after the consumption of a caffeinated beverage is it safe to
take turmeric drinks or supplements?
A. Turmeric is a safe supplement and should not interfere with the
timing of caffeine ingestion.
Where is caffeine found?
Caffeine is a xanthine
alkaloid found in the leaves and beans of the
coffee tree, in tea including
green tea,
yerba mate,
guarana
berries, and
in small quantities in cocoa, the
kola nut and the Yaupon holly. In
plants, caffeine acts as a natural pesticide that paralyzes and kills many
insects feeding upon them. One common source of caffeine is the coffee
plant, the beans of
which are used to make coffee. Caffeine content varies substantially
between Arabica and Robusta species and to a lesser degree between
varieties of each species.
Effects on the body
Caffeine is the most widely used
pharmacologic substance in the world. It is found in common nonessential grocery
items (e.g., coffee, tea, cocoa, and chocolate). Caffeine is a central nervous system stimulant, having the effect of
warding off drowsiness and restoring alertness. Caffeine-containing
beverages, such as coffee and tea, enjoy great popularity, making caffeine
the world's most popular psychoactive substance and a concern for caffeine
addiction and caffeine withdrawal.
Caffeine is a central nervous system stimulant, has mild bronchial
tube dilating potential, is a mild vasoconstrictor, and has mild diuretic
and anorexic effects. Caffeine acts as a
potent antagonist of central and peripheral nervous system
adenosine
receptors. If you would like to feel a nice alertness as an alternative,
try CDP Choline pills.
Caffeine has a stronger disruptive effect on daytime, catch-up sleep after a
night of sleep deprivation than it does on a normal night's sleep. Consuming
caffeine at night is known to make it more difficult to fall asleep and to
worsen sleep quality.
Blood pressure
Drinking three or more cups of caffeinated espresso per day increases blood
pressure and blood glucose.
Blood sugar
Reducing caffeine consumption could help patients with diabetes better
control their blood sugar levels. Giving caffeine to those with type 2
diabetes causes their levels of the blood sugar (glucose) to rise
throughout the day, especially after meals.
Caffeine and blood vessels
The effects of caffeine on cardiovascular diseases, including hypertension,
remain controversial, and there is little information on its direct effect on
vascular function. Caffeine increases systolic and diastolic blood pressures.
Acute administration of caffeine augments endothelium-dependent vasodilation in
healthy young men through an increase in nitric oxide production.
Cancer
Colon cancer patients who regularly drink caffeinated coffee may be lowering
their risk of tumor recurrence and death from the disease,
Exercise and athletes
Many competitive athletes think that taking caffeine pills or drinking
coffee gives them an edge. Studies do not show caffeine to be an effective help
for athletes. The placebo effect is more likely an explanation why some
athlete's think caffeine helps their performance.
Hair growth
What's your opinion on caffeine based shampoos like Alpecin and others? How much
difference in slowing down hair loss do you think they make?
A. This is an area I am not familiar with.
Caffeine and headache
When used occasionally, caffeine has a mild analgesic effect for headache
treatment or may help the actions of other pain medications. Chronic repetitive
exposures to caffeine increase the risks for development of analgesic-overuse
headache, chronic daily headache, and physical dependency. Stopping the use of
caffeine use after chronic exposures leads to a withdrawal syndrome with
headache as a dominant symptom.
Miscarriage
Pregnant women who consume more than 200 milligrams of caffeine a day,
equivalent to about two cups of coffee, have twice the risk of miscarriage as
women who consume no caffeine at all.
Caffeine during pregnancy
Sons born to women who drink the equivalent of three cups of coffee a day during
pregnancy are more likely to have undescended testes.
In 1980 the Food and Drug Administration issued a warning to avoid
caffeine during pregnancy. Since then, the question of having caffeine or not
having caffeine has been on the minds of many pregnant women. There have been
studies that have linked caffeine to miscarriages, low birth weight, Sudden
Infant Death Syndrome, heartbeat abnormalities, and other effects. At this time
it is best to limit caffeine intake during
pregnancy.
Sleep, insomnia
Caffeine does more than serve as an eye-opener: When consumed a few hours
before bed, the most widely consumed psychoactive drug in the world seems to
disrupt the body's internal clock. And this could cause jet lag-style
sluggishness during daylight hours.
Use of caffeine in dietary
supplements
Caffeine is added to certain dietary supplements to increase energy and
alertness. In my opinion, caffeine is not a good energy enhancer. Caffeine is
also added to certain dietary supplements to compliment headache relief products
and as an addition to weight loss supplements.
Caffeine Content in Coffee and
Caffeine Pill
One 'shot' of coffee contains about 40 mg of caffeine. Thus, a "double
shot" espresso contains about 80 mg. A single serving (6 fl oz / 150 ml) of
strong drip coffee would deliver about 100 mg. However, there is a large
variation in the amount of caffeine per serving, ranging from about 40 mg to 120
mg. Caffeine pills made by various companies contain caffeine in varying doses
ranging from 40mg to 150 mg.
Caffeine Content in different beverages.
Brewed Coffee (6oz.) 80 to 120mg
Instant Coffee (6 oz.) 40 to 60mg
Decaffeinated Coffee 3 to 5 mg
Cola (12 oz.) 40 to 50 mg
Black Tea (6oz.) 30 to 40mg
Cocoa (6 oz.) 6 to 10 mg
Decaffeinated Black Tea (6oz.) 3 to 5mg
Green Tea (6oz.) 20 to 40 mg
Decaffeinated Green Tea (6oz.) 2mg
Caffeine Content in Decaf Coffee
Decaf coffee is not caffeine free. Most often it has about a fifth to a tenth of
the amount of caffeine in regular coffee. Instant decaffeinated Folgers Coffee
Crystals does not have any caffeine, but decaf coffee from many coffee shops,
including major chains such as Starbucks, contained caffeine averaging about 1
mg of caffeine per ounce of decaf coffee. In some people who are sensitive to
caffeine and drink several cups a day, even moderate caffeine levels can
increase heart rate, blood pressure, agitation and anxiety.
Caffeine content in chocolate
Hershey's Special Dark
Chocolate Bar 1 bar (1.5 ounces) has 30 mg of
caffeine, Hershey Bar (milk chocolate) 1 bar (1.5 ounces) has 10 mg, cocoa or
hot chocolate has 5 mg in 8 ounces.
Green tea caffeine
Caffeine is consumed from a variety of sources including coffee, tea,
cola, and cocoa. Many medications also contain caffeine. In the case of tea,
both the type of tea and brewing time affect caffeine content. A typical cup of
green tea contains less than a cup of regular black tea. Two cups of tea provide
less than half the US average daily consumption of caffeine (200 mg). Those who
are sensitive to caffeine should limit their tea drinking to decaffeinated
varieties.
Q. I wanted to share my opinion - contrary to
conventional wisdom - no variety of tea (green, white, or black) has any less or
more caffeine than any other. The caffeine in any cup of tea is directly and
solely proportional to the number of minutes steeping (it takes 15 minutes to
extract 100% of the caffeine, which may be too much for good taste). (This also
means that the idea that "steep for 30 seconds, throw out that tea because it
will have most of the caffeine" is FALSE, a myth also.)So, in particular your
statement: " A typical cup of green tea contains less than a cup of regular
black tea." is false. In general, the widespread idea " In the evening, I'll
drink green tea because it has less caffeine" is false.
A. Thanks for writing to us.
Caffeine withdrawal
If you missed your morning coffee and now you have a headache and
difficulty concentrating, you might be able to blame it on caffeine withdrawal.
In general, the more caffeine consumed, the more severe caffeine withdrawal
symptoms are likely to be.
Caffeine addiction
As little as one standard cup of coffee a day can produce caffeine
addiction.
Caffeine overdose can cause nausea, diarrhea, light-headedness and
urinary frequency.
Caffeine headache
Many people's headaches are related to their consumption of caffeine,
most commonly in the form of coffee, tea, soft drinks, chocolate, and
medications. Generally the headache is due to a "withdrawal" effect. Caffeine is
very similar in structure to another chemical in our body called adenosine. One
of adenosine's jobs is to dilate blood vessels in the head. Caffeine blocks this
dilation. Your body then has to become more sensitive to adenosine to
compensate. The only problem being that when caffeine is withdrawn, your body is
overly sensitive to adenosine and blood vessels will dilate, creating a pounding
headache.
Caffeine allergy
In very rare cases, caffeine can cause hypersensitivity or anaphylaxis.
Caffeine and cellulite
I have not come across any good evidence that caffeine ingestion reduces
cellulite.
Does caffeine lead to weigh loss?
It appears that those who drink coffee or tea on a regular basis have a
slightly less incidence of gaining weight over time.
Caffeine and high blood pressure
Adolescents, particularly black adolescents, who drink several soft
drinks each day may increase their blood pressure and their risk for
hypertension. In these situations, excess caffeine is deleterious to health. Caffeine free
herbal teas are available widely.
Coffee, Caffeine and Heart Disease
Studies have
produced mixed results.
Heart attacks might be a risk for coffee drinkers with
a common genetic trait that makes caffeine linger in their bodies. Research on
more than 4,000 people in Costa Rica found that about half had the trait and
were considered "slow caffeine metabolizers." The other half had the opposite
trait, which caused their bodies to rapidly break down or metabolize caffeine,
and coffee-drinking in this group appeared to reduce heart attack risks. Among
slow-metabolizers, those who drank two or more cups of coffee daily were at
least 36 percent more likely to have a nonfatal heart attack than those who
drank little or no coffee. Even higher risks were found for younger slow
metabolizers -- those under 50. They were up to four times more likely to have a
heart attack than slow metabolizers in their age group who drank little or no
coffee. The findings, though preliminary, might explain why there have been such
mixed results in previous studies investigating caffeine's effects on the
cardiovascular system. Caffeine is thought to block the effects of a certain
chemical that is believed to help protect against tissue damage. Some previous
research has linked coffee-drinking to a higher risk of heart disease, but other
studies have suggested the opposite. While there's evidence to suggest caffeine
can cause short-term blood pressure increases, a study last year said
coffee-drinking didn't appear to cause long-term high blood pressure, at least
in women.
Exercise
In healthy volunteers, the equivalent of two cups of
coffee reduces the body's ability to boost blood flow to the heart muscle in
response to exercise, and the effect is stronger when the participants are in a
chamber simulating high altitude. Whenever we do a physical exercise, myocardial blood flow has to increase in
order to match the increased need of oxygen. Caffeine may adversely affect this
mechanism. It partly blunts the needed increase in flow.
The caffeine dose does not affect blood flow within the heart muscle while the
participants are at rest. However, the blood flow measurements taken
immediately after exercise were significantly lower after the participants had
taken caffeine tablets. The effect was pronounced in the group in the
high-altitude chamber. Caffeine may block certain receptors in the walls of
blood vessels, interfering with the normal process by which adenosine signals
blood vessels to dilate in response to the demands of physical activity.
Although it is a stimulant, these results indicate that coffee may
not necessarily boost athletic performance.
Caffeine for post exercise muscle
pain
In a small study of female college students, a caffeine supplement seemed
to lessen the familiar muscle
pain that crops up the day after a particularly challenging workout. Known as
delayed-onset muscle soreness, or DOMS, the pain is common in the day or two
after a workout that was more intense than normal. Exercise that involves
eccentric contraction of the muscles is particularly likely to cause delayed
muscle pain. In eccentric contraction, the muscle produces a force while it's
being lengthened. This happens when a person runs downhill, for example, or
lowers a weight during a bicep curl. Researchers at the University of Georgia in
Athens looked at the effects of a caffeine supplement on delayed muscle pain in
nine young women. First, in a simulated workout, the researchers used electrical
stimulation to produce eccentric contractions in the women's thigh muscles --
enough to cause moderate day-after soreness. Next, they repeated the procedure
over the next two days, but on each day, the women took either a caffeine pill
or placebo pill one hour before the muscle workout. Neither the women nor the
researchers knew which pill was given on which day. Overall, the women reported
significantly less muscle soreness during the workout when they took caffeine
instead of the placebo. The supplement had about the amount of caffeine found in
two cups of coffee. The theory is that caffeine eases delayed muscle pain by
blocking the activity of a chemical called adenosine, which is released as part
of the inflammatory response to injury. Adenosine can activate pain receptors in
body cells, explained Victor Maridakis, the study's lead author. The negative
side effects of caffeine are increased feelings of anxiety, heart palpitations,
increased blood pressure, upset stomach, increased urination and disrupted
sleep. Journal of Pain, February 2007.
Stress
Caffeine has significant hemodynamic and humoral effects in habitual
coffee drinkers that persist for many hours during the activities of everyday
life. Furthermore, caffeine may exaggerate sympathetic adrenal-medullary
responses to the stressful events of normal daily life. Repeated daily blood
pressure elevations and increases in stress reactivity caused by caffeine
consumption could contribute to an increased risk of coronary heart disease in
the adult population.
High Caffeine in Energy Drinks
Energy drinks that promise to boost performance and rev up metabolism can
contain three to four times as much caffeine as a typical soda. Consumers who
are vulnerable to the ill effects of caffeine -- including children, pregnant
women and people with cardiovascular disease -- may unknowingly ingest large
amounts.
Energy drinks like Red Bull, Red Devil and Sobe "No Fear" typically contain a
mix of carbohydrates, B vitamins, amino acids and caffeine. Given the danger of
high caffeine intake to some people, critics say energy drinks should be
required to state their caffeine content clearly, The Food and Drug
Administration has had a long-standing "proposed" rule that soft drinks limit
their caffeine content to no more than 65 mg per 12-ounce serving. But neither
sodas nor energy drinks are required to put their caffeine content on the label.
Most soft drinks contain less than the recommended 65 mg of caffeine per 12
ounces. Most of the energy drinks, however, boast at least that much caffeine in
an 8-ounce serving.
Diabetes
Drinking caffeinated green tea and coffee may protect women and
overweight men against developing type 2 (non-insulin dependent) diabetes,
according to a Japanese study. Among 17,413 men and women aged 40 to 65 who were
free of diabetes at baseline, new cases of diabetes occurred in 231 men and 213
women over a 5-year follow up period. Compared to subjects who did not consume
these caffeine beverages, those who reported drinking six or more cups of green
tea per day were 33 percent less likely to develop type 2 diabetes. Those who
reported drinking three or more cups of coffee per day were 42 percent less
likely to develop the condition than non-coffee drinkers. Drinking black or
oolong teas did not appear to protect against type 2 diabetes. These findings
from a Japanese population mirror results obtained in European and US
populations in which people who drank seven or more cups of coffee per day had a
29 to 52 percent reduced risk of diabetes compared with those who drank fewer
cups of coffee per day or none at all. The researchers think these associations
are mostly due to caffeine, because green tea and coffee are both major sources
of caffeine in Japan. Annals of Internal Medicine April 18, 2006.
Questions
Q. Can caffeine by taken with
lipoic acid,
acetylcarnitine
supplement or
CoQ10?
A. Anytime a stimulant nutrient or herb is taken with
caffeine, there could be an unpleasant effect of overstimulation and
restlessness which could occur with the combination of caffeine with the above
mentioned nutrients and a number of herbs such as ginseng. I prefer limiting
coffee intake to one cup in the morning when combined with such supplements.
Q. When I drink coffee it causes to have
anxiety, is this common?
Would kava help?
A. Some people are very sensitive to caffeine and do
get restless, irritability and anxiety even from one cup of regular coffee with
caffeine. Some people even get anxiety from decaffeinated coffee either due to
the caffeine remnants or the theobromine. Kava can help relieve anxiety, so can
5-htp.
Q. Are there any herbs which should not be used on days
when caffeine is ingested?
A. There are many herbs that have stimulating
properties and it would be best to reduce the amount of caffeine ingested on
those days. Some of these herbs include
tongkat ali extract,
horny goat weed,
ginseng, lj100 and others.
Q. Hi Dr. Sahelian and company. This may be a strange
question, and I'm not sure if it's too personal or specific to me, but:
I've been taking a (very) popular fat-burner for about three weeks now. This
fat-burner of course contains much caffeine (the equivalent of two cups of
coffee in each two-tablet serving, and this is for three times daily). The
caffeine is in the form of green tea and other teas (same plant), as well as the
Garcinia cambogia and Gymnema sylvestris. But I've noticed for about a week and
a half now that I seem to have less libido (I'm a 25 year old male by the way),
and I can't think of any other lifestyle or any other issue in the last MONTH or
so that could be a contributing factor. The fatburner is the only change I've
made. So can a high-dose caffeine fatburner possibly decrease libido -even
though it's supposed to be stimulating otherwise? And I haven't found it
otherwise stimulating either funny enough.
A. It's possible that caffeine could cause shallow
sleep or the other ingredients in the product could cause this decrease in
libido. A good way to find out is by stopping the caffeine and the other
supplements to see if the libido returns.
Q. What is it about coffee that kills inositol? I drink
green tea, which has caffine, so I was wondering about the caffine.
A. We are not aware of coffee or caffeine 'killing' inositol.
Q. On your information site about
yohimbe, it states "I
don't recommend you mix yohimbe with alcohol or stimulant drugs, including high
doses of caffeine." Question: What constitutes high doses of caffeine?
A. Each person is different, but more than one cup of
coffee could contain enough caffeine be high for someone while more than 2 or 3
cups could be considered high for another. Caffeine can stimulate heart tissue
and may contribute to palpitations in those taking yohimbe.
Q. I have a question about Mind Power RX. I was told to
quit caffeine intake, therefore, I am looking for a replacement esp. for days
when I do not get enough sleep. I know that caffeine improves mental performance
and is found to provide restoration to almost complete rested state. However,
how does Mind Power RX compare to caffeine intake (i.e., compared to 300 mg of
caffeine intake per day)? In other words, does Mind Power RX provide as much
improvements in all areas of mental performance as 300 mg of caffeine intake per
day?
Q. We have not compared the two but it is like comparing apples not
just to oranges but to a vegetable since they are so different. Mind Power Rx
has more than a dozen nutrients that influence mental function and herbs that
stimulated brain function. The effects are very different.
Q. How would you compare the sleep disturbing effects
of Passion Rx vs. coffee taken at the same time in the morning? I'm an
occasional insomniac and sensitive to the effects of caffeine.
A. Passion Rx is stronger than caffeine in terms of alertness, you
may consider using half a capsule if you are prone to insomnia, and also it is a
good idea to be physically active to use up excess energy.
Q. Can you possibly tell me how many mg of caffeine
would be in 50 mg of green tea (leaf) extract?
A. This is impossible to say accurately since there are countless
extract potencies of green tea and countless varieties of green tea leaf and
herb. The level of caffeine could vary significantly between different extracts,
growers, processors, and manufacturers.
Q. I'm considering purchasing Mind-Power RX and
MultiVit Rx, but I want to know if the "stimulating effects" result from
caffeine. I try to avoid caffeine as much as possible.
A. There is no caffeine in these products.